Jig and method for correcting measurement device for measuring three-dimensional shape and measurement system

Abstract

To easily correct a measurement device for measuring the three-dimensional shape of a measurement target.SOLUTION: The present invention relates to a jig for correction having a plurality of imaging units for imaging a measurement target, the jig correcting a measurement device for measuring the three-dimensional shape of a measurement target. The jig for correction includes a plurality of measurement target elements and a frame part to which the measurement target elements are attached. Each of the measurement target elements has a body part in a predetermined shape and a plurality of label parts in the body part indicating identification codes for identifying the measurement target elements.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a calibration jig, a calibration method, and a measurement system for a measurement apparatus that measures a three-dimensional shape. [Background technology]

[0002] There is known a measuring device that includes multiple imaging devices and that measures the three-dimensional shape of a measurement object in a non-contact manner based on the results of imaging the measurement object from multiple directions (see, for example, Patent Document 1). In such a measuring device, the multiple imaging devices image the same calibration jig, or the multiple imaging devices image a calibration jig of known dimensions, thereby calibrating the device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-507885 [Non-patent literature]

[0004] [Non-Patent Document 1] Toru Tamaki, "Pose Estimation and Rotation Matrix", IEICE Technical Report, Institute of Electronics, Information and Communication Engineers, 2009, SIP2009-48, SIS2009-23, pp.59-64 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the multiple imaging devices each image the calibration jig from a different angle, it can be difficult to identify which part of the calibration jig is being imaged from each imaging result. Also, in the case of a measuring device that measures the three-dimensional shape of a large measurement object or a measuring device that measures the three-dimensional shape of a complex measurement object, the multiple imaging devices are arranged in various positions, so it can be difficult for the multiple imaging devices to image the same calibration jig.

[0006] The present invention has been made in consideration of these points, and has an object to easily calibrate a measuring device that measures the three-dimensional shape of a measurement target. [Means for solving the problem]

[0007] In a first aspect of the present invention, there is provided a calibration jig for calibrating a measuring device for measuring the three-dimensional shape of a measurement object, the calibration jig comprising a plurality of imaging sections for imaging a measurement object, the calibration jig comprising a plurality of elements to be measured and a frame section to which the plurality of elements to be measured are attached, each of the plurality of elements to be measured having a main body section of a predetermined shape and a label section provided in plurality on the main body section and displaying an identification code for identifying the elements to be measured.

[0008] The label portion may further include an identification code common to the plurality of elements to be measured for identifying the label portion.

[0009] The identification code may be composed of a combination of basic parts of a predetermined first shape, and the recognition code may be composed of a combination of basic parts of a predetermined second shape having a different size from the first shape.

[0010] The identification code may be composed of a combination of basic parts of a predetermined first shape, and the recognition code may have basic parts of a predetermined color different from the colors of the basic parts of the first shape.

[0011] The identification code may be composed of a combination of basic portions of a predetermined first shape, and the recognition code may have a portion on which a predetermined image is displayed.

[0012] Each of the plurality of elements to be measured may further include a band-shaped plate member provided around the main body portion, and a plurality of the label portions may be provided on the plate member.

[0013] The apparatus may further include a frame moving section that moves the frame section together with the plurality of devices under test.

[0014] The frame portion may have a spherical or ellipsoidal shape, and each of the plurality of elements to be measured may be provided on a surface of the spherical or ellipsoidal shape of the frame portion.

[0015] In a second aspect of the present invention, there is provided a calibration method for calibrating a measuring device for measuring a three-dimensional shape of a measurement object using a calibration jig, the calibration jig including a plurality of imaging units for imaging a measurement object, the measurement device including a plurality of measurement target elements, each of the plurality of measurement target elements having a main body portion of a predetermined shape and a label portion provided in a plurality of the main body portion and displaying an identification code for identifying the measurement target element, the calibration jig is imaged by a first imaging unit so that a first measurement target element among the plurality of measurement target elements is within a field of view, and the first measurement target element imaged by the first imaging unit is determined as a measurement target element. The present invention provides a calibration method, comprising: a first imaging step of imaging the calibration jig with a second imaging unit different from the first imaging unit so that a different portion of second measured elements is within the field of view; a step of analyzing the label portion of the measured element from the image captured by the first imaging unit to identify the first measured element and analyzing the label portion of the measured element from the image captured by the second imaging unit to identify the second measured element; and a step of identifying calibration parameters for calibrating the first imaging unit and the second imaging unit from the identified positional relationship between the first measured element and the second measured element.

[0016] a second imaging step of imaging the first measured element by the first imaging unit and the second measured element by the second imaging unit after the first imaging step, moving the calibration jig in a predetermined first direction, and then imaging the first measured element by the first imaging unit and the second measured element by the second imaging unit after the second imaging step, a third imaging step of imaging the first measured element by the first imaging unit and the second measured element by the second imaging unit after the second imaging step, and a fourth imaging step of imaging the second measured element by the second imaging unit; a fifth imaging step of, after the fourth imaging step, rotating the calibration jig about an axis in a predetermined third direction, imaging the first measured element by the first imaging unit, and imaging the second measured element by the second imaging unit; and, after the fifth imaging step, rotating the calibration jig about an axis in a predetermined fourth direction different from the third direction, imaging the first measured element by the first imaging unit, and imaging the second measured element by the second imaging unit. and a step of identifying a first coordinate position indicating a position of the first measured element in a first coordinate based on a field of view of the first imaging unit in a plurality of captured images captured by the first imaging unit and a second coordinate position indicating a position of the second measured element in a second coordinate based on a field of view of the second imaging unit in a plurality of captured images captured by the second imaging unit, and the step of identifying the calibration parameters may include a step of identifying a first rotation matrix for rotating the first coordinates to perform coordinate conversion and a second rotation matrix for rotating the second coordinates to perform coordinate conversion such that a direction in which the first coordinate position moves and a direction in which the second coordinate position moves coincide before and after movement of the calibration jig in the first direction and the second direction, and a step of identifying a first translation vector for translating the first coordinates and a second translation vector for translating the second coordinates such that a distance between the first measured element and the second measured element coincide before and after rotation of the calibration jig.

[0017] After identifying the first rotation matrix, the second rotation matrix, the first translation vector, and the second translation vector, the method may further include a step of coordinate converting the first coordinate position and the second coordinate position into calibration coordinates by rotating the first coordinate position by the first rotation matrix and translating it by the first translation vector, and rotating the second coordinate position by the second rotation matrix and translating it by the second translation vector.

[0018] In a third aspect of the present invention, there is provided a measurement system comprising the measurement device that measures a three-dimensional shape of the object to be measured, and the calibration jig for calibrating the measurement device, wherein the measurement device comprises a moving unit for mounting and moving the object to be measured, a light source for irradiating the object to be measured with light, a plurality of imaging units that respectively image a plurality of different areas of the object to be measured, a measurement unit that measures the three-dimensional shape of the object to be measured based on the imaging results of the plurality of imaging units, a control unit that controls the moving unit, the imaging units, and the measurement unit, and an identification unit that identifies the calibration parameters for calibrating the measurement results of the measurement unit, and the calibration jig comprises a plurality of the elements to be measured, and and a frame portion to which the plurality of measured elements are attached, each of the plurality of measured elements having the main body portion of a predetermined shape and the label portion, which is provided in plurality on the main body portion and displays an identification code for identifying the measured element, the control unit causes the plurality of imaging units to respectively image different parts of the plurality of measured elements, the measurement unit analyzes the label portions of the plurality of measured elements corresponding to each of a plurality of imaged images captured by the plurality of imaging units to identify the positional relationship of the plurality of measured elements, and the identification unit identifies calibration parameters for calibrating the plurality of imaging units from the identified positional relationship of the plurality of measured elements. Effect of the Invention

[0019] The present invention has an effect of making it possible to easily calibrate a measuring device that measures the three-dimensional shape of a measurement target. [Brief description of the drawings]

[0020] [Figure 1] 1 shows an example of the configuration of a measurement system S according to this embodiment. [Diagram 2] An example is shown in which a calibration jig 30 is mounted on the measurement device 10 according to the present embodiment. [Diagram 3] 2 shows an example of the configuration of a control unit 140 according to the present embodiment. [Figure 4] 1 shows an example of an operation flow of the measurement device 10 according to the present embodiment. [Diagram 5] 1 shows a first example of the coordinate position of the device under test 31 identified by the measuring section 243 according to the present embodiment. [Figure 6] 13 shows a second example of the coordinate position of the device under test 31 identified by the measuring section 243 according to the present embodiment. [Figure 7] 13 shows an example of an operation flow of the control unit 240 according to the present embodiment. [Figure 8] 1 shows an example of the configuration of a calibration jig 300 according to the present embodiment. [Figure 9] 1 shows a first configuration example of a device under test 31 according to the present embodiment. [Figure 10] An example of a luminance signal that can be acquired based on the label portion 33 shown in FIG. 9 is shown below. [Figure 11] 11 shows an example of a process in which the control unit 240 according to the present embodiment processes the image pickup result of the imaging unit 132. [Figure 12] 2 shows a second configuration example of the device under test 31 according to the present embodiment. [Figure 13] An example of a luminance signal that can be acquired based on the label portion 33 shown in FIG. 12 is shown below. [Figure 14] 13 shows a third configuration example of the device under test 31 according to the present embodiment. [Figure 15] 13 shows a fourth configuration example of the device under test 31 according to the present embodiment. [Figure 16] 2 shows a second configuration example of the calibration jig 300 according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] <Example of measurement system S configuration> 1 shows an example of the configuration of a measurement system S according to this embodiment. The measurement system S includes a measurement device 10 and a calibration jig 30.

[0022] The measuring device 10 irradiates light from multiple directions onto a measurement object W (hereinafter also referred to as workpiece W) arranged in a three-dimensional space, and receives the reflected light to measure the three-dimensional shape of the measurement object W. The measuring device 10 also irradiates light from multiple directions onto a calibration jig 30 arranged in a three-dimensional space, and receives the reflected light to identify calibration parameters used for its own calibration. The measuring device 10 includes a stage 110, a moving section 120, an optical unit 130, and a control unit 140.

[0023] The stage 110 carries a measurement target W. When the measurement system S calibrates the measurement device 10, the stage 110 carries a calibration jig 30. The stage 110 is configured to be movable in a plurality of predetermined directions. In this embodiment, an example will be described in which the stage 110 is configured to be movable in a first direction and a second direction different from the first direction. The first direction and the second direction are, for example, perpendicular to each other.

[0024] For example, the stage 110 has a function of an XY stage that is movable in the X and Y directions on an XY plane. In this case, the first direction is the X or Y direction, and the second direction is the Y or X direction.

[0025] Moreover, the stage 110 is configured to be rotatable around a plurality of predetermined directions as axes. In this embodiment, an example will be described in which the stage 110 is configured to be rotatable around a third direction and a fourth direction different from the third direction as axes. The third direction and the fourth direction are, for example, perpendicular to each other. Here, the first direction and the third direction may be the same, and the second direction and the fourth direction may be the same.

[0026] For example, the stage 110 has a function of a rotation stage that can rotate about an axis in the X direction and a function of a rotation stage that can rotate about an axis in the Y direction. In this case, the third direction is the X direction or the Y direction, and the fourth direction is the Y direction or the X direction. Note that the measuring device 10 only needs to be configured to be able to move the calibration jig 30, and instead of the stage 110, a movable arm or the like that can move the calibration jig 30 while fixing it may be provided.

[0027] The moving unit 120 moves the stage 110. In other words, when the stage 110 has a measurement target W mounted thereon, the moving unit 120 moves the measurement target W. Furthermore, when the stage 110 has a calibration jig 30 mounted thereon, the moving unit 120 moves the calibration jig 30. The moving unit 120 has an actuator such as a motor, and moves the stage 110 in a first direction or a second direction. Furthermore, the moving unit 120 rotates the stage 110 around an axis in the third direction. Similarly, the moving unit 120 rotates the stage 110 around an axis in the fourth direction.

[0028] The optical unit 130 has a light source 131 and an imaging section 132. The light source 131 irradiates light onto the measurement object W. The light source 131 has at least one of a halogen lamp, an LED, a laser, or the like. The light source 131 is, for example, a projector that irradiates light of a predetermined pattern. The light irradiated from the light source 131 is reflected by the measurement object W. The imaging section 132 receives the reflected light from the measurement object W and images the measurement object W. The imaging section 132 has a camera capable of capturing still images, videos, and the like. The imaging section 132 may have multiple cameras.

[0029] The optical units 130 are provided at different positions in the measurement device 10. In other words, the light sources 131 irradiate different regions of the measurement target W with light, and the imaging units 132 image different regions of the measurement target W, respectively. The imaging units 132 of the optical units 130 image different parts of the measurement target W, for example. In this case, it is desirable that the optical units 130 are arranged so that the overall configuration of the measurement target W can be grasped by combining the imaging results of the imaging units 132. In this embodiment, for the sake of simplicity, an example in which two optical units 130 are arranged will be described, but the present invention is not limited to this. Three or more optical units 130 may be arranged.

[0030] The control unit 140 controls the moving section 120 and the optical unit 130. When the stage 110 is carrying the measurement object W, the control unit 140 acquires an imaging result of the measurement object W by the imaging section 132 from the optical unit 130, and measures the three-dimensional shape of the measurement object W based on the acquired imaging result. When the stage 110 is carrying the calibration jig 30, the control unit 140 acquires an imaging result of the calibration jig 30 by the imaging section 132 from the optical unit 130, and identifies calibration parameters to be used for calibrating the measuring device 10 based on the acquired imaging result. The control unit 140 will be described later.

[0031] The calibration jig 30 has a plurality of elements to be measured 31 of a predetermined shape, and is a jig for calibrating the measuring device 10. In this embodiment, an example will be described in which the calibration jig 30 has the elements to be measured 31 on its upper surface. It is desirable that the calibration jig 30 is provided with the plurality of elements to be measured 31 so that the plurality of elements to be measured 31 are within the field of view of the imaging section 132 of one optical unit 130 when the calibration jig 30 is mounted on the stage 110.

[0032] Fig. 2 shows an example in which the measuring device 10 according to this embodiment is equipped with the calibration jig 30. Fig. 2 shows an example in which a first measured element 31a is included in a field of view 133a of a first imaging section 132a of a first optical unit 130a, and a second measured element 31b is included in a field of view 133b of a second imaging section 132b of a second optical unit 130b.

[0033] In this embodiment, an example has been shown in which different elements 31 are included in the field of view 133a of the first imaging section 132a and the field of view 133b of the second imaging section 132b, but the present invention is not limited to this. For example, a part or all of the first element 31a may be included in the field of view 133a of the first imaging section 132a, and a part or all of the first element 31a may be included in the field of view 133b of the second imaging section 132b.

[0034] Each optical unit 130 can image the measured element 31 in the field of view by irradiating the calibration jig 30 with light from the light source 131 and capturing an image with the imaging section 132. Then, the control unit 140 acquires the image capturing result from the imaging section 132 and measures the three-dimensional shape of the measured element 31. The measured element 31 has a predetermined size and a predetermined shape. The measured element 31 may be formed with predetermined dimensions. Furthermore, the measured elements 31 may each have a different shape, mark, color, etc. In this embodiment, an example will be described in which the measured element 31 has a spherical shape, and the control unit 140 measures the center position of the sphere.

[0035] Here, the dimensions and positional relationship of the multiple elements under measurement 31 provided on the calibration jig 30 may be known in advance. In this case, the control unit 140 can calibrate the measuring apparatus 10 by comparing the known dimensions and positional relationship of the elements under measurement 31 with the measurement results of the three-dimensional shape of the elements under measurement 31. For example, the control unit 140 specifies, as calibration parameters, coefficients or the like to be multiplied with the measurement results of the three-dimensional shape of the elements under measurement 31 so that the measurement results of the three-dimensional shape of the elements under measurement 31 match the dimensions and positional relationship of the elements under measurement 31.

[0036] However, in the case of a measuring device 10 for measuring a large measurement target, the calibration jig 30 also becomes large, which can make it difficult to measure precise dimensions. Also, in the case of a measuring device 10 for measuring a complex measurement target, the shape, arrangement, etc. of the calibration jig 30 becomes complex, which can make it difficult to measure precise dimensions.

[0037] On the other hand, even if the dimensions of such a calibration jig 30 can be measured, the dimensions may fluctuate due to environmental changes, or may be subject to impacts, causing dimensional deviations, making it difficult to easily calibrate the measuring device 10. Therefore, the measuring system S according to this embodiment makes it possible to calibrate the measuring device 10 even when using a calibration jig 30 in which the dimensions and positional relationship of multiple elements to be measured 31 are unknown. The control unit 140 of such a measuring device 10 will be described next.

[0038] <Configuration example of control unit 140> 3 shows an example of the configuration of the control unit 140 according to this embodiment. The control unit 140 is, for example, a computer. The control unit 140 includes a communication unit 210, a storage unit 220, a display unit 230, and a control unit 240.

[0039] The communication unit 210 communicates with the moving unit 120 and the optical unit 130. The communication unit 210 transmits, for example, a control signal for moving the measurement target W or the calibration jig 30 to the moving unit 120. The communication unit 210 may also transmit a control signal for controlling the light source 131 and the imaging unit 132 to the optical unit 130. The communication unit 210 may receive an imaging result of the imaging unit 132 from the optical unit 130.

[0040] The communication unit 210 communicates via a dedicated connection line, a communication network, etc. The communication unit 210 may function as an interface for connecting to a communication network such as an Internet line, a wireless LAN, or a mobile phone network.

[0041] The storage unit 220 is a storage medium including, for example, a read only memory (ROM) and a random access memory (RAM). The storage unit 220 may also include a large-capacity storage device such as a hard disk drive (HDD) and / or a solid state drive (SSD). For example, when a computer functions as the control unit 140, the storage unit 220 may store information such as an operating system (OS) that causes the computer to function, and programs. The storage unit 220 may also store various information including data referenced when a program is executed.

[0042] The storage unit 220 may also store intermediate data, calculation results, thresholds, reference values, parameters, etc. that are generated (or used) by the control unit 140 during the operation process. The storage unit 220 may also supply the stored data to a request source in response to a request from each section in the control unit 140.

[0043] Display unit 230 displays information related to the measurement by measurement device 10. Display unit 230 displays information such as measurement conditions, measurement items, and measurement results. Display unit 230 may also display the communication state of control unit 140, the OS, the execution state of applications, and the like. Display unit 230 is, for example, a liquid crystal display or the like, a monitor, or the like.

[0044] The control unit 240 controls each unit of the measuring device 10. For example, the control unit 240 transmits and receives various information via the communication unit 210. The control unit 240 is, for example, a CPU (Central Processing Unit). The control unit 240 controls the moving unit 120 and the imaging unit 132 to measure the three-dimensional shape of the measurement target W based on the imaging results of the multiple imaging units 132.

[0045] The control unit 240 has a signal output unit 241, an acquisition unit 242, a measurement unit 243, a rotation matrix identification unit 244, and a translation vector identification unit 245. In other words, the CPU executes a program stored in the storage unit 220 to function as the control unit 240 having the signal output unit 241, the acquisition unit 242, the measurement unit 243, the rotation matrix identification unit 244, and the translation vector identification unit 245.

[0046] The signal output unit 241 outputs a control signal for controlling each unit of the measurement device 10 to the communication unit 210. The signal output unit 241 outputs, for example, a control signal for controlling the light source 131 and the imaging unit 132 of the optical unit 130. As an example, the signal output unit 241 outputs a control signal for causing the light source 131 of the one optical unit 130 to emit light in a predetermined pattern, and a control signal for causing the imaging unit 132 of the one optical unit 130 to capture an image. As a result, the communication unit 210 transmits the control signal to the one optical unit 130, and the one optical unit 130 captures an image of a subject (for example, the measured element 31) in the field of view.

[0047] Furthermore, the signal output unit 241 outputs a control signal for driving the moving unit 120. The signal output unit 241 may output a control signal for displaying information or the like on the display unit 230. The signal output unit 241 may generate a control signal corresponding to an operation purpose, or may output a control signal of a predetermined signal pattern. The signal pattern of the control signal may be stored in the storage unit 220.

[0048] The acquisition section 242 acquires data of an image captured by the imaging section 132 of the optical unit 130 as an imaging result. The acquisition section 242 may store the acquired imaging result of the imaging section 132 in the storage section 220. The acquisition section 242 may also acquire information on the current position of the stage 110.

[0049] The measuring unit 243 measures the three-dimensional shape of the measurement object W or the calibration jig 30 based on the imaging results of the imaging unit 132 acquired by the acquiring unit 242. The measuring unit 243 measures, for example, the length of a predetermined portion of the measurement object W, the dimensions of a predetermined shape, etc. By using the imaging results of the multiple imaging units 132, the measuring unit 243 can also measure the length and shape of a predetermined portion of the measurement object W that cannot fit within the field of view of one imaging unit 132. The operation of the measuring unit 243 to measure the three-dimensional shape of the measurement object W from the imaging results of the multiple imaging units 132 is known, so a detailed description will be omitted here.

[0050] The rotation matrix identifying unit 244 identifies a rotation matrix used for calibrating the measurement device 10. The translation vector identifying unit 245 identifies a translation vector used for calibrating the measurement device 10. The operations of the rotation matrix identifying unit 244 and the translation vector identifying unit 245 will be described next.

[0051] <An example of an operation flow of the measuring device 10> Fig. 4 shows an example of an operation flow of the measurement device 10 according to this embodiment. The measurement device 10 executes the operations from S51 to S66 shown in Fig. 4 to identify calibration parameters used for its own calibration. Although the measurement device 10 is configured to include multiple optical units 130, this operation flow will be simplified and an operation example using the first optical unit 130a and the second optical unit 130b will be described.

[0052] First, the measuring device 10 calibrates each optical unit 130 before calibrating the measuring device 10 using the calibration jig 30. In this case, the measuring device 10 calibrates each optical unit 130 using a reference jig that is smaller in size than the calibration jig 30. The size of the reference jig is, for example, large enough to fit within the field of view of the imaging section 132 included in one optical unit 130.

[0053] The reference jig has a plurality of reference measurement elements whose dimensions and / or positional relationship are known. As an example, the reference measurement elements have substantially the same shape as the measured element 31. Alternatively, the reference jig may have a shape whose dimensions are known. Such a small reference jig is a commonly used jig whose dimensions change little over time and is easy to handle. Calibration of each optical unit 130 using such a reference jig is known, so the calibration operation will be briefly described here.

[0054] First, a reference jig is mounted on stage 110 of measuring device 10 (S51). A plurality of reference jigs may be mounted on stage 110, or alternatively, a single reference jig may be mounted. When a plurality of reference jigs are mounted on stage 110, it is desirable to arrange the plurality of reference jigs so that they are within the field of view of each of optical units 130. Then, control unit 240 performs calibration for each optical unit 130 (S52).

[0055] For example, the control unit 240 captures an image of the reference jig with the first imaging unit 132a of the first optical unit 130a, and calibrates a first coordinate indicating a coordinate position in the field of view 133a of the first imaging unit 132a based on the imaging result of the first imaging unit 132a. Then, the control unit 240 specifies a first coefficient by which to multiply the measurement result of the three-dimensional shape of the reference measuring element of the reference jig so that the measurement result of the three-dimensional shape of the reference measuring element coincides with the known dimensions and positional relationship of the reference measuring element.

[0056] Next, the control unit 240 captures an image of the reference jig with the second imaging unit 132b of the second optical unit 130b, and calibrates second coordinates indicating a coordinate position in the field of view 133b of the second imaging unit 132b based on the imaging result of the second imaging unit 132b. Note that when one reference jig is mounted on the stage 110, for example, when the calibration of the first optical unit 130a is completed, the control unit 240 moves the stage 110 so that the reference jig is included in the field of view of the second optical unit 130b to be calibrated next, and then starts the calibration of the second optical unit 130b.

[0057] The control unit 240, similar to the calibration of the first optical unit 130a, specifies a second coefficient by which to multiply the measurement result of the three-dimensional shape of the reference measurement element based on the imaging result of the second imaging unit 132b so that the measurement result of the three-dimensional shape of the reference measurement element based on the imaging result of the second imaging unit 132b matches the known dimensions and positional relationship of the reference measurement element. As described above, the control unit 240 calibrates each of the multiple optical units 130. The control unit 240 may store the specified coefficient in the storage unit 220.

[0058] Next, the stage 110 of the measuring device 10 mounts the calibration jig 30 (S53). Next, the control unit 240 captures an image of the calibration jig 30 placed at the first reference position (S54). The first reference position is a predetermined position, such as the initial position of the stage 110. For example, it is desirable that the positional relationship between the calibration jig 30, the multiple optical units 130, and the first reference position is determined in advance so that multiple elements to be measured 31 of the calibration jig 30 fall within the fields of view 133 of the multiple imaging units 132 when the calibration jig 30 is placed at the first reference position.

[0059] The control unit 240, for example, moves the stage 110 to place the calibration jig 30 at a first reference position. Then, the control unit 240 turns on the light sources 131 of the multiple optical units 130 and then images the calibration jig 30 with the imaging unit 132. As a result, at the first reference position, among the multiple measured elements 31 included in the calibration jig 30, the first imaging unit 132a images the first measured element 31a, and the second imaging unit 132b, which is different from the first measured element 31a, images the second measured element 31b, which is different from the first imaging unit 132a.

[0060] Next, the control unit 240 moves the calibration jig 30 in a predetermined first direction from the first reference position (S55). The control unit 240 moves, for example, the stage 110 in the first direction by a predetermined distance. Note that it is desirable for the control unit 240 to move the stage 110 in the first direction within a range in which a plurality of elements to be measured 31 of the calibration jig 30 are included in the fields of view of the plurality of imaging units 132.

[0061] Then, the control unit 240 images the calibration jig 30 using the multiple optical units 130 (S56). The control unit 240 turns on the light sources 131 of the multiple optical units 130 and then images the calibration jig 30 with the imaging unit 132. As a result, the first imaging unit 132a images the first measured element 31a that has moved in the first direction, and the second imaging unit 132b images the second measured element 31b that has moved in the first direction.

[0062] Next, the control unit 240 moves the calibration jig 30 from the first reference position in a predetermined second direction different from the first direction (S57). For example, the control unit 240 returns the stage 110 to the first reference position and then moves it a predetermined distance in the second direction. Alternatively, the control unit 240 may move the stage 110 a predetermined distance in the second direction and then return it in the direction opposite to the first direction by the distance moved in S55.

[0063] Alternatively, the control unit 240 may move the stage 110 a predetermined distance in the second direction and subtract the distance moved in S55 from the measurement result. It is desirable that the control unit 240 moves the stage 110 in the second direction within a range in which a plurality of elements to be measured 31 of the calibration jig 30 are included in the fields of view of the plurality of imaging units 132.

[0064] Then, the control unit 240 captures an image of the calibration jig 30 using the multiple optical units 130 (S58). The control unit 240 captures an image of the calibration jig 30 by the same operation as in S56. As a result, the first imaging unit 132a captures an image of the first measured element 31a that has moved in the second direction, and the second imaging unit 132b captures an image of the second measured element 31b that has moved in the second direction.

[0065] Next, the control unit 240 captures an image of the calibration jig 30 placed at the second reference position (S59). The second reference position is a predetermined position, for example, an initial position of the stage 110. The second reference position is a position where, like the first reference position, a plurality of elements to be measured 31 of the calibration jig 30 fall within the fields of view 133 of the imaging units 132 when the calibration jig 30 is placed at the second reference position.

[0066] For example, the control unit 240 moves the stage 110 to the second reference position, and then captures an image of the calibration jig 30 with the imaging unit 132 in the same manner as in the operation of S54. The second reference position may be a position after the calibration jig 30 is moved in the second direction. In this case, the operation of S59 will have the same result as the operation of S58, so the operation of S59 may be omitted. The second reference position may be the same position as the first reference position, and in this case, the result of the operation of S59 will be the same as the result of the operation of S54, so the control unit 240 may simply move the calibration jig 30 to the second reference position.

[0067] Next, the control unit 240 rotates the calibration jig 30 in a predetermined direction around a predetermined third direction as an axis (S60). The control unit 240 rotates the stage 110 by a predetermined angle θ within a range in which a plurality of elements to be measured 31 of the calibration jig 30 are included in the fields of view 133 of the plurality of imaging units 132, for example.

[0068] Then, the control unit 240 captures an image of the calibration jig 30 using the multiple optical units 130 (S61). The control unit 240 captures an image of the calibration jig 30 by the same operation as in S56. As a result, the first imaging unit 132a captures an image of the first measured element 31a after it has been rotated about the third direction as an axis, and the second imaging unit 132b captures an image of the second measured element 31b after it has been rotated about the third direction as an axis.

[0069] Next, the control unit 240 rotates the calibration jig 30 in a predetermined direction around a predetermined fourth direction different from the third direction as an axis (S62). For example, the control unit 240 returns the stage 110 by a predetermined angle θ around the third direction as an axis, and then rotates the stage 110 by a predetermined angle φ around the fourth direction as an axis within a range in which a plurality of elements to be measured 31 of the calibration jig 30 are included in the fields of view 133 of the plurality of imaging units 132.

[0070] Alternatively, the control unit 240 may rotate the stage 110 by a predetermined angle φ around the fourth direction as an axis, and then return it by a predetermined angle θ around the third direction as an axis. Alternatively, the control unit 240 may rotate the stage 110 by a predetermined angle φ around the fourth direction as an axis, and subtract from the measurement result the amount of rotation by the predetermined angle φ around the fourth direction as an axis.

[0071] Then, the control unit 240 captures an image of the calibration jig 30 using the multiple optical units 130 (S63). The control unit 240 captures an image of the calibration jig 30 by the same operation as in S61. As described above, the control unit 240 outputs a control signal from the signal output unit 241 to move the calibration jig 30, while capturing images of the measured elements 31 by the multiple imaging units 132 before and after the movement of the calibration jig 30. Then, the acquisition unit 242 acquires the imaging results of the imaging units 132.

[0072] 4, an example in which the control unit 240 executes the movement of the calibration jig 30 in the first direction, the movement in the second direction, the rotation by the angle θ, and the rotation by the angle φ in this order has been described, but the present invention is not limited to this. The control unit 240 may execute the movement of the calibration jig 30 in the first direction, the movement in the second direction, the rotation by the angle θ, and the rotation by the angle φ in an order different from that shown in FIG.

[0073] Next, the control unit 240 specifies the coordinate position of the measured element 31 for each position to which the calibration jig 30 has been moved based on the imaging results of the multiple imaging units 132 (S64). For example, the measurement unit 243 specifies a first coordinate position indicating the position of the first measured element 31a in the first coordinate based on the field of view of the first imaging unit 132a in the multiple captured images captured by the first imaging unit 132a. The measurement unit 243 also specifies a second coordinate position indicating the position of the second measured element 31b in the second coordinate based on the field of view of the second imaging unit 132b in the multiple captured images captured by the second imaging unit 132b.

[0074] <First example of coordinate position of device under test 31> Fig. 5 shows a first example of the coordinate position of the measured element 31 identified by the measuring unit 243 according to this embodiment. Fig. 5 shows an example in which the measuring unit 243 measures the center positions of three spherical measured elements 31 based on the operation results from S53 to S58 shown in Fig. 4, and plots the coordinate positions of the measurement results. Note that it is preferable that the measuring unit 243 calculates the coordinate positions of the measurement results using the first coefficient and the second coefficient identified in the calibration operation from S51 to S52.

[0075] Fig. 5(A) shows the first coordinates based on the imaging result of the first imaging section 132a. For example, the first coordinate position shown by a circle indicates the coordinate position of the first measured element 31a at the first reference position. The first coordinate position shown by a square indicates the coordinate position of the first measured element 31a moved in the first direction from the first reference position, and the first coordinate position shown by a triangle indicates the coordinate position of the first measured element 31a moved in the second direction from the first reference position. In the first coordinates shown in Fig. 5(A), the first direction is Tx1 and the second direction is Ty1.

[0076] Fig. 5(B) shows the second coordinates based on the imaging result of the second imaging section 132b. For example, the second coordinate position shown by a circle indicates the coordinate position of the second measured element 31b at the first reference position. The second coordinate position shown by a square indicates the coordinate position of the second measured element 31b moved in the first direction from the first reference position, and the second coordinate position shown by a triangle indicates the coordinate position of the second measured element 31b moved in the second direction from the first reference position. In the second coordinates shown in Fig. 5(B), the first direction is Tx2 and the second direction is Ty2.

[0077] The measurement results of the coordinate positions of the same coordinates as shown in Fig. 5 can be measured with the accuracy of the device performance if each optical unit 130 has been calibrated by operations from S51 to S52. For example, in Fig. 5(A), the distance between two different first elements to be measured 31a almost coincides with the distance between the actual first elements to be measured 31a. Similarly, in Fig. 5(B), the distance between two different second elements to be measured 31b almost coincides with the distance between the actual second elements to be measured 31b.

[0078] However, since no calibration (sometimes called group calibration) is performed between the different optical units 130, the distance between the coordinate positions of different coordinates may not be measured with the accuracy of the device performance. For example, the distance between the coordinate position of one first measured element 31a in the first coordinates shown in Fig. 5(A) and the coordinate position of one second measured element 31b in the second coordinates shown in Fig. 5(B) may not match the actual distance between the first measured element 31a and the second measured element 31b.

[0079] Therefore, in order to perform group calibration, the control unit 240 first specifies a matrix for performing coordinate conversion so as to approximately match the first direction Tx1 and the second direction Ty1 in Fig. 5(A) with the first direction Tx2 and the second direction Ty2 in Fig. 5(B), respectively. By specifying such a rotation matrix, the control unit 240 can calibrate the movement direction when the calibration jig 30 (measurement target M) moves between multiple different optical units 130.

[0080] 4, the rotation matrix specifying unit 244 of the control unit 240 specifies a rotation matrix for rotating the coordinates such that the direction in which the first coordinate position moves coincides with the direction in which the second coordinate position moves before and after the movement of the calibration jig 30 in the first and second directions (S65). The rotation matrix includes a first rotation matrix for rotating the first coordinates to perform coordinate conversion, and a second rotation matrix for rotating the second coordinates to perform coordinate conversion. Details of the operation of S65 will be described later.

[0081] <Second Example of Coordinate Position of Element under Test 31> Next, the control unit 240 calibrates the translation direction between the different optical units 130. Fig. 6 shows a second example of the coordinate position of the measured element 31 identified by the measurement unit 243 according to this embodiment. Fig. 6 shows an example in which the measurement unit 243 measures the center position of one spherical measured element 31 based on the operation results of S59 to S63 in Fig. 4, and plots the coordinate position of the measurement result.

[0082] It is preferable that the measurement unit 243 calculates the coordinate position of the measurement result by using the first coefficient and the second coefficient specified in the calibration operation from S51 to S52. Also, when the rotation matrix specification unit 244 specifies the rotation matrix in S65, it is preferable that the measurement unit 243 performs coordinate conversion of the coordinate position of the measurement result by using the specified rotation matrix.

[0083] 6A shows a first coordinate based on the imaging result of the first imaging unit 132a. For example, the first coordinate position shown by a circle corresponds to the reference position P i The first coordinate position indicated by a rectangle is the first rotational position P of the i-th first measured element 31a rotated by θ from the first reference position around the third direction as an axis. θi The first coordinate position indicated by a triangle is the second rotational position P of the i-th first measured element 31a rotated by φ around the fourth direction as an axis from the first reference position. φi Shows.

[0084] 6B shows the second coordinates based on the imaging result of the second imaging unit 132b. For example, the second coordinate position shown by a circle corresponds to the reference position p j The second coordinate position indicated by a rectangle is the first rotational position p of the j-th second measured element 31b rotated by θ from the second reference position around the third direction as an axis. θj The second coordinate position indicated by a triangle is the second rotational position p of the j-th second measured element 31b rotated by φ around the fourth direction as an axis from the second reference position. φj Shows.

[0085] Here, the distance between the first element under measurement 31a and the second element under measurement 31b does not change before and after the rotation of the calibration jig 30. However, if group calibration is not performed, the measurement result of the distance between the first element under measurement 31a and the second element under measurement 31b may change before and after the rotation beyond the measurement accuracy.

[0086] Therefore, the translation vector specification unit 245, for example, in the example of FIG.i From the reference position p j and the first rotation position P θi to the first rotation position p θj and the second rotation position P φi to the second rotation position p φj A translation vector is specified to perform coordinate conversion so as to substantially match the distance to the calibration jig 30. By specifying such a translation vector, the control unit 240 can calibrate the distance to the calibration jig 30 (measurement target M) between multiple different optical units 130.

[0087] 4, after the operation of S65, the translation vector identification unit 245 identifies a translation vector for translating the coordinates so that the distance between the first element under measurement 31a and the second element under measurement 31b matches before and after the rotation of the calibration jig (S66). The translation vector includes a first translation vector for translating the first coordinate and a second translation vector for translating the second coordinate. Details of the operation of S66 will be described later. The control unit 240 may store the identified rotation matrix and translation vector in the storage unit 220 as calibration parameters.

[0088] As described above, the specified rotation matrix can calibrate the moving direction of the calibration jig 30 (measurement target M) between different optical units 130, and the specified translation vector can calibrate the distance of the calibration jig 30 (measurement target M). Therefore, the control unit 240 can perform group calibration by using the rotation matrix and translation vector specified by the above operations.

[0089] For example, after executing the operation flow shown in Fig. 4, the measurement apparatus 10 mounts the measurement target M on the stage 110 and measures the three-dimensional shape of the measurement target M using the first optical unit 130a and the second optical unit 130b. Then, the measurement unit 243 performs coordinate conversion to the calibration coordinates by rotating the coordinate position of the first coordinates by a first rotation matrix and translating it by a first translation vector. Also, the measurement unit 243 performs coordinate conversion to the calibration coordinates by rotating the coordinate position of the second coordinates by a second rotation matrix and translating it by a second translation vector.

[0090] This allows the control unit 240 to output the measurement values ​​of the three-dimensional shape in the calibration coordinates as calibrated measurement values. The control unit 240 may cause the display unit 230 to display the calibrated measurement values, or may cause the storage unit 220 to store the same. The control unit 240 may also output the calibrated measurement values ​​to the outside via a network or the like.

[0091] As described above, the measurement system S according to this embodiment can identify the calibration parameters used for its own calibration and reflect them in the measurement results, even when using the calibration jig 30 in which the dimensions and positional relationship of the multiple elements under measurement 31 are unknown. Therefore, the measurement system S according to this embodiment can easily calibrate the measurement device 10 that measures the three-dimensional shape of a large measurement target W.

[0092] <An example of an operation flow of the control unit 240> Fig. 7 shows an example of an operation flow of the control unit 240 according to this embodiment. Fig. 7 shows an example of an operation flow for explaining details of the operations of S65 and S66 in the operation flow of the measurement device 10 shown in Fig. 4. For example, the operations of S71 to S73 in Fig. 7 are detailed operations of S65 in Fig. 3.

[0093] First, the rotation matrix determination unit 244 generates a first center of gravity matrix x based on a matrix X1 indicating a first coordinate position, a matrix X2 indicating the first coordinate position after the calibration jig 30 is moved in a first direction, and a matrix X3 indicating the first coordinate position after the calibration jig 30 is moved in a second direction (S71).

[0094] The rotation matrix specifying unit 244 calculates a matrix x 1i Let be an element of matrix X1. Element x 1i is, for example, a 3-row, 1-column matrix indicating one point in the Cartesian coordinate system. In other words, the rotation matrix specifying unit 244 calculates a matrix indicating N first coordinate positions, which are the result of measuring the positions of the N first measured elements 31a by the first optical unit 130a, as a matrix X1=[x11 ,x 1N ].

[0095] Furthermore, the rotation matrix specifying unit 244 calculates a matrix x 2i element x of matrix X2 2i Let matrix X2 be [x 21 ,···,x 2N Similarly, a matrix x 3i element x of matrix X3 3i Let matrix X3 be [x 31 ,···,x 3N ].

[0096] Then, the rotation matrix determination unit 244 calculates the centers of gravity of the generated matrices X1, X2, and X3, respectively, and generates a matrix having the calculated three centers of gravity x1, x2, and x3 as elements as a first center of gravity matrix x=[x1, x2, x3]. k is calculated using the following formula (k=1,2,3).

number

[0097] Next, the rotation matrix determination unit 244 generates a second center of gravity matrix y based on a matrix Y1 indicating the second coordinate position, a matrix Y2 indicating the second coordinate position after the calibration jig 30 is moved in the first direction, and a matrix Y3 indicating the second coordinate position after the calibration jig 30 is moved in the second direction (S72).

[0098] Similarly to the case of generating the first centroid matrix x, the rotation matrix specifying unit 244 generates a matrix indicating the second coordinate position of the i-th second element under test 31b as element y 1i Then, the rotation matrix specifying unit 244 calculates a matrix Y1 having the number of elements equal to the number M of second elements to be measured as [y 11 ,···,y 1M ], and the element y of the matrix indicating the second coordinate position after the calibration jig 30 is moved in the first direction is2i Let Y2 be the matrix [y 21 ,···,y 2M ], and the element y of the matrix indicating the second coordinate position after the calibration jig 30 is moved in the second direction is 3i Let Y3 be [y 31 ,···,y 3M ].

[0099] The rotation matrix determination unit 244 calculates the centers of gravity of the generated matrices Y1, Y2, and Y3, respectively, and generates a matrix having the calculated three centers of gravity y1, y2, and y3 as elements as a second center of gravity matrix y=[y1, y2, y3]. k is calculated using the following formula (k=1,2,3).

number

[0100] Next, the rotation matrix determination unit 244 performs pairwise alignment between the coordinate positions indicated by each element of the first barycentric matrix x and the coordinate positions indicated by each element of the second barycentric matrix y, thereby determining the first rotation matrix and the second rotation matrix (S73). Here, the pairwise alignment is a known technique as described in Non-Patent Document 1, but will be described in detail below.

[0101] <An example of pairwise alignment> Pairwise alignment of two data matrices is, for example, a technique for calculating a rotation matrix R and a translation vector t that relate corresponding points (elements) as follows:

number

[0102] First, initialize the rotation matrix R and the translation vector t. Then, define the evaluation function C PRE Set the initial value (for example, 0).

number

[0103] Next, an evaluation function C that indicates an average amount of positional deviation of coordinate positions is calculated as follows: When this example is applied to the following formula, L=3.

number

[0104] Next, the center of gravity of the two data matrices is calculated as follows:

number

[0105] Next, the two data matrices are transformed into a matrix W in the coordinate system centered on the center of gravity, and the matrix W is subjected to singular value decomposition as shown in the following equation.

number

[0106] Using the matrices U and V obtained by singular value decomposition, the rotation matrix R is calculated as follows: C can be calculated.

number

[0107] In addition, the calculated rotation matrix R C Using the translation vector t C can be calculated.

number

[0108] The calculated rotation matrix R C and the translation vector t C Using these, the data matrix, the rotation matrix, and the translation vector are updated as follows:

number

[0109] Next, the change in the value of the evaluation function |C pre -C| is calculated, and the result is compared with the threshold value d Cth For example, |C pre -C|≧d Cth In the case of C pre The value of is updated to the value of C, and the calculations from (Equation 5) to (Equation 10) are performed. Then, |C pre -C| <d Cth The calculations from (Equation 5) to (Equation 10) are repeated until pre -C| <d Cth If |C pre -C| <d Cth If not, the pairwise alignment may be determined to be bad.

[0110] Using the rotation matrix R and translation vector t calculated as above, the data matrix y can be coordinate-transformed as shown in the following equation, thereby aligning it with the data matrix x.

number

[0111] By applying the above pair-wise alignment, the rotation matrix determination unit 244 can determine the first rotation matrix as a unit matrix and the second rotation matrix R as shown on the right side of Equation 11. For example, the measurement unit 243 applies such a rotation matrix R to convert the second coordinates shown in FIG. 5B into the third coordinates shown in FIG. 5C. As a result, the measurement unit 243 can convert the first direction Tx2 and the second direction Ty2 of the second coordinates into the first direction Tx3 and the second direction Ty3 of the third coordinates so as to substantially match the first direction Tx1 and the second direction Ty1 of FIG. 5A.

[0112] As described above, the rotation matrix determination unit 244 determines the rotation matrix R by performing pair-wise alignment using the first barycentric matrix x and the second barycentric matrix y as two corresponding data matrices.

[0113] Next, the translation vector identification unit 245 identifies the translation vector in S66 of Fig. 4. In this case, the operations from S74 to S76 in Fig. 7 correspond to the detailed operation of S66 in Fig. 4. Note that in S64, the control unit 240 identifies the coordinate position of the element under test 31 for each position to which the calibration jig 30 is moved.

[0114] For example, the control unit 240 calculates a matrix indicating the first coordinate position as element x 1i The matrix X1=[x 11 ,···,x 1N In addition, the control unit 240 generates a matrix indicating the first coordinate position after rotating the calibration jig 30 around the third direction in S60 as element x 4i Matrix X4=[x 41 ,···,x 4N ], and a matrix indicating the first coordinate position after rotating the calibration jig 30 around the fourth direction in S62 is defined as element x 5i Matrix X5=[x 51 ,···,x 5N ] is generated.

[0115] Similarly, the control unit 240 calculates a matrix indicating the second coordinate position as element y based on the imaging result when the calibration jig 30 is placed at the second reference position in S59. 1i The matrix Y1=[y 11 ,···,y 1M In addition, the control unit 240 generates a matrix indicating the second coordinate position after rotating the calibration jig 30 around the third direction in S60 as element y 4i The matrix Y4=[y 41 ,···,y 4M ], and a matrix indicating the second coordinate position after rotating the calibration jig 30 around the fourth direction in S62 is defined as element y 5i The matrix y5=[y 51 ,···,y 5M ] is generated.

[0116] Then, the translation vector identification unit 245 generates a first calibration matrix, a second calibration matrix, and a third calibration matrix by rotating and calibrating the generated matrices X1, X4, and X5 by the first rotation matrix, respectively (S74). Here, the i-th element of the first calibration matrix is ​​P i , the i-th element of the second calibration matrix is ​​P θi , the i-th element of the third calibration matrix is ​​P φi FIG. 6(A) shows such a P i , P θi , and P φi An example of plotting is shown below.

[0117] Furthermore, the translation vector identification unit 245 generates a fourth calibration matrix, a fifth calibration matrix, and a sixth calibration matrix by rotating and calibrating the generated matrices Y1, Y4, and Y5 by the second rotation matrix, respectively. Here, the i-th element of the fourth calibration matrix is ​​p i , the i-th element of the fifth calibration matrix is ​​p θi , the i-th element of the sixth calibration matrix is ​​p φi FIG. 6(B) shows such a p i , p θi , and p φi An example of plotting is shown below.

[0118] Next, the translation vector identification unit 245 determines the distance from the coordinate position where the first translation vector T1 is added to the first calibration matrix to the coordinate position where the second translation vector T2 is added to the fourth calibration matrix as the first distance. The translation vector identification unit 245 also determines the distance from the coordinate position where the first translation vector T1 is added to the second calibration matrix to the coordinate position where the second translation vector T2 is added to the fifth calibration matrix as the second distance. Similarly, the translation vector identification unit 245 determines the distance from the coordinate position where the first translation vector T1 is added to the third calibration matrix to the coordinate position where the second translation vector T2 is added to the sixth calibration matrix as the third distance.

[0119] Then, the translation vector identification unit 245 identifies the first translation vector T1 and the second translation vector T2 so that the first distance, the second distance, and the third distance match. In this embodiment, an example is shown in which the first translation vector T1 is set to a zero vector, and the second translation vector T2 is set to T to calculate the second translation vector T.

[0120] For example, the coordinate position after the coordinate conversion is expressed as follows using a translation vector T for converting the second coordinate based on the imaging result of the second imaging section 132b shown in Fig. 6(B): Fig. 6(C) shows the third coordinate after the coordinate conversion from the second coordinate.

number

[0121] Next, the distance from the coordinate position of the i-th first measured element 31a in the first coordinate to the coordinate position of the j-th second measured element 31b in the third coordinate is expressed as follows. Here, the first distance is d ij , the second distance is d θij , and the third distance is d φij It is.

number

[0122] A function S of the following equation is used to evaluate the magnitude of the error in the distance from the coordinate position of the first measured element 31a in the first coordinate to the coordinate position of the second measured element 31b in the third coordinate before and after rotating the calibration jig 30. Here, N1 is the number of the first measured elements 31a, and N2 is the number of the second measured elements 31b.

number

[0123] The translation vector identification unit 245 calculates T at which the value of the function S shown in the formula (14) becomes minimum (S75). Note that instead of the formula (14), T at which the value of the following formula becomes minimum may be calculated.

number

[0124] The operation of calculating T by minimizing S in equation (14) or S in equation (15) can be performed by a known method, so a detailed explanation of the operation will be omitted here. Then, the translation vector identification unit 245 identifies T that minimizes the value of S in equation (14) or S in equation (15) as the translation vector T (S76).

[0125] In this way, the rotation matrix specifying unit 244 and the translation vector specifying unit 245 can specify the rotation matrix R and the translation vector T, which are parameters used for calibrating the measurement device 10. The measurement device 10 calibrates itself using the specified rotation matrix R and translation vector T, and can measure the three-dimensional shape of the measurement target W with the accuracy of the device performance.

[0126] As described above, the measuring apparatus 10 according to this embodiment identifies calibration parameters for calibrating itself based on the change in position of the element under test 31 accompanying the movement of the calibration jig 30. Here, since the calibration jig 30 is provided with a plurality of elements under test 31, it is desirable for the measuring apparatus 10 to be able to identify each of the elements under test 31.

[0127] In particular, it is desirable that the measuring device 10 can identify each of the elements 31 to be measured from the imaging results of imaging the elements 31 to be measured. For example, the elements 31 to be measured may have different shapes, marks, colors, etc., as described above. However, since the imaging units 132 image the calibration jig 30 from different angles, it may be difficult to identify the elements 31 to be measured from the imaging results. Therefore, the calibration jig 30 that enables the measuring device 10 to easily identify the elements 31 to be measured will be described next.

[0128] <Configuration example of calibration jig 300> 8 shows a first configuration example of the calibration jig 300 according to this embodiment. In the calibration jig 300 shown in FIG. 8, parts that operate substantially the same as those in the calibration jig 30 according to this embodiment shown in FIG. 2 are given the same reference numerals, and duplicated explanations will be omitted. In other words, the calibration jig 300 functions as the calibration jig 30 shown in FIG. 2. The calibration jig 300 may be formed as a reference jig for performing calibration for each optical unit 130. The calibration jig 300 includes a plurality of elements to be measured 31 and a frame portion 40.

[0129] A plurality of elements to be measured 31 are attached to the frame portion 40. Fig. 8 shows an example in which the frame portion 40 is a plate-shaped member, but the present invention is not limited to this. The frame portion 40 may be any member capable of fixing the elements to be measured 31, and may be a rod-shaped member or the like.

[0130] Fig. 8 shows an example in which the first measured element 31a is included in the field of view 133a of the first imaging section 132a of the first optical unit 130a, and the second measured element 31b is included in the field of view 133b of the second imaging section 132b of the second optical unit 130b, similar to Fig. 2. Note that Fig. 8 shows fewer measured elements 31 than Fig. 2, but more measured elements 31 may be attached to the frame section 40.

[0131] <First Configuration Example of Measured Device 31> 9 shows a first configuration example of the device to be measured 31 according to this embodiment. As shown in FIG. 9(A), the device to be measured 31 has a main body 32, a label part 33, and a plate-like member 34. The main body 32 has a predetermined shape. The shape of the main body 32 is, for example, a body of revolution such as a sphere, an ellipsoid, or a cylinder. Alternatively, the shape of the main body 32 may be a polyhedron.

[0132] 9 shows an example in which a plurality of label parts 33 are attached to a plate-like member 34 by a known method such as printing or pasting, and the label parts 33 are provided to the main body part 32 via the plate-like member 34. It is desirable that the label parts 33 are provided in as many places as possible on the main body part 32. For example, the main body part 32 has a plurality of plate-like members 34, and the plurality of label parts 33 are provided in a plurality of different positions on the main body part 32 to the extent that at least one label part 33 is included in the captured image when the measured element 31 is captured from various angles.

[0133] The plate-shaped member 34 is a strip-shaped member provided around the main body 32. A plurality of label units 33 may be provided on the plate-shaped member 34. It is desirable that a plurality of label units 33 are provided on the front and back surfaces of the plate-shaped member 34. FIG. 9 shows an example in which four label units 33 are provided on one surface of the plate-shaped member 34. In this way, the label units 33 may be provided on the plate-shaped member 34, or alternatively or in addition, the label units 33 may be provided on the main body 32 other than the plate-shaped member 34.

[0134] Fig. 9(B) shows an example in which one label unit 33 displayed between L1 and L2 of the plate-like member 34 shown in Fig. 9(A) is displayed in a rectangular shape. The label unit 33 has, for example, a recognition code 35 and an identification code 36.

[0135] The recognition code 35 is a code common to the multiple measured elements 31 for recognizing the label portion 33. The identification code 36 is a code for identifying the measured element 31. It is desirable that the recognition code 35 and the identification code 36 are codes of different shapes or different types. For example, the identification code 36 is composed of a combination of basic parts of a predetermined first shape, and the recognition code 35 is composed of a combination of basic parts of a predetermined second shape that is different in size from the first shape.

[0136] 9 shows an example in which the recognition code 35 and the identification code 36 are displayed as barcodes with different line widths. As an example, the minimum line width d of the recognition code 35 is half the minimum line width D of the identification code 36. Furthermore, the recognition code 35 and the identification code 36 each indicate a predetermined value. As an example, the recognition code 35 indicates a predetermined 8-bit value (01010101), and the identification code 36 indicates a predetermined 8-bit value (01001010).

[0137] Fig. 10 shows an example of a luminance signal that can be acquired based on the label unit 33 shown in Fig. 9. The luminance signal resulting from the imaging of the label unit 33 by the imaging unit 132 corresponds to the recognition code 35 and the identification code 36. The control unit 240 can detect the label unit 33, for example, by pattern matching a predetermined signal pattern corresponding to the recognition code 35 with the luminance signal.

[0138] The predetermined signal pattern is set in advance, for example, by a pattern signal width W, a unit pattern width D, a luminance signal level H, a binarization reference level I0, etc. The predetermined signal pattern is preferably stored in the storage unit 220. When the predetermined signal pattern matches the luminance signal, the control unit 240 reads a predetermined number of bits (e.g., 8 bits) of the luminance signal next to the matching luminance signal for each reading width D. The control unit 240, for example, compares the read signal level with the binarization reference level I0 to identify the value of each bit of the identification code 36.

[0139] In this manner, the control unit 240 can read the identification code 36 by detecting the recognition code 35 from the captured image. Here, the minimum line width d of the recognition code 35 is different from the minimum line width D of the identification code 36, so that it is possible to reduce erroneous detection of a part of the identification code 36 as part of the recognition code 35. Also, by making the minimum line width D of the identification code 36 larger than the minimum line width d of the recognition code 35, it is possible to improve the reading accuracy of the identification code 36.

[0140] Since the imaging section 132 captures images of the element to be measured 31 from various angles, it may not be possible to capture an image of the label part 33 from the front as in Fig. 9(A). Therefore, the control section 240 may perform image processing on the imaging result of the imaging section 132 and convert the image so that the label part 33 can be easily detected.

[0141] FIG. 11 shows an example of a process in which the control unit 240 according to this embodiment processes the image captured by the imaging unit 132. FIG. 11(A) shows an example of the image captured by the imaging unit 132. The image captured in FIG. 11(A) shows an example of the label portion 33 captured from an oblique angle. FIG. 11(B) shows an example of an ideal image captured by the imaging unit 132. The ideal image captured shows an example of the label portion 33 captured from the front. It is desirable that such ideal image captured is stored in the memory unit 220 as image data.

[0142] The control unit 240 extracts image data ID of the measured element 31 from the imaging result of the imaging unit 132 as shown in Fig. 11(A), for example. The control unit 240 calculates a transformation matrix TI for image transformation from the image data IID of the ideal measured element 31 to the extracted captured image of the measured element 31. The control unit 240 calculates the transformation matrix TI such that the calculation result of IID x TI becomes ID, for example.

[0143] Then, the control unit 240 calculates the inverse matrix TI of the transformation matrix TI. -1 The inverse matrix TI calculated for the image data ID of the measured element 31 is calculated. -1 9(B) , the image of the label part 33 is converted into a rectangular shape by multiplying the image by the imager 132. FIG. 11(C) shows an example of the result of image conversion of the image captured by the imager 132. By the above image conversion, the control unit 240 can convert the label part 33, which is captured at an angle in the image captured by the imager 132, into an image viewed from the front. The control unit 240 may further process the image of the label part 33, and convert the label part 33 into a rectangular shape as shown in FIG. 9(B). In this case, the control unit 240 performs image processing such as polar coordinate conversion.

[0144] As a result, the control unit 240 can easily read the identification code 36 of the label unit 33 from the imaging result of the imaging unit 132. Therefore, the control unit 240 can identify each of the multiple elements under measurement 31 included in the captured image according to the identification code 36. This allows the control unit 240 to reduce erroneous recognition of the elements under measurement 31, for example, before and after the movement of the calibration jig 300. Therefore, the calibration jig 300 according to this embodiment makes it possible to easily calibrate the measuring device 10.

[0145] In the above embodiment of the measured element 31, the recognition code 35 and the identification code 36 are barcodes, but the present invention is not limited to this. The recognition code 35 and the identification code 36 may be a QR code (registered trademark), a predetermined symbol, a predetermined figure, etc. Furthermore, the recognition code 35 may have a basic portion of a predetermined color different from the color of the basic portion of the first shape constituting the identification code 36.

[0146] <Second Configuration Example of Measured Device 31> Fig. 12 shows a second configuration example of the measured element 31 according to this embodiment. In the measured element 31 of the second configuration example, parts that operate substantially the same as those in the measured element 31 of the first configuration example shown in Fig. 9 are given the same reference numerals, and duplicated explanations will be omitted. In the measured element 31 of the second configuration example, the recognition code 35 is composed of basic parts of a predetermined color.

[0147] The predetermined color is a color different from the color of the basic parts constituting the identification code 36. The predetermined color may be any color that the imaging unit 132 can handle as an image. For example, if the imaging unit 132 can output a color image, the predetermined color may be a color such as red, green, or blue, or may be a mixture of these colors. If the imaging unit 132 can output a black and white image, the predetermined color may be a grayscale color. The minimum line width d of the recognition code 35 may be the same as the minimum line width D of the identification code 36, or may be different.

[0148] Fig. 13 shows an example of a luminance signal that can be acquired based on the label unit 33 shown in Fig. 12. The luminance signal resulting from the imaging of the label unit 33 by the imaging unit 132 corresponds to the recognition code 35 and the identification code 36. As described in Fig. 10, the control unit 240 can detect the label unit 33 by pattern matching a predetermined signal pattern corresponding to the recognition code 35 with the luminance signal.

[0149] The predetermined signal pattern may be, for example, a pattern signal width D and a luminance signal level I S , binarization reference level I0, etc. Since the luminance signal of the recognition code 35 has a signal level corresponding to a predetermined color, the predetermined signal pattern can be simpler than the predetermined signal pattern shown in FIG.

[0150] When a predetermined signal pattern matches a luminance signal, the control unit 240 reads a predetermined number of bits (e.g., 8 bits) of the luminance signal next to the matching luminance signal for each reading width D. Note that the control unit 240 desirably performs pattern matching between the luminance signals of the two recognition codes 35 that sandwich the identification code 36 and the predetermined signal pattern. This allows the control unit 240 to identify the identification code 36 while reducing erroneous detection of the recognition code 35.

[0151] <Third Configuration Example of Measured Device 31> Fig. 14 shows a third configuration example of the device under test 31 according to this embodiment. In the device under test 31 of the third configuration example, parts that operate substantially the same as those in the device under test 31 of the first configuration example shown in Fig. 9 are given the same reference numerals, and duplicated explanations will be omitted. The device under test 31 of the third configuration example has a portion where the recognition code 35 displays a predetermined image.

[0152] The predetermined image may be an image different from the combination of basic parts constituting the identification code 36. The predetermined image may use the same color as the basic parts constituting the identification code 36, or a different color. Furthermore, the width of the parts of the recognition code 35 may be the same as the minimum line width D of the identification code 36, or may be different.

[0153] The control unit 240 can detect the label portion 33 by pattern matching a search pattern corresponding to a predetermined image of the recognition code 35 from within the captured image of the measured element 31. In this case as well, it is preferable for the control unit 240 to perform pattern matching between the predetermined search pattern and the images of the two recognition codes 35 that sandwich the identification code 36. When the predetermined search pattern matches the image of the recognition code 35, the control unit 240 can identify the identification code 36 by reading the luminance signal of the image next to the matching recognition code 35.

[0154] <Fourth Configuration Example of Measured Device 31> Fig. 15 shows a fourth configuration example of the device under test 31 according to this embodiment. In the device under test 31 of the fourth configuration example, parts that operate substantially the same as those in the device under test 31 of the first configuration example shown in Fig. 9 are given the same reference numerals, and duplicated explanations will be omitted. The device under test 31 of the fourth configuration example has a portion where the recognition code 35 displays a predetermined image, similar to the device under test 31 of the third configuration example.

[0155] The predetermined image includes a pattern of a predetermined shape, a pattern of a combination of predetermined shapes, etc. Fig. 15 shows an example in which the predetermined image includes a pattern of a circular shape. Alternatively, the predetermined image may include a pattern of a polygon, a heart shape, a spade shape, etc. Since such a shape is not formed by chance in the captured image of the calibration jig 300, the control unit 240 can improve the accuracy of pattern matching between the image of the recognition code 35 and the predetermined search pattern.

[0156] As described above, even when the measured element 31 of the second to fourth configuration examples is used, the control unit 240 can read the identification code 36 from the captured image based on the recognition code 35. Furthermore, even when the measured element 31 of the second to fourth configuration examples is used, it goes without saying that the label portion 33 can be made easier to read by performing the image processing described in Fig. 11. Therefore, the calibration jig 300 using the measured element 31 of the second to fourth configuration examples can also make it easier to calibrate the measuring device 10.

[0157] In the above calibration tool 300 according to the present embodiment, an example has been described in which the element to be measured 31 includes the plate-like member 34 on which the label portion 33 is provided, but the present invention is not limited to this. The label portion 33 may be provided on the main body portion 32 of the element to be measured 31. Note that when a plurality of label portions 33 are provided on the main body portion 32, the plate-like member 34 may be omitted.

[0158] In addition, in the calibration tool 300 according to the present embodiment, an example in which the frame portion 40 is a plate-shaped member has been described, but the present invention is not limited to this. For example, the frame portion 40 may have a spherical or ellipsoidal shape.

[0159] <Second Configuration Example of Calibration Tool 300> 16 shows a second configuration example of the calibration jig 300 according to this embodiment. The calibration jig 300 of the second configuration example shows an example in which the frame portion 40 has a spherical or ellipsoidal shape. At least a part of the frame portion 40 may be configured to have a spherical or ellipsoidal shape by combining a plurality of rod-shaped members or the like. Furthermore, the frame portion 40 may have a member having at least a part of the shape of a sphere or an ellipsoid.

[0160] The frame unit 40 has, for example, a plurality of arc-shaped bar-shaped members 41, a columnar member 42, and a pedestal 43. The plurality of bar-shaped members 41 may be attached to the columnar member 42 so as to be rotatable about the columnar member 42 as an axis. The columnar member 42 is attached to the pedestal 43. It is desirable that the surface of the plurality of bar-shaped members 41 that contacts the outside is configured to be spherical or ellipsoidal.

[0161] Each of the arc-shaped rod members 41 is provided so as to be movable in the Z direction. Each of the arc-shaped rod members 41 may be configured so as to be movable in the circumferential direction of the circle described by the arc. A plurality of elements to be measured 31 are fixed to the outside of the rod members 41. This allows the plurality of elements to be measured 31 to be arranged in a spherical or ellipsoidal shape. FIG. 16 shows an example of a spherical frame part 40 in which a columnar member 42 extends in the Z direction and a plurality of rod members 41 are provided so as to be rotatable about an axis in the Z direction.

[0162] The positions and / or orientations of the multiple imaging units 132 may be changed depending on the measurement target. By arranging the multiple measured elements 31 in such a spherical manner, even if the position and / or orientation of the imaging units 132 is changed, the multiple measured elements 31 can be included within the field of view of each imaging unit 132. Furthermore, the imaging units 132 may be arranged so as to surround the measurement target. In this case, the positions and orientations of the imaging units 132 differ from one another. Even in such a case, by arranging the multiple measured elements 31 in a spherical manner, the multiple measured elements 31 can be included within the field of view of each imaging unit 132.

[0163] Each of the multiple elements under test 31 is provided on the spherical or ellipsoidal surface of the frame section 40. The multiple elements under test 31 are provided, for example, on the spherical surface of the sphere formed by the frame section 40 so that adjacent elements under test 31 are within a predetermined distance. Here, the predetermined distance is, for example, about two to four times the diameter of the sphere when the main body section 32 of the element under test 31 is a sphere. The predetermined distance may be about two to four times the major axis of the ellipsoid when the main body section 32 of the element under test 31 is an ellipsoid.

[0164] It is desirable that the elements to be measured 31 are arranged so that the label section 33 falls within the field of view of as many imaging sections 132 as possible. For example, the frame section 40 is regarded as a spheroid with the Z direction as the axis of rotation, and is considered in spherical coordinates similar to those of celestial bodies. It is desirable that the multiple elements to be measured 31 are arranged in the same latitude direction and / or the same longitude direction of such a spheroid. Also, each of the elements to be measured 31 is arranged, for example, so that at least one label section 33 is displayed on a surface that is perpendicular to the normal direction of the spheroid and faces the outside of the frame section 40.

[0165] For example, it is desirable that the multiple elements to be measured 31 are densely arranged on the spherical surface of a sphere so that multiple elements to be measured 31 whose label portions 33 can be read are included in the captured image even if the imaging section 132 captures an image of a portion of the calibration jig 300. Thereby, by simply mounting only one calibration jig 300 of the second configuration example on the stage 110, the multiple elements to be measured 31 can be identified in the captured image of the calibration jig 300 captured by the multiple imaging sections 132.

[0166] Therefore, as described above, it is possible to identify calibration parameters used for calibrating the multiple imaging units 132 based on images of the calibration jig 300 captured by the multiple imaging units 132 before and after the movement of the calibration jig 300. Note that, in the above-mentioned identification of the calibration parameters, an example has been described in which the calibration jig 300 is mounted on the stage 110 and moved, but the present invention is not limited to this. Apart from the movement of the stage 110, the calibration jig 300 may be configured to be able to move the multiple elements to be measured 31 while maintaining the relative positional relationship between the multiple elements to be measured 31.

[0167] The calibration jig 300 further includes, for example, a frame moving unit that moves the frame unit 40 together with the plurality of elements 31 to be measured. The frame moving unit has an actuator such as a motor and moves the frame unit 40 in a plurality of predetermined directions. The frame moving unit may also rotate the frame unit 40 around an axis in a predetermined direction. The frame moving unit is configured to be able to move the plurality of elements 31 to be measured in, for example, the X direction, the Y direction, and the Z direction. The frame moving unit may also be configured to be able to rotate the plurality of elements 31 to be measured around the X direction, the Y direction, and the Z direction, respectively, as rotation axes. This allows the measuring apparatus 10 to identify the calibration parameters used for calibration by moving the frame unit 40 of the calibration jig 300 without moving the stage 110.

[0168] For example, in S54 of the operation flow shown in Fig. 4, the control unit 240 images the calibration jig 300 placed at the first reference position. The first imaging unit 132a images the calibration jig 300 so that some of the first measured elements 31a among the multiple measured elements 31 provided in the calibration jig 300 are within the field of view. In addition, the second imaging unit 132b different from the first imaging unit 132a images the calibration jig 300 so that some of the second measured elements 31b different from the first measured elements 31a imaged by the first imaging unit 132a are within the field of view.

[0169] It should be noted that the imaging of the calibration jig 300 in S58, S59, S61, and S63 is similar to that in S54. In addition, in S55, S57, S60, and S62, the control unit 240 may move the stage 110, or alternatively, may control a frame moving unit of the calibration jig 300 to move the calibration jig 300.

[0170] Then, in S64, the measurement unit 243 analyzes the label portion 33 of the measured element 31 from the captured image captured by the first imaging unit 132a to identify the first measured element 31a. The measurement unit 243 identifies a first coordinate position indicating the position of the identified first measured element 31a in the first coordinate based on the field of view of the first imaging unit 132a.

[0171] Similarly, the measurement unit 243 analyzes the label portion 33 of the element to be measured from the image captured by the second imaging unit 132b to identify the second element to be measured 31b. The measurement unit 243 identifies a second coordinate position indicating the position of the identified second element to be measured 31b in the second coordinate based on the field of view of the second imaging unit 132b.

[0172] After S64, as described above, calibration parameters for calibrating the first imaging section 132a and the second imaging section 132b can be identified from the identified positional relationship between the first measured element 31a and the second measured element 31b.

[0173] 4, an example has been described in which the optical unit 130 is calibrated using a reference jig smaller in size than the calibration jig 30. Here, the size of the calibration jig 300 in the second configuration example can be made smaller than the size of the calibration jig 30, and therefore it may also function as a reference jig.

[0174] For example, the calibration jig 300 can be used as a reference jig by previously measuring the dimensions and positional relationships of at least some of the multiple elements under test 31 and storing them in the storage unit 220, etc. In other words, the measuring apparatus 10 can execute the operation flow shown in FIG.

[0175] Although the present invention has been described above using the 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 present 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 combines the effect of the original embodiment. [Explanation of symbols]

[0176] 10. Measuring Equipment 30 Calibration fixture 31 Element to be measured 32 Main body 33 Label section 34 Plate-shaped members 35 Recognition Code 36 Identification Code 40 Frame section 110 Stages 120 Mobile Unit 130 Optical Unit 131 Light source 132 Imaging unit 133 Field of view 140 Control Unit 210 Communications Department 220 Storage section 230 Display section 240 Control Unit 241 Signal output section 242 Acquisition Department 243 Measuring section 244 Rotation matrix specification part 245 Translation Vector Identification Unit 300 Calibration fixture

Claims

1. A calibration tool for calibrating a measuring device for measuring a three-dimensional shape of a measurement object, the calibration tool comprising a plurality of imaging units for imaging a measurement object, the measurement device comprising: A plurality of devices under test; a frame portion to which a plurality of the devices under test are attached; Equipped with Each of the plurality of devices under test comprises: A body portion having a predetermined shape; a label portion provided in a plurality of parts on the main body and displaying an identification code for identifying the device under test; A calibration fixture having a

2. 2. The calibration jig according to claim 1, wherein the label portion further includes an identification code common to the plurality of elements to be measured for identifying the label portion.

3. The identification code is composed of a combination of basic parts of a predetermined first shape, The recognition code is composed of a combination of basic parts of a predetermined second shape having a size different from that of the first shape. The calibration jig according to claim 2 .

4. The identification code is composed of a combination of basic parts of a predetermined first shape, the recognition code has a basic portion of a predetermined color different from the color of the basic portion of the first shape; The calibration jig according to claim 2 .

5. The identification code is composed of a combination of basic parts of a predetermined first shape, The recognition code has a portion on which a predetermined image is displayed. The calibration jig according to claim 2 .

6. Each of the plurality of devices under test further includes a strip-shaped plate member provided around the main body, The label portion is provided in plurality on the plate-like member. The calibration jig according to claim 1 .

7. a frame moving unit that moves the frame together with the plurality of devices under test, The calibration jig according to claim 1 .

8. The frame portion has a spherical or ellipsoidal shape, Each of the plurality of test elements is provided on a spherical or ellipsoidal surface of the frame portion. The calibration jig according to claim 1 .

9. A calibration method for calibrating a measuring device for measuring a three-dimensional shape of a measurement object, the measuring device including a plurality of imaging units for imaging a measurement object, using a calibration jig, the method comprising: the calibration jig includes a plurality of devices to be measured; Each of the plurality of devices under test comprises: A body portion having a predetermined shape; a label portion provided in a plurality of parts on the main body and displaying an identification code for identifying the device under test; having a first imaging step of imaging the calibration jig with a first imaging section so that some first measured elements among the plurality of measured elements are within a field of view, and imaging the calibration jig with a second imaging section different from the first imaging section so that some second measured elements different from the first measured elements imaged by the first imaging section are within a field of view; A step of identifying the first measured element by analyzing the label part of the measured element from the image captured by the first imaging unit, and identifying the second measured element by analyzing the label part of the measured element from the image captured by the second imaging unit; specifying calibration parameters for calibrating the first imaging unit and the second imaging unit based on the specified positional relationship between the first device under test and the second device under test; The calibration method includes:

10. a second imaging step of, after the first imaging step, moving the calibration jig in a predetermined first direction, and then imaging the first device under test with the first imaging unit and imaging the second device under test with the second imaging unit; a third imaging step of, after the second imaging step, moving the calibration jig in a predetermined second direction different from the first direction, and then imaging the first device under test with the first imaging unit and imaging the second device under test with the second imaging unit; a fourth imaging step of imaging the first device under test by the first imaging unit and imaging the second device under test by the second imaging unit; a fifth imaging step of, after the fourth imaging step, rotating the calibration jig about an axis in a predetermined third direction, imaging the first device under test with the first imaging unit, and imaging the second device under test with the second imaging unit; a sixth imaging step of rotating the calibration jig around an axis in a predetermined fourth direction different from the third direction after the fifth imaging step, and then imaging the first device under test with the first imaging unit and imaging the second device under test with the second imaging unit; identifying a first coordinate position indicating a position of the first measured element at a first coordinate based on a field of view of the first imaging unit in a plurality of captured images captured by the first imaging unit, and a second coordinate position indicating a position of the second measured element at a second coordinate based on a field of view of the second imaging unit in a plurality of captured images captured by the second imaging unit; Further comprising: In the step of identifying the calibration parameters, specifying a first rotation matrix for rotating and transforming the first coordinates and a second rotation matrix for rotating and transforming the second coordinates such that a direction in which the first coordinate position moves and a direction in which the second coordinate position moves coincide with each other before and after movement of the calibration jig in the first direction and the second direction; specifying a first translation vector for translating the first coordinate and a second translation vector for translating the second coordinate such that a distance between the first measured element and the second measured element coincides before and after rotation of the calibration jig; Including, The calibration method according to claim 9.

11. 11. The calibration method of claim 10, further comprising, after identifying the first rotation matrix, the second rotation matrix, the first translation vector, and the second translation vector, a step of coordinate converting the first coordinate position and the second coordinate position into calibration coordinates by rotating the first coordinate position by the first rotation matrix and translating it by the first translation vector, and rotating the second coordinate position by the second rotation matrix and translating it by the second translation vector.

12. A measurement system including a measurement device that measures a three-dimensional shape of a measurement object and a calibration jig that calibrates the measurement device, The measuring device is A moving unit for mounting and moving the measurement object; A light source for irradiating the measurement object with light; A plurality of imaging units each capturing an image of a different region of the measurement target; a measurement unit that measures a three-dimensional shape of the measurement object based on imaging results of the plurality of imaging units; A control unit that controls the moving unit, the imaging unit, and the measurement unit; a determination unit that determines a calibration parameter for calibrating the measurement result of the measurement unit; Equipped with The calibration jig is A plurality of devices under test; a frame portion to which a plurality of the devices under test are attached; Equipped with Each of the plurality of devices under test comprises: A body portion having a predetermined shape; a label portion provided in a plurality of parts on the main body and displaying an identification code for identifying the device under test; having The control unit causes the imaging units to respectively capture images of different parts of the plurality of devices under test, the measurement unit analyzes the label parts of the plurality of elements to be measured corresponding to the plurality of captured images captured by the plurality of imaging units, and identifies a positional relationship between the plurality of elements to be measured; the specifying unit specifies the calibration parameters for calibrating the plurality of imaging units based on the specified positional relationship of the plurality of elements under measurement. Measurement system.

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