JPH0886622A - Apparatus for measuring shape - Google Patents

Abstract

PURPOSE: To improve the measuring accuracy by setting a driving timing means which performs correction, before a driving signal for driving a polarizing/ illuminating device is transmitted, with taking an actual deflection angle of the device into consideration. CONSTITUTION: A driving amplifier 11 of a deflection angle control part S transmits a driving signal to a polarizing/illuminating device 3 so that the whole measuring area is deflected and scanned within the photographing time of one frame by a CCD camera 6. A timing circuit 13 generates a driving pattern read signal synchronously with the image take timing of the camera 6, thereby, a driving pattern memory 12 transmits a driving instruction to the amplifier 11. A stripe pattern on an object Q to be measured which is photographed by the camera 6 is, via an operational device 10, stored in a space memory 16 together with deflection angle data supplied from the memory 12. Three dimensional coordinates of each point on the surface of the object Q are operated based on the data, and the shape is hence measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring apparatus for measuring a three-dimensional shape of an object to be measured in a non-contact manner by using optical means. More specifically, the invention relates to driving a scanner and a blinking pattern of laser light. The present invention relates to a shape measuring apparatus characterized in that measurement accuracy is improved by shortening the measurement time by correcting the measurement.

[0002]

2. Description of the Related Art Conventionally, a spatial coding method is known as one of typical optical shape measuring methods. The spatial coding method is one of the active measurement methods in which a measuring device has a light projecting device and measures reflected light from a measurement target of projected light.
As an example of a conventional shape measuring apparatus using the spatial coding method, the one disclosed in Japanese Patent Laid-Open No. 5-332737 will be described with reference to FIG. The shape measuring device of FIG.
A laser light source 87, a lens system 88 that shapes the laser light into a slit shape, a scanning device 89 that scans and irradiates the measured object Q with the shaped laser light, and a measurement object Q.
It has a CCD camera 81 for detecting the reflected light by and a control section 82 for controlling these.

The laser light source 87 is controlled to blink according to a predetermined rule. Therefore, on the surface of the measuring object Q, a striped pattern is formed between a portion irradiated with laser light and a portion not irradiated with laser light. Since the scanning of the laser light by the scanning device 89 is performed once within the accumulation time of one frame of the CCD camera 81, the stripe of the measurement object Q is included in the image data of one frame. Pattern data is accumulated. Then, when scanning is performed a plurality of times with different blinking patterns, a plurality of different striped pattern data are stored for each spatial code. Based on these striped pattern data, the arithmetic unit incorporated in the control unit 82 calculates the coordinates of the point on the measurement object Q corresponding to each pixel using the principle of triangulation, and the shape is measured. This shape measuring apparatus is intended to realize the downsizing of the apparatus and the quick measurement by blinking the laser light source 87 without the need for a mechanical pattern mask and its replacement operation.

[0004]

However, there are some problems that cannot be solved even by the above-mentioned shape measuring device. First, there is a problem of accuracy of angular deflection of laser light by the scanning device 89. Since the data of the deflection angle of the laser light is used to calculate the point coordinates on the measurement object Q, if there is an error in this, the calculated coordinates will also include an error, and the accuracy of shape measurement will decrease. Is. The scanning device 89 oscillates a reflecting mirror such as a galvano mirror or a polygon mirror in a predetermined pattern. However, in general, it is difficult to obtain a highly accurate oscillating motion, which causes such a problem. The accuracy of the swing angle of the reflecting mirror is considered to be low because of a non-linear relationship such as time delay with respect to driving due to inertia or other reasons.

FIG. 3 shows the relationship between the command value and the actual follow-up angle of the reflecting mirror. In FIG. 3, the horizontal axis represents time and the vertical axis represents angle. It can be understood that the follow-up value shown by the broken line is slightly behind in time the command value of the triangular waveform shown by the solid line. This time delay causes a non-negligible error factor of the deflection angle data, which leads to a decrease in accuracy of shape measurement.

Second, the spatial code is a reference plane for measurement (CC
There is a problem that they are not evenly spaced on the surface perpendicular to the optical axis of the D camera 81. This problem is not due to the non-linearity of the deflection angle described above. As shown in FIG. 10, the space code is a serial number assigned to a position on the reference plane for each division when the angular range of the laser light dispersed by the scanning device 89 is divided by the blinking interval of the laser light. That is. Needless to say, it is easiest to control the blinking of the laser light at equal intervals in time. In that case, the angles indicated by φ in FIG. The section width (l _{1 to} l _{6 in the} figure) is not constant. This is because the larger the space code number, the larger the distance from the scanning device 89 to the reference plane and the smaller the angle of intersection between the laser beam and the reference plane.

For this reason, in the reference plane, the distance C from the scanning device 89 is far from the distance C from the scanning device 89.
A difference occurs in the code width of the space code taken in by the CD camera 81. Therefore, the resolution of the spatial code data becomes coarser as the distance increases. Therefore, the spatial resolution cannot be uniquely determined in the visual field, and the effect of eliminating the need for the mechanical pattern mask cannot be fully utilized. There is also a problem in that the illuminance of the laser light becomes non-uniform within the field of view. As shown in FIG. 11, even if the spread angle ω of the slit-shaped laser light is constant, the scanning device 89
This is because there is a difference in the lengths d ₁ and d ₂ of the slit light depending on the distance from. Therefore, the brightness value captured by the CCD camera 81 is not constant within the field of view, and is not ideal as a measurement condition.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to calibrate an error in the deflection angle of laser light in advance and perform correction in consideration of the error. While performing coordinate calculation while controlling the blinking interval of the laser light so that it is evenly spaced on the reference plane for measurement and simplifying the calculation process, the measurement accuracy is improved and the spatial resolution and illuminance are uniform. It is to provide a simplified shape measuring device.

[0009]

In order to achieve the above object, a shape measuring apparatus (1) of the present invention comprises a laser light source for generating a slit-shaped laser beam by blinking it, and the laser beam to be measured. A shape measuring device comprising: a deflection irradiating device that deflects and scans an object to be measured placed on a surface; and an image capturing unit that captures an image of a stripe pattern generated on the surface of the object to be measured by the irradiation of the laser beam. Driving means for driving the deflection irradiation device so that deflection scanning by the irradiation device over the entire measurement range is performed in the imaging time of one frame of the imaging means, a drive signal by the driving means, and an actual deflection irradiation device Drive timing means for adjusting the transmission of the drive signal of the drive means so as to correct the non-linear relationship with the deflection angle, the image pickup data by the image pickup means and the deflection angle data. It is configured to have a shape operation means for calculating the shape of the measured object from the data.

Further, the shape measuring device (2) of the present invention is
The shape measuring apparatus according to (1), wherein the drive timing means measures the image data of the image pickup means when only the reference plane perpendicular to the optical axis of the image pickup means is measured in the absence of the object to be measured. , The amount of correction of the drive signal is calculated. Further, the shape measuring device (3) of the present invention is
The shape measuring apparatus according to (1) or (2), wherein the laser light source is such that stripe patterns generated on the surface of the object to be measured by the laser light are evenly spaced on a reference plane perpendicular to the optical axis of the image pickup means. Blinking timing means for controlling blinking light emission, and the shape calculation means determines the shape of the object to be measured by calculating the position coordinates in the spatial coordinate system from the imaging data and the deflection angle data. It is configured to do.

The shape measuring apparatus (4) of the present invention is
In the shape measuring apparatus according to (3), the flashing timing means has a stripe pattern on the reference surface based on image data obtained by the image capturing means when the reference surface is measured in the absence of an object to be measured. It is characterized by determining blinking patterns that are evenly spaced.

The shape measuring apparatus (5) of the present invention is
The shape measuring apparatus according to (3) or (4), wherein blinking pattern changing means for changing the blinking light emission pattern of the laser light source for each deflection scan, and the image pickup data by the image pickup means can be stored for a plurality of frames. Image data storage means, wherein the shape calculation means calculates the shape of the object to be measured based on a plurality of imaging data captured by different blinking patterns and deflection angle data corresponding to each of the plurality of imaging data. It is configured to do. The shape measuring apparatus (6) of the present invention is the shape measuring apparatus according to (5), characterized in that the blinking pattern changing means changes the blinking light emitting pattern of the laser light source according to a gray code.

[0013]

In the shape measuring device (1) of the present invention having the above-mentioned structure, the slit-shaped laser light generated by the blinking of the laser light source is deflected and scanned toward the object to be measured by the deflection irradiation device and is irradiated. It Then, the driving means drives the deflection irradiation device so that the deflection scanning is performed over the entire measurement range during the image pickup time of one frame of the image pickup means, so that the stripe pattern generated on the surface of the object to be measured is imaged by the image pickup means. It Here, since the drive timing means adjusts the transmission of the drive signal of the drive means so as to correct the nonlinear relationship between the drive signal by the drive means and the actual deflection angle of the deflection irradiation apparatus, the deflection irradiation apparatus Indicates ideal movement. Then, the shape calculation means calculates the shape of the object to be measured from the image pickup data of the image pickup means and the actual deflection angle data.

Further, in the shape measuring device (2) of the present invention,
The measurement is performed in the absence of the measured object, and the drive timing means calculates the correction amount of the drive signal from the data. Further, in the shape measuring apparatus (3) of the present invention, the blinking timing means controls the blinking emission of the laser light so that the stripe pattern is generated at equal intervals on the reference plane, and the shape calculating means is the imaging data and the deflection angle. The position coordinate in the spatial coordinate system is calculated from the data. Further, in the shape measuring apparatus (4) of the present invention, the measurement is performed in the absence of the object to be measured, and the blinking timing means determines the blinking pattern that produces the stripe pattern at equal intervals from the data.

Further, in the shape measuring apparatus (5) of the present invention,
The blinking pattern changing means changes the blinking light emitting pattern of the laser light source every deflection scanning, and the image data of a plurality of frames with different blinking patterns are stored in the image data storage means. Then, the shape calculation means calculates the shape of the object to be measured based on the plurality of imaging data and the corresponding deflection angle data. Further, in the shape measuring device (6) of the present invention, the blinking pattern changing means changes the blinking light emitting pattern of the laser light source according to the gray code.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the shape measuring apparatus of the present invention will be described in detail below with reference to the drawings. In Figure 1,
1 shows a schematic configuration of a shape measuring apparatus according to this embodiment. The shape measuring apparatus shown in FIG. 1 is roughly divided into an irradiation system L, an imaging system P, and a control system C.

The irradiation system L includes a laser light source 1 for generating a laser beam, a lens system 2 for shaping the laser beam generated by the laser light source 1 into a slit shape, and a laser beam shaped into the slit shape for deflection. A deflection irradiation device 3 for irradiating the measurement object Q so as to scan it is included. The laser light source 1 may be any known laser light source such as a semiconductor laser, a gas laser, a solid-state laser, and a liquid laser, but the semiconductor laser is most suitable from the viewpoint that the device can be downsized and high-speed switching can be performed. . The deflection irradiation device 3 reflects the laser light shaped into a slit shape by the lens system 2 toward the object to be measured Q, and swings or rotates to deflect and scan the reflected light 4 to measure the object to be measured. It has a function of scanning on Q. As the deflection irradiation device 3 having such a function, a known galvanometer mirror, polygon mirror, or the like can be considered.

The image pickup system P includes a CCD camera 6 for picking up an image of the laser beam 4 irradiated on the object to be measured Q, and the object to be measured Q.
And a CCD camera 6 and a filter 5 for removing noise components such as background light.
The filter 5 may be omitted when used in an environment where the background light is sufficiently small. The control system C is centered on the arithmetic processing unit 10, a blinking control unit F that controls blinking and emitting of laser light in the laser light source 1, a deflection angle control unit S that controls change scanning of the deflection irradiation device 3, and a CCD camera. 6
And an image processing unit D that stores and processes the image data of the object to be measured Q captured. The arithmetic processing unit 10 is a combination of a known CPU and a ROM or a RAM.

The blinking control section F includes an oscillation amplifier 7 that controls the laser oscillation of the laser light source 1, a blinking pattern memory 8 that stores data of a blinking signal that is transmitted to the oscillation amplifier 7, and a timing circuit 9 that controls blinking synchronization. Have The deflection angle control unit S includes a drive amplifier 11 that transmits a drive signal to the deflection irradiation device 3, and a drive pattern memory 1 that stores drive pattern data for causing the deflection irradiation device 3 to perform an optimum operation.
2 and a timing circuit 13 that controls driving synchronization. The image processing unit D includes an A / D converter 14 for digitizing image data captured by the CCD camera 6, memories 15, 16 and 17 for storing the data, and an arithmetic unit for performing a data comparison operation. 18 and a decoder 19 for generating position information.

Next, the operation of the shape measuring apparatus having the above-mentioned schematic structure will be described. First, the operation of the deflection irradiation device 3 and the deflection angle control unit S will be described. The drive amplifier 11 of the deflection angle control unit S has a basic function of transmitting a drive signal to the deflection irradiation device 3 so that deflection scanning is performed over the entire measurement range within an imaging time of one frame in the CCD camera 6. It is a thing. Here, the timing circuit 13 is CC
A drive pattern read signal is generated in synchronization with the video capture timing of the D camera 6. Based on this signal, the drive pattern memory 12 transmits a drive command to the drive amplifier 11.

This drive command is given by data which is calibrated and set in advance. This is because the actual follow-up angle of the deflection irradiation device 3 with respect to the command value from the drive amplifier 11 has a time delay as shown in FIG. 3, and therefore data for correcting this is required. Furthermore, the time delay of the deflection irradiation device 3 is theoretically difficult to accurately obtain due to the influence of the measurement frequency and individual differences, so it is necessary to calibrate and set in advance. The calibration method and the like will be described later.

FIG. 2 shows the relationship between the drive command including the correction for the time delay and the actual follow-up angle of the deflection irradiation device 3 for the case where the follow-up angle has a triangular waveform. In FIG. 2, as in FIG. 3, the horizontal axis represents time and the vertical axis represents angle. It can be understood that the command value is slightly advanced so that the follow-up angle indicated by the broken line has an ideal triangular waveform. In FIG. 2, an example in which the follow-up angle is a triangular waveform is shown. In the triangular waveform, except for the vicinity of the turning point, the change in deflection angle with time is constant, so that it is easy to grasp the deflection angle with time. This is because there is an advantage that almost the entire range from the turning point to the turning point can be effectively used for measurement. However, the deflection irradiation device 3 is controlled by the deflection angle control unit S.
Can be controlled with extremely high precision, so that it is possible to drive with a waveform other than a triangular waveform such as a sine waveform.

The advantages and disadvantages of employing a waveform other than the triangular waveform will be described. First, as an advantage, it is possible to reduce the influence of the inertia of the deflection irradiation device 3 at the turning point. With the triangular waveform, the angular acceleration at the turnaround point is very large, so even if a drive command that considers correction is performed,
This is because it is difficult to eliminate the occurrence of overshoot and hunting. If a sine waveform or the like is used, it will not be affected. In addition, in this shape measuring device, as will be described later, the laser light blinks so that the spatial codes are evenly spaced on the reference plane for measurement, but if a drive waveform other than a triangular waveform is adopted, in addition to this, the measurement field of view It is also possible to make the illuminance uniform. As shown in FIG. 11, even if the spread angle ω of the slit-shaped laser light is constant, the deflection irradiation device 3
Since the slit light lengths d ₁ and d ₂ differ depending on the distance from the distance, in order to make the luminance value taken in by the CCD camera 6 constant within the visual field, the deflection irradiation device is designed with a waveform taking this into consideration. This is because 3 must be driven.

On the other hand, the disadvantages of waveforms other than the triangular waveform are that the effective measurement range is narrow and that the grasping of the deflection angle over time is complicated. This is because the angular velocity is different near the turning point and near the midpoint. Therefore, not all the laser light can be effectively used for measurement. In actual measurement, the above-mentioned matters are taken into consideration to determine the optimum drive waveform. In the following description, various measurements are made with a triangular waveform unless otherwise specified.

Next, the operation of the laser light source 1 and the blinking control section F will be described. The oscillation amplifier 7 of the blinking control unit F has a basic function of oscillating the laser light source 1 to emit laser light. However, since it receives a blinking signal from the blinking pattern memory 8, the emitted laser light is emitted. Becomes a flashing light. This is because the laser beam 4 applied to the object to be measured Q is a blinking light in which light and dark are repeated so that a stripe pattern of light and dark is generated on the surface of the object to be measured Q. Since this stripe pattern is distorted by reflecting the shape of the object to be measured Q, the shape can be measured.
Therefore, the timing circuit 9 generates a blinking pattern read signal in synchronization with the image capturing timing of the CCD camera 6. Based on this signal, the blinking pattern memory 8 transmits a blinking signal to the oscillation amplifier 7 according to the stored predetermined blinking pattern data.

The blinking of the laser emission is performed in a pattern so that optimum space code data can be obtained. That is, when the blinking of the laser emission is set at equal intervals in time, the intervals on the reference plane for measurement do not become equal as shown in FIG. 10, so that complicated numerical conversion is required to determine the coordinates from the image data. This is because it is necessary to obtain the optimum spatial code, and the spatial resolution is not constant in the field of view. Therefore, as shown in FIG. 4, blinking pattern data is required so that equal intervals can be obtained on the reference plane for measurement. The distance on the reference plane indicated by l in FIG. 4 is represented by l = htan θ (1). Here, h is the distance from the deflection irradiation device 3 to the reference surface, and θ is the deflection angle of the laser light. Therefore, in order to make l evenly spaced, the blinking interval must be reduced in a region where θ is large. This state is shown in FIG. In FIG. 5, the vertical axis represents 1 and the horizontal axis represents time t.

This blinking pattern data can be theoretically calculated by a trigonometric function as shown in equation (1) when the deflection irradiation device 3 is driven with a triangular waveform.
In practice, it is better to calibrate and set the same as the drive pattern of the deflection irradiation device 3. The reason is that the entire amplitude of the angular deflection of the laser beam is not always used for measurement, and the deflection irradiation device 3 may be driven with a waveform other than the triangular waveform. The calibration method and the like will be described later. The measurement surface is divided into 2 n-th power of 128, 256, 512, etc. by such a blinking pattern of laser emission, and a stripe pattern is formed by assigning a bright or dark state to each.

The blinking pattern memory 8 has a large number of bright and dark patterns, and changes the bright and dark pattern every deflection scanning. Therefore, a different stripe pattern is projected on the object to be measured Q for each deflection scan. The change of the light-dark pattern is performed according to the gray code shown in FIG. A code other than the Gray code may be used as long as it has regularity, and a binary code (binary code) or the like is also conceivable. In this shape measuring device, any code having regularity and capable of identifying the spatial code can be adopted. However, the gray code is superior to other codes in that carry error due to noise is small because only one bit is bright / dark inverted at the time of shifting from one light / dark pattern to the next light / dark pattern. Further, this shape measuring device has an advantage that the adjustment can be performed on the order of several MHz, and is superior to the mechanical method in these points.

Next, the operation of the image pickup system P and the image processing section D will be described. The CCD camera 6 images the stripe pattern projected on the surface of the object to be measured Q. CC
The deflection irradiation device 3 is adjusted so as to perform deflection scanning over the entire measurement range within an image pickup time of one frame of the D camera 6. Therefore, the CCD camera 6 captures the entire stripe pattern on the surface of the object to be measured Q in one frame. If the driving pattern of the deflection irradiation device 3 and the blinking pattern of the laser have been calibrated, the image data of the CCD camera 6 is handled as follows.

The stripe pattern on the object to be measured Q imaged by the CCD camera 6 is binarized by the A / D converter 14 and then stored in the comparison memory 15. Then, it is stored as an arbitrary bit in the spatial memory 16 via the operation unit 18. Further, the deflection angle data supplied from the drive pattern memory 12 via the arithmetic processing unit 10 is also stored in the spatial memory 16. By repeating this for a plurality of frames, the spatial code data is stored in the spatial memory 16. Based on the spatial code data, the three-dimensional coordinates R (x, y, z) at each point on the surface of the object to be measured Q are calculated by using the principle of triangulation, and the shape is measured. The most important factor in the calculation of such three-dimensional coordinates is the determination of z, according to the following equation. z = {χ · H−f (LM−tan θ)} / (χ + f · tan θ) (2)

Here, χ is the position on the image pickup surface of the CCD camera 6, H is the distance from the measurement reference plane to the principal point of the lens, and f
Is the focal length of the imaging system, L is the distance parallel to the measurement reference plane between the deflection irradiation device 3 and the CCD camera 6, M is the distance from the measurement reference plane to the deflection axis of the deflection irradiation device 3, and θ is the deflection angle. ,
Respectively. Among these, f, H, L, and M are previously obtained at the time of calibration and are known. Therefore, z can be obtained from χ obtained from the imaging data and θ obtained from the spatial code. In this shape measuring apparatus, since the conversion memory 17 to which the value corresponding to θ is transferred from the spatial memory 16 and the value of χ is supplied from the decoder 19 is provided, the load on the arithmetic processing apparatus 10 is small.

Next, the calibration necessary before performing the shape measurement with this shape measuring apparatus will be described. As described above, the calibration is performed to optimize the driving of the deflection irradiation device 3 and the blinking pattern of laser emission. The operation flow of calibration is shown in the flowcharts of FIGS. The calibration measurement is performed on the reference surface without placing the object to be measured Q.
The reference plane is a plane perpendicular to the optical axis of the CCD camera 6. FIG. 6 is a flow of drive pattern calibration. First, in step (hereinafter referred to as “S”) 1, the drive pattern data of the deflection irradiation device 3 is written. This writing is performed from the arithmetic processing unit 10 to the drive pattern memory 12. The drive pattern written at this time includes various patterns such as the triangular waveform pattern and the sine waveform pattern as described above, but it is the pattern before considering the correction.

Next, in S2, the light and dark pattern data for blinking the laser light is written. This writing is performed from the arithmetic processing unit 10 to the blinking pattern memory 8. The pattern written at this time is before correction is taken into consideration. Then, in S3, the laser light is emitted and deflected. At this time, the driving pattern of the deflecting irradiation device 3 and the blinking light and dark pattern are written in S1 and S2, and both are performed in synchronization with the image data acquisition by the CCD camera 6. At this time, a stripe pattern is generated on the reference surface and is taken in as brightness data by the CCD camera 6 (S4). The imported data is A
It is binarized by the / D converter 14.

In S5, it is determined whether 8-bit video data has been fetched. If 8 bits have not yet been fetched (S5: No), the process returns to S3 to continue data acquisition. If 8 bits have been captured (S
5: Yes), the process proceeds to S6, and the delay amount of driving the deflection irradiation device 3 is calculated. The drive delay is calculated by comparing the video data captured in S3 to S5 with the drive pattern data written in S1.

In S7, it is determined whether the drive delay calculated in S6 is less than or equal to a predetermined allowable value. If the allowable value is exceeded and a non-negligible error occurs in the shape measurement (S7: No), the process proceeds to S8. In S8, correction data for correcting the delay amount is created, and the drive pattern memory 1
Write to 2. Then, the process returns to S3, and the measurement after S3 is performed again according to the corrected drive pattern data. When the delay amount is less than or equal to the predetermined allowable value in S7 (S7: Ye
s), since it indicates that the drive calibration is completed, the process proceeds to the next step of blink calibration.

FIG. 7 shows a flow of blink calibration. When the flashing calibration is started, first in S9, the code pattern of the highest resolution of the flashing memory 8 is written in the flashing pattern memory 8. The maximum resolution at this time is
It means the highest resolution as a memory and is smaller than the pixels of the CCD camera 6. The code pattern at this time is arbitrary. Then, in S10, laser irradiation is performed bit by bit. The laser irradiation is performed while driving the deflection irradiation device 3 and in synchronization with the image data acquisition by the CCD camera 6. The laser image generated at this time is the CCD camera 6
Are taken in as luminance data by the A / D converter 14
Is binarized by (S11).

In S12, it is determined whether 8-bit video data has been captured. If 8 bits have not yet been fetched (S12: No), the process returns to S10 to continue data acquisition. If 8 bits have been fetched (S12: Yes), the process proceeds to S13, and it is determined whether or not all the data up to the maximum resolution of the memory has been fetched. If the maximum resolution has not yet been reached (S13: No), the process returns to S10 to continue data acquisition. When the maximum resolution is reached (S13: Yes),
Proceed to S14. In S14, a correction table for laser blinking is created based on the captured data. When new blinking pattern data is created based on this correction table and written in the blinking pattern memory 8 (S15), the blinking calibration ends.

Thus, the driving of the deflection irradiation device 3 and the optimization of the blinking pattern of laser emission are completed. After that, when the actual measurement object Q is placed and main measurement is performed, highly accurate shape measurement can be performed based on the correction data obtained by the calibration.

As described in detail above, in the shape measuring apparatus of the present embodiment, the drive pattern memory 12 is provided, the calibration for correcting the actual drive characteristics of the deflection irradiation apparatus 3 is performed, and based on the correction data. DUT Q
Therefore, there is no error in driving the deflection irradiation device 3. Further, since the flashing pattern memory 8 is provided and the laser flashing pattern is calibrated, the object to be measured Q is measured in a flashing pattern in which bright and dark fringes due to the flashing are evenly spaced on the measurement reference plane. , The optimal spatial code is obtained, the resolution is constant within the field of view,
Moreover, the load on the arithmetic element for calculating the three-dimensional coordinates for determining the shape is small. Therefore, the shape of the object Q to be measured can be measured with high accuracy and speed. Further, by selecting the drive waveform of the deflection irradiation device 3, it is possible to make the illuminance uniform in the measurement visual field. It is needless to say that the above embodiments do not limit the present invention and various modifications and improvements can be made without departing from the gist of the present invention.

[0040]

As described above, in the shape measuring apparatus of the present invention, when the drive means for driving the deflection irradiation device transmits the drive signal, the drive for performing the correction in consideration of the actual deflection angle of the deflection irradiation device. Since the timing means is provided, the deflection angle of the deflection irradiation device is high and the shape measurement can be performed with high precision. The correction of the drive signal of the deflection irradiation device is performed according to the measurement condition by performing the calibration using the image pickup data of the background measurement in advance.

Further, since the shape measuring apparatus of the present invention is provided with the blinking timing means for controlling the blinking emission of the laser light source so that the stripe patterns formed on the surface of the object to be measured are evenly spaced on the reference plane for measurement, A constant spatial resolution can be obtained, the measured spatial code data can be easily converted into coordinate data, and the calculation time in the shape calculation means can be shortened. The optimization of the blinking light emission pattern is performed according to the measurement condition by performing calibration using the image pickup data of the background measurement in advance. Further, in the shape measuring apparatus of the present invention, the blinking pattern of the laser light is changed every deflection scanning, and the shape of the measured object is calculated based on a plurality of imaged data with different blinking patterns. Here, since the blinking pattern of the laser light is changed according to the gray code, no extra error component is generated due to carry of noise.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a shape measuring apparatus according to an embodiment.

FIG. 2 is a graph showing a relationship between a drive command of the deflection irradiation device and an actual follow-up angle in consideration of correction.

FIG. 3 is a graph showing the relationship between the drive command of the deflection irradiation device and the actual following angle when correction is not considered.

FIG. 4 is a diagram for explaining a state where the blinking of laser light is equidistant on the measurement surface.

FIG. 5 is a graph illustrating the relationship between the drive time and the distance of the irradiation position on the measurement surface from the reference point when the deflection irradiation device is driven with a triangular waveform.

FIG. 6 is a flowchart for calibrating a drive pattern of the deflection irradiation device.

FIG. 7 is a flowchart of calibration of a blinking pattern of laser light.

FIG. 8 is a diagram showing a Gray code.

FIG. 9 is a diagram showing a configuration of a conventional shape measuring device.

FIG. 10 is a diagram for explaining a state in which the deflection angles are not evenly spaced and are not evenly spaced on the measurement surface due to blinking of the laser.

FIG. 11 is a diagram illustrating a state in which the illuminance of laser light is not constant in the field of view due to the difference in the distance from the light source to the measurement surface.

[Explanation of symbols]

 1 Laser Light Source 2 Lens System 3 Deflection Irradiation Device 6 CCD Camera 7 Oscillation Amplifier 8 Flashing Pattern Memory 9 Timing Circuit 10 Arithmetic Processing Device 11 Drive Amplifier 12 Drive Pattern Memory 13 Timing Circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsunori Ishigure 3005 Hayasaki, Kita Sotoyama, Komaki City, Aichi Prefecture CKD Co., Ltd. (72) Inventor Yukio Sato 1-29, Mitsuki-cho, Chikusa-ku, Nagoya, Aichi Prefecture

Claims (6)

[Claims] 1. A laser light source for generating a slit-shaped laser beam by blinking, a deflection irradiation device for deflecting and scanning the laser beam toward an object to be measured placed on a surface to be measured, and the laser beam. In a shape measuring device having an image pickup means for picking up a stripe pattern formed on the surface of an object to be measured by irradiating the object, the deflection irradiation device performs deflection scanning over the entire measurement range in an image pickup time of one frame of the image pickup means. Adjusting the transmission of the drive signal of the drive means so as to correct the non-linear relationship between the drive means for driving the deflection irradiation device and the drive signal by the drive means and the actual deflection angle of the deflection irradiation device. And a shape calculation means for calculating the shape of the object to be measured from the image data obtained by the image pickup means and the deflection angle data. Shape measuring device to be collected. 2. The shape measuring apparatus according to claim 1, wherein the drive timing means measures only a reference plane perpendicular to an optical axis of the image pickup means in the absence of an object to be measured. A shape measuring device, characterized in that a correction amount of a drive signal is calculated from image pickup data by the means. 3. The shape measuring device according to claim 1 or 2, wherein the stripe patterns formed on the surface of the object to be measured by the laser light are equally spaced on a reference plane perpendicular to the optical axis of the image pickup means. The shape calculation means determines the shape of the object to be measured by calculating the position coordinates in the spatial coordinate system from the imaging data and the deflection angle data so that the shape calculation means controls the blinking light emission of the laser light source. A shape measuring device characterized by: 4. The shape measuring device according to claim 3, wherein the blinking timing unit is a stripe pattern based on image data obtained by the image capturing unit when measuring only the reference plane in the absence of an object to be measured. Determines a blinking pattern having equal intervals on the reference plane. 5. The shape measuring device according to claim 3 or 4, wherein a plurality of blinking pattern changing means for changing the blinking light emission pattern of the laser light source for each deflection scan, and a plurality of image data obtained by the image pickup means. An image data storage unit capable of storing frames, and the shape calculation unit calculates the shape of the object to be measured based on a plurality of imaging data captured by different blinking patterns and deflection angle data corresponding to each of the plurality of imaging data. A shape measuring device characterized by: 6. The shape measuring device according to claim 5, wherein the blinking pattern changing means changes the blinking light emitting pattern of the laser light source according to a gray code.