JP2011153922A - Shape measurement apparatus and shape measurement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape measurement apparatus for measuring a three-dimensional shape of a target by a simple method using one type of a projection pattern. <P>SOLUTION: The shape measurement apparatus 1 is equipped with: a pattern projection section 10 for projecting a stripe pattern to a partial area of a target 5; an imaging section 20 for imaging the stripe pattern projected to the target 5; and a computer 40 for calculating a contrast distribution of an image of the stripe pattern on a predetermined line passing on a surface of the image, calculating a center position of the pattern projected area on the predetermined line based on the contrast distribution, and calculating a cross-sectional shape of the target 5, based on the center position obtained by a center position calculation while the predetermined line is moved along the surface of the image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a shape measuring apparatus and a shape measuring method for measuring the shape of a test object.

  A pattern projection method has been conventionally known as one of methods for measuring a three-dimensional shape of a test object with high accuracy without contact (see, for example, Non-Patent Document 1). In this pattern projection method, for example, a stripe pattern in which the light intensity distribution is arranged in black and white in one direction is projected on the entire surface of the test object, and the light intensity distribution of the stripe pattern is moved in the one direction by a quarter period. (By performing fringe scanning), four pattern images having different phases are acquired. The pattern projection method is a method for obtaining the phase of the fringe pattern at each point from the obtained four pattern images, calculating the height of the test object from the phase information, and determining the three-dimensional shape of the test object. is there.

Edited by Toru Yoshizawa, “Latest optical three-dimensional measurement (pp. 44-52)”

  By the way, in such a pattern projection method, when a fringe pattern is projected onto an object having a step on the surface, it is difficult to measure the amount of the step because the relationship between the fringe pattern at the top and the bottom of the step is unknown. Become. Therefore, it has been necessary to determine the three-dimensional shape of the test object by measuring the amount of the step using a method of projecting a plurality of fringe patterns having different fringe pitches (space coding method). In the pattern projection method, as described above, it is necessary to perform stripe scanning to acquire a plurality of pattern images, and also in this respect, it is necessary to sequentially project a plurality of stripe patterns. As described above, in the conventional pattern projection method, it is necessary to project a plurality of types of patterns in order to measure the three-dimensional shape of the test object. In addition, since the fringe pattern is projected onto the entire surface of the test object, the light emitted from the light source is irradiated onto the entire surface of the test object. However, there is a problem that a high performance is required for the projection lens (a projection lens having a small distortion is required).

  The present invention has been made in view of such problems, and provides a shape measuring apparatus and a shape measuring method capable of measuring the three-dimensional shape of a test object by a simple method using one kind of projection pattern. With the goal.

  In order to achieve such an object, a shape measuring apparatus according to a first aspect of the present invention includes a pattern projection unit that projects a projection pattern having a periodic light intensity distribution on a partial region of a test object, An imaging unit that images the projection pattern projected onto the test object by a pattern projection unit, and an image of the projection pattern that is captured by the imaging unit, the image of the image on a predetermined straight line passing through the image surface A center calculation unit that calculates a contrast distribution or an intensity distribution, and calculates a center position of a pattern projection region on the predetermined line based on the contrast distribution or the intensity distribution; and the center calculation unit converts the predetermined line into the image A shape calculation unit that calculates a cross-sectional shape of the test object based on each of the center positions acquired by calculating the center position while moving along the surface Characterized in that it comprises a.

  In order to achieve the above object, the shape measuring apparatus according to the second aspect of the present invention includes a pattern projection unit that projects a projection pattern having a periodic light intensity distribution onto a partial region of a test object. And an imaging unit that images the projection pattern projected onto the test object by the pattern projection unit, and a predetermined line on a predetermined straight line that passes through the image surface in the image of the projection pattern captured by the imaging unit. A central calculation unit that calculates a maximum luminance value distribution of the image in the region and calculates a center position of the pattern projection region on the predetermined line based on the maximum luminance value distribution; and A shape calculating unit that calculates a cross-sectional shape of the test object based on each of the center positions obtained by calculating the center position while moving the straight line along the image surface. And wherein the door.

  In order to achieve the above object, the shape measuring method according to the third aspect of the present invention projects the first projection pattern having a periodic light intensity distribution onto a partial region of the test object. A contrast distribution of the image on a predetermined straight line in a step, a second step of capturing the projection pattern projected on the test object, and an image of the projection pattern captured in the second step. A third step of calculating, a fourth step of calculating a center position of the pattern projection region on the predetermined straight line based on the contrast distribution calculated in the third step, and A fifth step of calculating a cross-sectional shape of the test object based on each of the center positions acquired by performing the calculations of the third and fourth steps while moving along the image surface. Characterized in that it obtain.

  In order to achieve the above object, the shape measuring method according to the fourth aspect of the present invention is configured to project a first projection pattern having a periodic light intensity distribution onto a partial region of the test object. A predetermined region on a predetermined straight line passing through the image surface in the step, a second step of imaging the projection pattern projected on the test object, and an image of the projection pattern captured in the second step And calculating the center position of the pattern projection region on the predetermined straight line based on the maximum luminance value distribution calculated in the third step. And a cross section of the test object based on each of the center positions acquired by performing the calculations of the third and fourth steps while moving the predetermined straight line along the image surface. Characterized in that it comprises a fifth step of calculating a Jo.

  According to the present invention, the three-dimensional shape of a test object can be measured by a simple method using one kind of projection pattern.

It is a figure which shows the shape measuring apparatus of this embodiment. It is a schematic diagram which shows the pattern image acquired using the said shape measuring apparatus. It is a flowchart which shows the shape measuring method of 1st Embodiment which concerns on this invention. (A) is a graph which shows the case where the luminance distribution on the straight line x shown in FIG. 2 becomes a binarized periodic function, and (b) shows the contrast distribution calculated from the luminance distribution shown in (a). It is a graph. It is a flowchart which shows the shape measuring method of 2nd Embodiment which concerns on this invention. (A) is a graph which shows the case where the luminance distribution on the straight line x shown in FIG. 2 becomes a sinusoidal periodic function, and (b) is the maximum within a predetermined region calculated from the luminance distribution shown in (a). It is a graph which shows luminance value distribution.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the shape measuring apparatus 1 of this embodiment includes a pattern projecting unit 10 that projects a fringe pattern 15 having a periodic light intensity distribution on a partial region of a test object 5; An imaging unit 20 that images the test object 5 on which the fringe pattern 15 is projected, a moving mechanism 30 that moves the test object 5 in a direction orthogonal to the fringe pattern 15 projected by the pattern projection unit 10, and the imaging unit 20. And the computer 40 that calculates the three-dimensional shape of the test object 5 based on the image of the test object 5 and the fringe pattern 15 captured by the above.

  The pattern projection unit 10 is provided at a position where a light source 11 that emits illumination light, a collimator lens 12 that converts illumination light emitted from the light source 11 into parallel light, and parallel light converted by the collimator lens 12 are incident. The projection chart 13 that gives the parallel light a stripe pattern whose light intensity distribution is a periodic function in one direction, and the projection lens 16 that condenses the light transmitted through the projection chart 13 are configured. The projection chart 13 is formed with a slit penetrating in the optical axis direction and having a pattern mask 14 in the slit. The pattern mask 14 is composed of a light transmissive liquid crystal element, DMD (Digital Mirror Device), or the like, and receives a control signal from the computer 40 to form a stripe pattern whose light intensity distribution is a periodic function in one direction.

  In the pattern projection unit 10 configured as described above, the illumination light emitted from the light source 11 is incident on the projection chart 13 via the collimator lens 12, and the light transmitted through the pattern mask 14 of the projection chart 13 is transmitted by the projection lens 16. By condensing, the fringe pattern formed on the pattern mask 14 can be projected as a fringe pattern 15 onto a partial region of the test object 5. As described above, in the pattern projection unit 10, since the region where the fringe pattern is projected is narrower than that in the conventional method, the projection lens only needs to satisfy the imaging performance only for the narrow projection region. It becomes easy. For this reason, the projection lens has a simple configuration, and can be reduced in size and weight.

  The imaging unit 20 includes an imaging lens 21 and an imaging element 22. The fringe pattern 15 projected on the test object 5 is imaged on the imaging surface of the imaging element 22 by the imaging lens 21. The image sensor 22 captures an image of the stripe pattern 15 formed on the imaging surface and outputs the image data to the computer 40. As described above, since the projection area by the pattern projection unit 10 is narrower than the conventional method, the illuminance of the light irradiated on the test object 5 is increased. For this reason, in the imaging part 20, imaging time becomes short compared with the conventional method.

  The moving mechanism 30 scans the fringe pattern 15 projected onto a partial area of the test object 5 by the pattern projection unit 10 and sequentially projects it onto the entire area of the test object 5. This is a mechanism for moving the test object 5 in a direction orthogonal to the fringe pattern 15. The moving mechanism 30 includes a sensor (length measuring sensor) that measures the amount of movement at this time.

  The computer 40 drives and controls the light source 11, the image sensor 22, and the moving mechanism 30, and sequentially acquires image data of the fringe pattern 15 while scanning the fringe pattern 15 projected on the test object 5 on the surface of the test object 5. To do. And the computer 40 calculates the cross-sectional shape in each position of the test object 5 from the acquired image data of each fringe pattern 15, and connects those cross-sectional shapes, and measures the three-dimensional shape of the test object 5. . This measuring method will be described later. Note that a display device 45 is connected to the computer 40, and the image data of the stripe pattern 15 acquired by the computer 40 and the shape measurement result of the test object 5 are output and displayed on the display device 45.

  A measuring method for measuring the three-dimensional shape of the test object 5 using the shape measuring apparatus configured as described above will be described with reference to FIGS. First, the fringe pattern 15 is projected onto a partial region of the test object 5 by the pattern projection unit 10 (step S1). At this time, the illumination light emitted from the light source 11 passes through the pattern mask 14 of the projection chart 13 and is condensed on the surface of the test object 5 by the projection lens 16, and the light intensity distribution formed on the pattern mask 14 is uniform. A fringe pattern that is a periodic function in the direction is projected as a fringe pattern 15 onto a partial region of the test object 5 (see FIG. 4B). FIG. 4 shows a case where a fringe pattern 15 is projected that is a periodic function in which the light intensity distribution is binarized in one direction.

  And the to-be-tested object 5 with which the fringe pattern 15 was projected by the imaging part 20 is imaged, and the image of the fringe pattern 15 is acquired (step S2). The fringe pattern 15 projected onto the test object 5 by the pattern projection unit 10 is imaged on the imaging surface of the imaging element 22 by the imaging lens 21 of the imaging unit 20. The image sensor 22 captures an image of the stripe pattern 15 formed on the imaging surface and outputs the image data to the computer 40.

  When the image of the stripe pattern 15 is acquired in step S2, the computer 40 calculates the contrast distribution on the straight line x (see FIG. 2) orthogonal to the stripe pattern 15 based on the luminance value of each pixel of the acquired image. (Step S3) Based on the calculated contrast distribution, the center position of the fringe projection area on the straight line x is calculated (Step S4). The contrast distribution is calculated using the following equation (1).

  Here, I (n) is a luminance value of a calculation target pixel (hereinafter referred to as a target pixel). Further, I (n−T / 2) and I (n + T / 2) are the luminance values of the pixels separated from each other by a distance of 1/2 of the period of the pattern projected from the target pixel. That is, D is the absolute value of the difference between the luminance value of the target pixel and the average value of the luminance of the pixels separated by a distance of 1/2 the pattern period projected from the target pixel.

  For example, in FIG. 4A, the period of the light intensity distribution of the fringe pattern 15 (hereinafter simply referred to as the fringe pattern 15) is shown on a straight line x orthogonal to the fringe pattern 15 that is a periodic function with the light intensity distribution binarized. (Referred to as “cycle”) corresponds to four pixels of the image sensor 22 and indicates the luminance value of each pixel on the straight line x at that time. In this case, when the contrast distribution (difference D) is calculated using the above equation (1), it is calculated as shown in FIG.

  When the contrast distribution is obtained in step S3, a predetermined threshold value is provided for the contrast distribution, and the center position of the region on the straight line x having a contrast value exceeding the threshold value is calculated, whereby the center of the fringe projection region on the straight line x is calculated. A position C (see FIG. 4B) is obtained. The center position C of the fringe projection region may be obtained by integrating the contrast distribution calculated in step S3 and calculating the center of gravity position.

  In step S3 described above, the case where the contrast distribution (difference D) is calculated using the above equation (1) has been described. For example, as shown in the following equation (2) or (3), the target pixel and the target The contrast distribution may be calculated using an equation for calculating the absolute value of the difference from the average value of the luminance values of a plurality of pixels near the pixel. For example, when the brightness distribution of each pixel on the straight line x is distributed as shown in FIG. 4A, the contrast distribution (B5, B9) is calculated using the following equation (2) or (3). Calculated as shown in 4 (b).

  Here, I (n) is the luminance value of the target pixel as described above. Further, I (n−1) and I (n + 1) are the luminance values of the pixels adjacent to the target pixel, and the luminance values of the pixels adjacent to the respective pixels are sequentially I (n−2) and I (n + 2). , I (n−3) and I (n + 3),. That is, B5 is the absolute value of the difference between the luminance value of the target pixel and the average value of the luminances of the five pixels near the target pixel. B9 is the absolute value of the difference between the luminance value of the target pixel and the average value of the luminance of nine pixels near the target pixel.

  In addition to the above formulas (1) to (3), the contrast is calculated using an equation for calculating the absolute value (B13) of the difference between the luminance value of the target pixel and the average value of the luminance of 13 pixels near the target pixel. The distribution may be calculated. Thus, the contrast distribution can be calculated using any one of a plurality of formulas (for example, the above formulas (1) to (3)). However, a high contrast value can be obtained only in the fringe projection area and its neighboring areas. The equation to be used is selected and used according to the cycle of the projected stripe pattern 15.

  When the center position C of the fringe projection area on the straight line x is obtained in step S4, the height of the center position C is calculated using the triangulation method (step S5). Since the triangulation method is a known calculation method, description thereof is omitted here.

  As described above, when the height of the center position C of the fringe projection area on the straight line x is obtained through steps S3 to S5, the calculation of steps S3 to S5 is performed while moving the straight line x along the image surface of the fringe pattern 15. The cross-sectional shape of the test object 5 is obtained by connecting the calculated heights of the center positions (step S6).

  When the cross-sectional shape of the test object 5 is obtained in step S6, the test object 5 is moved in the direction orthogonal to the fringe pattern 15 by the moving mechanism 30, and the fringe pattern 15 projected by the pattern projection unit 10 is scanned. The image of the fringe pattern 15 is sequentially acquired (step S7), the calculations of the above steps S3 to S6 are performed on each acquired image, and the calculated cross-sectional shapes of the test object 5 are joined to form a three-dimensional image of the test object 5. The shape is obtained (step S8), and the shape measurement is finished.

  As described above, in the present embodiment, images of the stripe pattern 15 are sequentially acquired while scanning the stripe pattern 15 projected onto a partial region of the test object 5 on the surface of the test object 5, and each acquired stripe pattern is acquired. In the 15 images, the three-dimensional shape of the test object 5 can be obtained by calculating the cross-sectional shape of the test object 5 based on the contrast distribution of the image. As described above, in the conventional pattern projection method, it is necessary to project a plurality of types of patterns in order to obtain the three-dimensional shape of the test object, whereas in this embodiment, one type of projection pattern ( The three-dimensional shape of the test object 5 can be measured by a simple method using the stripe pattern 15).

  In the above-described embodiment, the case where the fringe pattern 15 that is a periodic function in which the light intensity distribution is binarized in one direction is projected has been described. However, in the following, the light intensity distribution is a sinusoidal periodic function in one direction. A measurement method in the case of projecting the stripe pattern 15 will be described with reference to FIGS. 5 and 6.

  First, as in the above-described embodiment, the pattern projection unit 10 projects the fringe pattern 15 onto a partial region of the test object 5 (step S11). At this time, the illumination light emitted from the light source 11 passes through the pattern mask 14 of the projection chart 13 and is condensed on the surface of the test object 5 by the projection lens 16, and the light intensity distribution formed on the pattern mask 14 is uniform. A fringe pattern having a sinusoidal periodic function in the direction is projected as a fringe pattern 15 onto a partial region of the test object 5 (see FIG. 6A).

  And the to-be-tested object 5 with which the fringe pattern 15 was projected by the imaging part 20 is imaged, and the image of the fringe pattern 15 is acquired (step S12). The fringe pattern 15 projected onto the test object 5 by the pattern projection unit 10 is imaged on the imaging surface of the imaging element 22 by the imaging lens 21 of the imaging unit 20. The image sensor 22 captures an image of the stripe pattern 15 formed on the imaging surface and outputs the image data to the computer 40.

  When the image of the stripe pattern 15 is acquired in step S12, the computer 40 determines the maximum in a predetermined region on the straight line x (see FIG. 2) orthogonal to the stripe pattern 15 based on the luminance value of each pixel of the acquired image. A luminance value distribution is calculated (step S13), and the center position of the fringe projection region on the straight line x is calculated based on the calculated maximum luminance value distribution (step S14). The calculation of the maximum luminance value distribution is performed using the following equation (4).

  Here, similarly to the above, I (n) is the luminance value of the target pixel, I (n−1) and I (n + 1) are the luminance values of the pixels adjacent to the target pixel, and I (n−2). ) And I (n + 2) are the luminance values of the pixels adjacent to the pixels of I (n−1) and I (n + 1), respectively. That is, M5 is the maximum value of luminance in the target pixel and four pixels in the vicinity of the target pixel (a total of five pixels).

  For example, in FIG. 6A, the period of the stripe pattern 15 corresponds to 4 pixels of the image sensor 22 on the straight line x orthogonal to the stripe pattern 15 whose light intensity distribution is a sinusoidal periodic function. The luminance value of each pixel on the straight line x is shown. In this case, when the maximum luminance value distribution (M5) is calculated using the above equation (4), it is calculated as shown in FIG.

  When the maximum luminance value distribution is obtained in step S13, a predetermined threshold value is provided for the maximum luminance value distribution, and the center position of the region on the straight line x having the maximum luminance value exceeding the threshold value is calculated. The center position C ′ of the fringe projection area (see FIG. 6B) is obtained. Note that the center position C ′ of the fringe projection region may be obtained by integrating the maximum luminance value distribution calculated in step S13 and calculating the center of gravity position.

  In step S13 described above, the case where the maximum luminance value distribution (M5) is calculated using the above equation (4) has been described. For example, the target pixel and eight pixels in the vicinity of the target pixel (total of nine pixels) The maximum luminance value distribution may be calculated using the following equation (5) for calculating the maximum luminance value in the pixel). For example, when the luminance value of each pixel on the straight line x is distributed as shown in FIG. 6 (a), the contrast distribution (M9) is calculated using the following equation (5), as shown in FIG. 6 (b). Is calculated as follows.

  Here, similarly to the above, I (n) is the luminance value of the target pixel, and I (n−1) and I (n + 1) are the luminance values of the pixels adjacent to the target pixel, respectively. The luminance values of adjacent pixels are I (n−2) and I (n + 2), I (n−3), I (n + 3),.

  In addition to the above equations (4) and (5), the maximum luminance value is calculated using an equation for calculating the maximum luminance value (M13) in the target pixel and 12 pixels in the vicinity of the target pixel (a total of 13 pixels). The distribution may be calculated. As described above, the maximum luminance value distribution can be calculated using any one of a plurality of formulas (for example, the above formulas (4) and (5)). An expression that takes a value is selected and used according to the period of the projected stripe pattern 15.

  When the center position C ′ of the fringe projection area on the straight line x is obtained in step S14, the height of the center position C ′ is calculated using the triangulation method (step S15). Since the triangulation method is a known calculation method as described above, the description thereof is omitted here.

  As described above, when the height of the center position C ′ of the fringe projection area on the straight line x is obtained through the steps S13 to S15, the straight line x is moved along the image surface of the fringe pattern 15 and the above steps S13 to S15 are performed. A calculation is performed, and the calculated heights of the respective center positions are connected to obtain the cross-sectional shape of the test object 5 (step S16).

  When the cross-sectional shape of the test object 5 is obtained in step S16, the test object 5 is moved in the direction orthogonal to the fringe pattern 15 by the moving mechanism 30, and the fringe pattern 15 projected by the pattern projection unit 10 is scanned. The image of the fringe pattern 15 is sequentially acquired (step S17), the calculations of steps S13 to S16 are performed on the acquired images, and the calculated cross-sectional shapes of the test object 5 are joined together to obtain the three-dimensional shape of the test object 5. The shape is obtained (step S18), and the shape measurement is finished.

  As described above, in the present embodiment, images of the stripe pattern 15 are sequentially acquired while scanning the stripe pattern 15 projected onto a partial region of the test object 5 on the surface of the test object 5, and each acquired stripe pattern is acquired. In the 15 images, the three-dimensional shape of the test object 5 can be obtained by calculating the cross-sectional shape of the test object 5 based on the maximum luminance value distribution within the predetermined range of the image. Therefore, also in this embodiment, compared with the conventional pattern projection method, the three-dimensional shape of the test object 5 can be measured by a simple method using one type of projection pattern (stripe pattern 15).

  In the above-described embodiment, the configuration in which the test object 5 is moved by the moving mechanism 30 and the fringe pattern 15 projected by the pattern projection unit 10 is scanned on the surface of the test object 5 has been described. It is not limited to. That is, the pattern projection unit and the imaging unit may be moved together, or the pattern projection unit and the test object may be moved to scan the projection pattern on the surface of the test object.

  In the embodiment described above, in steps S3 and S13, the contrast distribution on the straight line x orthogonal to the fringe pattern 15 or the maximum luminance value distribution in a predetermined region on the straight line x is calculated. Instead of calculating the contrast distribution or maximum luminance value distribution on the straight line x, the contrast distribution or maximum luminance value distribution on an arbitrary straight line may be calculated. However, as in the present embodiment, the projection pattern has a light intensity distribution that is a periodic function in one direction, and the calculation time is calculated by calculating the contrast distribution or the maximum luminance value distribution in the direction orthogonal to the projection pattern (on the straight line x). And can be measured efficiently.

  In the above-described embodiment, when a fringe pattern that is a periodic function in which the light intensity distribution is binarized in one direction is projected, and a fringe pattern in which the light intensity distribution is a sinusoidal periodic function in one direction. Although the case where it projected is demonstrated, a projection pattern is not limited to such a pattern. However, the projection pattern is preferably a high contrast pattern having a light intensity distribution with a substantially constant period. Further, the projection pattern is preferably a pattern having a light intensity distribution with a period not exceeding the Nyquist frequency of the image sensor when imaged by the image sensor. Further, the projection pattern is preferably a pattern having a light intensity distribution with a period of two or more pixels of the image sensor when imaged by the image sensor.

DESCRIPTION OF SYMBOLS 1 Shape measuring apparatus 5 Test object 10 Pattern projection part 15 Stripe pattern (projection pattern)
20 Imaging unit 30 Movement mechanism (relative movement unit)
40 Computer (center calculation unit, shape calculation unit)

Claims (10)

A pattern projection unit that projects a projection pattern having a periodic light intensity distribution on a partial region of the test object;
An imaging unit that images the projection pattern projected onto the test object by the pattern projection unit;
In the image of the projection pattern captured by the imaging unit, the contrast distribution of the image on a predetermined straight line passing through the image surface is calculated, and the pattern projection area on the predetermined straight line is calculated based on the contrast distribution. A center calculation unit for calculating the center position;
A shape calculation unit that calculates a cross-sectional shape of the test object based on each of the center positions obtained by calculating the center position while moving the predetermined straight line along the image surface by the center calculation unit. A shape measuring device comprising:   The center calculation unit calculates an absolute value of a difference between a luminance value of a target point in the image and an average value of luminance of a point separated from the target point by a distance of 1/2 of the period of the projection pattern. The shape measuring apparatus according to claim 1, wherein the contrast distribution is obtained.   The center calculation unit calculates an absolute value of a difference between a luminance value of a target point in the image and an average value of luminances of a plurality of points near the target point to obtain the contrast distribution. The shape measuring apparatus according to 1. A pattern projection unit that projects a projection pattern having a periodic light intensity distribution on a partial region of the test object;
An imaging unit that images the projection pattern projected onto the test object by the pattern projection unit;
In the image of the projection pattern imaged by the imaging unit, a maximum luminance value distribution of the image in a predetermined area on a predetermined straight line passing through the image surface is calculated, and the predetermined luminance value distribution is calculated based on the maximum luminance value distribution. A center calculation unit for calculating the center position of the pattern projection area on the straight line;
A shape calculation unit that calculates a cross-sectional shape of the test object based on each of the center positions obtained by calculating the center position while moving the predetermined straight line along the image surface by the center calculation unit. A shape measuring device comprising:   5. The shape measurement according to claim 4, wherein the center calculation unit calculates the maximum luminance value distribution by calculating a maximum value of luminance at a target point in the image and a plurality of points near the target point. apparatus.   The center calculation unit sets a predetermined threshold value in the calculated contrast distribution or the maximum luminance value distribution, and calculates the center position of the region on the predetermined line having the contrast value or the maximum luminance value exceeding the threshold value. The shape measuring apparatus according to claim 1, wherein a center position of the pattern projection region is obtained.   The center calculation unit obtains the center position of the pattern projection region by integrating the calculated contrast distribution or the maximum luminance value distribution and calculating the center of gravity position thereof. The shape measuring device according to claim 1. A relative movement unit that changes a relative position between the projection pattern projected onto the test object and the test object by the pattern projection unit;
The shape calculating unit calculates a cross-sectional shape at a plurality of positions while changing a relative position between the projection pattern and the test object by the relative moving unit to obtain a three-dimensional shape of the test object. The shape measuring device according to any one of claims 1 to 7. A first step of projecting a projection pattern having a periodic light intensity distribution onto a partial region of the test object;
A second step of imaging the projection pattern projected onto the test object;
A third step of calculating a contrast distribution of the image on a predetermined straight line passing through the image surface in the image of the projection pattern captured in the second step;
A fourth step of calculating a center position of the pattern projection region on the predetermined straight line based on the contrast distribution calculated in the third step;
A fifth cross-sectional shape of the test object is calculated based on each of the center positions acquired by performing the operations of the third and fourth steps while moving the predetermined straight line along the image surface. A shape measuring method comprising: steps. A first step of projecting a projection pattern having a periodic light intensity distribution onto a partial region of the test object;
A second step of imaging the projection pattern projected onto the test object;
A third step of calculating a maximum luminance value distribution of the image in a predetermined region on a predetermined straight line passing through the image surface in the image of the projection pattern captured in the second step;
A fourth step of calculating a center position of the pattern projection region on the predetermined straight line based on the maximum luminance value distribution calculated in the third step;
A fifth cross-sectional shape of the test object is calculated based on each of the center positions acquired by performing the operations of the third and fourth steps while moving the predetermined straight line along the image surface. A shape measuring method comprising: steps.

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