JP2925871B2 - Solid-state imaging camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a solid-state imaging camera using a solid-state imaging device as a photoelectric conversion device, such as a still video.

[0002]

2. Description of the Related Art Conventionally, in this type of solid-state image pickup camera, correction of aberration of an image pickup zoom lens to be used, in particular, correction of geometrical deformation (ie, distortion) and signal chromatic aberration has been strictly performed.

In the case of a camera using an image pickup tube, it is possible to electrically correct aberrations generated in the image pickup zoom lens by controlling the trajectory of electron beam deflection of the image pickup tube.

[0004]

However, in a solid-state imaging camera, the geometric distortion caused by the imaging lens is read out by interpolating the pixel signal of the solid-state imaging device along the geometric deformation and interpolating. Although a method of correcting aberration has been proposed, when a zoom lens is used as an imaging lens, if aberration correction is performed at each imaging position by signal processing, a huge amount of calculation and calculation time are required for signal processing. , And a large-scale signal processing circuit is required,
At present, it has been studied in only a few fields, such as for broadcasting stations, which require high-quality images, and is not common.

As described above, in a solid-state imaging camera using a conventional zoom lens, it is difficult to easily perform this type of correction at a low cost, so that the imaging zoom lens does not need to be corrected by itself. However, there is a problem that the cost increases due to an increase in size, an increase in the number of lenses, an increase in weight, and the use of special glass.

Next, another problem to be solved by the invention will be described.

Conventionally, in Japanese Patent Application Laid-Open No. Hei 2-252375, aberration correction is performed by reading a geometric distortion generated by an imaging lens as a pixel signal of a solid-state imaging device along the geometric deformation and interpolating the pixel signal. It is configured to perform.

However, in the above conventional example, when a zoom lens is used as an imaging lens, if the geometric distortion is always corrected by the same method during zooming, the correction cannot catch up with the zooming, and the output cannot be corrected. There is a problem that an image becomes unnatural.

Further, it is possible to make the output image natural by limiting the zoom speed. However, in this case, a new problem that the zooming time becomes longer occurs.

(Object of the Invention) A first object of the present invention is to provide a solid-state imaging camera which has good image quality and can be manufactured at low cost not only in terms of circuit scale but also imaging zoom lens. That is.

A second object of the present invention is to provide a solid-state imaging camera capable of increasing the zoom speed and making an output image natural.

[0012]

According to the present invention, there is provided an imaging zoom lens formed by concentrating distortion only at a part of an imaging position, detecting means for detecting the imaging position of the imaging zoom lens, When the detecting unit detects that the imaging position of the imaging zoom lens in the position within the large distortion is,
Correction means for correcting the geometric distortion of the image caused by the imaging zoom lens by reading out the image data of the solid-state imaging device based on the geometric deformation; When the imaging zoom lens is formed by focusing only on the position, and the imaging position of the imaging zoom lens during photographing is within the distortion, the geometrical distortion of the image caused by the imaging zoom lens The image data of the solid-state imaging device is read out along with the geometric deformation to correct the distortion.

Further, according to the present invention, during a zooming operation,
Providing control means for switching the correction of the geometric distortion between when the zooming operation is not performed, and during the zooming operation, to prevent the geometric distortion correction operation from being performed,
A correction operation for geometric distortion is performed using the zooming speed information.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a diagram showing the optical performance of an imaging zoom lens and a general imaging zoom lens according to a first embodiment of the present invention.

FIG. 1 (b) shows the distortion of a general zoom lens.
Distortion occurs on the positive side on the telephoto side.

In order to design a zoom lens while satisfying the conditions of small size, light weight, and compact size, it is very difficult to reduce distortion at both wide-angle and telephoto ends. It is designed so that the amount of distortion at the telephoto end is distributed so as to be substantially the same. Therefore, the absolute amount of distortion does not decrease. However, the portion where the distortion is large is near the wide-angle end and the telephoto end, and the intermediate band changes almost monotonously, and it can be seen that the aberration is not so large.

For this reason, in the first embodiment,
As shown in FIG. 1A, a design is performed during optical design so that distortion is concentrated only in a part of the photographing positions. Specifically, as described above, the amount of distortion is substantially the same at the wide-angle end and the telephoto end, and the distortion at an intermediate focal length changes monotonously.

When the imaging position of the imaging zoom lens is detected at the time of photographing, and it is determined that the imaging position is near the imaging position where distortion is large, which is stored in advance in the storage unit, the imaging position of the imaging zoom lens is generated. The geometrical distortion of the image is interpolated by reading out the image data of the solid-state imaging device along the geometrical deformation, thereby correcting the aberration and obtaining an image quality free of distortion.

That is, in the first embodiment, an imaging position for correcting distortion is assumed in advance,
It is designed in consideration of this at the time of optical design, and as described later, the imaging position of the zoom lens currently being photographed is detected at the time of photographing, and only when correction is necessary (in this embodiment, near the wide-angle end and near the telephoto end). Only the distortion aberration correction is performed.) The pixel signals of the scanning lines having the geometric deformation are calculated one by one using the pixel data of a plurality of rows, and the aberration generated by the imaging zoom lens is corrected, thereby achieving a relatively low cost. Excellent image quality can be obtained even with the use of lenses.

FIG. 2 is a block diagram showing a schematic configuration of a solid-state imaging camera provided with an imaging zoom lens having the above optical performance.

Reference numeral 1 denotes a photoelectric conversion unit of the CCD 10 which is a solid-state image sensor (image sensor). Reference numeral 2 denotes an example of an image pattern, which is formed on the photoelectric conversion unit 1. 3 is CCD
Reference numeral 10 denotes a storage unit, 4 denotes a charge pattern, and 5 denotes a shift register.

The CCD 10 includes the above-described photoelectric conversion unit 1, storage unit 3, and shift register 5.

Reference numeral 17 denotes a signal from the CCD 10 which will be described later.
A switch for sorting according to the instruction of the PU 16, an amplifier 6, a sample / hold (S / H) circuit 7, and an analog / digital (A / D) converter 8 are provided. Reference numeral 9 denotes a line memory, which has a capacity to store output from the CCD 10 for several rows.

Reference numeral 11 denotes an address storage circuit, which stores in advance address information for reading from the line memory 9 in two types, that is, a wide-angle end and a telephoto end. It has the function of sending out the distortion information (outputting the address information). Reference numeral 16 denotes a CPU for controlling the progress of the present system, which supplies ON / OFF information as to whether or not to perform a distortion aberration correction operation to a switch 17 (SW1) based on current focal length information of the imaging zoom lens to correct distortion aberration. When the operation is to be performed, distortion correction amount information at the wide-angle end or the telephoto end is selected via the address storage circuit 11, and the data is transmitted to the line memory 9.

Reference numeral 12 denotes an interpolation circuit, 13 denotes a video signal processing circuit, 14 denotes a synchronization signal adding circuit, and 15 denotes a video signal output from the video signal processing circuit 13.

The operation of each circuit described above is controlled by a timing control circuit, but the control circuit and control signals are not shown for simplicity.

FIG. 3 is a mechanism diagram showing an imaging zoom lens and a focal length detector of the solid-state imaging camera.

In FIG. 3, reference numeral 71 denotes a first group lens (focus lens) for focus adjustment, 72 denotes a second group lens (variator lens) having a zooming action, and 73 denotes a third group lens (compensator lens) for correcting the focal position. ), 7
Reference numeral 4 denotes a four-group lens having an image forming action, and these constitute an imaging zoom lens.

Reference numeral 75 denotes a position detector for detecting the position of the variator lens 72 having a zooming action, and 76 calculates the focal length from the position information from the position detector 75 (position information of the variator lens 72). This is a focal length detection circuit for transmitting focal length information.

FIG. 4 is a flowchart showing the operation of the solid-state imaging camera according to the first embodiment of the present invention. [Step 91] The photographing operation is started. [Step 92] The focal length information is detected via the focal position detection circuit 76, and the current focal length information is obtained. [Step 93] It is determined whether the focal length information is within a predetermined distortion correction range near the wide-angle end or near the telephoto end. If it is within the distortion correction range, the process proceeds to step 94; otherwise, the process proceeds to step 95. [Step 94] Since the current focal length information of the imaging zoom lens (variator lens 72) is within the distortion correction range, the variable SW1 is turned on. As a result, the switch SW1 is turned on, and the signal from the CCD 10 is connected to the amplifier 6 side. [Step 95] Since the current focal length information of the imaging zoom lens is outside the distortion aberration correction range, the variable SW1 is set to O.
Set to FF. As a result, the switch SW1 is turned off, and the signal from the CCD 10 is directly connected to the video signal processing circuit 13 side. [Step 96] It is determined whether the variable SW1 is ON or OFF. If the variable SW1 is ON, the process proceeds to Step 97. If the variable SW1 is OFF, the process proceeds to Step 98. [Step 97] Here, the amplifier 6 and the interpolation circuit 12
By operating the distortion correction circuit formed by the above, distortion correction is performed based on the signal from the CCD 10 and the address information from the address storage circuit 11 (the details of the operation of each circuit will be described later). Then, the process proceeds to step 98. [Step 98] The video signal processing circuit 13 is operated to generate a video signal based on the signal from the distortion correction circuit or the CCD 10 and output the video signal. [Step 99] It is determined whether or not the zoom mechanism has been operated. If the zoom mechanism has been operated,
Since there is a possibility that the focal length has changed from the previous state due to the operation during the above-described calculation, the process returns to step 92, where the focal length information is newly detected again, and the operations from step 93 onward are performed. On the other hand, if the operation of the zoom mechanism has not been performed, the focal length has not changed, so the flow returns to step 96, and
The operation after step 96 is performed.

FIG. 5 is a schematic diagram for explaining the operation of the imaging zoom lens.

In FIG. 5, reference numeral 21 denotes an object plane;
Is an example of an object. An imaging zoom lens 23 includes the lens groups shown in FIG. 24 is an image plane, 2
5 is an image.

The object 22 on the object plane 21 is formed on the image plane 24 by the imaging zoom lens 23 to form an image 25.
The above-mentioned CCD 10 which is a solid-state image sensor has an image 25
Is arranged on the image plane 24 in order to perform photoelectric conversion. In the imaging zoom lens 23, distortion (hereinafter referred to as distortion) is set to be larger than a normal allowable value. Therefore, the image 25 is distorted as compared with the object 22 as illustrated.

However, in the lens design, as is well known, if a certain aberration value is allowed to be larger, it is easy to correct other aberrations, and the imaging zoom lens 23 can be reduced in size, the number of lenses can be reduced, and inexpensive glass can be used. Use of materials and the like can be achieved.

In FIG. 2, an image pattern 2 corresponding to an image 25 formed by the imaging zoom lens 23 is formed on the photoelectric conversion unit 1 of the CD 10. The CCD 10 shown in this embodiment is of a frame transfer type. That is, the image pattern 2 photoelectrically converted by the photoelectric conversion unit 1 is transferred to the storage unit 3 as the charge pattern 4. Then, the charge patterns 4 are read by the shift register 5 line by line.

FIG. 6 is a schematic diagram showing the relationship between the image and the pixels of the CCD.

In FIG. 6, reference numeral 31 denotes a pixel of the CCD 10,
32 _1, 32 _2, 32 ₃ first, respectively, second, and third scanning lines.

The first to third scanning lines 32 _{1 to} 32 ₃ indicate the first three scanning lines, which should be straight lines but are curved for distortion. That is, the shapes of these curves are the curved shapes themselves caused by distortion when the horizontal line on the object plane 21 of the imaging zoom lens 23 forms an image on the image plane 24.

The reading of the electric charge pattern is performed one row at a time, and one pixel at a time in one row. Among the pixels 31, the lower right pixel is read first, then the pixels shown in the left diagram are read, and one row is sequentially read first. Then 1
The pixel signal in the next higher row is read from the rightmost pixel. The same applies to the third and subsequent lines.

In FIG. 2, the pixel signal read from the shift register 5 of the CCD 10 is directly sent to the video signal processing circuit 13 when the switch SW1 is OFF as described above.

On the other hand, when the switch SW1 is ON, the signal is output to the distortion correction circuit. That is, after being amplified by the amplifier 6, the signal is held by the S / H 7 and then the A / H
The data is digitized by the D converter 8 and sent to the line memory 9. And it is stored here. This line memory 9
Before the start of reading, signals of several rows of the CCD 10 are accumulated. This is because a pixel signal is read out according to a curved scanning line, and this scanning line extends over several rows of pixels.

The type of data necessary for distortion correction is sent from the CPU 16 to the address storage circuit 11 from the focal length information of the imaging zoom lens 23, and the address storage circuit 11 reads the shape data of the designated scanning line, and Address information for reading a pixel signal in the line memory 9 is generated. The scanning line shape data may be in the form of a direct sampling of the scanning line, or an appropriate relation approximation may be made.
It may be in the form of the coefficient. The scanning line shape data corresponding to these lens states is obtained at the time of designing the imaging zoom lens or at the time of optical measurement after trial production.

Since the positions of the pixels obtained by the CCD 10 generally do not coincide with each other, the positions of the pixels on the curved scanning line require interpolation processing. Therefore, data of several pixels is read from the line memory 9 and sent to the interpolation circuit 12, where the value of one pixel on the scanning line is calculated.

Here, the capacity of the line memory 9 is determined as follows.

FIG. 7 shows the relationship between the pixels of the line memory 9 and the scanning lines.

In FIG. 7, reference numeral 41 denotes a pixel of the line memory 9 and corresponds to the pixel 31 of the CCD 10 on a one-to-one basis. Reference numeral 42 denotes the most curved scanning line. In other words, it extends over the most pixel rows of the line memory 9 among the scanning lines. 43 is a scanning line next to the most curved scanning line 42. 44 and 45 are the most curved scanning lines 4 respectively.
Pixels of the second and next scanning lines 43. It is necessary to calculate the value of the pixel data at the position of the pixel 44 of the most curved scanning line 42 and the pixel 45 of the next scanning line 43 represented by the black circle.

Reference numeral 46 denotes the size of the line memory 9. The size 46 of the line memory 9 is a capacity capable of storing the data of the pixel 31 of the CCD 10 so that all the values of the pixel 44 of the curved scanning line 42 can be calculated. That is, if the number of rows of the pixels 31 of the CCD 10 over which the most curved scanning line 42 extends is necessary, the number of rows obtained by adding peripheral rows necessary for the interpolation processing becomes the size 46 of the line memory 9. Of course, it may be more than this.

The calculation of the value of the pixel 44 on the most curved scanning line 42 is performed when the line memory 9
If there are only six capacities, it can be calculated completely from the pixels 41 of the line memory 9.

Next, when calculating the value of the pixel 45 on the next scanning line 43, the pixel data of the lowermost row is discarded from the line memory 9 and the next row not yet stored in the line memory 9 is calculated. For example, in FIG. 4, the pixel data in the top row is read. The size 46 of the line memory 9 is guaranteed to store enough pixel data 41 of the line memory 9 to calculate the values of all pixels on a scanning line for any scanning line. All values are calculated for the pixel 45 on the line 43 as well. Pixel values are calculated for other scanning lines in exactly the same manner.

Depending on the shape of the scanning line, it may not be necessary to read new pixel data when calculating pixel values, or it may be necessary to read two or more rows of pixel data. These are adjusted by a timing control circuit (not shown) in response to a signal from the address storage circuit 11. If the final output signal of the solid-state imaging camera is a video signal, it is necessary to output pixel data of one line at a fixed time interval. In some cases, the line memory 9 is further provided with a buffer memory for timing adjustment. It is possible.

Next, the interpolation processing performed in the interpolation circuit 12 will be described with reference to FIG.

In FIG. 8, reference numeral 51 denotes a scanning line, and 52 ₁ , 5
2 ₂ are the pixels of each scan line. Also, 53 ₁ , 5
3 _2, ..., 53 ₅ is the pixel of the line memory 9.

[0054] When calculating the value of a pixel with respect to the scanning line 51, the position of the pixel 52 _1, 52 ₂ of the scanning line is a line memory 9
Since different pixel 53 _{1-53 5} position, it is necessary to calculate the value as an interpolation value. Most simply give a recent pixel 52 _1, 52 ₂ of the value of the value beside the pixel scanning lines from among the pixels 53 ₁ to 53 ₅ of the line memory 9. That is,
Pixel 52 _1, 52 ₂ of the value of scan lines each of which the value of pixel 53 _4, 53 ₇ of the line memory 9. In the case of this processing, if the address is appropriately determined by the address storage circuit 11, the interpolation processing is performed at the time of reading from the line memory 9, and the special interpolation circuit 12 is not required.

Another method of approximation is a method of calculating an interpolation value by linear approximation from four pixels of the adjacent line memory 9. That is, the computation of the pixel 52 _1, 52 ₂ of the value of the scan lines, the pixel 53 ₁ of each line memory 9, 53 _2, 5
3 _4, 53 ₅ and 53 _2, 53 _3, 53 _5, 53 ₄ 4
Each pixel is sent to the interpolation circuit 12, and the interpolation is performed using linear approximation.

As a method of approximating the value, there is a "cubic convolution method". In this method, interpolation is performed by using a cubic spline curve from the values of neighboring pixels. In this case, the value of 16 neighboring pixels is required for one pixel calculation.

In FIG. 2, the output of the interpolation circuit 12 is sent to a video signal processing circuit 13, where it is converted into a signal of a predetermined format such as an NTSC signal and a high definition signal. The synchronization signal is supplied from the synchronization signal adding circuit 14 to the video signal processing circuit 13 to form a final video signal. Output video signal 15 from video signal processing circuit 13
Is displayed on a monitor according to the configuration of the entire system, and is sent to the next processing circuit.

Next, the distortion correction processing will be described with reference to FIG.

Reference numeral 61 denotes an example of an object. 62 is the image obtained by the imaging zoom lens,
The charge pattern on the CCD 10 has the same shape. 63 is an image based on the output video signal.

In FIG. 9, the relationship between the scales of the three figures is exaggerated so as to be different from the actual one.

The image 62 is distorted with respect to the object 61 due to the distortion of the imaging zoom lens 23. However, since the aberration correction is performed electrically as described above, it is shown that pixels similar to the original object 61 of the image 63 by the output video signal 15 can be obtained.

(Second Embodiment) FIG. 10 is a diagram showing an example of the optical performance of the imaging zoom lens used in the second embodiment of the present invention.

Here, the distortion of the imaging zoom lens used in the second embodiment is very large at the wide-angle end, has substantially the same amount of aberration at the telephoto end and at the middle, and has a focal length from the middle to the telephoto end. But the distortion is monotonically changing. Therefore, in this embodiment, distortion correction is performed only near the wide-angle end.

FIG. 11 is a diagram showing an example of a change in distortion due to a shooting distance near the wide-angle end. When shooting at infinity from the left, the distortion at the object distance of 3 m and the shortest shooting distance (1.2 m) is shown. is there.

It can be seen that even with the same focal length, the fluctuation of distortion due to the shooting distance is large. Thus, in the second embodiment, as described below, not only the focal length information but also the photographing distance information is used as the distortion aberration correction determination information.

FIG. 12 is a block diagram of a focal length and photographing distance detecting section of the solid-state imaging camera according to the second embodiment of the present invention. Other configurations are the same as those in FIG. 2 and thus are omitted here.

In FIG. 12, reference numeral 101 denotes a first group lens (focus lens) having a focal position adjusting function, 102 denotes a second group lens (variator lens) having a zooming function,
Reference numeral 103 denotes a third group lens (compensator lens) having a function of correcting a focal position, and 104 denotes a fourth group lens having an image forming function.
At 4, an imaging zoom lens is formed.

Reference numeral 105 denotes a detector for detecting the position of the variator lens 102, reference numeral 106 denotes a focal length detection circuit which calculates the focal length from the position of the variator lens 102, and sends focal length information to the CPU 16, and reference numeral 107 denotes the position of the focus lens 101. A detector 108 for detecting a photographing distance is a photographing distance detecting circuit that calculates the photographing distance from the position of the focus lens 10 and sends the photographing distance information to 16 CPUs.

FIG. 13 is a flowchart showing the operation of the solid-state imaging camera, and the operation will be described below. [Step 111] The photographing operation is started. [Step 112] The focal length is detected via the focal position detection circuit 106, and the current focal length information is obtained. [Step 113] It is determined whether or not the focal length information is within a predetermined distortion correction range near the wide angle end. Then, if it is within the distortion correction range, step 114
Go to step 115, otherwise go to step 115. [Step 114] Since the current focal length information of the imaging zoom lens (variator lens 102) is within the distortion aberration correction range, the variable SW2 is turned on. As a result, the switch SW1 is turned on, and the signal from the CCD 10 is connected to the amplifier 6 side. And step 11
Proceed to 6. [Step 115] Since the current focal length information of the imaging zoom lens is outside the distortion correction range, the variable SW2 is turned off. As a result, the switch SW1 is turned off, and the signal from the CCD 10 is directly transmitted to the video signal processing circuit 13.
Connected to the side. Then, the process proceeds to step 117. [Step 116] The current photographing distance information is detected via the photographing distance detecting circuit 108. Next, it is determined where the photographing distance falls within a predetermined photographing distance zone, and this is stored as a variable SW3. I do. Then, the process proceeds to step 117.

Here, specifically, when the distance is short, the variable SW3 is set to 1; when the distance is intermediate, the variable SW3 is set to 2;
SW3 = 3 is stored. [Step 117] Determine whether the variable SW2 is ON or OFF. If the variable SW2 is ON, the process proceeds to Step 118; [Step 118] Here, from the amplifier 6 to the interpolation circuit 1
Activate the distortion correction circuit formed by
The signal from the CCD 10 and the photographing distance data (variable SW
(3 signal types), distortion correction is performed based on the address information selected according to (3), and the process proceeds to step 119. [Step 119] Here, the video signal processing circuit 13
To operate the distortion correction circuit or the CCD 10
A video signal is generated based on the signal from the CPU, and a video signal is output. Then, the process proceeds to step 120. [Step 120] It is determined whether or not the operation of the zoom mechanism has been performed. If the operation has been performed, there is a possibility that the focal length has changed due to the operation of the zooming mechanism after outputting the video signal. Returning to step 112, the focal length information is newly detected, and the operation after step 113 is performed. If the zoom mechanism is not operating, the process proceeds to step 121. [Step 120] It is determined whether the variable SW2 is ON (= the focal length is within the distortion correction range) and the focus adjustment mechanism is operating.
The process proceeds to step 6 and the above-described operation after step 116 is performed. On the other hand, if the condition is other than the above, the process proceeds to step 117, and the operation after step 117 is performed.

The above operation is repeated to perform photographing.

According to the above-described first and second embodiments, at the time of optical design, the photographing conditions for performing correction at the time of photographing are configured to be limited to a very small part of the entire photographing pattern. Since the imaging position of the zoom lens during shooting is detected and the aberration generated by the imaging zoom lens is corrected only when correction is necessary, that is, only when the distortion is within the distortion correction, a signal processing circuit during shooting. Can be reduced in size, and the signal processing capacity during shooting can be afforded. Also, the number of imaging zoom lenses is small, and a lightweight and compact design is possible, so that a cheaper and smaller solid-state imaging camera can be obtained.

(Third Embodiment) FIG. 5 is a schematic diagram showing an image pickup zoom lens according to a third embodiment of the present invention.

In FIG. 5, reference numeral 21 denotes an object plane;
Is an example of an object. An imaging zoom lens 23 includes the lens groups shown in FIG. 24 is an image plane, 2
5 is an image.

The object 22 on the object plane 21 is formed on the image plane 24 by the imaging zoom lens 23 to form an image 25.
The CCD 216, which is a solid-state imaging device to be described later,
5 is arranged on the image plane 24 for photoelectric conversion. In the imaging zoom lens 23, distortion (hereinafter referred to as distortion) is set to be larger than a normal allowable value. Therefore, the image 25 is distorted as compared with the object 22 as illustrated.

However, in the lens design, as is well known, if a certain aberration value is allowed to be larger, it is easier to correct other aberrations, and the imaging zoom lens 23 can be reduced in size, the number of lenses can be reduced, and inexpensive glass can be used. Use of materials and the like can be achieved.

FIG. 14 is a block diagram showing a schematic configuration of a solid-state imaging camera provided with the above-described imaging zoom lens.

Reference numeral 201 denotes a solid-state image sensor (image sensor)
The photoelectric conversion unit 202 of the CCD 216 is an example of an image pattern and is formed on the photoelectric conversion unit 201. Reference numeral 203 denotes a storage unit of the CCD 216, and reference numeral 204 denotes a charge pattern. Reference numeral 205 denotes a shift register, and a CCD 216 is formed by the photoelectric conversion unit 201, the storage unit 203, and the shift register 205.

Reference numeral 206 denotes an amplifier, and 207 denotes S / H (S / H).
H) A circuit 208 is an analog / digital (A / D) converter. 209, a line memory;
6 has the capacity to store several digits of output. Reference numeral 210 denotes a lens state signal. The lens state signal 210 indicates a current state of the imaging zoom lens 23, and includes information on a zoom state, a focus state, a zoom speed, and the like. Reference numeral 211 denotes an address storage circuit, which outputs address information for reading from the line memory 209. 212 is an interpolation circuit. 213 is a video signal processing circuit, 214 is a synchronization signal adding circuit, and 215 is an output video signal.

The operation of the above element circuits is controlled by a timing control circuit, but the control circuit, control signals, and the like are not shown for simplicity.

Next, the operation will be described.

In FIG. 14, the signal of the pixel of the CCD 216 read from the shift register 205 is
After being amplified at 06, it is sent to the S / H circuit 207, where it is held. Further, the output signal of the S / H circuit 207 is digitized by an A / D converter 208, sent to a line memory 209, and stored therein. The line memory 209 stores the CCD 216 before starting reading.
Are stored for several lines. This is because a pixel signal is read out according to a curved scanning line, and this scanning line extends over several rows of pixels. Lens state signal 21
When 0 is input to the address storage circuit 211, the address storage circuit 211 can know the current lens state.

The address storage circuit 211 has a ROM
(Read-only memory), and stores shape data of scanning lines corresponding to the lens state. The shape data of the scanning line may be in the form of directly sampling the scanning line, or in the form of a coefficient obtained by performing an appropriate function approximation. Scan line shape data corresponding to these lens states is obtained at the time of designing the imaging zoom lens 23 or at the time of optical measurement after trial production.

When the zoom is stopped, the address storage circuit 211 reads the data in accordance with the data in the ROM and the lens state, thereby generating an address for reading the pixel signal in the line memory 209. This signal is sent to the video signal processing circuit 213 via the path A by the CCD 216.
Are corrected and output. Since the positions of the pixels obtained by the CCD 216 generally do not match, interpolation is necessary for the positions of the pixels on the curved scanning line. Therefore,
Data of several pixels is read from the line memory 209 and sent to the interpolation circuit 212, where the value of one pixel on the scanning line is calculated.

FIG. 15 is an explanatory diagram showing the distortion correction processing.

In FIG. 15, reference numeral 231 denotes an example of an object.
An image 232 is obtained by the imaging zoom lens 23. The charge pattern on the CCD 216 has the same shape. 233 is the output video signal 1
5 is an image according to FIG.

In FIG. 15, the relationship between the scales of the three figures is exaggerated so as to be different from the actual one.

With respect to the object 231, the image 232 is distorted due to the distortion of the imaging zoom lens 23. However, since the aberration correction is performed electrically as described above, it is shown that an image similar to the original object 231 of the image 233 based on the output video signal can be obtained.

During the zoom operation, as described above, the data for correcting the image distortion in the ROM data is not used, and therefore, no interpolation is performed, and the distorted image itself on the CCD 216 is output according to the path B.

The above-described distortion correcting operation will be described with reference to the flowchart of FIG. [Step 241] A photographing operation is started. [Step 242] Zoom ON / OFF is determined. If the signal is ON, the distortion correction is not performed in the row WA, so that the process remains at this step. On the other hand, if it is OFF, the process proceeds to step 243 to perform distortion correction. [Step 243] The zoom position and the focus position are detected, and the process proceeds to Step 244. [Step 244] Shape data of the scanning line corresponding to the above lens state is extracted, and the process proceeds to step 245. [Step 245] Interpolation processing is performed based on the scan line shape data to correct distortion.

Although distortion has been described as an example of the geometric distortion, another geometric distortion may be used.

When the zoom is ON, the image on the CCD 216 may be directly output to the video signal processing circuit 213 by an analog circuit.

According to the third embodiment, since the distortion correction is not performed during zooming, the arithmetic processing can be simplified and the zooming can be performed quickly.

(Fourth Embodiment) FIG. 17 is a flowchart showing a distortion correction operation of a solid-state photographing camera according to a fourth embodiment of the present invention, and FIG. 18 is a view for explaining the calculation of a correction amount in step 253 in FIG. FIG.

When the zoom is OFF, when the focal length is f = Z, distortion correction is performed through an interpolation circuit using scanning line shape data based on the lens state at that time.

However, when the zoom is ON, the correction amount f (Z ′) at the focal length Z ′, which will change when Δt has elapsed from the current focal length Z due to zooming, is:
Assuming that the zoom speed is v and the distortion correction calculation processing time is Δt, Z ′ = Z + v · Δt is obtained in advance, and the correction is simultaneously performed when the focal length Z ′ is reached by zooming.

The operation when the zoom is ON is shown in steps 251 to 254 in FIG.

By performing such control, it is possible to solve the unnaturalness of the image due to the distortion correction not being able to catch up with the zoom speed at the time of zooming without delaying the zoom speed.

According to the fourth embodiment, since the distortion is corrected based on the zoom speed during zooming, a natural image can be obtained in real time.

[0100]

As described above, according to the present invention, according to the present invention, an imaging zoom lens formed by concentrating distortion only at a part of an imaging position, and a detection method for detecting the imaging position of the imaging zoom lens And geometric distortion of an image caused by the imaging zoom lens when the detection means detects that the imaging position of the imaging zoom lens during imaging is within a position having large distortion. A correction means for correcting by reading the image data of the solid-state imaging device based on geometric deformation, to form an imaging zoom lens by focusing the distortion only at some imaging positions during optical design, When the imaging position of the imaging zoom lens at the time of shooting is within the distortion, geometric distortion of an image caused by the imaging zoom lens And it is to perform the distortion correction image data is read out of the solid-state image pickup device along the geometric deformation.

Therefore, the image quality is good, and the cost can be reduced not only in the imaging zoom lens but also in the circuit scale.

Further, according to the present invention, there is provided a control means for switching the correction of the geometric distortion between when the zooming operation is not performed and when the zooming operation is not performed. Or the operation of correcting geometric distortion is performed using the zooming speed information.

Therefore, the zoom speed is increased, and
The output image can be made natural.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating optical performances of an imaging zoom lens and a general imaging zoom lens according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a solid-state imaging camera according to the first embodiment of the present invention.

FIG. 3 is a mechanism diagram illustrating an imaging zoom lens and a focal length detection unit of the solid-state imaging camera in FIG. 2;

FIG. 4 is a flowchart illustrating an operation of the solid-state imaging camera in FIG. 2;

FIG. 5 is a schematic diagram for explaining the operation of the imaging zoom lens of FIG. 2;

FIG. 6 is a schematic diagram showing a relationship between a pixel and an image of the CCD in FIG. 2;

FIG. 7 is a diagram illustrating a relationship between pixels and scanning lines of the line memory of FIG. 2;

FIG. 8 is a diagram for explaining an interpolation process in the interpolation circuit of FIG. 2;

FIG. 9 is a diagram for explaining a distortion correction process according to the first embodiment of the present invention.

FIG. 10 is a diagram illustrating an example of optical performance of an imaging zoom lens used in a second example of the present invention.

FIG. 11 is a diagram illustrating an example of a change in distortion due to a shooting distance near a wide-angle end of an imaging zoom lens used in a second example of the present invention.

FIG. 12 is a mechanism diagram showing respective focal length and shooting distance detection units of the solid-state imaging camera according to the second embodiment of the present invention.

FIG. 13 is a flowchart illustrating an operation of the solid-state imaging camera in FIG. 12;

FIG. 14 is a block diagram illustrating a schematic configuration of a solid-state imaging camera according to a third embodiment of the present invention.

FIG. 15 is a diagram for describing distortion correction processing according to a third embodiment of the present invention.

FIG. 16 is a flowchart illustrating a distortion correction operation of the solid-state imaging camera according to the third embodiment of the present invention.

FIG. 17 is a flowchart illustrating a distortion correction operation of the solid-state imaging camera according to the fourth embodiment of the present invention.

FIG. 18 is an explanatory diagram of correction amount calculation in step 253 of FIG. 17;

[Explanation of symbols]

 9, 209 Line memory 10, 216 CCD 11, 211 Address storage circuit 12, 212 Interpolation circuit 13, 213 Video signal processing circuit 16 CPU 23 Imaging zoom lens 76 Focus position detection circuit 108 Shooting distance detection circuit

Continuation of front page (56) References JP-A-4-304786 (JP, A) JP-A-4-61570 (JP, A) JP-A-4-23575 (JP, A) JP-A-2-252375 (JP) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H04N 5/228

Claims (4)

(57) [Claims] An imaging zoom lens configured to concentrate distortion only at a part of an imaging position; a solid-state imaging device that photoelectrically converts an image formed by the imaging zoom lens; A detecting means for detecting an imaging position, and an imaging position generated by the imaging zoom lens when the imaging position of the imaging zoom lens during imaging is within a position having a large distortion. The geometric distortion of the image,
A solid-state imaging camera comprising: correction means for correcting the image data of the solid-state imaging device by reading the image data based on geometric deformation. 2. An image pickup zoom lens, and a solid-state image pickup device for photoelectrically converting an image formed by the image pickup zoom lens, wherein geometrical distortion of an image caused by the image pickup zoom lens is reduced by the solid-state image pickup device. A solid-state imaging camera for correcting by reading out the image data based on geometric deformation, wherein a control means for switching the above-mentioned correction between when the zooming operation is not performed and when the zooming operation is not performed is provided. camera. 3. The solid-state imaging camera according to claim 2, wherein the control unit is a unit that does not perform a geometric distortion correction operation during a zooming operation. 4. The solid-state imaging camera according to claim 2, wherein the control unit performs a geometric distortion correction operation using the zooming speed information during the zooming operation.