JP5256745B2 - 3D shape measuring device - Google Patents

Description

  The present invention relates to a three-dimensional shape measuring apparatus using a light cutting method.

  2. Description of the Related Art Conventionally, as a non-contact type three-dimensional measurement method, a light cutting method for obtaining a three-dimensional shape of an object by projecting pattern light onto a measurement object is known. Here, the reflectance of light changes greatly according to the shape and surface state of the measurement object. For this reason, when measuring a 3D shape using the light-cutting method and scanning the measurement object with the shooting conditions fixed, insufficient brightness and white stripes occur in the image of the pattern light, and the measurement accuracy is significantly reduced. Yes.

As an example of the countermeasure, Patent Document 1 discloses a configuration of an optical measurement device that generates an image of a light section line at an arbitrary scanning position by combining a plurality of images having different shooting conditions. .
JP 2002-357408 A

  However, since the technique of the above-mentioned Patent Document 1 generates a single pattern (light cutting line) image by combining a plurality of images, there is still room for improvement in that a high processing capability is required for the measuring device. there were.

  Therefore, an object of the present invention is to provide means capable of measuring the shape of a measurement object with high accuracy with relatively little processing capability in three-dimensional shape measurement by the light cutting method.

A three-dimensional shape measurement apparatus according to one aspect includes a light projecting unit that irradiates a measurement target with pattern light, an imaging unit, a luminance condition adjusting unit, a scanning unit, a control unit, and a calculation unit. . The imaging unit captures an image including a pattern formed on the surface of the measurement object by the pattern light. Brightness condition adjusting unit changes its parameters in response to parameters that affect the brightness of the plurality of predetermined image. The scanning unit relatively scans the measurement object and the irradiation position of the pattern light in a predetermined direction. The measurement object and the pattern light are relatively scanned in a predetermined direction. The control unit acquires a plurality of images at different scanning positions while scanning the pattern light irradiation position relative to the measurement object by the scanning unit, and the plurality of images are captured with different parameters. The image pickup unit and the luminance condition adjustment unit are controlled as described above. The arithmetic unit extracts, as a target image, an image in which the luminance level of pixels in a region where the pattern image is formed falls within a predetermined range from a plurality of images, and measures using the luminance information of the pattern corresponding to the target image Find the 3D shape of the object.

  In addition, what expressed operation | movement of the three-dimensional shape measuring apparatus of said one form as a three-dimensional shape measuring method, the program for making an apparatus perform this three-dimensional shape measuring method, etc. are the specific aspects of this invention. It is effective as

In the present invention, in the three-dimensional shape measurement by the light cutting method, the shape of the measurement object can be accurately measured with a relatively small processing capability.

<Description of Embodiment>
FIG. 1 shows a configuration example of a three-dimensional shape measuring apparatus according to an embodiment. 1 includes a stage 11 having a driving device 11a, a light projecting unit 12, an illumination unit 13, a camera unit 14, a first memory 15, a timing controller 16, and a pattern light extraction unit. 17, the luminance determination unit 18, the subpixel calculation unit 19, the point cloud data generation unit 20, the imaging condition calculation unit 21, the luminance control unit 22, the operation unit 23, the CPU 24, and the second memory 25. have. Here, the driving device 11a of the stage 11, the light projecting unit 12, the camera unit 14, the timing controller 16, the luminance determining unit 18, the point cloud data generating unit 20, the luminance controlling unit 22, the operating unit 23, and the second memory 25 are respectively provided. It is connected to the CPU 24 (note that signal lines between the luminance control unit 22 and the CPU 24 are not shown in FIG. 1).

  A measurement object 10 is placed on the upper surface of the stage 11. The stage 11 in this embodiment can be moved in the scanning direction (left-right direction in FIG. 1) by a driving device 11a having a motor and a screw feed mechanism, for example. Therefore, the position of the measuring object 10 can be adjusted with respect to the light projecting unit 12 and the camera unit 14 by moving the stage 11. The driving device 11a has an encoder built therein and outputs stage position information to the CPU 24.

  The light projecting unit 12 irradiates the measurement target 10 on the stage 11 with slit-shaped pattern light that intersects (preferably orthogonally) the scanning direction. Moreover, the illumination part 13 illuminates the whole measuring object 10 as needed.

  The camera unit 14 is an electronic camera that captures a two-dimensional image by photoelectric conversion, and is arranged with the optical axis inclined with respect to the pattern light irradiation direction of the light projecting unit 12. Then, the camera unit 14 captures an image including a pattern (hereinafter appropriately referred to as a light cutting line) formed on the surface of the measurement object 10 by the pattern light. The image output of the camera unit 14 is connected to the first memory 15. Note that the positions of the light projecting unit 12 and the camera unit 14 in this embodiment are both fixed.

  The first memory 15 is a buffer memory that temporarily stores image digital data in a pre-process of processing by the pattern light extraction unit 17. The output of the first memory 15 is connected to the pattern light extraction unit 17.

  The timing controller 16 is an IC that synchronously controls the operations of the first memory 15 and the pattern light extraction unit 17. The timing controller 16 supplies a control signal for controlling reading of image data to the first memory 15 and the pattern light extraction unit 17. The timing controller 16 outputs a timing signal indicating the timing of image processing to the CPU 24.

  The pattern light extraction unit 17 reads the image data in a pipeline manner for each horizontal line, and extracts the pixel position of the light section line included in the image from the luminance level of the pixel in each horizontal line. Then, the pattern light extraction unit 17 outputs luminance distribution data indicating the position of the pixel corresponding to the light cutting line and its luminance level in each image. The output of the pattern light extraction unit 17 is connected to the luminance determination unit 18 and the imaging condition calculation unit 21.

  Based on the luminance distribution data, the luminance determination unit 18 extracts a target image for obtaining the three-dimensional shape of the measurement target object 10 from the images captured by the camera unit 14. Specifically, the luminance determination unit 18 extracts an image in which the luminance level of the pixel corresponding to the light section line is within a threshold value range as a target image. Note that the threshold when the luminance determination unit 18 extracts the target image is determined based on the output characteristics of the camera unit 14.

  In addition, the luminance determination unit 18 is connected to the subpixel calculation unit 19. Then, the luminance determining unit 18 outputs the luminance distribution data of the target image to the subpixel calculating unit 19. Further, the luminance determination unit 18 outputs determination result data for identifying the target image to the CPU 24.

  The sub-pixel calculation unit 19 obtains a displacement (sub-pixel displacement) of pattern light that is equal to or higher than the pixel resolution of the camera unit 14 using the luminance distribution data of the target image. The sub-pixel calculation unit 19 performs the above-described calculation process using a known sub-pixel estimation algorithm. Further, the output of the sub-pixel calculation unit 19 is connected to the point cloud data generation unit 20.

  The point cloud data generation unit 20 uses the sub pixel displacement data of the light section line obtained from the luminance distribution data of the target image by the sub pixel calculation unit 19 to indicate point cloud data (3) indicating the three-dimensional shape of the measurement object 10 ( Spatial coordinate value data) is generated. The output of the point cloud data generation unit 20 is connected to a recording unit (not shown).

  The imaging condition calculation unit 21 performs luminance distribution analysis of the image using the luminance distribution data, and outputs a control signal based on the analysis result to the luminance control unit 22. For example, the imaging condition calculation unit 21 obtains imaging conditions to be applied in the main scan in the preliminary measurement performed prior to the main scan for generating the point cloud data. The imaging condition calculation unit 21 can also adjust the imaging condition by feeding back luminance distribution data during the main scanning.

  The brightness control unit 22 controls the light amount of the pattern light in the light projecting unit 12, the illumination light amount of the illumination unit 13, and the exposure time of the camera unit 14 based on the control signal input from the imaging condition calculation unit 21. In addition, the operation unit 23 receives various inputs including an instruction to execute three-dimensional shape measurement.

  The CPU 24 is a processor that comprehensively controls the operation of the three-dimensional shape measuring apparatus. For example, the CPU 24 performs preliminary measurement and main scanning according to a program. Further, the CPU 24 generates image management data indicating the correspondence between each image acquired in the main scan and the scan position of the measurement object 10. Further, the CPU 24 associates information indicating the target image with the image management data based on the determination result data.

  The second memory 25 stores image management data generated by the CPU 24. The second memory 25 stores a program executed by the CPU 24.

  Next, an example of point cloud data generation processing according to an embodiment will be described with reference to the flowchart of FIG. In the following example, the camera unit 14 captures a plurality of images while changing the imaging conditions during the main scan for generating the point cloud data. In FIG. 2, the three-dimensional shape of the measurement object 10 is obtained from the spatial center of gravity of the pattern light.

  Step S101: When the CPU 24 receives an instruction to perform three-dimensional shape measurement from the operation unit 23, the CPU 24 performs preliminary measurement of the measurement object 10. Specifically, the CPU 24 moves the stage 11 while irradiating pattern light from the light projecting unit 12, and the camera unit 14 captures a plurality of sample images of the measurement object 10 at different positions where the pattern light is superimposed. . Note that the number of frames of the sample image captured in the preliminary measurement is set to be smaller than the number of frames captured in the main scan described later. Then, based on a plurality of luminance distribution data generated from a series of sample images, the imaging condition calculation unit 21 has a plurality of imaging conditions (exposure time of the camera unit 14 and the amount of pattern light) for one cycle used in the main scan. ).

  Here, in the present embodiment, the description will be made on the assumption that an image is captured by alternately applying two types of imaging conditions (first imaging condition and second imaging condition) for one cycle during main scanning. . In the example of the present embodiment, both the first imaging condition and the second imaging condition have the same amount of pattern light, and the exposure time of the first imaging condition is set to four times the second imaging condition. Shall.

  Step S102: The CPU 24 returns the stage 11 to the initial position and starts a main scan of the measurement object 10. First, the brightness control unit 22 sets the imaging condition of the camera unit 14 to the first imaging condition. Then, the CPU 24 moves the stage 11 in the scanning direction while irradiating the pattern light from the light projecting unit 12. Note that the movement of the stage 11 continues until the main scanning is completed.

  Step S <b> 103: The camera unit 14 captures an image including a light cutting line formed on the surface of the measurement object 10 by the pattern light by applying the currently set imaging conditions. The image captured in S103 indicates the shape of the light section line at a predetermined scanning position when the measurement object 10 is scanned. The image data for one frame output from the camera unit 14 is stored in the first memory 15.

  Further, the CPU 24 records, in the second memory 25, image management data indicating the correspondence between the image captured in S103 and the scanning position of the measurement object 10 (in this case, the position of the stage 11).

  Step S104: The pattern light extraction unit 17 generates luminance distribution data indicating the position and luminance level of the pixel corresponding to the light section line using the data of the image captured in S103. Specifically, the pattern light extraction unit 17 sequentially reads data of the image captured in S103 from the first memory 15 for each horizontal line in accordance with the control signal of the timing controller 16.

  Next, the pattern light extraction unit 17 refers to the luminance value of each pixel in units of horizontal lines, and searches for high luminance pixels that have a peak luminance level in the horizontal line to be processed. As an example, the pattern light extraction unit 17 sets the pixel with the highest luminance in the horizontal line to be processed as the high luminance pixel. Thereafter, the pattern light extraction unit 17 extracts a high-luminance pixel and several pixels before and after it on the horizontal line to be processed, and indicates the position of the pixel extracted on each horizontal line and the luminance level of these pixels. Brightness distribution data is generated.

  Step S105: The luminance determination unit 18 refers to the luminance distribution data generated in S104, and determines whether or not the luminance levels of the pixels corresponding to the light cutting line are all within the threshold range. If the above requirement is satisfied (YES side), the process proceeds to S106. On the other hand, if the above requirement is not satisfied (NO side), the CPU 24 discards the luminance distribution data generated in S104 and proceeds to S109. In this case (NO side in S105), the data of the scanning position corresponding to the discarded luminance distribution data is lost in the final point cloud data.

  Here, the range of the threshold of the luminance level in S105 is based on the range in which the luminance level output with respect to the amount of light incident on the camera unit 14 has linearity, focusing on the output characteristics of the camera unit 14.

  FIG. 3 shows an example of output characteristics of the camera unit 14. The vertical axis in FIG. 3 indicates the luminance level value (16 bits: 0 to 65535) output from the camera unit 14. On the other hand, the horizontal axis in FIG. 3 indicates the exposure time when the camera unit 14 captures an image. In the output characteristics shown in FIG. 3, there is a knee region in which the slope of the output characteristics is nonlinearly reduced on the high luminance side (the portion where the luminance level exceeds 40000). When the luminance level output from the camera unit 14 is a value in the knee region, the linearity between the amount of light incident on the camera unit 14 and the luminance level is lost, so the accuracy when estimating the sub-pixel displacement is reduced. To do. Therefore, in the example of FIG. 3, the luminance determination unit 18 generates point cloud data using luminance distribution data having a luminance level of 40000 or less.

  Hereinafter, the gravity center calculation error when the output characteristics of the camera unit 14 are different will be described more specifically with reference to FIGS. FIG. 4 is a measurement example using the camera unit 14 having output characteristics that are linear up to the saturation level. On the other hand, FIG. 5 is a measurement example using the camera unit 14 having an output characteristic having a knee region on the high luminance side. In the example of FIGS. 4 and 5, the accurate value of the center of gravity position is 35.75. 4 and FIG. 5, the vertical axis represents the luminance level, and the horizontal axis of the graph represents the pattern light projection position. In the example of FIG. 5, the luminance level values corresponding to the encoder values 30, 40, and 50 are the output values of the knee region.

  As shown in FIG. 4, when the centroid calculation is performed using the measurement value of the camera unit 14 having output characteristics that have linearity up to the saturation level, the value of the calculation result of the centroid position is 35.78. On the other hand, as shown in FIG. 5, when the centroid calculation is performed using the measured value of the camera unit 14 having the output characteristic having the knee region on the high luminance side, the value of the calculation result of the centroid position is 35.69. From the above, it can be seen that when the centroid calculation is performed using the output value of the knee region, the error of the centroid position becomes large.

  Step S106: The luminance determination unit 18 sets the input luminance distribution data image as a target image. Then, the brightness determination unit 18 outputs determination result data indicating that the image currently being processed is the target image to the CPU 24. The CPU 24 records information indicating the target image in association with the image management data in the second memory 25.

  Step S107: The subpixel computing unit 19 obtains the subpixel displacement of the light section line using the luminance distribution data (S106) of the target image.

  Step S <b> 108: The point cloud data generation unit 20 performs a predetermined measurement of the measuring object 10 based on the subpixel displacement data (obtained in S <b> 107) of the light section line and the scanning position data input from the CPU 24. Point cloud data at the scanning position is generated. Then, the point cloud data generation unit 20 records the generated point cloud data in the recording unit.

  Step S109: The CPU 24 determines whether or not the main scanning is finished. When the main scanning is finished (YES side), the CPU 24 finishes a series of processes and shifts to a standby state. On the other hand, if the main scan is not completed (NO side), the process proceeds to S110.

  Step S110: The luminance control unit 22 executes switching of the imaging conditions that are currently set in accordance with an instruction from the CPU 24. In the example of the present embodiment, the brightness control unit 22 switches between the first imaging condition and the second imaging condition (exposure amount is ¼ of the first imaging condition). Thereafter, the CPU 24 returns to S103 and repeats the above operation. Thereby, at the next scanning position, the camera unit 14 captures an image under an imaging condition different from that of the previous scanning position. This is the end of the description of the flowchart of FIG.

  FIG. 6 shows an example of extraction of a target image in the main scan in one embodiment. In FIG. 6, for the sake of simplicity, the state of the luminance level in the same horizontal line (1H) for four frames is schematically shown. In FIG. 6, the first frame and the second frame correspond to portions where the surface reflectance of the measurement object 10 is low, and the third frame and the fourth frame correspond to portions where the surface reflectance of the measurement object 10 is high. To do.

  Each frame in the main scan corresponds to a light contour line at a different scanning position. The odd frames in the main scan are imaged under the first imaging condition with a long exposure time, and the even frames in the main scan are imaged under the second imaging condition with a short exposure time.

  In a portion where the surface reflectance of the measurement object 10 is low and the pattern light scattering is small, the luminance level of the first frame imaged under the first imaging condition is within an appropriate range, while the image is captured under the second imaging condition. In the second frame, the luminance gradation is buried due to insufficient light quantity. In this case, the luminance determining unit 18 excludes the second frame from the target image while using the first frame as the target image.

  In addition, in the portion where the surface reflectance of the measurement object 10 is high and the pattern light is scattered, white stripes occur in the third frame imaged under the first imaging condition, while the image captured under the second imaging condition. The luminance level of the 4 frames is within an appropriate range. In this case, the luminance determining unit 18 excludes the third frame from the target image while using the fourth frame as the target image. With the above processing, even when there is a portion where the surface reflectance of the measurement object 10 is greatly different, it is possible to generate point cloud data with high accuracy.

  Next, the effect in one embodiment is demonstrated. The three-dimensional shape measurement apparatus according to an embodiment sequentially captures images of light cutting lines while periodically changing imaging conditions at each scanning position during the main scanning. Then, the three-dimensional shape measuring apparatus extracts an image whose luminance level falls within a predetermined range as a target image, and generates point cloud data using luminance distribution data corresponding to the target image.

  Therefore, in one embodiment, the light cutting line projected on the measurement object 10 is imaged under a plurality of different imaging conditions, and the point level data is generated by excluding the image whose luminance level is outside the appropriate range. The three-dimensional shape of the measurement object 10 can be obtained with high accuracy by one main scan. In one embodiment, since complicated image processing such as image composition is not performed, the three-dimensional shape of the measurement object 10 can be accurately obtained with a smaller calculation load.

  Furthermore, in one embodiment, even when there is a place where the shape of the measurement object 10 is complicated and the surface reflectance is greatly different, it is possible to secure an image having a luminance level in an appropriate range at each place with a high probability. For this reason, it is possible to greatly suppress the possibility of occurrence of a part that cannot be measured or a part that has low measurement accuracy.

<Description of other embodiments>
FIG. 7 shows a configuration example of a three-dimensional shape measuring apparatus according to another embodiment. The three-dimensional shape measuring apparatus shown in FIG. 7 is a modification of the three-dimensional shape measuring apparatus shown in FIG. 1, and the same reference numerals are given to components common to both, and duplicate description is omitted.

  The three-dimensional shape measuring apparatus according to another embodiment shown in FIG. 7 obtains the three-dimensional shape of the measuring object 10 based on the time centroid of the pattern light. In the three-dimensional shape measuring apparatus in FIG. 7, the positions of the stage 11 and the camera unit 14 are fixed, and the position of the light projecting unit 12 is moved by the driving device 12a.

  Next, an example of point cloud data generation processing in another embodiment will be described. In the main scanning in the other embodiment, the CPU 24 causes the camera unit 14 to capture a plurality of images by periodically changing the imaging condition while moving the light projecting unit 12. For example, as in the above-described embodiment, an image may be captured by alternately switching two imaging conditions. Also in other embodiments, the luminance determination unit 18 generates point cloud data using data of a target image in which the luminance levels of the pixels corresponding to the light section line are all within the threshold range.

  Here, when attention is paid to one point (target pixel) of a plurality of images acquired under the same imaging conditions during the main scan, the target pixel is transmitted at the timing when the pattern light passes through the surface of the measurement object 10 in the range captured by the target pixel. The brightness level of becomes higher. Therefore, the three-dimensional shape measurement apparatus according to another embodiment calculates the time centroid of the luminance level of each pixel, and calculates the shape of the measurement object 10 from the pattern light incident position corresponding to the timing of the time centroid.

  Hereinafter, an example in which the time centroid is obtained using image groups having different imaging conditions will be described with reference to FIG. In the example of FIG. 8, for the sake of simplicity, it is assumed that images of 6 frames are captured by alternately switching two imaging conditions. At this time, it is assumed that the odd-numbered frames are imaged under the first imaging condition of the one embodiment, and the even-numbered frames are imaged under the second imaging condition of the one embodiment. Note that each graph in FIG. 8 shows a change in luminance level between three frames captured under the same imaging condition for the same target pixel.

  FIG. 8A shows the result of time centroid calculation using the luminance level of the odd frame imaged under the first imaging condition. On the other hand, FIG. 8B shows the result of time centroid calculation using the luminance level of the even frame imaged under the second imaging condition. Since the exposure time of the odd frame is four times longer than that of the even frame, the time center of gravity calculation (in the case of FIG. 8A) using the odd frame is particularly effective in a portion where the pattern light scattering is small. On the other hand, the time centroid calculation using even frames (in the case of FIG. 8B) is particularly effective in a portion where pattern light scattering is large.

  According to such another embodiment, the three-dimensional shape of the measurement object 10 is measured by temporal centroid calculation using images with the same imaging conditions and the luminance level in an appropriate range. Therefore, even when there is a place where the shape of the measurement object 10 is complicated and the surface reflectance is greatly different, the time center of gravity calculation is performed by applying the image group having the same imaging condition and the luminance level within the appropriate range. Thus, the three-dimensional shape of the measuring object 10 can be obtained with high accuracy.

<Supplementary items of the embodiment>
(1) In each of the embodiments described above, the preliminary scanning step may be omitted and the main scanning may be started from the beginning. Moreover, in the preliminary measurement of the said embodiment, the whole measurement object 10 may be imaged with the camera unit 14, and the surface reflectance of the measurement object 10 may be calculated | required by one imaging.

  (2) The combination of imaging condition parameters adjusted by the luminance control unit 22 is not limited to the above embodiments. For example, the luminance control unit 22 may periodically apply three or more types of imaging conditions during the main scan. Further, the brightness control unit 22 may adjust the light amount of the pattern light while keeping the exposure time of the camera unit 14 constant, or may change both the exposure time of the camera unit 14 and the light amount of the pattern light. . Further, the luminance control unit 22 may control the light amount of the illumination unit 13 that illuminates the entire measurement object 10.

  (3) In the above-described embodiment, the imaging condition calculation unit 21 may perform feedback control using the luminance distribution data acquired in the main scanning so that the imaging conditions in the subsequent main scanning become appropriate. Good.

  As an example, when the luminance level of the image acquired under the second imaging condition falls within an appropriate range, but the state where the luminance level of the image acquired under the first imaging condition deviates from the threshold range continues for a predetermined period, the imaging condition calculation The unit 21 changes the setting to perform imaging under the first imaging condition in the main scanning. After that, when the luminance level of the image acquired under the first imaging condition deviates from the threshold range, the imaging condition calculation unit 21 switches the first imaging condition and the second imaging condition alternately in the main scan and performs imaging. Return to the setting you want to make again. In this case, since the data of the image captured at an appropriate luminance level during the main scan increases, the measurement accuracy of the three-dimensional shape of the measurement object 10 is further improved.

  (4) In the three-dimensional shape measuring apparatus according to the above-described embodiment, the main scanning may be performed by fixing the position of the stage 11 and moving the camera unit 14 and the light projecting unit 12.

  Many features and advantages of the present invention will become apparent from the detailed description. It is intended that the scope of the claims extend to the features and advantages of the embodiments without departing from the spirit and scope of the claims. Further, those having ordinary skill in the art should be able to easily come up with any improvements and modifications, and limit the scope of the inventive embodiments herein to the configurations described and represented herein. There is no intention to do. Therefore, the scope of the present invention can be based on appropriate improvements and equivalents included in the scope disclosed in the embodiments.

The block diagram which shows the structural example of the three-dimensional shape measuring apparatus which is one Embodiment A flow chart showing an example of generation processing of point cloud data in one embodiment The figure which shows an example of the output characteristic of a camera unit Diagram showing an example of measurement using a camera unit with output characteristics that are linear up to the saturation level The figure which shows the example of a measurement using the camera unit of the output characteristic which has a knee area on the high luminance side The figure which shows the example of extraction of the target image in the main scanning in one Embodiment The block diagram which shows the structural example of the three-dimensional shape measuring apparatus in other embodiment. (A) The figure which shows the example of the time gravity center calculation using the odd frame imaged on the 1st imaging condition, (b) The figure which shows the example of the time gravity center calculation using the even frame imaged on the 2nd imaging condition

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Measurement object, 12 ... Light projection part, 13 ... Illumination part, 14 ... Camera unit, 17 ... Pattern light extraction part, 18 ... Luminance determination part, 19 ... Subpixel calculation part, 20 ... Point cloud data generation part, 21 ... Imaging condition calculation unit, 22 ... Luminance control unit, 24 ... CPU, 25 ... Second memory

Claims (9)

A light projecting unit that emits pattern light to the measurement object;
An imaging unit that captures an image including a pattern formed on the surface of the measurement object by the pattern light;
A luminance condition adjusting unit that changes the parameter in response to a predetermined parameter that affects the luminance of the image ;
Scanning means for relatively scanning the measurement object and the irradiation position of the pattern light in a predetermined direction;
While the irradiation position of the pattern light is scanned relative to the measurement object by the scanning unit, a plurality of images at different scanning positions are acquired, and the plurality of images are captured with the different parameters. A control unit for controlling the imaging unit and the luminance condition adjustment unit,
From the plurality of images, an image in which the luminance level of a pixel in the region where the pattern image is formed falls within a predetermined range is extracted as a target image, and the measurement target is extracted using luminance information of the pattern corresponding to the target image An arithmetic unit for obtaining a three-dimensional shape of an object;
A three-dimensional shape measuring apparatus comprising: The three-dimensional shape measuring apparatus according to claim 1,
The three-dimensional shape measuring apparatus, wherein the control unit periodically changes the parameter. In the three-dimensional shape measuring apparatus according to claim 1 or 2,
The three-dimensional shape measuring apparatus, wherein the scanning unit scans the light projecting unit and the imaging unit relative to the measurement object. In the three-dimensional shape measuring apparatus according to any one of claims 1 to 3,
The three-dimensional shape measuring apparatus, wherein the calculation unit extracts the target image in a range in which a correlation between a light amount incident on the imaging unit and the luminance level shows linearity. In the three-dimensional shape measuring apparatus according to any one of claims 1 to 4,
The luminance condition adjustment unit changes at least one of the light amount of the pattern light, the exposure time of the imaging unit, and the light amount of illumination light that illuminates the entire measurement object, and the three-dimensional shape measurement apparatus. In the three-dimensional shape measuring apparatus according to any one of claims 1 to 5,
The luminance condition adjusting unit determines a change amount of the parameter at the time of the scanning corresponding to the plurality of predetermined parameters based on a result of preliminary measurement performed prior to the scanning. A three-dimensional shape measuring device. The three-dimensional shape measuring apparatus according to any one of claims 1 to 6 ,
The three-dimensional shape measuring apparatus, wherein the calculation unit obtains a three-dimensional shape of the measurement object from a spatial center of gravity of the pattern light image. In the three-dimensional shape measuring apparatus according to claim 1 or 2,
The calculation unit obtains a three-dimensional shape of the measurement object from a time centroid of the intensity of the pattern light. The three-dimensional shape measuring apparatus according to claim 8,
The control unit adjusts the imaging condition and the luminance condition so as to obtain a plurality of images with a plurality of different parameter conditions for a region of the surface of the measurement target corresponding to an arbitrary pixel of the imaging unit. A three-dimensional shape measuring apparatus characterized by controlling a part.

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