JP7515979B2 - Three-dimensional shape measuring device and three-dimensional shape measuring method - Google Patents

Description

The present invention relates to a three-dimensional shape measuring device and a three-dimensional shape measuring method for measuring the three-dimensional shape of a measurement object.

The light pattern projection method uses the principle of triangulation, projecting a striped pattern from a projector onto the object to be measured, and capturing the pattern that deforms along the shape of the object to be measured with an optical device such as a camera to perform three-dimensional shape measurement. Patent Document 1 describes how the pattern projected onto the object to be measured in the light pattern projection method is captured using multiple optical devices.

Special Publication No. 2019-516983

The method described in Patent Document 1 had a problem in that the measurement results differed between measuring the shape of an object using one of the multiple optical devices and measuring the shape of an object using the other optical device.

The present invention has been made in consideration of this point, and aims to provide a three-dimensional shape measuring device and a three-dimensional shape measuring method that can suppress discrepancies in the measurement results when measuring the shape of a measurement object using different optical devices.

The three-dimensional shape measuring device of the first aspect of the present invention is a three-dimensional shape measuring device that measures the three-dimensional shape of a measurement object based on an image of the measurement object, and includes a plurality of optical devices, a preliminary measurement unit that creates a plurality of preliminary measurement data indicating the three-dimensional coordinates of a reference point on the reference instrument by imaging a reference instrument in a plurality of measurement systems consisting of a combination of different optical devices among the plurality of optical devices, a reference data creation unit that creates reference data based on one or more of the plurality of preliminary measurement data, a calculation unit that calculates a correction value based on the preliminary measurement data that does not match the reference data among the plurality of preliminary measurement data and the reference data, an object measurement unit that creates a plurality of object measurement data indicating the results of measuring a measurement point of the measurement object in the plurality of measurement systems, a correction unit that corrects the object measurement data in the measurement system corresponding to the preliminary measurement data that does not match the reference data based on the correction value, and a shape identification unit that identifies the shape of the measurement object using the object measurement data corrected by the correction unit.

The preliminary measurement unit may create the preliminary measurement data indicating the three-dimensional coordinates of the reference point of the reference instrument at the multiple installation positions by capturing images of the reference instrument installed at multiple installation positions, and the calculation unit may calculate the correction values corresponding to the reference points at the multiple installation positions. The reference data creation unit may create the reference data by calculating statistics of the three-dimensional coordinates of the reference points indicated by the multiple preliminary measurement data corresponding to the multiple measurement systems.

The three-dimensional shape measuring device may further include an acquisition unit that acquires relative position information indicating the positional relationship of the multiple reference points included in the reference instrument, the preliminary measurement unit creates the preliminary measurement data indicating the three-dimensional coordinates of the multiple reference points, and the reference data creation unit creates the reference data by selecting the preliminary measurement data indicating the three-dimensional coordinates of the multiple reference points based on an error from the positional relationship indicated by the relative position information.

The preliminary measurement unit may create the preliminary measurement data indicating the three-dimensional coordinates of the multiple reference points on the reference instrument, and the reference data creation unit may create one of the reference data by selecting, for each of the multiple reference points, one of the multiple preliminary measurement data corresponding to the multiple measurement systems.

The reference data creation unit may select the preliminary measurement data corresponding to the combination of the optical device that provides the best triangulation accuracy for the reference point from among the multiple preliminary measurement data corresponding to the multiple measurement systems. The preliminary measurement unit may project a projection image including a pattern for identifying the reference point onto the reference instrument. The calculation unit may identify a function for calculating the correction value corresponding to the three-dimensional coordinates of the measurement point measured by the measurement system corresponding to the preliminary measurement data that does not match the reference data, and calculate the correction value using the identified function. The calculation unit may further include a storage unit that stores a table that associates the three-dimensional coordinates of individual lattice points obtained by dividing the measurement space of the multiple measurement systems into an equally spaced cubic lattice, the multiple correction values, and an index for identifying each of the multiple measurement systems, and the correction unit may read out from the storage unit the correction value associated with the three-dimensional coordinates of the lattice point closest to the three-dimensional coordinates indicated by the target measurement data and the index indicating the measurement system corresponding to the lattice point, and correct the target measurement data based on the read correction value.

The three-dimensional shape measuring method of the second aspect of the present invention is a three-dimensional shape measuring method for measuring the three-dimensional shape of a measurement object based on an image of the measurement object, and includes the steps of: creating a plurality of preliminary measurement data indicating the three-dimensional coordinates of a reference point on a reference instrument by imaging a reference instrument in a plurality of measurement systems consisting of a combination of different optical devices among a plurality of optical devices; creating reference data based on one or more of the plurality of preliminary measurement data; calculating a correction value based on the preliminary measurement data that does not match the reference data among the plurality of preliminary measurement data and the reference data; creating a plurality of object measurement data indicating the results of measuring a measurement point of the measurement object in the plurality of measurement systems; correcting the object measurement data in the measurement system that corresponds to the preliminary measurement data that does not match the reference data based on the correction value; and identifying the shape of the measurement object using the corrected object measurement data.

The present invention has the effect of suppressing discrepancies in measurement results when measuring the shape of a measurement object using different optical devices.

1 is a diagram for explaining an overview of a three-dimensional shape measuring apparatus according to an embodiment; FIG. 1 is a diagram illustrating a configuration of a three-dimensional shape measuring apparatus. 1A to 1C are diagrams showing examples of types of projected images including a binary stripe pattern projected onto a measurement object. Examples of Gray codes corresponding to the binary stripe patterns shown in FIGS. 1 shows an example of a grayscale stripe pattern having a sinusoidal luminance distribution. FIG. 13 is a diagram illustrating the relationship between absolute projected coordinates and relative projected coordinates. 13 shows an example of an epipolar line in the second captured image corresponding to the first captured pixel. FIG. 1 illustrates an example of a reference instrument. FIG. 13 is a diagram showing the measurement of a reference instrument. 10 is a flowchart showing a processing procedure for calculating a correction value by the three-dimensional shape measuring apparatus. 4 is a flowchart showing a processing procedure for identifying a three-dimensional shape of a measurement object by the three-dimensional shape measuring device. 13 is a diagram showing the selection of a measurement system in the creation of reference data by a reference data creation unit; FIG.

[Overview of three-dimensional shape measuring device 100]
1(a) and 1(b) are diagrams for explaining an overview of a three-dimensional shape measuring device 100 according to this embodiment. Fig. 1(a) shows the configuration of the three-dimensional shape measuring device 100. The three-dimensional shape measuring device 100 includes a first imaging unit 1, a second imaging unit 2, and a projection unit 3 as optical devices. The three-dimensional shape measuring device 100 includes a control unit 4 that controls various operations of these optical devices.

The projection unit 3 is a projection device having a light source such as a light-emitting diode or a laser. The projection unit 3 projects a projection image including a pattern for identifying the projection coordinates onto the measurement surface of the measurement object. The projection coordinates indicate the positions of the projection pixels constituting the projection image projected by the projection unit 3. The projection coordinates may be one-dimensional coordinates indicating either the vertical or horizontal position of the projection image, or may be two-dimensional coordinates indicating both the vertical and horizontal positions of the projection image. The pattern is, for example, a stripe pattern. Furthermore, the number of projection units 3 is not limited to one, and the three-dimensional shape measuring device 100 may be equipped with any number of projection units.

The first imaging unit 1 has a lens 11 and an image sensor 12. When the projection unit 3 projects a projection image onto the measurement object, the first imaging unit 1 captures the projection image projected onto the measurement object to generate a first captured image. The first imaging unit 1 is positioned so that its optical axis forms a predetermined angle with the optical axis of the projection unit 3.

The second imaging unit 2 has a lens 21 and an image sensor 22. When the projection unit 3 projects the projection image onto the measurement object, the second imaging unit 2 captures the projected image projected onto the measurement object to generate a second captured image. The second imaging unit 2 is disposed so that its optical axis forms a predetermined angle with the optical axis of the projection unit 3. The optical axis of the second imaging unit 2 may be in the same plane as the optical axis of the first imaging unit 1 and the optical axis of the projection unit 3, but is not limited to this. The control unit 4 can be realized by, for example, a computer. The control unit 4 measures the three-dimensional shape of the measurement object based on the multiple captured images generated by the first imaging unit 1 and the second imaging unit 2. In addition, the number of imaging units is not limited to two, and the three-dimensional shape measuring device 100 may be equipped with any number of imaging units.

Figure 1(b) is a diagram for explaining errors in measuring the shape of a measurement object using multiple measurement systems of the three-dimensional shape measuring device 100. The three-dimensional shape measuring device 100 measures the three-dimensional shape using multiple measurement systems (first measurement system and second measurement system) consisting of a combination of different optical devices.

When the first measurement system is used, the three-dimensional shape measuring device 100 measures the three-dimensional coordinates of the measurement point P using the projection unit 3 and the first imaging unit 1. As shown in FIG. 1(b), the three-dimensional shape measuring device 100 identifies which projection pixel, among the projection pixels included in the projection image projected by the projection unit 3, is irradiated with the light of the measurement point P. In the example shown in FIG. 1(b), the measurement point P exists on the optical path L3 through which the light of the identified projection pixel passes.

In measuring the three-dimensional coordinates of the measurement point P, the three-dimensional shape measuring device 100 specifies in which first imaging pixel, included in the first captured image captured by the first imaging unit 1, the measurement point P appears.
The first captured pixel is the smallest unit included in the first captured image. In the example shown in Fig. 1B, a measurement point P exists on the optical path L1 corresponding to the identified first captured pixel. The three-dimensional shape measuring device 100 measures the three-dimensional coordinates of the measurement point P by determining the position of the intersection of the optical path L3 and the optical path L1 using a triangulation method.

On the other hand, when the second measurement system is used, the three-dimensional shape measuring device 100 measures the three-dimensional coordinates of the measurement point P using the projection unit 3 and the second imaging unit 2. When measuring the three-dimensional coordinates of the measurement point P, the three-dimensional shape measuring device 100 identifies which second imaging pixel in the second captured image captured by the second imaging unit 2 contains the measurement point P. The second imaging pixel is the smallest unit contained in the second captured image. In the example shown in FIG. 1(b), the measurement point P exists on the optical path L2 corresponding to the identified second imaging pixel. As described above, since the measurement point P exists on the optical path L3, the three-dimensional shape measuring device 100 measures the three-dimensional coordinates of the measurement point P by determining the position of the intersection of the optical paths L2 and L3.

When there is no error in the first and second measurement systems, as shown in FIG. 1(b), the intersection between optical paths L1 and L2 and the intersection between optical paths L1 and L3 both approximately coincide with measurement point P, so the measurement result of the three-dimensional coordinates does not change regardless of which measurement system is used to measure measurement point P. Therefore, the three-dimensional shape measuring device 100 can improve measurement accuracy by, for example, using the average value of the measurement results of multiple measurement systems.

However, if there is an error in the optical path through which the light of the projected pixel of the projection unit 3 passes due to distortion of the lens (not shown) of the projection unit 3 or the like, the three-dimensional shape measuring device 100 determines that the measurement point P exists on the optical path L3' shown by the dashed line in FIG. 1(b). In other words, when the three-dimensional shape measuring device 100 measures the measurement point P using the first measurement system consisting of the projection unit 3 and the first imaging unit 1, it erroneously measures the three-dimensional coordinates of the intersection point P1 of the optical paths L1 and L3' as the three-dimensional coordinates of the measurement point P.

Furthermore, when the three-dimensional shape measuring device 100 measures the measurement point P using the second measurement system consisting of the projection unit 3 and the second imaging unit 2, it measures the three-dimensional coordinates of the intersection point P2 of the optical path L2 and the optical path L3' as the three-dimensional coordinates of the measurement point P. If the difference between the measurement point P1 and the measurement point P2 is large in this way, the error in the measurement result of the three-dimensional shape measuring device 100 will be large.

The three-dimensional shape measuring device 100 corrects the errors in each measurement system to prevent such a decrease in the measurement accuracy of the three-dimensional coordinates. More specifically, the three-dimensional shape measuring device 100 creates reference data that indicates the standard of measurement data in multiple measurement systems by measuring a specified reference instrument in advance.

The three-dimensional shape measuring device 100 uses this reference data to calculate correction values for correcting the measurement data of the multiple measurement systems, and corrects the measurement data in the corresponding measurement systems using the calculated correction values. In this way, the three-dimensional shape measuring device 100 can improve the measurement accuracy of the three-dimensional coordinates of the measurement point P and suppress changes in the measurement results for each measurement system.

[Configuration of three-dimensional shape measuring device]
Fig. 2 is a diagram showing the internal configuration of three-dimensional shape measuring device 100. Three-dimensional shape measuring device 100 includes a storage unit 5 in addition to first imaging unit 1, second imaging unit 2, projection unit 3, and control unit 4 shown in Fig. 1.

The memory unit 5 includes storage media such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a hard disk. The memory unit 5 stores the programs executed by the control unit 4. The control unit 4 is, for example, a CPU (Central Processing Unit). The control unit 4 executes the programs stored in the memory unit 5, thereby functioning as a measurement unit 41, an acquisition unit 42, a reference data creation unit 43, a calculation unit 44, a correction unit 45, and a shape identification unit 46.

The measurement unit 41 projects a projection image including a predetermined light pattern onto a measurement object, etc., using the projection unit 3. The measurement unit 41 generates an image by capturing the projection image projected onto the measurement object, etc., using the first imaging unit 1 and the second imaging unit 2. The measurement unit 41 generates an image by capturing an image of a predetermined reference instrument. The measurement unit 41 includes an object measurement unit 411 and a preliminary measurement unit 412.

The object measurement unit 411 creates multiple object measurement data indicating the measurement results by measuring the measurement points of the measurement object using multiple measurement systems. Examples of the multiple measurement systems include the following first to fourth measurement systems.

First measurement system: first imaging unit 1 and projection unit 3
Second measurement system: second imaging unit 2 and projection unit 3
Third measurement system: first imaging unit 1, second imaging unit 2, and projection unit 3
Fourth measurement system: first imaging unit 1 and second imaging unit 2

[Measurement by the first measurement system]
In the first measurement system, the object measurement unit 411 measures a measurement point of the measurement object by combining one imaging unit and one projection unit. The object measurement unit 411 projects a projection image including a predetermined light pattern onto the measurement object by the projection unit 3. Fig. 3 is a diagram showing an example of a type of projection image including a binary stripe pattern projected by the object measurement unit 411. The black area in Fig. 3 indicates a non-projection area where the projection unit 3 does not project light, and the white area indicates a light projection area where the projection unit 3 projects light.

Figure 3(a) is a reference pattern (all black pattern) in which no light is projected onto the entire object to be measured. Figure 3(b) is a reference pattern (all white pattern) in which light is projected onto the entire object to be measured. Figures 3(c) to (f) show binary stripe patterns consisting of light projection areas and non-projection areas, with stripes of different widths arranged in the same direction for each projected image.

The stripe patterns shown in Figures 3(c) to (f) correspond to a gray code and are used to identify projection coordinates indicating the position of a projected pixel in a projected image corresponding to a first captured pixel in a captured image. Figure 4 shows an example of a gray code corresponding to the binary stripe patterns shown in Figures 3(c) to (f). By associating 0 in the gray code with a non-projected area and 1 with a light projection area, the binary stripe patterns shown in Figures 3(c) to (f) are generated.

Each position in the x-direction in Figures 3 and 4 is represented by a code value that combines the numbers 0 or 1 at the corresponding positions of each Gray code. Position 0 in Figure 4 corresponds to the code value "0000", position 1 corresponds to the code value "0001", and position 15 corresponds to the code value "1000".

The object measurement unit 411 projects a projection image including a grayscale stripe pattern having a sinusoidal luminance distribution onto the measurement object. Figures 5(a) to (d) show examples of grayscale stripe patterns having a sinusoidal luminance distribution. The binary stripe patterns of Figures 3(c) to (f) are binary images consisting of black and white areas, whereas the grayscale stripe patterns of Figures 5(a) to (d) have a sine wave-like change in shading from the white area to the black area along the stripe width direction. The grayscale stripe patterns of Figures 5(a) to (d) have a constant stripe spacing, and the spatial frequency of the stripes of these grayscale stripe patterns is, for example, four times that of the binary stripe pattern of Figure 3(f).

The gradation stripe patterns in Figures 5(a) to (d) show the same luminance distribution, except that the phases of the sine waves showing the luminance distribution differ by 90 degrees. The object measurement unit 411 projects a total of 10 projection images: two reference patterns shown in Figures 3(a) and (b), four binary stripe patterns shown in Figures 3(c) to (f), and four gradation stripe patterns shown in Figures 5(a) to (d). The gradation stripe pattern shown in Figure 5 is used to identify the projection coordinates, along with the stripe pattern shown in Figure 3.

In the first measurement system, the object measurement unit 411 generates a first captured image by capturing a projected image projected onto the measurement object using the first imaging unit 1. The object measurement unit 411 identifies the projection coordinates corresponding to the first captured pixel of the first captured image based on the pattern included in the first captured image. For example, the object measurement unit 411 identifies the projection coordinates indicating the position of the projected pixel corresponding to the first captured pixel included in the first captured image by analyzing the change in shading in the pattern included in the first captured image.

The object measurement unit 411 calculates the average of the luminance value when the all-black pattern shown in FIG. 3(a) is projected and the luminance value when the all-white pattern shown in FIG. 3(b) is projected for each pixel as an intermediate value. Similarly, the object measurement unit 411 identifies the code value of each first captured pixel by comparing the luminance value of each first captured pixel in each of the four first captured images in which the binary stripe patterns of FIG. 3(c) to FIG. 3(f) are projected onto the measurement object. By identifying the code value, the object measurement unit 411 can identify the position toward which the binary stripes are projected at the position of each first captured pixel. The object measurement unit 411 identifies the position from position 0 to position 15 shown in FIG. 4 in which each first captured pixel included in the first captured image is included.

Furthermore, the object measurement unit 411 identifies the phase of the sine wave corresponding to the first captured pixel in the first captured image when a gradation stripe pattern having a sine wave-like luminance distribution is projected onto the measurement object, and identifies the projection coordinates based on the identified phase. Since the gradation stripe pattern of the projected image has periodicity, multiple projected pixels have the same projection coordinates in the projected image. Hereinafter, the projection coordinates having periodicity in the projected image are also referred to as relative projection coordinates. On the other hand, the projection coordinates that are uniquely determined in the projected image are also referred to as absolute projection coordinates.

Figure 6 is a diagram showing the relationship between absolute projection coordinates and relative projection coordinates. The vertical axis in Figure 6 indicates the projection coordinates. The horizontal axis in Figure 6 indicates the position of the projection pixel in the width direction of the stripes included in the projection image. The width direction is a direction perpendicular to the direction in which the stripes extend. As the solid lines in Figure 6 indicate, the relative projection coordinates are periodic. The relative projection coordinates indicate the same value for each period of the repetition of the gradation stripe pattern having a sinusoidal luminance distribution. On the other hand, as the diagonally extending dashed lines in Figure 6 indicate, the absolute projection coordinates are uniquely determined in the projection image.

The object measurement unit 411 identifies the relative projection coordinates corresponding to the first imaging pixel by analyzing the shading of the gradation stripe pattern. Based on the gray code indicated by the binary stripe pattern, the object measurement unit 411 identifies which position, from position 0 to position 15, the first imaging pixel corresponds to. Based on the relative position indicated by the relative projection coordinates among the positions identified by the gray code, the object measurement unit 411 identifies the absolute projection coordinates corresponding to the first imaging pixel. Using the two-dimensional coordinates of the first imaging pixel and the identified one-dimensional absolute projection coordinates, the object measurement unit 411 identifies the three-dimensional coordinates of the measurement point on the measurement object corresponding to the first imaging pixel by utilizing the principles of triangulation.

The object measurement unit 411 may project multiple projection images with different stripe extension directions, and may identify projection coordinates corresponding to the first imaging pixel for each projection image with different stripe extension directions. The object measurement unit 411 may project multiple projection images with different stripe extension directions onto the measurement object, and may identify projection coordinates corresponding to the first imaging pixel for each projection image with different stripe extension directions.

[Measurement by the second measurement system]
The object measuring unit 411 measures the three-dimensional coordinates of a measurement point on the measurement object in the second measurement system by combining the second imaging unit 2 and the projection unit 3 in the same manner as the first measurement system.

[Measurement by the third measurement system]
The object measurement unit 411 measures a measurement point of the measurement object by a combination of the first imaging unit 1, the second imaging unit 2, and the projection unit 3 in the third measurement system. The object measurement unit 411 specifies projection coordinates indicating the position of a projected pixel corresponding to a first imaging pixel included in the first captured image, in the same manner as the first measurement system. The object measurement unit 411 specifies projection coordinates indicating the position of a projected pixel corresponding to a second imaging pixel included in the second captured image.

FIG. 7 shows an example of an epipolar line _EBA of the second captured image corresponding to the first captured pixel A. The focal point of the lens 11 of the first image capturing unit 1 is O1. The optical path corresponding to the first captured pixel A is a straight line extending from the focal point O1 to the measurement point MP, and the straight line indicating this optical path projected onto the image plane of the second image capturing unit 2 on the left side of FIG. 7 is the epipolar line _EBA . The second captured pixel B in the image plane of the second image capturing unit 2 on the left side of FIG. 7, which corresponds to the same measurement point MP as the first captured pixel A, is located somewhere on the epipolar line _EBA due to geometric constraints. The target measurement unit 411 reads out arrangement information indicating the arrangement of the first image capturing unit 1 and the second image capturing unit 2 stored in advance in the storage unit 5, and specifies the epipolar line _EBA of the second captured image corresponding to the first captured pixel A based on the read out arrangement information. The arrangement information is, for example, information indicating the focal length, position, and orientation.

7 , of the second imaging pixels located on the identified epipolar line _EBA , the object measurement unit 411 selects a second imaging pixel B that corresponds to the same absolute projection coordinates as the first imaging pixel A. The object measurement unit 411 measures the three-dimensional coordinates of a common measurement point MP corresponding to the first imaging pixel A and the selected second imaging pixel B by utilizing the principle of triangulation between the first imaging pixel A and the selected second imaging pixel B.

[Measurement by the fourth measurement system]
The object measuring unit 411 specifies a correspondence relationship between the first captured pixel of the first captured image and the second captured pixel of the second captured image in the fourth measurement system. When the measurement object has a feature point such as a texture or an edge, the object measuring unit 411 can measure the three-dimensional coordinates of the feature point without projecting a projection image onto the measurement object.

The object measurement unit 411 identifies a first imaging pixel that corresponds to a feature point of the measurement object. The object measurement unit 411 also identifies a second imaging pixel that corresponds to the same feature point. The object measurement unit 411 measures the three-dimensional coordinates of this feature point by utilizing the principle of triangulation using the first imaging pixel that corresponds to the feature point and the second imaging pixel that corresponds to the same feature point.

[Bidirectional stripe pattern]
In addition, the object measurement unit 411 is not limited to the example of creating the object measurement data using only a projection image including a stripe pattern extending in one direction. For example, the object measurement unit 411 may create the object measurement data by projecting a projection image including a stripe pattern extending in the horizontal direction in addition to a projection image including a stripe pattern extending in the vertical direction onto the measurement object. The object measurement unit 411 can identify both the vertical projection coordinates and the horizontal projection coordinates corresponding to the imaging pixel by projecting a projection image including a stripe pattern extending in the horizontal direction onto the measurement object. In this case, the object measurement unit 411 can uniquely identify the projection pixel corresponding to the imaging pixel without using an epipolar line.

[Measurement of reference instrument]
The preliminary measurement unit 412 creates a plurality of preliminary measurement data indicating the three-dimensional coordinates of a reference point on a reference instrument by capturing images of the reference instrument in a plurality of measurement systems each consisting of a combination of different optical devices among a plurality of optical devices. A plurality of reference points are arranged on the reference instrument. For example, the preliminary measurement unit 412 measures the three-dimensional coordinates of the reference points in each of the first to fourth measurement systems by a method similar to that of the target measurement unit 411.

Figures 8(a) and 8(b) are diagrams showing examples of a reference instrument. The reference instrument is shown as viewed from above. Figure 8(a) shows a reference instrument in which multiple black circles are aligned vertically and horizontally. Figure 8(b) shows a reference instrument with a checkered pattern. When using the reference instrument shown in Figure 8(a), the preliminary measurement unit 412 determines the center of the black circle as a reference point and creates preliminary measurement data indicating the three-dimensional coordinates of this reference point. When using the reference instrument shown in Figure 8(b), the preliminary measurement unit 412 determines each vertex of the white and black squares that make up the checkered pattern as a reference point and creates preliminary measurement data indicating the three-dimensional coordinates of the determined reference points. The preliminary measurement data each includes information indicating the three-dimensional coordinates of multiple reference points on the reference instrument.

Figure 9 is a diagram showing how the reference instrument 51 is measured. In the example of Figure 9, the reference instrument 51 is a flat plate-shaped member, but is not limited to this, and any shape can be used as the reference instrument. The preliminary measurement unit 412 images the reference instrument 51 one or more times. The reference instrument 51 is sequentially installed at multiple installation positions with different depth coordinates as indicated by the arrow in Figure 9 during measurement. The installation position of the reference instrument 51 does not need to be determined precisely, but may be approximate. In addition, the three-dimensional coordinates of the installation position of the reference instrument 51 do not need to be measured in advance, and the reference instrument 51 can be installed at any installation position. Therefore, in the three-dimensional shape measuring device 100, there is no need to prepare an instrument for positioning the reference instrument 51 or another measuring instrument, so that the measurement of the reference instrument 51 can be performed easily and at low cost.

The preliminary measurement unit 412 captures an image of the reference instrument 51 when the reference instrument 51 is placed at each installation position. The preliminary measurement unit 412 creates preliminary measurement data indicating the three-dimensional coordinates of the reference points of the reference instrument 51 at each of the installation positions based on the captured images of the reference instrument 51 installed at each of the installation positions. In addition, the present invention is not limited to an example in which multiple installation positions are determined by translating the reference instrument 51 so that the coordinates in the depth direction are different from each other, and the three-dimensional coordinates may be determined to be different from each other by changing the posture of the reference instrument 51.

The preliminary measurement unit 412 is not limited to the example of measuring the three-dimensional coordinates of a reference point that is placed in advance on the reference instrument 51. For example, the preliminary measurement unit 412 may project, onto the reference instrument 51, a projection image including a mark for using a specific position as a reference point, using the projection unit 3. The preliminary measurement unit 412 may determine the position where the mark is projected as a reference point, and measure the three-dimensional coordinates of this reference point.

The preliminary measurement unit 412 may also project a projection image including a pattern for identifying a reference point onto the reference instrument 51. The projection image including a pattern for identifying a reference point is, for example, a projection image including a stripe pattern extending in one direction. The preliminary measurement unit 412 may acquire a first captured image and a second captured image obtained by capturing the projection image projected onto the reference instrument 51. In this case, the preliminary measurement unit 412, like the target measurement unit 411, identifies the projection coordinates corresponding to the first imaging pixel and the projection coordinates corresponding to the second imaging pixel, and measures the three-dimensional coordinates of a specific position on the reference instrument 51 by utilizing the correspondence between the first imaging pixel, the second imaging pixel, and the projection image. The preliminary measurement unit 412 may use this specific position as a reference point. In other words, the preliminary measurement unit 412 may project a stripe pattern onto the reference instrument 51 and use a specific position commonly measured by multiple measurement systems as a reference point.

The preliminary measurement unit 412 may also obtain the projection coordinates corresponding to the first captured image and the projection coordinates corresponding to the second captured pixel by projecting a projection image including a stripe pattern extending vertically and a projection image including a stripe pattern extending horizontally onto the measurement object. In this case, the preliminary measurement unit 412 can obtain the correspondence between the first captured pixel and the second captured pixel without using the epipolar line by using a projection image including a stripe pattern extending vertically and a projection image including a stripe pattern extending horizontally. Therefore, the preliminary measurement unit 412 can reduce the risk of an error occurring when identifying the epipolar line, resulting in a decrease in measurement accuracy.

The acquisition unit 42 acquires from the storage unit 5 relative position information indicating the positional relationship of multiple reference points included in the reference instrument 51. The positional relationship of the multiple reference points is assumed to have been measured in advance by other measuring instruments. The positional relationship of the multiple reference points is, for example, the two-dimensional coordinates of one of the reference points of the reference instrument 51 when the other reference point is assumed to be the origin.

[Creating reference data]
The reference data generating unit 43 generates reference data based on one or more of the plurality of preliminary measurement data corresponding to the plurality of measurement systems. The reference data is data for making the measurement data of each of the plurality of measurement systems coincide with the measurement data of the other measurement systems.

For example, suppose that the first measurement system indicates that the distance from the projection unit 3 to a specific reference point is 199 millimeters, the second measurement system indicates that the distance from the projection unit 3 to the same reference point is 201 millimeters, and the third measurement system indicates that the distance from the projection unit 3 to the same reference point is 200 millimeters. In this case, for example, the reference data creation unit 43 determines the 199 millimeters measured by the first measurement system as the reference data, corrects the data measured by the second measurement system by subtracting 2 millimeters, and corrects the data measured by the third measurement system by subtracting 1 millimeter, thereby matching the measurement data of each measurement system. Although a method of correcting the distance has been described as an example, in practice it is desirable to correct the three-dimensional coordinates.

The reference data creation unit 43 calculates, for example, a statistical quantity such as the average or median of the three-dimensional coordinates of the same reference point contained in multiple preliminary measurement data corresponding to different measurement systems. The reference data creation unit 43 may create reference data in which the calculated statistical quantity is the three-dimensional coordinate of this reference point. For example, the reference data creation unit 43 calculates the average value of the three-dimensional coordinates of the same reference point measured by the first to third measurement systems. The reference data creation unit 43 creates reference data in which the calculated average value is the three-dimensional coordinate of this reference point.

The reference data creation unit 43 may also refer to the relative position information acquired by the acquisition unit 42, determine the error between the positional relationship indicated by this relative position information and the positional relationship of the multiple reference points indicated by the preliminary measurement data, and select one of the preliminary measurement data based on the determined error.

For example, the reference data creation unit 43 determines the relative coordinates of other reference points in the relative position information when one of the reference points of the reference instrument 51 is set as the origin, and the relative coordinates of other reference points in the preliminary measurement data when the same reference point is set as the origin. The reference data creation unit 43 determines the error between the relative coordinates of other reference points in the relative position information and the corresponding reference point in the preliminary measurement data for each reference point. The reference data creation unit 43 determines error statistics such as the sum of errors and standard deviation at multiple reference points of the reference instrument 51 for each measurement system, and selects the preliminary measurement data of the measurement system that has the smallest statistical amount such as the average of the errors among the multiple measurement systems. Note that the reference data creation unit 43 may use the relative distance from the origin instead of the relative coordinate from the origin.

When multiple reference points are located on a single plane on the reference instrument 51, the reference data creation unit 43 uses the least squares method or the like to identify a virtual plane that has the smallest sum of distances to the multiple reference points on the reference instrument 51 indicated by the preliminary measurement data. The reference data creation unit 43 identifies this plane in multiple pieces of preliminary measurement data corresponding to different measurement systems. The reference data creation unit 43 calculates, for each measurement system, the sum of distances between the identified plane and the multiple reference points on the reference instrument 51 in the preliminary measurement data of the measurement system corresponding to this plane. The reference data creation unit 43 may select the preliminary measurement data of the measurement system that has the smallest sum of calculated distances.

With this configuration, the reference data creation unit 43 can use the preliminary measurement data of the measurement system that most accurately reproduces the plane on which multiple reference points are arranged in the reference instrument 51. The reference data creation unit 43 creates reference data based on the selected preliminary measurement data. For example, the reference data creation unit 43 uses the selected preliminary measurement data as it is as the reference data.

When the deviation between multiple preliminary measurement data corresponding to multiple measurement systems is equal to or greater than a predetermined value, the reference data creation unit 43 may not create reference data and may display an error on a display unit (not shown) indicating that the deviation between the preliminary measurement data is large. In this way, the reference data creation unit 43 can prevent a decrease in the measurement accuracy of the three-dimensional shape due to a malfunction such as a misalignment of the optical device.

[Calculation of correction value]
The calculation unit 44 calculates a correction value based on the preliminary measurement data that does not match the reference data and the reference data created by the reference data creation unit 43. For example, when the reference data creation unit 43 uses preliminary measurement data corresponding to a single measurement system as reference data, the preliminary measurement data that does not match the reference data is preliminary measurement data measured by a measurement system different from the measurement system corresponding to the reference data.

The calculation unit 44 assumes that the reference data creation unit 43 has used the preliminary measurement data by the third measurement system as the reference data. The calculation unit 44 identifies three-dimensional coordinates indicating a predetermined reference point in the first measurement system different from the third measurement system, and identifies three-dimensional coordinates indicating the same reference point in the reference data. The calculation unit 44 calculates the difference ΔC(x _1,i,j , y _1,i,j , z _1,i,j ) between the two three-dimensional coordinates by the following formula (1).
ΔC(x _1,i,j , y _1,i,j , z _1,i,j ) = [x _1,i,j , y _1,i,j , z _1,i,j ] - [x _r,i,j , y _r,i,j z _r,i,j ]. ．． ．． (1)

In formula (1), the "1" in "x1 _,i,j " is an index indicating the first measurement system. i is an index for identifying the reference point (i = 1, 2, ...). j is an index for identifying the installation position of the reference instrument 51 (j = 1, 2, ...). [x1 _,i,j , y1 _,i,j , z1 _,i,j ] are three-dimensional coordinates indicated by the first measurement preliminary measurement data. [ _xr,i,j , _yr,i,j , zr _,i,j ] are three-dimensional coordinates indicated by the reference data.

The calculation unit 44 calculates a correction value for correcting the target measurement data by the first measurement system based on the obtained difference ΔC( _x1,i,j , y1 _,i,j , z1 _,i,j ). As an example, the calculation unit 44 uses the difference ΔC( _x1,i,j , y1,i,j, _z1,i,j ) as the correction value, but the correction value may be calculated by a known method based on the difference ΔC(x1 _{,i ,j} , _y1,i,j , _z1,i,j ).

When the reference data creation unit 43 creates the reference data by, for example, averaging the three-dimensional coordinates of the reference points indicated by multiple preliminary measurement data corresponding to different measurement systems, the preliminary measurement data used to create the reference data may not match the reference data. For this reason, when the calculation unit 44 creates the reference data by, for example, averaging the three-dimensional coordinates of the reference points indicated by multiple preliminary measurement data, the calculation unit 44 may calculate a correction value based on the difference between the three-dimensional coordinates of the reference points indicated by the preliminary measurement data used to create the reference data and the three-dimensional coordinates of the same reference points indicated by the reference data.

The calculation unit 44 calculates correction values corresponding to the reference points of the reference instrument 51 installed at multiple installation positions. For example, when the preliminary measurement unit 412 creates three pieces of preliminary measurement data corresponding to three installation positions with different coordinates in the depth direction, the calculation unit 44 creates correction values corresponding to each of these three pieces of preliminary measurement data. The calculation unit 44 associates an index of the installation position of the reference instrument 51, an index for identifying the measurement system that measured the reference instrument 51, an index for identifying the reference point, and the correction values, and stores them in the memory unit 5.

The calculation unit 44 may also specify a function for calculating a correction value corresponding to the three-dimensional coordinates of a measurement point measured by a measurement system corresponding to the preliminary measurement data that does not match the reference data. For example, the calculation unit 44 may refer to the relationship between the preliminary measurement data by the first measurement system and the corresponding correction value and specify a polynomial function for converting the target measurement data by the first measurement system into a correction value corresponding to the target measurement data by using a known method such as the least squares method. At this time, the function is stored in advance in the storage unit 5 as a part of a program or the like, and the calculation unit 44 specifies a plurality of coefficients of the function stored in the storage unit 5. The function for converting the target measurement data into a correction value [Δc _m,x Δc _m,y Δc _m,z ] can be expressed by the following formula (2). In formula (2), (x _m , y _m , z _m ) are the three-dimensional coordinates of the measurement point. In the function of formula (2), correction values corresponding to each component of the three-dimensional coordinates are calculated.
[Δc _m,x Δc _m,y Δc _m,z ]=[f _x (x _m , y _m , z _m ) f _y (x _m , y _m , z _m ) f _z (x _m , y _m , z _m )]...(2)
This function may be prepared in a plurality of parts, for example, by dividing it in the Z direction (depth direction). In this way, the calculation unit 44 can calculate the correction value using a more accurate function as each polynomial function, thereby obtaining a more accurate correction result.

An example in which the calculation unit 44 creates correction values corresponding to each reference point has been described. The calculation unit 44 may calculate correction values corresponding to positions other than the reference points at which preliminary measurement data was acquired by interpolating based on a plurality of correction values corresponding to a plurality of reference points. The calculation unit 44 may divide the measurement space of each measurement system into an equally spaced cubic lattice, calculate correction values corresponding to each lattice point by interpolating based on a plurality of correction values corresponding to a plurality of reference points, and store in the storage unit 5 a table in which the three-dimensional coordinates of the lattice points, an index for identifying the measurement system, and the calculated correction values are associated with each other. By the calculation unit 44 calculating the correction values for each of such lattice points, when correcting the results of measuring the three-dimensional coordinates of the measurement object, the correction can be performed using the correction value of the lattice point closest to the measured coordinate value.

[Correction of target measurement data]
As an example of the correction unit 45 correcting the target measurement data of the measurement system corresponding to the preliminary measurement data that does not match the reference data based on the correction value, when the reference data creation unit 43 creates the reference data by selecting the preliminary measurement data by the third measurement system, the correction unit 45 corrects the target measurement data of the first measurement system different from the third measurement system. The correction unit 45 reads out from the storage unit 5 a correction value associated with an index of an installation position where the difference between the depth coordinate indicated by the target measurement data and the depth coordinate of the reference point is minimum, an index indicating the first measurement system, and an index indicating a reference point having three-dimensional coordinates closest to the three-dimensional coordinates indicated by the target measurement data. The correction unit 45 corrects the target measurement data by the first measurement system based on the read correction value.

The correction unit 45 may read from the storage unit 5 correction values associated with the three-dimensional coordinates of the lattice point closest to the three-dimensional coordinates indicated by the target measurement data and an index indicating the measurement system corresponding to the lattice point, and correct the target measurement data based on the read correction values. The correction unit 45 may read from the storage unit 5 correction values associated with the three-dimensional coordinates of multiple lattice points relatively close to the three-dimensional coordinates indicated by the target measurement data, and obtain a correction value corresponding to the target measurement data by an interpolation process using the read correction values. Furthermore, when the correction unit 45 obtains a function for converting the target measurement data into a correction value, it may convert the target measurement data into a correction value using this function, and correct the target measurement data based on the converted correction value.

The shape identification unit 46 identifies the shape of the measurement object using the object measurement data corrected by the correction unit 45. The shape identification unit 46 identifies the three-dimensional shape of the measurement object by connecting together the three-dimensional coordinates of the measurement points indicated by the multiple object measurement data after correction. The shape identification unit 46 may also identify the shape of the measurement object by connecting together the three-dimensional coordinates indicated by the multiple object measurement data corresponding to different measurement systems.

The correction unit 45 may not correct the target measurement data of the measurement system corresponding to the reference data. Therefore, when using the target measurement data of the measurement system corresponding to the reference data, the shape identification unit 46 may identify the shape of the measurement object using the target measurement data that has not been corrected by the correction unit 45. The shape identification unit 46 may identify the shape of the measurement object by connecting the three-dimensional coordinates of the measurement point indicated by the target measurement data corresponding to the uncorrected reference data with the three-dimensional coordinates of the measurement point indicated by the corrected target measurement data.

[Processing procedure for calculating correction value]
10 is a flowchart showing a processing procedure for calculating correction values by three-dimensional shape measuring device 100. This processing procedure starts when an operation receiving unit (not shown) of three-dimensional shape measuring device 100 receives a user operation to instruct calibration of each measurement system.

First, the preliminary measurement unit 412 generates captured images of a specific reference instrument 51 in each of the multiple measurement systems (S101). The preliminary measurement unit 412 measures the three-dimensional coordinates of the reference point and creates preliminary measurement data indicating the measured three-dimensional coordinates (S102). The preliminary measurement unit 412 creates multiple pieces of preliminary measurement data corresponding to the multiple measurement systems in S102. The reference data creation unit 43 creates reference data based on one or more of the multiple pieces of preliminary measurement data that have been created (S103).

The calculation unit 44 calculates the difference between the preliminary measurement data that does not match the reference data among the multiple measurement systems and the reference data created by the reference data creation unit 43. Based on this difference, the calculation unit 44 calculates a correction value for correcting the target measurement data measured by the measurement system corresponding to the preliminary measurement data that does not match the reference data (S104), and ends the process.

[Procedure for identifying three-dimensional shapes]
11 is a flowchart showing a process for identifying the three-dimensional shape of a measurement object by three-dimensional shape measuring device 100. This process starts when an operation receiving unit of three-dimensional shape measuring device 100 receives a user operation to instruct the start of measurement of the three-dimensional shape.

First, the object measurement unit 411 projects a projection image including a predetermined light pattern onto the measurement object, etc., using the projection unit 3 (S201). The object measurement unit 411 generates a first captured image by capturing the projection image projected onto the measurement object using the first capture unit 1 (S202). The object measurement unit 411 creates object measurement data indicating the measurement results by measuring the measurement points of the measurement object (S203). The correction unit 45 corrects the object measurement data based on the correction value (S204). The shape identification unit 46 identifies the shape of the measurement object based on the object measurement data corrected by the correction unit 45 (S205).

[Effects of the three-dimensional shape measuring device of this embodiment]
According to the present embodiment, the correction unit 45 can correct the target measurement data by using the reference data for a plurality of measurement systems. Therefore, the correction unit 45 can suppress a decrease in measurement accuracy caused by an error in the measurement system.

The shape identification unit 46 can connect and measure the target measurement data from multiple measurement systems with high accuracy, so even if a location occurs where target measurement data cannot be obtained in one measurement system due to the effects of shadows, saturation, etc., the shape of the measured object can be identified using the target measurement data from another measurement system. This allows the shape identification unit 46 to identify the shape of the measured object more efficiently and with high accuracy.

[Modification]
In this embodiment, an example has been described in which the reference data creation unit 43 creates reference data including three-dimensional coordinates of multiple reference points using preliminary measurement data corresponding to a single measurement system. However, the present invention is not limited to this. The reference data creation unit 43 may create one reference data by selecting one of multiple preliminary measurement data corresponding to different measurement systems for each reference point. For example, the reference data creation unit 43 may select, from the multiple preliminary measurement data corresponding to different measurement systems, the preliminary measurement data corresponding to a measurement system consisting of a combination of optical devices with the largest parallax, for example, so that the accuracy of triangulation for the reference point is the highest.

Figures 12(a) and 12(b) are diagrams showing the selection of a measurement system when the reference data creation unit 43 creates reference data. The reference instrument 51 is shown as viewed from above. In the example of Figure 12, the three-dimensional shape measuring device includes a third imaging unit 300 in addition to the first imaging unit 1 and second imaging unit 2. In the example of Figure 12, the projection unit 3 is omitted. For example, when the preliminary measurement unit 412 uses a reference point on the reference instrument 51, it can create preliminary measurement data using the following fourth to sixth measurement systems.

Fourth measurement system: first imaging unit 1 and second imaging unit 2
Fifth measurement system: first imaging unit 1 and third imaging unit 300
Sixth measurement system: second imaging unit 2 and third imaging unit 300

Figure 12 (a) is a diagram showing the selection of a measurement system corresponding to the reference point at the right end of the bottom row of the reference instrument 51. The reference data creation unit 43 selects a measurement system consisting of a combination of optical devices that has the largest parallax relative to the reference point. When the reference data creation unit 43 selects the fourth measurement system, the parallax formed by the first imaging unit 1 and the second imaging unit 2 with respect to the reference point at the right end of the bottom row is α1. On the other hand, when the reference data creation unit 43 selects the fifth measurement system, the parallax formed by the first imaging unit 1 and the third imaging unit 300 with respect to the reference point at the right end of the bottom row is α2, and this parallax is the largest among the fourth to sixth measurement systems. Therefore, the reference data creation unit 43 selects the preliminary measurement data measured by the fifth measurement system in creating the reference data corresponding to the reference point at the right end of the bottom row.

Figure 12 (b) is a diagram showing the selection of a measurement system corresponding to the reference point at the left end of the top row of the reference instrument 51. When the reference data creation unit 43 selects the fourth measurement system, the parallax formed by the first imaging unit 1 and the second imaging unit 2 with respect to the reference point at the left end of the top row is β1. On the other hand, when the reference data creation unit 43 selects the sixth measurement system, the parallax formed by the second imaging unit 2 and the third imaging unit 300 with respect to the reference point at the left end of the top row is β2, and this parallax is the largest among the fourth to sixth measurement systems. Therefore, the reference data creation unit 43 selects the preliminary measurement data measured by the sixth measurement system in creating the reference data corresponding to the reference point at the left end of the top row. The reference data creation unit 43 creates a single reference data by combining the preliminary measurement data selected for each reference point of the reference instrument 51.

With this configuration, the reference data creation unit 43 creates reference data using preliminary measurement data from a measurement system that maximizes the parallax for each reference point, thereby improving the measurement accuracy of three-dimensional coordinates using the triangulation method.

When using reference points projected onto the reference instrument 51 by one or more projection units, the reference data creation unit 43 is not limited to the example of selecting, for each reference point, preliminary measurement data by a measurement system in which the parallax between two pairs of imaging units is maximum. For example, the reference data creation unit 43 may take into consideration the parallax between two pairs of imaging units and the parallax between a projection unit and an imaging unit, and select, for each reference point, preliminary measurement data by a measurement system including a pair with the maximum parallax.

When the specifications of the multiple imaging units are different from one another, or when the distances from the multiple imaging units to the reference point are different from one another, the measurement system that produces the largest parallax may not match the measurement system that produces the best measurement accuracy. The reference data creation unit 43 may read from the storage unit 5 a table that associates approximate values of the three-dimensional coordinates of the reference point with the measurement system that produces the best measurement accuracy, and may refer to this table to select preliminary measurement data for the measurement system that produces the best measurement accuracy.

The reference data creation unit 43 may also select the preliminary measurement data of the measurement system that provides the best measurement accuracy based on the relative distance from the origin to the reference point. For example, when measuring the reference instrument 51, the reference data creation unit 43 designates one of the reference points on the reference instrument 51 as the origin. The reference data creation unit 43 measures the distance from the designated origin to another reference point C. Meanwhile, the reference data creation unit 43 reads out from the storage unit 5 a value that is pre-stored as the distance from the origin to the reference point C. The reference data creation unit 43 may select the preliminary measurement data of the measurement system that provides the smallest difference between the measured distance and the distance read out from the storage unit 5 as the best measurement accuracy of the reference point C.

Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination also has the effect of the original embodiment.

Reference Signs List 1 First imaging unit 2 Second imaging unit 3 Projection unit 4 Control unit 5 Memory unit 11 Lens 12 Imaging element 21 Lens 22 Imaging element 41 Measurement unit 42 Acquisition unit 43 Reference data creation unit 44 Calculation unit 45 Correction unit 46 Shape specification unit 100 Three-dimensional shape measuring device 300 Third imaging unit 411 Object measurement unit 412 Preliminary measurement unit

Claims (9)

A three-dimensional shape measuring device that measures a three-dimensional shape of a measurement object based on an image of the measurement object, comprising:
A plurality of optical devices;
a preliminary measurement unit that creates a plurality of preliminary measurement data indicating three-dimensional coordinates of a plurality of reference points on the reference instrument by capturing images of the reference instrument using a plurality of measurement systems each consisting of a combination of different optical devices among the plurality of optical devices;
a reference data creation unit that creates one reference data by selecting, for each reference point, one of the plurality of preliminary measurement data corresponding to the plurality of measurement systems based on one or more of the plurality of preliminary measurement data;
a calculation unit that calculates a correction value based on the preliminary measurement data that does not match the reference data among the plurality of preliminary measurement data and the reference data;
an object measurement unit that generates a plurality of object measurement data indicating results of measuring a measurement point of the measurement object in the plurality of measurement systems;
a correction unit that corrects the target measurement data in the measurement system corresponding to the preliminary measurement data that does not match the reference data based on the correction value;
a shape specifying unit that specifies a shape of the measurement object using the object measurement data corrected by the correction unit;
A three-dimensional shape measuring apparatus comprising: the preliminary measurement unit creates the preliminary measurement data indicating three-dimensional coordinates of the reference point of the reference instrument at the multiple installation positions by capturing images of the reference instrument installed at multiple installation positions;
The calculation unit calculates the correction value corresponding to the reference point at the plurality of installation positions.
The three-dimensional shape measuring apparatus according to claim 1 . the reference data creation unit creates the reference data by calculating statistics of three-dimensional coordinates of the reference points indicated by the plurality of preliminary measurement data corresponding to the plurality of measurement systems.
The three-dimensional shape measuring apparatus according to claim 1 or 2. An acquisition unit that acquires relative position information indicating a positional relationship between a plurality of the reference points included in the reference instrument,
the preliminary measurement unit creates the preliminary measurement data indicating three-dimensional coordinates of the plurality of reference points;
the reference data creation unit creates the reference data by selecting the preliminary measurement data indicating three-dimensional coordinates of the plurality of reference points based on an error from the positional relationship indicated by the relative position information.
The three-dimensional shape measuring apparatus according to claim 1 . the reference data creation unit selects, from among the plurality of pieces of preliminary measurement data corresponding to the plurality of measurement systems, the preliminary measurement data corresponding to a combination of the optical devices that provides the best triangulation accuracy with respect to the reference point.
The three-dimensional shape measuring apparatus according to claim 1 . The preliminary measurement unit projects a projection image including a pattern for identifying the reference point onto the reference instrument.
The three-dimensional shape measuring apparatus according to claim 1 . the calculation unit specifies a function for calculating the correction value corresponding to the three-dimensional coordinates of the reference point measured by the measurement system corresponding to the preliminary measurement data that does not match the reference data, and calculates the correction value using the specified function.
The three-dimensional shape measuring apparatus according to claim 1 . the calculation unit further includes a storage unit configured to store a table in which three-dimensional coordinates of individual lattice points obtained by dividing a measurement space of the plurality of measurement systems by an equally spaced cubic lattice, the plurality of correction values, and an index for identifying each of the plurality of measurement systems are associated with each other;
the correction unit reads out from the storage unit the correction value associated with the three-dimensional coordinate of the lattice point closest to the three-dimensional coordinate indicated by the object measurement data and an index indicating the measurement system corresponding to the lattice point, and corrects the object measurement data based on the read correction value.
The three-dimensional shape measuring apparatus according to claim 1 . A three-dimensional shape measuring method for measuring a three-dimensional shape of a measurement object based on an image obtained by capturing an image of the measurement object, comprising:
A step of generating a plurality of preliminary measurement data indicating three-dimensional coordinates of a plurality of reference points on the reference instrument by capturing images of the reference instrument using a plurality of measurement systems each formed of a combination of different optical instruments among a plurality of optical instruments;
creating one reference data by selecting, for each reference point, any of the plurality of preliminary measurement data corresponding to the plurality of measurement systems based on one or more of the plurality of preliminary measurement data ;
calculating a correction value based on the preliminary measurement data that does not match the reference data among the plurality of preliminary measurement data and the reference data;
creating a plurality of object measurement data representing results of measuring the measurement points of the measurement object in the plurality of measurement systems;
correcting the target measurement data in the measurement system corresponding to the preliminary measurement data that does not match the reference data based on the correction value;
identifying a shape of the measurement object using the corrected object measurement data;
A three-dimensional shape measuring method comprising:

Images