JP3599239B2 - Displacement sensor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a displacement sensor that measures the displacement of an object using a light-section method and outputs the measured value as it is, or outputs a result of comparison between the measured value and a reference value, and more particularly to a light receiving element. The present invention relates to a displacement sensor capable of performing various measurements by using a two-dimensional imaging device having an elongated field of view.
[0002]
[Prior art]
FIG. 28 shows a conventional example of an optical system of a sensor head of an optical displacement sensor. 5, reference numeral 500 denotes a sensor head unit; 501, a laser diode that emits cutting light in the light cutting method; 502, a slit for making a cross section of the cutting light linear; 503, a light projecting lens; 504, a light receiving lens; Is a light receiving element composed of a PSD or a one-dimensional CCD, etc., 600 is an object to be measured, 700 is a stage, SP is an irradiation light image (linear bright line) of cutting light formed at a position to be measured on the object 600 to be measured. It is.
[0003]
As described above, as the light receiving element 505 of the conventional optical displacement sensor, an element such as a PSD or a one-dimensional CCD, which can acquire only one-dimensional information, is used. As shown in FIG. 29, a problem has been pointed out that a complicated scanning mechanism for relatively moving between the sensor head 500 and the measurement target object 600 is required, which leads to an increase in cost.
[0004]
Recently, an optical displacement sensor using a two-dimensional image sensor as a light receiving element has also been proposed. However, as a two-dimensional image sensor used in such a displacement sensor, a digital camera, a video camera, or the like is used from the viewpoint of cost reduction. The popular two-dimensional CCD used for the above is used.
[0005]
[Problems to be solved by the invention]
When a two-dimensional CCD is used as the light receiving element of the displacement sensor, a large number of pixels (for example, about several hundred pixels) is required in the displacement measurement direction in order to increase the accuracy or resolution, but the direction orthogonal to the measurement direction Is relatively small in the number of pixels (for example, about several tens to one hundred and several tens of pixels).
[0006]
However, as shown in FIG. 30, the pixel arrangement of this type of popular two-dimensional CCD has several hundreds to thousands of pixels both vertically and horizontally (aspect ratio is 3 to 4). However, there is a problem that it takes time to read out the received electric charge, and as a result, the measurement response is deteriorated. Note that OB is an optical black area.
[0007]
As one solution to enable higher-speed imaging, the present inventors have proposed a CCD imaging device having a small number of horizontal lines (for example, about 60 to 70 lines) so as to fit in such an elongated rectangular field of view for measurement. The possibility of producing and using the device for this purpose was examined. However, since such a CCD image pickup device is a custom-made product, it has been found that in addition to a large development cost, a development period is long and an increase in cost is inevitable.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to acquire image data at a required resolution at a high speed from a long and narrow field of view and perform various measurement processes with a high-speed response. An object of the present invention is to provide a displacement sensor which can be manufactured at low cost.
[0009]
[Means for Solving the Problems]
The displacement sensor according to the present invention processes an image obtained from the imaging unit, which captures the surface of the measurement target object having the cutting light irradiation light image from an angle at which the position of the optical image changes according to the measurement target displacement. And an image processing unit that calculates the displacement of the measurement target.
[0010]
The imaging unit includes a light receiving pixel group arranged in a matrix corresponding to the field of view of a standard imaging device, a vertical shift register of each column, and a horizontal shift receiving the output of the vertical shift register of each column in order from the top. It has a register, and by providing a former optical black pixel area and a latter optical black pixel area, a light sensitive pixel is provided between specific horizontal line bands sufficiently narrower than the total horizontal line width so as to be sandwiched therebetween. Based on the two-dimensional imaging device having an area formed therein, and the charge transfer operation from the light receiving pixel group to the vertical shift register of each column, the transfer operation of the vertical shift register, And a drive control unit for controlling the transfer operation.
[0011]
The image processing unit includes a charge transfer specification command unit that gives a charge transfer specification according to the content of the image processing to the drive control unit of the imaging unit.
[0012]
The “standard imaging device” includes at least a general-purpose digital still camera, a video camera, and the like. Looking at current products, there is an example of a two-dimensional imaging device for a digital still camera having a light receiving pixel array of 788 pixels in the vertical direction × 1077 pixels in the horizontal direction. Similarly, as an example of a two-dimensional imaging device for a video camera, there is one having a light receiving pixel array of 500 rows in the vertical direction × 500 to 700 columns in the horizontal direction.
[0013]
“Sufficiently narrow” is defined in consideration of the elongated rectangular field of view of the displacement sensor in which the element of the present invention is used. Assuming a field of view necessary for the displacement sensor, the number of lines constituting a specific horizontal line band is often less than about 20% of the total number of horizontal lines. If such an elongated visual field can be photographed at high speed while maintaining the resolution in the longitudinal direction, it becomes extremely suitable as an image sensor of a displacement sensor based on the light cutting method as a basic principle.
[0014]
An “optical black pixel” is a light-receiving pixel that has been modified so that light cannot be received by a light-shielding mask, no charge is accumulated even when light is received, or the charge accumulated by light reception cannot be taken out. Is always at a prescribed dark level regardless of the amount of received light. On the other hand, the "photosensitive pixel" is a normal light receiving pixel without such special modification, and its output is a light level corresponding to the amount of received light.
[0015]
According to the above configuration, the light-receiving pixel group belonging to the light-sensitive pixel region generates an electric charge corresponding to the amount of received light in response to the light image from the elongated object region to be photographed. The light receiving pixel groups belonging to the first and second optical black pixel regions are insensitive to a light image arriving from a region other than the elongated subject region to be photographed, and therefore generate no or almost no electric charge.
[0016]
Of the stages of the vertical shift register in each column, the charge corresponding to the amount of received light is transferred and stored in the stage located in the photosensitive pixel region. No or almost no charge is transferred and stored in the stages located in the front and rear optical black pixel regions.
[0017]
Therefore, when the drive control unit operates and all the charges from the photosensitive pixel area are read following the front and rear optical black pixel areas, reading of all or a part of the charges from the subsequent optical black pixel area is omitted. In other words, by reading at high speed, the time required to read the charges for one screen can be shortened, and the frame shooting cycle can be shortened to perform high-speed shooting. In addition, the two-dimensional imaging device itself can be manufactured at a low cost and does not increase the price of the entire imaging device because the existing device is only slightly modified.
[0018]
In a preferred embodiment, the cutting light for forming the irradiation light image of the cutting light on the surface of the measurement target object is a light beam having a cross-sectional line shape. Accordingly, a linear light image (bright line) extending in a direction perpendicular to the measurement direction (a direction perpendicular to a plane including the light projecting optical axis and the light receiving optical axis) is drawn on the light receiving surface of the image sensor. Information necessary for area measurement can be reliably obtained.
[0019]
In a preferred embodiment, a two-dimensional image sensor in which a specific horizontal line band is arranged close to a horizontal shift register is used.
[0020]
Regarding the pre-stage optical black pixel region interposed between the horizontal shift register and the specific horizontal line band (photosensitive pixel region), all lines are grouped together, or divided several times for each of a plurality of lines. In any case, all of them must be read out to the horizontal shift register. Therefore, the smaller the total number of lines in the preceding optical black pixel area, the shorter the time required to start reading an effective image. In addition, since the specific horizontal line band having a sufficiently small width is arranged close to the horizontal register, the subsequent optical black pixel area in which the charge readout time does not occur occupies most of the total number of horizontal lines. The time required for reading out the electric charges for one minute is greatly reduced.
[0021]
In a preferred embodiment, a two-dimensional image sensor is used in which the total number of lines in the specific horizontal line band is 20% or less or 10% or less of the total number of horizontal lines.
[0022]
In a preferred embodiment, the arrangement of the light receiving pixel groups corresponds to the field of view of a digital still camera or a TV or HDTV camera.
[0023]
In a preferred embodiment, the optical black pixel has a structure in which the photoelectric conversion element is covered with a light shielding mask, an element structure in which the photoelectric conversion element is inoperable, and / or a charge transfer path from the photoelectric conversion element to the vertical shift register. A two-dimensional image sensor having a cut structure is used.
[0024]
In a preferred embodiment, the horizontal line of the two-dimensional image sensor is directed in a direction in which the light image position on the two-dimensional image sensor changes according to the displacement of the measurement target.
[0025]
According to such a configuration, even if the position of the light image on the two-dimensional image sensor changes according to the displacement of the measurement target, the light sensitive pixel can receive the light image over a wide range. A large range can be obtained as a possible displacement range.
[0026]
In a preferred embodiment when measuring light having a linear cross section is used, the horizontal line of the two-dimensional image sensor is perpendicular to the direction in which the optical image position on the two-dimensional image sensor changes in accordance with the displacement of the measurement target. Oriented.
[0027]
According to such a configuration, a long region along the irradiation position having a linear cross section can be included in the field of view. You Height distribution can be measured at once.
[0028]
In the displacement sensor of the present invention, various contents can be considered as the contents of the charge transfer specification instructed from the image processing unit.
[0029]
In one of the charge transfer specifications, at the beginning of each vertical period, a signal charge taking-in process for taking in signal charges from the light receiving pixels to the vertical shift registers of each column, and a process of taking in each column taken in from the preceding optical black pixel region. Optical black pixel area pre-processing corresponding to the previous stage where the signal charge on the vertical shift register is dropped into the horizontal shift register, and the signal charge on the vertical shift register of each column taken from the photosensitive pixel area is shifted vertically by each column The transfer of the register and the transfer of the horizontal shift register are appropriately linked, and the light-sensitive pixel area corresponding processing for reading out to the outside is carried out. The signal charge on the vertical shift register of each column taken from the subsequent optical black pixel area is read out. Repeat the process for the optical black pixel area in the subsequent stage to be dropped into the horizontal shift register without intervening . According to such a charge transfer mode, the one-screen readout cycle can be shortened by the amount that the subsequent-stage optical black pixel region correspondence processing is not performed.
[0030]
That is, when the drive control unit operates, the shutter is immediately opened without waiting for the charge reading from the subsequent optical black pixel area when all the charges from the photosensitive pixel area have been read following the previous optical black pixel area. Opening and overwriting exposure are performed, and thereafter, reading of charges from the preceding optical black pixel region and the photosensitive pixel region and overwriting exposure to charges from the following optical black pixel region are repeated.
[0031]
At this time, if all the charges in the photosensitive pixel area have been read out, the charges in each stage of the vertical shift register belonging to the subsequent optical black pixel area are almost in a state of zero. Substantially no double shooting problem occurs.
[0032]
Therefore, by shortening the time required to read the charges for one screen by the amount that the charges are not read from the subsequent optical black pixel area, it is possible to shorten the frame shooting cycle and perform higher-speed shooting.
[0033]
In the above-described charge transfer specification, the preceding-stage optical black pixel region corresponding process causes an operation of performing a plurality of stages of continuous vertical transfer within one horizontal period to be repeatedly performed in one horizontal period or over two or more horizontal periods. Processing can be included. At this time, the operation of performing a plurality of stages of continuous vertical transfer within one horizontal period may be performed while the transfer of the horizontal shift register is stopped during the horizontal period. Thus, unnecessary images obtained from the preceding optical black pixel area can be discharged to the horizontal shift register at high speed. In the above-described charge transfer specification, the light-sensitive pixel area corresponding processing is performed by performing one or two or more continuous vertical transfer operations and a continuous horizontal transfer operation of one horizontal line pixel number within one horizontal period. A process for shifting the band back and forth may be included. Thus, the accumulated electric charge is output in the video signal every time the dropping of one or a plurality of target lines is completed, so that the image processing based on the video signal is simplified.
[0034]
In a preferred embodiment, the horizontal line of the two-dimensional image sensor is oriented in a direction in which the position of the light image on the two-dimensional image sensor changes in accordance with the displacement of the measurement target, and the charge transfer specification instructed by the image processing unit. At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column, and a signal charge capturing process for capturing the signal charges from the preceding optical black pixel region. And the signal charge on the vertical shift register of each column taken from the photosensitive pixel region is transferred to the vertical shift register of each column. The light-sensitive pixel area corresponding processing for reading out to the outside by appropriately linking the transfer of the horizontal shift register to the external optical black pixel area This process repeats the subsequent optical black pixel area processing that intercepts the signal charge on the vertical shift register of each column that is taken into the horizontal shift register without intervening, thereby supporting the subsequent optical black pixel area. The one-screen reading cycle is shortened by the amount of no processing.
[0035]
In addition, the light-sensitive pixel area corresponding processing is performed by shifting the time zone forward and backward within one horizontal period between the continuous vertical transfer operation of two or more stages and the continuous horizontal transfer operation of the number of stages corresponding to one horizontal line pixel. Including processing to be performed.
[0036]
According to such a charge transfer specification, the averaging process of the optical image position information appearing on a plurality of horizontal lines inside the two-dimensional image sensor can be performed at high speed. If this processing is used to remove the influence of the rough surface of the measurement target object and the influence of noise, highly accurate displacement measurement can be stably performed.
[0037]
In the above case, the photosensitive pixel area corresponding processing stops the horizontal transfer operation for one or two or more horizontal periods, during which charges of all the horizontal lines in the photosensitive pixel area are transferred collectively to the horizontal shift register. Alternatively, pixel charges may be overlapped between the same vertical columns. This makes it possible to perform the averaging process for all the lines in the photosensitive pixel area in the two-dimensional image sensor. That is, the contents of the horizontal shift register are output from the two-dimensional image sensor once per image pickup, and the peak position of the output signal is the average value of the height or displacement of the surface of the measurement object corresponding to the photosensitive pixel area. Is represented.
[0038]
In another one of the charge transfer specifications, at the beginning of each vertical period, a signal charge taking-in process for taking in signal charges from the light receiving pixels to the vertical shift registers of each column, and a process of taking each signal taken from the preceding optical black pixel region. The signal charge on the vertical shift register of each column taken from the photosensitive pixel area and the processing of the optical black pixel region corresponding to the former stage, in which the signal charges on the vertical shift register of the column are quickly dropped into the horizontal shift register, Processing for reading out the photosensitive pixel area corresponding to the transfer of the vertical shift register of the column and the transfer of the horizontal shift register to the outside as appropriate, and the signal charge on the vertical shift register of each column taken from the subsequent optical black pixel area And the subsequent step of dropping the data into the horizontal shift register at high speed. To.
[0039]
In such a charge transfer specification, when the drive control unit operates, the charges in the optical black pixel regions in the preceding and subsequent stages are read out collectively for a plurality of horizontal lines. At this time, the stored charges of the stages belonging to the optical black pixel area at the previous stage and the succeeding stage of the vertical shift register of each column are almost zero. Therefore, in principle, the charge of several lines is added at each stage of the horizontal shift register. However, there is no possibility that the charge is saturated in any stage of the horizontal shift register. Therefore, while unnecessary charges on horizontal lines are added together and read out as quickly as possible, charges on a specific horizontal line band, which is a photosensitive pixel area, are read out one or several lines at a desired accuracy. First, by shortening the time required to read the charges for one screen, it is possible to shorten the frame shooting cycle and perform high-speed shooting.
[0040]
In the above-described charge transfer specification, the process corresponding to the first-stage optical black pixel region and / or the process corresponding to the second-stage optical black pixel region are performed in one horizontal period. Inside Operation to perform a plurality of stages of continuous vertical transfer During the horizontal period of Or over two or more horizontal periods repetition, Including processing to be performed be able to . At this time, one horizontal period Inside The operation of performing a plurality of stages of continuous vertical transfer can be performed while the transfer of the horizontal shift register is stopped during the horizontal period.
[0041]
In the above-described charge transfer specification, the effective image correspondence processing includes the continuous vertical transfer operation of one or more stages and the continuous horizontal transfer operation of the number of stages corresponding to one horizontal line pixel in a time zone within one horizontal period. It may include a process to be shifted back and forth.
[0042]
In a preferred embodiment, the horizontal line of the two-dimensional image sensor is oriented in a direction in which the optical image position of the two-dimensional image sensor changes according to the displacement of the measurement target, and the content of the charge transfer specification instructed by the image processing unit At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column, and a signal on the vertical shift register of each column captured from the preceding optical black pixel region. Optical black pixel area pre-processing corresponding to the charge dropping into the horizontal shift register, and transfer of signal charge on the vertical shift register of each column taken from the photosensitive pixel area to the vertical shift register of each column and horizontal shift The transfer of the register is appropriately linked to the light-sensitive pixel area processing for reading out to the outside, and the processing from the subsequent optical black pixel area is performed. And a post-stage optical black pixel region corresponding process of rapidly dropping the signal charges on the vertical shift register of each column into the horizontal shift register. One-screen reading is reduced by the amount by which the signal charges on the vertical shift registers of each column taken in from the pixel area are dropped into the horizontal shift register at a high speed.
[0043]
In addition, the light-sensitive pixel area corresponding processing is performed by shifting the time zone forward and backward within one horizontal period between the continuous vertical transfer operation of two or more stages and the continuous horizontal transfer operation of the number of stages corresponding to one horizontal line pixel. Including processing to be performed.
[0044]
According to such a charge transfer specification, the averaging process of the optical image position information appearing on a plurality of horizontal lines inside the two-dimensional image sensor can be performed at high speed. If this processing is used to remove the influence of the rough surface of the measurement target object and the influence of noise, highly accurate displacement measurement can be stably performed.
[0045]
In the above case, the photosensitive pixel area corresponding processing stops the horizontal transfer operation for one or two or more horizontal periods, during which charges of all the horizontal lines in the photosensitive pixel area are transferred collectively to the horizontal shift register. Alternatively, pixel charges may be overlapped between the same vertical columns. This makes it possible to perform the averaging process for all the lines in the photosensitive pixel area in the two-dimensional image sensor. That is, the contents of the horizontal shift register are output from the two-dimensional image sensor once per image pickup, and the peak position of the output signal is the average value of the height or displacement of the surface of the measurement object corresponding to the photosensitive pixel area. Is represented.
[0046]
The basic image processing performed by the image processing unit is to calculate the height of each measurement line. Here, the measurement line refers to one horizontal line or a plurality of horizontal lines in which charge information is added or averaged in the vertical line direction in the photosensitive pixel area of the two-dimensional image sensor. Further, the height of the measurement line is the height or displacement of the surface of the measurement target object calculated corresponding to the peak position of the charge amount on the measurement line.
[0047]
As the content of the image processing performed in the image processing unit, it is possible to calculate the height of each measurement line to determine the distance between peaks (peak to peak), or to calculate the variance of each measurement line, This makes it possible to measure flaws.
[0048]
As the contents of the image processing performed by the image processing unit, the height of each measurement line can be calculated and their peaks can be obtained, whereby the projection can be measured.
[0049]
As the contents of the image processing performed by the image processing unit, the height of each measurement line can be calculated, and the bottom thereof can be obtained, whereby the groove can be measured.
[0050]
As the contents of the image processing performed by the image processing unit, the height of each measurement line can be calculated, and their inclinations can be obtained. As a result, the inclination of the surface can be measured.
[0051]
As the contents of the image processing performed by the image processing unit, it is possible to calculate the height of each measurement line and take an average value in the time series direction, whereby the relative movement between the sensor and the work can be obtained. Thereby, the coplanarity can be measured.
[0052]
In the displacement sensor described above, the charge transfer specification command means of the image processing unit commands the drive control unit of the imaging unit to specify the charge transfer specification. With this configuration, the image processing unit can change the charge transfer specification in accordance with the content of the image processing. Therefore, there is an advantage that it is easy to execute image processing of various contents. However, even if the displacement sensor is configured with the charge transfer specification fixed, the feature that high-speed imaging is possible remains the same. In this case, dynamic cooperation between the imaging unit and the image processing unit regarding the charge transfer specification is not necessary, and the same charge transfer specification may be used in advance for the imaging unit and the image processing unit.
[0053]
In addition, by providing a charge transfer specification from outside the imaging unit and the image processing unit as needed, the same charge transfer specification can be adopted for the imaging unit and the image processing unit.
[0054]
From these viewpoints, the present invention can also be expressed as follows. That is, the displacement sensor according to the present invention includes an imaging unit that captures the surface of a measurement target object having an irradiation light image of cutting light from an angle at which an optical image position changes according to the measurement target displacement, and an image obtained from the imaging unit. And an image processing unit that calculates the displacement to be measured.
[0055]
The imaging unit includes a light receiving pixel group arranged in a matrix corresponding to the field of view of a standard imaging device, a vertical shift register of each column, and a horizontal shift receiving the output of the vertical shift register of each column in order from the top. It has a register, and by providing a former optical black pixel area and a latter optical black pixel area, a light sensitive pixel is provided between specific horizontal line bands sufficiently narrower than the total horizontal line width so as to be sandwiched therebetween. Based on a two-dimensional imaging device having an area formed therein, and a charge transfer operation from a light receiving pixel group to a vertical shift register of each column, a transfer operation of a vertical shift register, a transfer of a horizontal shift register based on a predetermined charge transfer specification And a drive control unit for controlling the operation.
[0056]
Further, the image processing unit is configured to perform image processing based on the same charge transfer specification as the charge transfer specification employed in the drive control unit of the imaging unit.
[0057]
Any features such as the optical arrangement, the configuration of the two-dimensional image sensor, the contents of the charge transfer specification, and the like as described above for the displacement sensor in the case where the image processing unit instructs the image pickup unit of the charge transfer specification are included in the present invention. Can be applied.
[0058]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing an electrical hardware configuration of a displacement sensor according to an embodiment of the present invention.
[0059]
As shown in FIG. 1, the displacement sensor 1 is an imaging unit that captures the surface of a measurement target object 300 having an irradiation light image of cutting light from an angle at which the position of an optical image changes according to the displacement of the measurement target. A main part includes a certain sensor head unit 200 and a sensor main body unit 100 which is an image processing unit that calculates a displacement to be measured and outputs it as displacement data by processing an image obtained from the sensor head unit 200. I have.
[0060]
The sensor head unit 200 generates a necessary timing signal based on the oscillator (OSC 201) and the transfer specification setting data stored in the register 109 in the sensor main unit 100, and sends the necessary timing signal to the CCD drive 203 and the slit light source 206. And send it out. The slit light source 206 includes a laser diode 207 and a slit 208, as described later, and generates cutting light in a so-called light cutting method to irradiate the measurement target object 300. An irradiation light image (linear bright line) of the cutting light is formed on the surface of the detection target object 300 by the measuring light cutting light. The surface of the detection target object on which the linear bright line is formed is photographed by the CCD 205 which is a two-dimensional image sensor. The transfer operation of the CCD 205 is controlled by transfer pulses TP1 to TP3 sent from the CCD drive 203 as described later. The video signal read from the CCD 205 is smoothly shaped by the sample and hold circuit 204 and sent to the sensor body 100 as a video signal.
[0061]
The optical system of the sensor head is shown in FIG. In the figure, 207 is a laser diode, 208 is a slit, 209 is a projection lens, 210 is an irradiation light image of cutting light, 211 is a light receiving lens, 205 is a CCD, 300 is a measurement target object, and 400 is a placement of a measurement target object. It is a stage that was set. Thus, the laser beam emitted from the laser diode 207 is formed into a light beam having a cross-sectional line shape (a so-called line beam) through the slit 208, and then applied to the surface of the measurement target object 300 via the light projecting lens 209. On the other hand, the irradiation light image 210 of the cutting light generated by this irradiation is photographed by the CCD 205 from the predetermined angle via the light receiving lens 211. As is well known, the shooting angle of the CCD 205 is determined so that the position of the light image 210 formed on the CCD 212 changes according to the change in the height of the measurement target object 300.
[0062]
FIG. 31 schematically illustrates an application example in which the imaging apparatus of the present invention is used for a displacement sensor based on a light-section method as a detection principle. FIG. 2A is a schematic perspective view of the displacement sensor head, and FIG. 2B is a schematic sectional view of the displacement sensor head.
[0063]
In the drawing, reference numeral 91 denotes an object to be measured, 92 denotes a line beam for measurement (beam having a cross-sectional line shape), 93 denotes reflected light, 94 denotes a lens system, 95 denotes a two-dimensional image sensor, and 96 denotes a horizontal scan of the two-dimensional image sensor. The direction 97 is the vertical scanning direction of the two-dimensional image sensor, and 98 is a specific horizontal line band on the light receiving surface of the two-dimensional image sensor. In this example, a line beam having a line width of 0.1 × 5 mm is used as the line beam 92. The height displacement of the measurement object 91 appears as a displacement of the optical image position of the line beam reflected light in the horizontal scanning direction of the two-dimensional image sensor 97. The elongated field of view comprised of the particular horizontal line band 98 is directed in a direction along this displacement.
[0064]
The CCD 212 has a novel configuration proposed by the present inventors. FIG. 3 schematically shows an example of a pixel array on the light receiving surface of the CCD image sensor. It should be noted that, even in this example, the size of the pixel is considerably exaggerated from the actual size.
[0065]
In the figure, Ph is each light receiving pixel constituting a light receiving pixel group arranged in a matrix of 788 rows in the vertical direction × 1077 columns in the horizontal direction corresponding to the visual field of a digital still camera which is a standard imaging device, and VR is A vertical shift register HR which transfers the output of each light receiving pixel Ph constituting the light receiving pixel group in a vertical direction for each column, and HR receives the charge transferred from the vertical shift register VR in each column and transfers it in the horizontal direction. Aout is an output buffer for outputting the charges transferred from the horizontal shift register HR to the outside.
[0066]
Among the light receiving pixels Ph, the light receiving pixels Ph2 filled with hatching in the drawing are so-called optical black pixels (OB pixels), and the white light receiving pixels Ph1 not filled with hatching in the drawing are photosensitive pixels. . Each of the light receiving pixels Ph1 and Ph2 has an element structure based on a photodiode. The vertical and horizontal shift registers VR, HR have a CCD-based element structure.
[0067]
As described above, the optical black pixel Ph2 is a light-receiving pixel in which light cannot be received by a light-shielding mask, electric charge is not accumulated even when light is received, or electric charge accumulated by light reception cannot be taken out. Thus, the output is always fixed to a specified dark level (almost zero charge) regardless of the amount of received light. The photosensitive pixel Ph1 is a normal light receiving pixel that does not employ such a special structure, and its output has a light level corresponding to the amount of received light.
[0068]
Various methods can be considered as a method for setting the target pixel as the optical black pixel Ph2 instead of the photosensitive pixel Ph1. As a first method, there is a structure in which a photoelectric conversion element (for example, a photodiode, a phototransistor, or the like) included in a target light-receiving pixel is covered with a light-shielding mask. Specifically, in a semiconductor manufacturing process, a light-shielding mask can be realized by forming a metal mask that does not transmit light on a photodiode constituting a light-receiving pixel. Realizing a light-shielding mask also by attaching a mask (for example, aluminum foil or the like) that does not transmit light on the light-receiving surface of the device at a stage after the end of the semiconductor manufacturing process (for example, after a product purchase). Can be. However, if a light-shielding mask is attached after the semiconductor manufacturing process is completed, an error is likely to occur in the alignment with the pixel, or the distance between the pixel and the mask may cause a difference between the optical black pixel region and the photosensitive pixel region. It is preferable to form a light-shielding mask in the semiconductor manufacturing process, because a pixel region that is incompletely shielded from light may occur along the boundary.
[0069]
As a second method, in a semiconductor manufacturing process, the element structure itself of a photodiode constituting a target light-receiving pixel is modified to make the element incapable of receiving light or incapable of performing photoelectric conversion.
[0070]
A third method is to cut off a charge transfer path from a photodiode constituting a target light receiving pixel to a vertical shift register in a semiconductor manufacturing process.
[0071]
Even if any one of the first to third methods is adopted, a CCD image sensor having a small number of horizontal lines (for example, about 60 to 70) is designed from the beginning so as to fit into a long and narrow rectangular visual field for measurement. Design costs and design time can be significantly reduced compared to repairing. It goes without saying that the first to third methods can be used together.
[0072]
Returning to FIG. 3, the light receiving pixel group arranged in a matrix includes the first pixel group belonging to the specific horizontal line band HLB having a sufficiently small number of lines (60 lines) compared to the total number of horizontal lines (788 lines). , And a second pixel group that does not belong to the specific horizontal line band HLB.
[0073]
That is, in this example, 60 horizontal lines from the eighth horizontal line to the 67th horizontal line from the top of the screen are set as the specific horizontal line band HLB, and the pixel group included in the specific horizontal line band HLB Are the first pixel group. Also, seven horizontal line bands from the first horizontal line to the seventh horizontal line, and 721 horizontal lines from the 68th horizontal line to the 788th horizontal line at the lowermost stage The pixel group included in the band is the second pixel group.
[0074]
All or most of the pixels Ph constituting the first pixel group are light-sensitive pixels Ph1, and all or most of the pixels Ph constituting the second pixel group (all in this example) are photosensitive pixels Ph1. The optical black pixel Ph2 is set.
[0075]
Strictly speaking, among the pixels belonging to the 60 horizontal lines constituting the specific horizontal line band HLB, the pixels belonging to the three vertical lines near the left edge of the screen and the 40 pixels near the right edge of the screen All pixels belonging to the vertical line are optical black pixels Ph2. Pixels belonging to 1034 vertical lines located at the center between the three vertical lines on the left edge and the 40 vertical lines on the right edge are all light-sensitive pixels Ph1. As a result, the photosensitive pixel area (60 rows × 1034 columns) is surrounded by the optical black pixel area, and the outline of the effective image area is clarified.
[0076]
FIG. 4 shows the relationship between the size of the photosensitive pixel region and the size of the optical black pixel region in the CCD image sensor in terms of the actual screen aspect ratio. As shown in the figure, it is understood that the photosensitive pixel area (60 rows × 1034 columns) occupies only a part of the entire light receiving surface (788 rows × 1077 columns). It can also be understood that the specific horizontal line band HLB constituting the photosensitive pixel area is arranged close to the top of the screen where the horizontal shift register HR exists. Further, it is understood that most of the entire light receiving surface (788 rows × 1077 columns) is occupied by the optical black pixel area.
[0077]
In such a CCD image pickup device, when a first transfer pulse TP1 is externally applied as shown in FIG. 5, the output of the light receiving pixel Ph belonging to each vertical line (in the case of the photosensitive pixel Ph1, the electronic shutter open period (In the case of the optical black pixel Ph2, almost zero charge corresponding to a prescribed dark level) is transferred to the corresponding stage of the adjacent vertical shift register VR1 to VRn. When a second transfer pulse TP2 is externally applied, each of the vertical shift registers VR1 to VRn is shifted upward by one stage in the figure, and the electric charges stored in the first stage of each of the vertical shift registers VR1 to VRn are shifted horizontally. The data is transferred to the corresponding stage of the register HR. When a third transfer pulse TP3 is applied from the outside, the horizontal shift register HR is shifted to the left by one stage in the figure, and the electric charge stored in the first stage of the horizontal shift register HR is supplied to the external unit via the output unit Aout. Is output to.
[0078]
The configuration of the drive control unit of the CCD image sensor described above will be described. This drive control unit includes a timing signal generation unit 202 and a CCD drive 203 as shown in FIG. The timing signal generator 202 includes a transfer pulse generator and a transfer controller (not shown).
[0079]
The transfer control unit determines the number of lines of image data to be transferred within one horizontal period, and outputs the third transfer pulse TP3 by the number corresponding to one horizontal line pixel in each horizontal period to output image data to the outside. The set number of transfer lines is converted into 2-bit transfer line number signals L1 and L2, and the presence / absence of an external output is converted into an output presence / absence control signal OE to generate a transfer pulse. Output to the section 2.
[0080]
FIGS. 9A and 9B show the data structures of the transfer line number signals L1 and L2 and the external output presence / absence control signal OE, respectively. As shown in the figure, codes of “00”, “10”, “01”, and “11” are assigned to the numbers of transfer lines 1, 2, 4, and 7, respectively. The bit is set as L1 and the lower bit is set as L2. As for the output presence / absence control signal OE, “0” is set for no TP3 output and “1” is set for TP3 output.
[0081]
FIG. 6 shows the internal configuration of the generation unit of the first, second, and third transfer pulses TP1, TP2, and TP3 in the transfer pulse generation unit 2. The first transfer pulse generator includes a timing generator 21 that generates and outputs a first transfer pulse TP1 for pixel charge conversion in response to a vertical period start command XVD externally applied.
[0082]
The second transfer pulse generator includes four timing generators 22a, 22b, 22c, and 22d, and a multiplexer 23 that selectively outputs a pulse train from each of the timing generators 22a to 22d.
[0083]
Each of the timing generators 22a to 22d is used for transfer of 1, 2, 4, and 7 lines, respectively, and within a period having the same length as a horizontal period of a normal video standard, the number of transfer lines corresponding to the number of transfer lines is reduced. Is output as the second transfer pulse TP2. FIG. 7 shows an output mode of the transfer pulse TP2 from each of the timing generators 22a to 22d.
[0084]
As shown in the drawing, the one-line transfer timing generator 22a outputs one pulse during the horizontal blanking period.
[0085]
The timing generator 22b for two-line transfer outputs two pulses during the horizontal blanking period.
[0086]
The timing generator 22c for four-line transfer outputs two pulses during the horizontal blanking period and two pulses outside the horizontal blanking period.
[0087]
The timing generator 22d for seven-line transfer outputs two pulses during the horizontal blanking period and five pulses outside the horizontal blanking period.
[0088]
The multiplexer 23 selects a timing generator for the number of transfer lines indicated by the transfer line number signals L1 and L2 from the timing generators 22a to 22d, and sets an input path of the signal to an output path to the CCD image pickup device 205. Connecting. As a result, the output pulse of the selected timing generator is adopted as the transfer pulse TP2 and is supplied to the CCD image pickup device 205.
[0089]
The third transfer pulse generator includes a timing generator 24 that generates and outputs third transfer pulses TP3 corresponding to one line pixel, and an external output of the third transfer pulse TP3 in response to the output presence / absence signal OE. A gate circuit 25 for controlling availability is included. When the output presence / absence control signal OE is “1”, the gate 25 opens, and when the output presence / absence signal OE is “0”, the gate 25 closes.
[0090]
As described above with reference to FIG. 3, in the CCD image pickup device 205 of this embodiment, 60 lines from 8 to 67 lines on the light receiving surface are set as photosensitive pixel regions (effective image regions). , 1 to 7 lines and 721 lines 68 to 788 are optical black pixel regions (unnecessary image regions) in the preceding and subsequent stages. In order to realize a visual measurement device with good responsiveness, it is necessary to read out such one-screen image data (signal charge) as quickly as possible without destroying the data of the effective image area. There are two types of high-speed image reading methods for that purpose.
[0091]
In the first high-speed image reading method, at the beginning of each vertical period, the drive control unit performs a signal charge capturing process for capturing signal charges from the light receiving pixels Ph to the vertical shift registers VR1 to VRn of each column. A preceding optical black pixel region corresponding process for dropping signal charges on the vertical shift registers VR1 to VRn of each column taken from the optical black pixel region into the horizontal shift register HR, and each column taken from the photosensitive pixel region Processing for reading out the signal charges on the vertical shift registers VR1 to VRn to the outside by appropriately linking the transfer of the vertical shift registers VR1 to VRn and the transfer of the horizontal shift register HR of each column to the outside. To the signal voltages on the vertical shift registers VR1 to VRn of each column captured from the subsequent-stage optical black pixel area. Is dropped into the horizontal shift register HR, and the subsequent optical black pixel area corresponding processing is repeated without being interposed. Thus, the one-screen readout cycle is reduced by the amount that the subsequent optical black pixel area corresponding processing is not performed. Shorten.
[0092]
In the second high-speed image reading method, at the beginning of each vertical period, the drive control unit performs a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers VR1 to VRn of each column; A first-stage optical black pixel region corresponding process for rapidly dropping signal charges on the vertical shift registers VR1 to VRn of each column taken from the black pixel region into the horizontal shift register HR; A light-sensitive pixel area corresponding process for reading out signal charges on the column vertical shift registers VR1 to VRn to the outside by appropriately transferring the transfer of the vertical shift registers VR1 to VRn and the transfer of the horizontal shift register HR of each column to the outside; The signal charges on the vertical shift registers VR1 to VRn of each column captured from the subsequent optical black pixel area are And a subsequent-stage optical black pixel region corresponding process for rapidly dropping the data into the flat shift register HR is configured to be repeatedly executed. The one-screen read cycle is reduced by the amount by which the signal charges on the shift registers VR1 to VRn are dropped into the horizontal shift register HR at high speed.
[0093]
A specific example of the first high-speed image reading method will be described with reference to FIGS. In this example, the drive control unit (including the transfer pulse generation unit 2 and the transfer control unit 3 shown in the flowchart of FIG. 10) performs the signal charge capture processing (A) and the pre-stage optical black pixel The processing (B) and the photosensitive pixel area processing (C) are repeated without interposing the subsequent optical black pixel area processing (D).
[0094]
Here, the signal charge capturing process (A) is a process of capturing signal charges from the light receiving pixels Ph (m, n) to the vertical shift registers VR1 to VRn of each column at the beginning of each vertical period.
[0095]
The pre-stage optical black pixel corresponding processing (B) is a process of dropping signal charges on the vertical shift registers VR1 to VRn of each column taken from the pre-stage optical black pixel area (1 to 7 lines) to the horizontal shift register HR. This is the process of inserting.
[0096]
The photosensitive pixel area correspondence processing (C) means that the signal charges on the vertical shift registers VR1 to VRn of each column taken from the photosensitive pixel area (8 to 67 lines) are converted into the vertical shift registers VR1 of each column. ... VRn and the transfer of the horizontal shift register HR are appropriately linked and read out to the outside.
[0097]
Further, the post-stage optical pixel region correspondence processing (D) is a process of dropping signal charges on the vertical shift registers VR1 to VRn of each column taken from the post-stage optical black pixel region (line 68 to 788) to the horizontal shift register HR. This is post-processing.
[0098]
In this example, the first-stage optical black pixel region correspondence processing (B) is performed for one horizontal period. Inside 1 includes an operation of performing seven-stage continuous vertical transfer. And this one horizontal period Inside The operation of performing the seven-stage continuous vertical transfer is performed until the transfer of the horizontal shift register is stopped during the horizontal period (see FIGS. 11 and 12).
[0099]
In this example, the photosensitive pixel area correspondence processing (C) includes a two-stage continuous vertical transfer operation and a continuous horizontal transfer operation of the number of stages corresponding to the number of pixels of one horizontal line before and after a time zone within one horizontal period. Includes processing to be shifted. As will be described later, in this example, the two-stage continuous vertical transfer operation is performed within the horizontal blanking period (see FIGS. 11 and 13).
[0100]
FIG. 8 shows a setting example of a transfer specification table (stored in a register 109 to be described later) used in the first high-speed image reading method. As shown in the figure, in this transfer specification table, the set values of the number of transfer lines and the presence or absence of output in the horizontal period are respectively associated with the horizontal period counter value indicating the number of the horizontal period. It is stored in the form of transfer line number signals L1, L2.
[0101]
In this example, a video signal corresponding to the preceding optical black pixel region is transferred continuously for seven lines in one horizontal period, and a video signal corresponding to the subsequent photosensitive pixel region is transferred two lines in each horizontal period. In this example, the number of transfer lines in the first horizontal period is set to 7 (L2, L1 = 1, 1), and then the number of transfer lines in the second to 31st horizontal periods is set to 2 (L2, L2). L1 = 1, 0). Regarding the presence or absence of output by horizontal transfer, the presence or absence of output in the first one horizontal period is “none” (OE = 0), and the presence or absence of output in the second to 31st horizontal periods is “present” (OE = 1).
[0102]
The transfer control unit (the operation of which is shown in the flowchart of FIG. 10) reads the set values of the transfer line number signals L1 and L2 and the output presence / absence signal OE stored in the transfer specification table for each horizontal period, and The transfer line number signals L1 and L2 and the output presence / absence signal OE are set to levels according to the set values and output to the transfer pulse generator 2. The transfer pulse generator 2 sets the output timing of the first transfer pulse based on the MAX value (“31” in FIG. 8) of the horizontal period counter set in the transfer specification table (that is, the output timing of the vertical period of the video standard). The transfer pulse TP1 is output at a time interval of 31/788).
[0103]
The transfer pulse generating unit 2 performs the output of the second transfer pulse TP2 and the third transfer pulse TP3 in each horizontal period based on the transfer line number signals L1 and L2 and the output presence / absence signal OE given by the transfer control unit. Is set, and a series of controls on the CCD image pickup device 205 are performed.
[0104]
The sensor main body 100 (see FIG. 1) is configured to set the number of transfer lines and the value of output / non-output of the transfer specification table via the register 109 as necessary.
[0105]
An outline of the transfer control processing executed in the transfer control unit is shown in the flowchart of FIG. This transfer control process is started in response to the arrival of the horizontal period start signal HD (see FIG. 11) coming from the transfer pulse generator 2. A series of subsequent operations are periodically repeated based on the value of the horizontal period counter LC incorporated in the transfer control unit.
[0106]
It is now assumed that the horizontal period counter LC is cleared. In this state, when the horizontal period start signal HD arrives, the process of FIG. 10 is started, and the value of the horizontal period counter LC is counted up from "0" to "1" (step 1001).
[0107]
When the value of the horizontal period counter LC becomes "1", the transfer specification table is referred to using the count value "1" as an argument, whereby the set values of the transfer line number signals L1 and L2 and the output presence / absence signal OE are read. As is clear from the conversion table of FIG. 9, the number of transfer lines is "7" at this time, and the external output by horizontal transfer is "none" (step 1002).
[0108]
According to the contents of the set values read from the transfer specification table, the values of the transfer line number signals L1, L2 and the horizontal transfer presence / absence signal OE are set to L1 = 1, L2 = 1, and OE = 0, respectively ( Step 1003). Then, as shown in FIGS. 11 and 12, in the first horizontal period corresponding to the count value “1”, the second transfer pulse TP3 for horizontal transfer is not output, and the second transfer pulse TP3 for vertical transfer is output. Only seven transfer pulses TP2 are continuously output from the transfer pulse generator 2. As a result, although nothing is output in the video signal (empty state), empty charges for seven lines from 1 to 7 are dropped and superimposed on each stage of the horizontal shift register HR. Thereafter, the process ends (NO in step 1004), and a state in which the process waits for the next horizontal period start signal HD to arrive.
[0109]
When the second horizontal period start signal HD arrives, the process of FIG. 10 is started, and the value of the horizontal period counter LC is counted up from "1" to "2" (step 1001).
[0110]
When the value of the horizontal period counter LC becomes "2", the transfer specification table is referred to using the count value "2" as an argument, whereby the set values of the transfer line number signals L1 and L2 and the output presence / absence signal OE are read. As is apparent from the conversion table of FIG. 8, at this time, the number of transfer lines is “2”, and the external output by horizontal transfer is “present” (step 1002).
[0111]
According to the contents of the set values read from the transfer specification table, the values of the transfer line number signals L1, L2 and the horizontal transfer presence / absence signal OE are set to L1 = 0, L2 = 1, and OE = 1, respectively ( Step 803). Then, as shown in FIGS. 11 and 13, in the second horizontal period corresponding to the count value “2”, the transfer pulse generator 2 outputs the second transfer pulse TP2 for vertical transfer from the horizontal blanking. After two signals are output during the period, the third transfer pulse TP3 for horizontal transfer is output by the number corresponding to one horizontal line pixel after the end of the horizontal blanking period.
[0112]
When two second transfer pulses TP2 are output during the horizontal blanking period, the charges for the seven lines from 1 to 7 accumulated in each stage of the horizontal shift register HR are further added to 8, 9 The charges of two lines are dropped, and the charges of nine lines of 1 to 9 lines are superimposed as a whole. Thereafter, when the third transfer pulse TP3 for horizontal transfer is output by the number corresponding to one horizontal line pixel, the above-mentioned superimposed charges for nine lines are output in the video signal. As shown by hatching in FIG. 11 and surrounded by a dotted line in FIG. 13, the video signal portion on which the charges for the nine lines are superimposed becomes an OB unnecessary video signal. As a result, the first two lines in the video signal become an invalid image portion. Thereafter, the process ends (NO in step 1004), and a state in which the process waits for the next horizontal period start signal HD to arrive.
[0113]
When the third horizontal period start signal HD arrives, the process of FIG. 10 is started, and the value of the horizontal period counter LC is counted up from "2" to "3" (step 1001).
[0114]
When the value of the horizontal period counter LC becomes "3", the transfer specification table is referred to using the count value "3" as an argument, whereby the set values of the transfer line number signals L1, L2 and the output presence / absence signal OE are read. As is clear from the conversion table of FIG. 9, the number of transfer lines is also "2" at this time, and the external output by horizontal transfer is determined to be "present" (step 1002).
[0115]
According to the contents of the set values read from the transfer specification table, the values of the transfer line number signals L1, L2 and the horizontal transfer presence / absence signal OE are set to L1 = 0, L2 = 1, and OE = 1, respectively ( Step 1003). Then, as shown in FIG. 11 and FIG. 13, in the third horizontal period corresponding to the count value “3”, the transfer pulse generator 2 outputs the second transfer pulse TP2 for vertical transfer from the horizontal blanking. After two signals are output during the period, the third transfer pulse TP3 for horizontal transfer is output by the number corresponding to one horizontal line pixel after the end of the horizontal blanking period.
[0116]
When two second transfer pulses TP2 are output during the horizontal blanking period, charges of two lines of 10 and 11 lines are dropped into each empty stage of the horizontal shift register HR. Superimposed. At this time, although the charge on each stage of the horizontal shift register HR is superimposed on two lines, the characteristics of the original image still remain sufficiently. Thereafter, when the third transfer pulse TP3 for horizontal transfer is output by the number corresponding to one horizontal line pixel, the above-mentioned superposed charges of two lines are output in the video signal. As shown in FIGS. 11 and 13, the video signal portion on which the electric charges of two lines 10 to 11 are superimposed becomes an effective video signal.
[0117]
Thereafter, the operation when the fourth to 31st horizontal period start signals HD arrive is the same as the operation when the third vertical period start signal HD arrives. Therefore, when the fourth to 31st vertical period start signals HD arrive, as shown in FIG. 11 and FIG. 13, two lines of 12, 13, 14, 15, and 66, 67 lines are superimposed. The output video signals are sequentially output.
[0118]
When the 31st horizontal period start signal arrives, the value of the line counter LC reaches the maximum value (step 1004 YES), and a vertical period start command XVD is output (step 1005). It is cleared to "0" (step 1006). In response to the vertical period start command XVD, the first transfer pulse TP1 for taking in pixel charges is output from the transfer pulse generator 12, and thereafter, the signal charges of lines 68 to 788 are placed on the vertical shift registers VR1 to VRn. The processing at the arrival of the first to 31st horizontal period start signals described above is repeated with the remainder.
[0119]
When the transfer pulse TP1 for capturing the second and subsequent pixel charges is output, the signal charges are again captured from each of the light receiving pixels Ph (m, n) to the vertical shift registers VR1 to VRn of each column. At this time, electric charges transferred from the subsequent optical black pixel region should exist in each stage of the vertical shift registers VR1 to VRn located in the photosensitive pixel region. However, since the charge from the subsequent optical black pixel area is very small or equal to zero, even if the effective image charge is taken in and superimposed thereon, the effective image will not be obtained due to the so-called double shooting phenomenon. There is no risk of deterioration. That is, even if the electric charge from the optical black pixel region in the subsequent stage is overwritten, the double shooting phenomenon does not occur.
[0120]
Therefore, according to the first high-speed image reading method, it is possible to proceed to the next photographing while leaving the signal charges of 68 to 788 lines on the vertical shift registers VR1 to VRn. By increasing the number, so-called high-speed shooting becomes possible.
[0121]
FIG. 14 is a table showing image data for one screen obtained by adopting the first high-speed image reading method. As shown in the figure, two lines of 1-2 lines are regarded as invalid images, and 29 lines of 3-31 lines are regarded as valid images.
[0122]
Next, a specific example of the second high-speed image reading method will be described with reference to FIGS. In this example, the drive control unit (which includes the transfer pulse generation unit 2 shown in FIG. 6 and the transfer control unit whose operation is shown in FIG. 10) performs the signal charge capture processing (A) and the preceding optical black The pixel area corresponding processing (B), the photosensitive pixel area corresponding processing (C), and the subsequent optical black pixel area corresponding processing (D) are configured to be repeatedly executed, whereby the preceding and subsequent optical blacks are configured. The one-screen read cycle is shortened by the amount by which the signal charges on the vertical shift registers VR1 to VRn of each column taken from the pixel areas (B) and (D) are rapidly dropped into the horizontal shift register HR.
[0123]
Here, the signal charge capturing process (A) is a process of capturing signal charges from the light receiving pixels Ph (m, n) to the vertical shift registers VR1 to VRn of each column at the beginning of each vertical period.
[0124]
The preceding-stage optical black pixel region corresponding process (B) is a process of rapidly dropping signal charges on the vertical shift registers VR1 to VRn of each column taken from the preceding-stage optical black pixel region into the horizontal shift register HR. .
[0125]
The photosensitive pixel area correspondence processing (C) means that the signal charges on the vertical shift registers VR1 to VRn of each column taken from the photosensitive pixel area are transferred to the vertical shift registers VR1 to VRn of each column and the horizontal shift register is transferred. This is a process of reading out to the outside by appropriately linking the transfer of the HR with the transfer.
[0126]
The post-stage optical black pixel region corresponding process (D) is a process of rapidly dropping signal charges on the vertical shift registers VR1 to VRn of each column taken from the post-stage optical black pixel region into the horizontal shift register HR. .
[0127]
In this example, the first-stage optical black pixel region corresponding process (B) and / or the second-stage optical black pixel region corresponding process (D) correspond to one horizontal period. Inside Operation to perform seven-stage continuous vertical transfer to During the horizontal period of Or over two or more horizontal periods repetition, The processing to be performed is included. And this one horizontal period Inside The operation of performing the seven-stage continuous vertical transfer is performed until the transfer of the horizontal shift register HR is stopped during the horizontal period (see FIG. 16).
[0128]
In the photosensitive image area corresponding processing (C), the continuous vertical transfer operation of two stages and the continuous horizontal transfer operation of the number of stages corresponding to the number of one horizontal line pixel are performed by shifting the time zone back and forth within one horizontal period. The processing is included (see FIG. 16).
[0129]
FIG. 15 shows a setting example of a transfer specification table used in the second high-speed image reading method. As shown in the figure, in this transfer specification table, the set values of the number of transfer lines and the presence or absence of output in the horizontal period are respectively associated with the horizontal period counter value indicating the number of the horizontal period. It is stored in the form of transfer line number signals L1, L2.
[0130]
In this example, a video signal corresponding to the preceding optical black pixel area is transferred continuously for seven lines in one horizontal period, and a video signal corresponding to the subsequent photosensitive pixel area is transferred two lines in each horizontal period. This is an example in which a subsequent optical black pixel region is set and transferred seven lines continuously in one horizontal period. After the number of transfer lines in the first one horizontal period is set to seven, the second to 31st horizontal lines are transferred. The transfer lines in the period are set to 2 lines, and the transfer lines in the 32nd to 134th horizontal periods are set to 7 lines. Regarding the presence / absence of output by horizontal transfer, the presence / absence of output in the first one horizontal period is “absent”, the presence / absence of output in the second to 31st horizontal periods is “present”, and then the presence of 32 to 134th The presence / absence of output during the horizontal period is set to “none” again.
[0131]
The transfer control processing executed in the transfer control unit is basically the same as that shown in the flowchart of FIG. Therefore, the second high-speed image reading method will be described with reference to the flowchart again.
[0132]
The operation of the horizontal period counter LC during the count from “1” to “31” is the same as in the first high-speed image reading process. That is, in the horizontal period (mainly, the preceding optical black pixel region) corresponding to the count values “1” and “2”, the charge of seven lines from 1 to 7 accumulated in each stage of the horizontal shift register HR is increased. Further, charges of two lines of 8, 9 lines are dropped, and charges of nine lines of 1 to 9 lines are superimposed as a whole, and are output in the vertical period of the count value "2" in the video signal. You. The video signal portion on which the charges for the nine lines are superimposed becomes an OB unnecessary video signal, and as a result, the first two lines in the video signal become invalid image portions (the count values “1” and “2” in FIG. 16). "reference).
[0133]
In the third to 31st horizontal periods (mainly photosensitive pixel areas) corresponding to the count values “3” to “31”, 10,11 lines, 12,13 lines, 14,15 lines, to 66,67 lines Are superimposed on each other and are sequentially output. The video signal portion on which these two lines of charges are superimposed becomes an effective video signal (see count values “3” to “31” in FIG. 16).
[0134]
In the 32nd to 134th horizontal periods corresponding to the count values “32” to “134” (mainly, in the latter-stage optical black pixel area), the transfer pulse generation unit 12 sends a second vertical transfer signal every horizontal period. Although two transfer pulses TP2 are output during the horizontal blanking period, even when the horizontal blanking period ends, the third transfer pulse TP3 for horizontal transfer is not output, and as a result, the video signal contains Nothing is output (see count values "32" to "134" in FIG. 16).
[0135]
FIG. 17 is a table showing image data for one screen acquired by employing the second high-speed image reading method. As shown in the figure, two lines of 1 to 2 lines are regarded as a preceding invalid image, 29 lines of 3 to 31 lines are regarded as valid images, and 103 lines of 32 to 134 lines are regarded as a succeeding invalid image. Is done.
[0136]
As a pixel array serving as a base of the CCD image sensor 205 constituting the above-described sensor head unit 200, a pixel array of a popular CCD image sensor corresponding to the screen aspect ratio of a standard digital still camera can be used as it is. . Therefore, there is no need to newly design a special pixel array, so that the development cost or development period can be reduced and the cost can be reduced.
[0137]
Next, the contents of the image processing performed by the sensor main body 100 will be described with reference to FIG. The sensor main unit 100 includes a CPU 101 which is a one-chip microcomputer, a display LED 102, an operation switch 103, an input / output circuit (I / O) 104, a calculation unit 105, a memory control unit 106, a frame buffer 107, , D / A converter 108, register 109, synchronization signal generator 110, and oscillator (OSC) 111. BUS1 is a synchronous bus, and BUS2 is a CPU bus.
[0138]
The CPU 101 constituting the one-chip microcomputer performs overall control of the entire sensor main body 100. The calculation unit 105 is a dedicated hardware circuit that performs various calculations required for image processing. The calculation unit 105 performs various processes on the image data captured via the A / D converter 112. The image processed here is stored in the frame buffer 107 via the memory control unit 106, and is sent to an external CRT display or the like as an NTSC image via the D / A converter 108 as needed. The register 109 stores a transfer specification table required for the operation of the sensor head unit 200, and the contents of the transfer specification table are stored in each horizontal direction as described above with reference to FIGS. L1, L2, and OE are set corresponding to the period counter value. The display LED 102 is for displaying the operating state of the sensor main body 100 to the outside, and the operation switch 103 is for giving various instructions to the sensor main body 100. The input / output circuit (I / O) 104 outputs displacement data measured by the sensor main body 100 to the outside. The displacement data includes a switching signal indicating a comparison result between the measured value and the reference value, in addition to the measured value itself. The operation of the sensor body 100 is controlled by a synchronization signal obtained via an oscillator (OSC) 111 and a synchronization signal generator 110.
[0139]
Next, various measurement processes in the displacement sensor 1 having the above configuration will be described with reference to specific examples.
[0140]
First, the case of measuring the height of a metal plate having a hairline on its surface will be described with reference to FIGS. In such a case, as shown in FIG. 18, the all-line collective averaging process is executed. FIG. 19 shows the contents of the transfer specification table in this case, and FIG. 20 shows an example of driving the image sensor. As shown in FIG. 19, in this case, when the value of the horizontal period counter is “1”, the number of transfer stages is “7”, and when the value of the horizontal counter is “2” to “31”, the number of transfer stages is “2”. It is said. On the other hand, while the value of the horizontal counter is “1” to “30”, horizontal transfer is “none”. As a result of executing the processing of FIG. 10 described above in accordance with such a transfer specification table, as shown in FIG. 20, the charge addition results of 29 lines are output collectively for each vertical cycle. As a result, when an object having a hairline on its surface is measured as shown in FIG. 21A, a zigzag line which is an irradiation light image of the cutting light is formed on the object surface as shown in FIG. Although a beam appears, such data is averaged by the area effect on the light receiving surface of the image sensor as shown in FIG. 3C, so that the influence of the hairline is reduced and accurate measurement is performed. It is possible. As described above, according to the present invention, instead of reading out image data line by line from the CCD image pickup device and performing averaging processing on the memory, the multi-stage vertical operation of the CCD and the horizontal transfer stop control are combined to realize the CCD internal device. , The averaging process can be performed at high speed, and it is not necessary to provide a special averaging operation circuit externally.
[0141]
Next, a description will be given of a process of performing various measurements by performing various image processing operations on data read out from the CCD image pickup device on a memory. In these measurement processes, the contents of the transfer specification table stored in the register 109 are appropriately replaced according to the measurement type.
[0142]
First, the measurement processing of the flaw will be described with reference to FIG. As shown in FIG. 23A, when an object having a flaw on the surface is photographed by the sensor head, a large waveform bright line corresponding to the depth of the flaw is formed on the surface of the object as shown in FIG. The following line beam image appears. Therefore, as shown in FIG. 3C, the height of each measurement line is detected, and peak-to-peak (PP) is obtained. Alternatively, the variance of the height of each measurement line is obtained. Then, the width or depth of such a flaw can be obtained as a measured value.
[0143]
Next, measurement of protrusions will be described with reference to FIG. When a measurement object having a protrusion is photographed by the sensor head as shown in FIG. 7A, a line beam image composed of an arc-shaped bright line appears on the surface of the object as shown in FIG. Therefore, as shown in FIG. 3C, the height of each measurement line is detected, and peak-to-peak (PP) is obtained. Then, the height of such a protrusion can be obtained as a measured value.
[0144]
Next, the measurement of the groove will be described with reference to FIG. When the surface of an object having a V-shaped groove on the surface is photographed by the sensor head as shown in FIG. 7A, the surface of the object has a depth corresponding to the depth of the scratch as shown in FIG. A line beam image serving as a large V-shaped waveform bright line appears. Therefore, as shown in FIG. 3C, the height of each measurement line is detected, and the bottom is obtained. Then, the depth of such a groove can be obtained as a measured value.
[0145]
Next, measurement of the inclination will be described with reference to FIG. As shown in FIG. 3A, when an object having a tilted surface is measured from above, a line beam having a tilt angle θ is formed on the surface of the object as shown in FIG. 3B. An image appears. Therefore, as shown in FIG. 3C, the height of each measurement line is calculated from the image data obtained in this way, and the inclination is obtained, so that the inclination of the object whose surface is inclined is used as the measurement value. Obtainable. At the same time, by using this function, the mounting state of the sensor can be confirmed.
[0146]
Next, measurement of coplanarity (height uniformity) will be described with reference to FIG. As shown in FIG. 3A, when an object having a BGA (Ball Grid Array) on the surface is measured from above, a half of the surface of the object is formed as shown in FIG. A line beam image as a circular bright line appears. Therefore, as shown in FIG. 4C, the height of each measurement line is calculated and the peak is obtained while moving such an object, thereby obtaining the coplanarity of the BGA, that is, the height of the vertices of a plurality of BGAs. It is possible to measure how much is complete.
[0147]
The relationship between the above-described processing and the measurement target is summarized in the flowchart of FIG. As shown in the figure, in the case of measuring a flaw (YES in step 2201), the height of each measurement line is calculated, and PP is obtained. Alternatively, the variance of the height of each measurement line is obtained (step 2202).
[0148]
In the case of measuring a protrusion (YES in step 2203), the height of each measurement line is calculated, and a peak is obtained (step 2204).
[0149]
In the case of groove measurement (step 2205 YES), the height of each measurement line is calculated, and the bottom is determined (step 2206).
[0150]
In the case of measuring the inclination (YES in step 2207), the height of each measurement line is calculated to determine the inclination (step 2208).
[0151]
In the case of coplanarity measurement (step 2209 YES), the height of each measurement line is calculated to determine the peak. By measuring while moving the work, measurement of coplanarity such as lead and BGA becomes possible (step 2210).
[0152]
In the embodiment described above, the direction of the horizontal line of the image sensor is directed to the direction in which the position of the line beam image formed on the light receiving surface of the image sensor changes in accordance with the displacement of the measurement target. The direction may be a direction rotated by 90 degrees in the light receiving surface. That is, the direction of the horizontal line of the image sensor may be directed in a direction perpendicular to the direction in which the position of the line beam image formed on the light receiving surface of the image sensor changes in accordance with the displacement of the measurement target. With this configuration, a long region along the irradiation position of the line beam can be included in the field of view, so that the height distribution in this long region can be measured at once. For example, a plurality of leads or BGAs can be placed in a field of view, and variations in their height can be measured at once.
[0153]
【The invention's effect】
As is apparent from the above description, according to the displacement sensor of the present invention, it is possible to acquire image data at a required resolution at a high speed from a long and narrow field of view, perform various measurement processes with a high-speed response, and at a low cost. And a displacement sensor that can be manufactured.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an electrical configuration of a displacement sensor according to the present invention.
FIG. 2 is a diagram showing an optical system of a sensor head of a displacement sensor according to the present invention.
FIG. 3 is a diagram schematically illustrating a pixel array on a light-receiving cotton in an imaging element of a sensor head unit.
FIG. 4 is a diagram illustrating a relationship between a photosensitive pixel area and an optical black pixel area in an image sensor of a sensor head unit by an actual screen aspect ratio.
FIG. 5 is a block diagram illustrating a charge transfer circuit in the image sensor.
FIG. 6 is a diagram showing an internal configuration of a transfer pulse generator.
FIG. 7 is a time chart showing an output mode of a horizontal transfer pulse (TP2).
FIG. 8 is a diagram showing the contents of a transfer specification table (first high-speed image reading method).
FIG. 9 is a diagram showing semantic contents of L1, L2, and OE.
FIG. 10 is a flowchart illustrating an operation of a transfer control unit.
FIG. 11 is a time chart (first high-speed image reading method) illustrating an example of driving the image sensor.
FIG. 12 is a diagram illustrating a main part of the time chart of FIG. 11;
FIG. 13 is a diagram illustrating a main part of the time chart of FIG. 11;
FIG. 14 is a diagram (first high-speed image reading method) showing a tabular data configuration of one screen in one driving example of an image sensor.
FIG. 15 is a diagram showing the contents of a transfer specification table (second high-speed image reading method).
FIG. 16 is a time chart (second high-speed image reading method) showing one driving example of an image sensor.
FIG. 17 is a diagram (a second high-speed image reading method) showing a tabular data configuration of one screen in a driving example of the element of the present invention.
FIG. 18 is a conceptual diagram illustrating an all-line batch averaging process performed on an image sensor.
FIG. 19 is a diagram showing the contents of a transfer specification table for batch averaging of all lines.
FIG. 20 is a time chart illustrating a driving example of an image sensor at the time of all-line collective averaging processing.
FIG. 21 is a diagram illustrating an application example of the all-line collective averaging process.
FIG. 22 is a flowchart illustrating the entire image processing executed by the sensor body.
FIG. 23 is an explanatory diagram of image processing for flaw measurement.
FIG. 24 is an explanatory diagram of image processing for projection measurement.
FIG. 25 is an explanatory diagram of image processing for groove measurement.
FIG. 26 is an explanatory diagram of image processing for tilt measurement.
FIG. 27 is an explanatory diagram of image processing for coplanarity measurement.
FIG. 28 is a diagram showing an optical system of a sensor head of a conventional displacement sensor.
FIG. 29 is a diagram schematically showing an operation in a case where area measurement is performed using a conventional displacement sensor.
FIG. 30 is a diagram illustrating a photosensitive region of a conventional two-dimensional CCD.
FIG. 31 is a diagram illustrating an application example of the imaging apparatus.
FIG. 32 is a block diagram illustrating a configuration of a visual measurement device.
[Explanation of symbols]
1 Displacement sensor
7 Imaging device
8 Image processing device
71 CCD
72 Transfer pulse generator
73 Transfer control unit
74 amplifier
75 Transfer specification table
81 Image input section
82 Image processing unit
83 Output unit
91 Measurement object
92 Line beam for measurement
93 Reflected light
94 lens system
95 Two-dimensional image sensor
96 Horizontal scanning direction of 2D image sensor
97 Vertical operation direction of 2D image sensor
98 Specific horizontal line zone
100 Sensor body
101 CPU (one-chip microcomputer)
102 Display LED
103 Operation switch
104 input / output (I / O) circuit
105 arithmetic unit
106 Memory control unit
107 frame buffer
108 D / A converter
109 registers
110 Synchronous signal generator
111 Oscillator (OSC)
112 A / D converter
200 Sensor head
201 Oscillator (OSC)
202 Timing signal generator
203 CCD drive
204 Sample hold circuit
205 CCD (two-dimensional image sensor)
206 slit light source
207 laser diode
208 slit
209 Floodlight lens
210 Cut Light Trace
211 Light receiving lens
300 Object to be measured
400 stages
500 Sensor head
501 laser diode
502 slit
503 Floodlight lens
504 light receiving lens
505 light receiving element
600 Object to be measured
700 stages
800 Image processing device
SP cutting light trace
Ph1 photosensitive pixel
Ph2 optical black pixel
HR horizontal shift register
VR vertical shift register
Aout output buffer
HLB Specific horizontal line zone

Claims (10)

By processing the image obtained from the imaging unit, which captures the surface of the measurement target object having the irradiation light image of the cross-section linear cutting light from an angle at which the optical image position changes according to the displacement of the measurement target, and an image obtained from the imaging unit , An image processing unit that calculates a displacement to be measured,
In the imaging unit,
A light-receiving pixel group arranged in a matrix corresponding to the field of view of a standard imaging device, a vertical shift register of each column, and a horizontal shift register that sequentially receives the output of the vertical shift register of each column from the top, And, by providing the former optical black pixel region and the latter optical black pixel region formed in the semiconductor process, all or most of them are photosensitive pixel regions so as to be sandwiched between them, and A two-dimensional image sensor, which also includes a specific horizontal line band having a sufficiently narrow width, and a horizontal line is directed in a direction in which an optical image position on a light receiving surface changes according to a displacement of a measurement target,
A drive control unit that controls a charge take-in operation from the light receiving pixel group to the vertical shift register of each column, a transfer operation of the vertical shift register, and a transfer operation of the horizontal shift register based on the commanded charge transfer specification. And the image processing unit
A displacement sensor including charge transfer specification command means for giving a charge transfer specification according to image processing contents to a drive control unit of an imaging unit. The content of the charge transfer specification instructed by the image processing unit is
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A preceding optical black pixel area corresponding process of dropping signal charges on the vertical shift register of each column taken from the preceding optical black pixel area into the horizontal shift register;
A photosensitive pixel area for reading signal charges on the vertical shift register of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register of each column and the transfer of the horizontal shift register. The corresponding process,
The subsequent optical black pixel region corresponding process of dropping the signal charges on the vertical shift register of each column taken from the subsequent optical black pixel region into the horizontal shift register is repeated without being sandwiched in the middle,
Thereby, the one-screen readout cycle is shortened by the amount that the post-stage optical black pixel region corresponding processing is not performed.
The photosensitive pixel area corresponding processing is a processing in which a continuous vertical transfer operation of two or more stages and a continuous horizontal transfer operation of a number of stages corresponding to one horizontal line pixel are performed by shifting a time zone back and forth within one horizontal period. The displacement sensor according to claim 1, comprising: The content of the charge transfer specification instructed by the image processing unit is
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A preceding optical black pixel area corresponding process of dropping signal charges on the vertical shift register of each column taken from the preceding optical black pixel area into the horizontal shift register;
A photosensitive pixel area for reading signal charges on the vertical shift register of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register of each column and the transfer of the horizontal shift register. The corresponding process,
The subsequent optical black pixel region corresponding process of dropping the signal charges on the vertical shift register of each column taken from the subsequent optical black pixel region into the horizontal shift register is repeated without being sandwiched in the middle,
Thereby, the one-screen readout cycle is shortened by the amount that the post-stage optical black pixel region corresponding processing is not performed.
In the photosensitive pixel area corresponding processing, the horizontal transfer operation is stopped for one or more horizontal periods, during which charges of all the horizontal lines in the photosensitive pixel area are collectively transferred to the horizontal shift register, and the same vertical column is transferred. To superimpose the pixel charge,
The displacement sensor according to claim 1, wherein the collective averaging process of all lines in the photosensitive pixel area is performed in the two-dimensional image sensor. The content of the charge transfer specification instructed by the image processing unit is
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A first-stage optical black pixel region corresponding process for quickly dropping signal charges on the vertical shift register of each column taken from the first-stage optical black pixel region into the horizontal shift register;
A photosensitive pixel area corresponding process for reading out the signal charges on the vertical shift registers of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register and the transfer of the horizontal shift register of each column to the outside. When,
A post-stage optical black pixel region corresponding process of rapidly dropping signal charges on the vertical shift register of each column taken from the post-stage optical black pixel region into the horizontal shift register,
It is something that is executed repeatedly,
Thereby, the one-screen readout cycle is shortened by the amount by which the signal charges on the vertical shift register of each column taken in from the optical black pixel regions at the preceding and subsequent stages are dropped into the horizontal shift register at a high speed.
The photosensitive pixel area corresponding processing is a processing in which a continuous vertical transfer operation of two or more stages and a continuous horizontal transfer operation of a number of stages corresponding to one horizontal line pixel are performed by shifting a time zone back and forth within one horizontal period. The displacement sensor according to claim 1, comprising: The content of the charge transfer specification instructed by the image processing unit is
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A first-stage optical black pixel region corresponding process for quickly dropping signal charges on the vertical shift register of each column taken from the first-stage optical black pixel region into the horizontal shift register;
A photosensitive pixel area corresponding process for reading out the signal charges on the vertical shift registers of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register and the transfer of the horizontal shift register of each column to the outside. When,
A post-stage optical black pixel region corresponding process of rapidly dropping signal charges on the vertical shift register of each column taken from the post-stage optical black pixel region into the horizontal shift register,
It is something that is executed repeatedly,
Thereby, the one-screen readout cycle is shortened by the amount by which the signal charges on the vertical shift register of each column taken in from the optical black pixel regions at the preceding and subsequent stages are dropped into the horizontal shift register at a high speed.
In the photosensitive pixel area corresponding processing, the horizontal transfer operation is stopped for one or more horizontal periods, during which charges of all the horizontal lines in the photosensitive pixel area are collectively transferred to the horizontal shift register, and the same vertical column is transferred. To superimpose the pixel charge,
The displacement sensor according to claim 1, wherein the collective averaging process of all lines in the photosensitive pixel area is performed in the two-dimensional image sensor. By processing the image obtained from the imaging unit, which captures the surface of the measurement target object having the irradiation light image of the cross-section linear cutting light from an angle at which the optical image position changes according to the displacement of the measurement target, and an image obtained from the imaging unit , An image processing unit that calculates a displacement to be measured,
In the imaging unit,
A light-receiving pixel group arranged in a matrix corresponding to the field of view of a standard imaging device, a vertical shift register of each column, and a horizontal shift register for sequentially receiving the output of the vertical shift register of each column from the top, And, by providing the former optical black pixel region and the latter optical black pixel region formed in the semiconductor process, all or most of them are photosensitive pixel regions so as to be sandwiched between them, and A two-dimensional image sensor having a sufficiently narrow specific horizontal line band, and a horizontal line directed in a direction in which an optical image position on an imaging surface changes according to a displacement of a measurement target,
A drive control unit that controls a charge taking operation from the light receiving pixel group to the vertical shift register of each column, a transfer operation of the vertical shift register, and a transfer operation of the horizontal shift register based on predetermined charge transfer specifications. , And the image processing unit,
A displacement sensor that performs image processing based on the same charge transfer specifications as those used in the drive control unit of the imaging unit. The content of the predetermined charge transfer specification,
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A preceding optical black pixel area corresponding process of dropping signal charges on the vertical shift register of each column taken from the preceding optical black pixel area into the horizontal shift register;
A photosensitive pixel area for reading signal charges on the vertical shift register of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register of each column and the transfer of the horizontal shift register. The corresponding process,
The subsequent optical black pixel region corresponding process of dropping the signal charges on the vertical shift register of each column taken from the subsequent optical black pixel region into the horizontal shift register is repeated without being sandwiched in the middle,
Thereby, the one-screen readout cycle is shortened by the amount that the post-stage optical black pixel region corresponding processing is not performed.
The photosensitive pixel area corresponding processing is a processing in which a continuous vertical transfer operation of two or more stages and a continuous horizontal transfer operation of a number of stages corresponding to one horizontal line pixel are performed by shifting a time zone back and forth within one horizontal period. The displacement sensor according to claim 6, comprising: The content of the predetermined charge transfer specification,
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A preceding optical black pixel area corresponding process of dropping signal charges on the vertical shift register of each column taken from the preceding optical black pixel area into the horizontal shift register;
A photosensitive pixel area for reading signal charges on the vertical shift register of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register of each column and the transfer of the horizontal shift register. The corresponding process,
The subsequent optical black pixel region corresponding process of dropping the signal charges on the vertical shift register of each column taken from the subsequent optical black pixel region into the horizontal shift register is repeated without being sandwiched in the middle,
Thereby, the one-screen readout cycle is shortened by the amount that the post-stage optical black pixel region corresponding processing is not performed.
In the photosensitive pixel area corresponding processing, the horizontal transfer operation is stopped for one or more horizontal periods, during which charges of all the horizontal lines in the photosensitive pixel area are collectively transferred to the horizontal shift register, and the same vertical column is transferred. To superimpose the pixel charge,
7. The displacement sensor according to claim 6, wherein the process of averaging all lines in the photosensitive pixel region is performed in the two-dimensional image sensor. The content of the predetermined charge transfer specification,
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A first-stage optical black pixel region corresponding process for quickly dropping signal charges on the vertical shift register of each column taken from the first-stage optical black pixel region into the horizontal shift register;
A photosensitive pixel area corresponding process for reading out the signal charges on the vertical shift registers of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register and the transfer of the horizontal shift register of each column to the outside. When,
A post-stage optical black pixel region corresponding process of rapidly dropping signal charges on the vertical shift register of each column taken from the post-stage optical black pixel region into the horizontal shift register,
It is something that is executed repeatedly,
Thereby, the one-screen readout cycle is shortened by the amount by which the signal charges on the vertical shift register of each column taken in from the optical black pixel regions at the preceding and subsequent stages are dropped into the horizontal shift register at a high speed.
The photosensitive pixel area corresponding processing is a processing in which a continuous vertical transfer operation of two or more stages and a continuous horizontal transfer operation of a number of stages corresponding to one horizontal line pixel are performed by shifting a time zone back and forth within one horizontal period. The displacement sensor according to claim 6, comprising: The content of the predetermined charge transfer specification,
At the beginning of each vertical period, a signal charge capturing process for capturing signal charges from the light receiving pixels to the vertical shift registers of each column;
A first-stage optical black pixel region corresponding process for quickly dropping signal charges on the vertical shift register of each column taken from the first-stage optical black pixel region into the horizontal shift register;
A photosensitive pixel area corresponding process for reading out the signal charges on the vertical shift registers of each column taken from the photosensitive pixel area to the outside by appropriately linking the transfer of the vertical shift register and the transfer of the horizontal shift register of each column to the outside. When,
A post-stage optical black pixel region corresponding process of rapidly dropping signal charges on the vertical shift register of each column taken from the post-stage optical black pixel region into the horizontal shift register,
It is something that is executed repeatedly,
Thereby, the one-screen readout cycle is shortened by the amount by which the signal charges on the vertical shift register of each column taken in from the optical black pixel regions at the preceding and subsequent stages are dropped into the horizontal shift register at a high speed.
In the photosensitive pixel area corresponding processing, the horizontal transfer operation is stopped for one or more horizontal periods, during which charges of all the horizontal lines in the photosensitive pixel area are collectively transferred to the horizontal shift register, and the same vertical column is transferred. To superimpose the pixel charge,
7. The displacement sensor according to claim 6, wherein the process of averaging all lines in the photosensitive pixel region is performed in the two-dimensional image sensor.

Images