Measuring system, measuring method, and measuring program

Abstract

To provide a measuring system, a measuring method, and a measuring program with which cross-sectional shapes are accurately compared even in shape measurement when an extrusion direction is shifted relative to the coordinate system of a workpiece.SOLUTION: A measuring system comprises an optimization calculation unit and a correction unit. The optimization calculation unit uses an optimization algorithm using a plurality of pieces of contour data corresponding respectively to a plurality of cross sections to be measured by a measuring device obtained by performing copy measurement of the plurality of cross sections, to calculate the direction of a projection surface to minimize a projection error in the plurality of pieces of contour data. The correction unit corrects the respective pieces of contour data on the basis of the direction of the projection surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The embodiments relate to a measurement system, a measurement method, and a measurement program. [Background technology]

[0002] A three-dimensional coordinate measuring machine (CMM) is a type of shape measurement device that measures the three-dimensional shape of an object by detecting the three-dimensional coordinate values ​​of the object by moving a probe that follows the object on a stage. This type of shape measurement device is used, for example, to inspect processed parts (workpieces) with extruded shapes. Here, an extruded shape is a three-dimensional shape obtained by linearly extending a specific cross-sectional shape drawn on a certain plane in a direction normal to the plane while maintaining that shape. This constant direction of extrusion is called the extrusion direction. When cut on a plane perpendicular to the extrusion direction, all cut surfaces have the same shape.

[0003] Here, machining errors usually exist in the shape of the workpiece. As a result, the extrusion direction often deviates from the workpiece coordinate system, which serves as the reference for the probe movement direction. When measuring a shape where the extrusion direction is deviated from the workpiece coordinate system, a surface cut at an angle to the extrusion direction is measured. In this way, when the extrusion direction is deviated from the workpiece coordinate system, it is difficult to measure the true cross-sectional shape of the workpiece. When measuring a shape where the extrusion direction is deviated from the workpiece coordinate system, there is a possibility that each measured cross-sectional shape is the shape of a cross-section cut from a different direction, making it difficult to compare cross-sectional shapes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6924953 Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiments provide a measurement system, a measurement method, and a measurement program that can perform cross-sectional shape comparison with high accuracy even when measuring a shape in which the extrusion direction is misaligned with the coordinate system of the workpiece. [Means for solving the problem]

[0006] According to one aspect of the present invention, a measurement system includes an optimization calculation unit and a correction unit. The optimization calculation unit calculates a projection plane direction that minimizes a projection error of the plurality of contour data by using an optimization algorithm that uses a plurality of contour data corresponding to the plurality of cross sections of the measurement object obtained by scanning and measuring the plurality of cross sections of the measurement object with a measurement device. The correction unit corrects each contour data based on the projection plane direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a measurement system according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of the configuration of the control device. [Figure 3] FIG. 3 is a diagram illustrating an example of a hardware configuration of the control device. [Figure 4] FIG. 4 is a flowchart showing the operation of the measurement system. [Figure 5] FIG. 5 is a flowchart showing an example of optimization calculation processing. [Figure 6A] FIG. 6A is a diagram illustrating projection of contour data in the embodiment. [Figure 6B] FIG. 6B is a diagram illustrating projection of contour data in the embodiment. [Figure 7A] FIG. 7A is a diagram for explaining the step width in the steepest descent method. [Figure 7B] FIG. 7B is a diagram for explaining the step width in the steepest descent method. [Figure 8A] FIG. 8A is a diagram for explaining projection correction. [Figure 8B] FIG. 8B is a diagram for explaining projection correction. [Figure 8C] FIG. 8C is a diagram for explaining projection correction. [Figure 9] FIG. 9 is a diagram showing an example of a display on the display device. [Figure 10] FIG. 10 is a diagram illustrating an example of a configuration of a measurement system according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing an example of the configuration of a measurement system according to an embodiment. As shown in FIG. 1, the measurement system 1 has a measurement device 10 and a control device 20. The control device 20 is configured to be able to communicate with a display device 30. The communication between the control device 20 and the display device 30 may be wireless or wired.

[0009] The measuring device 10 is a shape measuring device configured to measure information related to the three-dimensional shape of a measurement object O. The measurement object O is, for example, a machined part (workpiece). The measuring device 10 is, for example, a CMM. For example, the measuring device 10 may be a gantry-type CMM equipped with a probe 11, a probe receiving portion 12, a z-axis movement mechanism 13, an x-axis movement mechanism 14, a y-axis movement mechanism 15, and a stage 16. Here, a machine coordinate system is defined for the measuring device 10. The x-axis of the machine coordinate system is an axis parallel to the horizontal direction of the stage 16. The y-axis of the machine coordinate system is an axis parallel to the vertical direction of the stage 16. The z-axis of the machine coordinate system is an axis parallel to the thickness direction of the stage 16.

[0010] The probe 11 has a ball-shaped contactor at its tip, which comes into contact with the measurement object O and generates a signal. The contactor may be made of ruby, ceramic, or the like. The probe 11 is held by a probe receiving part 12. The probe receiving part 12 holds the probe 11 so that when the contactor of the probe 11 comes into contact with the measurement object O, the contactor can move to follow the shape of the measurement object O. The probe receiving part 12 is attached to a z-axis movement mechanism 13.

[0011] The z-axis moving mechanism 13 is attached to the x-axis moving mechanism 14 so as to be able to move the probe receiving portion 12 in the z-axis direction. The x-axis moving mechanism 14 holds the z-axis moving mechanism 13 so as to be able to move the z-axis moving mechanism 13 in the z-axis direction, and is attached to the y-axis moving mechanism 15 so as to be able to move in the x-axis direction. The y-axis moving mechanism 15 is gate-shaped so as to be able to move the x-axis moving mechanism 14 in the x-axis direction, and is attached to the stage 16 so as to be able to move in the y-axis direction.

[0012] The stage 16 has a flat plate shape and holds the y-axis moving mechanism 15 so that the y-axis moving mechanism 15 can move in the y-axis direction. The measurement object O is placed on the stage 16.

[0013] The control device 20 controls the z-axis movement mechanism 13, the x-axis movement mechanism 14, and the y-axis movement mechanism 15 to move the probe 11 so as to follow the shape of the measurement object O. The control device 20 also processes the signal obtained from the probe 11 when the probe 11 comes into contact with the measurement object O to generate contour data representing the cross-sectional shape of the measurement object O. The control device 20 also estimates the extrusion direction based on the data on the cross-sectional shape of the measurement object O. The extrusion direction is the normal vector direction of the cutting plane that can measure the true cross-sectional shape data of the measurement object O with the least error. The control device 20 also displays various information on the display device 30.

[0014] The display device 30 is a display device such as a liquid crystal display or an organic EL display. The display device 30 displays various images based on data transferred from the control device 20. For example, the display device 30 displays an image of the contour shape of the measurement object O and information on the extrusion direction.

[0015] 2 is a block diagram showing an example of the configuration of the control device 20. The control device 20 is a computer such as a personal computer or a tablet terminal, and includes a drive control unit 21, a contour data generation unit 22, a database 23, an optimization calculation unit 24, a projection correction unit 25, and a display control unit 26.

[0016] The drive control unit 21 controls the z-axis movement mechanism 13, the x-axis movement mechanism 14, and the y-axis movement mechanism 15 to move the probe 11 so as to follow the shape of the object O to be measured.

[0017] The contour data generator 22 generates contour data of the measurement object O from signals obtained via the probe 11. The contour data is point cloud data along the contour of the measurement object O, based on signals output from the probe 11 when the probe 11 is moved, for example, so as to trace the circumferential direction of the measurement object O. The point cloud data can be composed of three-dimensional information according to the xyz coordinates of the probe 11. By performing measurements multiple times while changing the z coordinate of the probe 11, multiple contour data representing the three-dimensional shape of the measurement object O are generated.

[0018] The database 23 is a database for storing the contour data generated by the contour data generating unit 22 as measurement data 231 .

[0019] The optimization calculation unit 24 performs optimization calculations to calculate the extrusion direction based on the measurement data 231 stored in the database 23. As will be described in detail later, in this embodiment, by making several assumptions, the extrusion direction is considered to be parallel to the datum axis of the measurement object O. The datum axis of the measurement object O is, for example, the axis of the smallest circumscribing cylinder of the measurement object O when the measurement object O is viewed as an approximately cylinder. When the extrusion direction can be considered to be parallel to the datum axis of the measurement object O, the extrusion direction becomes the normal to the projection plane that minimizes the projection error among the projections of the respective contour data of the measurement data 231 onto the projection planes in various projection directions. The projection of the contour data onto the projection plane is performed by applying a rotation matrix and a projection transformation matrix. The optimization calculation is a calculation to find the rotation matrix that minimizes the projection error.

[0020] The projection correction unit 25 generates contour data that has been projection-corrected in a projection direction that minimizes the projection error. Projection correction is a process in which the contour data obtained by applying the rotation matrix obtained by the optimization calculation unit 24 to each contour data is projected onto the projection plane using a projective transformation matrix.

[0021] The display control unit 26 is an output control unit that displays various information on the display device 30 using the contour data after projection correction obtained by the projection correction unit 25. For example, the display control unit 26 displays various information such as an image in which the contour image is superimposed and information on the extrusion direction.

[0022] Fig. 3 is a diagram showing an example of the hardware configuration of the control device 20. The control device 20 may be various types of terminal devices such as a personal computer (PC) or a tablet terminal. As shown in Fig. 3, the control device 20 has, as hardware, a processor 201, a ROM 202, a RAM 203, a storage 204, an input interface 205, and a communication device 206.

[0023] The processor 201 controls the overall operation of the measurement system 1. The processor 201 operates as a drive control unit 21, a contour data generation unit 22, an optimization calculation unit 24, a projection correction unit 25, and a display control unit 26, for example, by executing a program stored in the storage 204. The processor 201 is, for example, a CPU (Central Processing Unit). The processor 201 may be an MPU (Micro-Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like. The processor 201 may be a single CPU or the like, or multiple CPUs or the like.

[0024] The ROM (Read Only Memory) 202 is a non-volatile memory. The ROM 202 stores a startup program and the like for the measurement system 1. The RAM (Random Access Memory) 203 is a volatile memory. The RAM 203 is used as a working memory for processing in the processor 201, for example.

[0025] The storage 204 is, for example, a storage such as a hard disk drive or a solid state drive. The storage 204 stores various programs, such as a measurement program, that are executed by the processor 201. The storage 204 can also store measurement data 231 as a database 23.

[0026] The input interface 205 includes input devices such as a touch panel, a keyboard, a mouse, etc. When an input device of the input interface 205 is operated, a signal corresponding to the operation content is input to the processor 201. The processor 201 performs various processes according to this signal.

[0027] The communication device 206 is a communication device that enables the control device 20 to communicate with external devices such as the measuring device 10 and the display device 30. The communication device 206 may be a communication device for wired communication or a communication device for wireless communication.

[0028] Next, a description will be given of the operation of the measurement system 1 in this embodiment. Fig. 4 is a flowchart showing the operation of the measurement system 1. The processing in Fig. 4 is executed by the processor 201.

[0029] In step S1, the processor 201 performs measurement of the measurement object O. Specifically, the processor 201 controls the z-axis movement mechanism 13, the x-axis movement mechanism 14, and the y-axis movement mechanism 15 of the measurement device 10 to perform scanning measurement in which the probe 11 moves so as to scan the outer periphery of the measurement object O, thereby acquiring contour data representing the cross-sectional shape of the measurement object O. The processor 201 performs scanning measurement multiple times while changing the height relative to the measurement object O, i.e., the z coordinate, to acquire multiple pieces of contour data representing the three-dimensional shape of the measurement object O. The processor 201 stores each acquired piece of contour data in the database 23 as measurement data 231. After the measurement is completed, the process proceeds to step S2.

[0030] In step S2, the processor 201 performs optimization calculations using the measurement data 231 stored in the database 23. After the optimization calculations are completed, the process proceeds to step S3.

[0031] The optimization calculation will be described below. Fig. 5 is a flowchart showing an example of the optimization calculation process. Fig. 5 shows an example in which the steepest descent method is used as the optimization calculation algorithm. However, the optimization calculation algorithm is not limited to the steepest descent method. For example, an optimization algorithm based on a gradient method other than the steepest descent method, such as Newton's method, may be used as the optimization algorithm.

[0032] First, the concept of optimization calculation in this embodiment will be described. In the following description, it is assumed that the measurement object O satisfies the following three assumptions. The extrusion direction for the measurement object O that satisfies all of the following three assumptions will be the normal direction of the projection plane that minimizes the projection error when the contour data of the measurement data 231 is projected onto the projection plane in various projection directions. Therefore, the extrusion direction can be estimated by determining the direction of the projection plane that satisfies these conditions. Assumption (1) The extrusion direction is a straight line. In other words, the datum axis of the measurement object O is not bent. Assumption (2): The measurement object O has the same cross section no matter which cross section it is cut in. In other words, the measurement object O is not deformed. Assumption (3): The measurement object O does not deviate in the rotation direction no matter which cross section it is cut in. In other words, there is no twist in the measurement object O.

[0033] 6A and 6B are diagrams for explaining the projection of contour data in the embodiment. As described above, contour data is point cloud data along the contour of the measurement object O. Therefore, the projection of contour data in the embodiment means projecting each point constituting the contour data onto a certain projection plane PP.

[0034] FIG. 6A is a conceptual diagram of projecting one point P onto a projection plane PP. For the sake of later explanation, a projection plane coordinate system ξηζ is defined on the projection plane PP. The ξ axis is a projection direction vector e, which is a unit vector representing the horizontal direction of the projection plane PP. ξ The η axis is the projection direction vector e, which is a unit vector representing the vertical direction of the projection plane PP. η The ζ axis is the projection direction vector e, which is a unit vector that represents the normal direction of the projection plane PP. ζ The projection plane coordinate system can also be said to be a coordinate system based on the end face of the measurement object O.

[0035] The coordinates of each point of the contour data measured by the measuring device 10 are obtained as coordinates in the machine coordinate system. Here, when the coordinates of point P are (x, y, z), the coordinates (ξ, η, ζ) of point P based on the projection surface coordinate system are calculated from the following equation (1). Here, t in equation (1) is a vector whose start point is the origin of the machine coordinate system and whose end point is the origin of the projection surface coordinate system. Also, R is e ξ , e η , e ζ In addition, p is a vector whose starting point is the origin of the machine coordinate system and whose ending point is point P.

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[0036] Next, consider the projection error of two contour data. FIG. 6B is a conceptual diagram illustrating the projection of point P of one contour data and point Q corresponding to point P of another contour data onto a projection plane PP. If the three assumptions described above are met, and both contour data are contour data for a cross section perpendicular to the datum axis, point P' after projection of point P and point Q' after projection of point Q will be projected to the same position on the projection plane PP. In other words, the distance between points P' and Q' after projection will be zero. On the other hand, if one or both of the two contour data are not contour data for a cross section perpendicular to the datum axis, points P' and Q' after projection will be projected to different positions on the projection plane PP. In other words, the distance between points P' and Q' after projection will not be zero. This distance between points P' and Q' is the projection error. The distance between points P' and Q' in the case of FIG. 6B can be expressed as the following equation (3) from equation (2). As shown in equation (3), the distance between the two points after projection can also be expressed using a rotation matrix R.

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[0037] Equation (3) corresponds to the projection error when the corresponding points of two contour data are known. In reality, the corresponding points of two contour data are not known. In addition, the two contour data may have different numbers of constituent points. In order to calculate the projection error between point groups that may have different numbers of constituent points, in this embodiment, the Chamfer Distance is used. i} and {Q j}Chamfer Distance CD({P i},{Q j}) is defined as shown in equation (4). Here, N in equation (4) p is the set of points {P i} is the number of constituent points. q is the set of points {Q j} is the number of constituent points.

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[0038] In reality, the number of contour data is not limited to two. Therefore, in this embodiment, the sum of the chamfer distances between the constituent point groups of M contour data is set as the error function f(R), and a rotation matrix R that minimizes this f(R) is calculated. The error function f(R) can be expressed as in equation (6). Here, in equation (6), the point group {p i} is a group of constituent points of the reference contour data among the M pieces of contour data. The reference contour data may be any data among the M pieces of contour data. For example, the reference contour data may be the data that is first selected among the M pieces of contour data. Also, the group of points {q j (1)}, point cloud {q j (2)},…, point cloud {q j (M-1)} is a group of constituent points of the contour data other than the reference contour data among the M contour data.

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[0039] 5, the optimization calculation for calculating the rotation matrix R that minimizes f(R) in equation (6) will be described. In step S101, the processor 201 calculates the rotation matrix R k The initial value R0 is determined. For example, the initial value R0 is the projection direction vector e parallel to the x-axis, y-axis, and z-axis of the machine coordinate system. ξ , e η , e ζ It can be a rotation matrix with elements

[0040] In step S102, the processor 201 calculates the error function f(R k) satisfies the convergence condition. The convergence condition is the error function f(R k ) is the minimum value. For example, the error function f(R k ) is below a certain threshold, the error function f(R k ) is determined to be the minimum value. k If it is determined that the error function f(R k ) satisfies the convergence condition, the process proceeds to step S106.

[0041] In step S103, the processor 201 calculates the error function f(R k ) search direction. The search direction is the error function f(R k ) gradient d k =-grad f(R k ) is determined based on

[0042] In step S104, the processor 201 calculates φ(α)=f(R k +αd k ) and find the α that minimizes φ(α). k Calculate the function f(x k ) reveals that the function f(x k ) is only in the decreasing direction. k ) with high accuracy, as shown in Figure 7B, k It is necessary to find an appropriate step size α (α>0) that indicates how much to decrease the value. k is the α that minimizes φ(α). For example, the processor 201 calculates the value of φ(α) while changing α, and when φ(α) changes from decreasing to increasing, it sets the previous α as α. k A search is carried out to find α kAfter f(x) is calculated, the process proceeds to step S104. Here, FIG. 7A shows an example where f(x) is a function of two variables. In practice, the processor 201 calculates f(R k ) for α k Calculate.

[0043] In step S105, the processor 201 k+1 R k +α k d k The processor 201 also sets k to k+1. Then, the process returns to step S102.

[0044] In step S102, if it is determined that the convergence condition is satisfied, in step S106, the processor 201 calculates R k The optimal solution is R k After that, the process in FIG. 5 ends.

[0045] Returning to the description of Fig. 4, in step S3 after the optimization calculation, the processor 201 performs projection correction. The projection correction is performed by applying a rotation matrix R k After applying the projection transformation matrix P, the contour data O1, O2, and O3 representing cross sections perpendicular to the datum axis are projected onto the projection plane PP using the projection transformation matrix P. For a measurement object O that satisfies all of the above-mentioned assumptions (1) to (3), the shapes of the contour data O1, O2, and O3 representing cross sections perpendicular to the datum axis will all be the same, as shown in FIG. 8A. On the other hand, if the extrusion direction of the measurement object O is tilted with respect to the datum axis, i.e., if the extrusion direction is not parallel to the normal direction of the projection plane PP, a projection error will occur between the contour data O1, O2, and O3 projected onto the projection plane PP, as shown in FIG. 8B. In contrast, by rotating the contour data O1, O2, and O3 so that the datum axis of the measurement object O is parallel to the normal direction of the projection plane PP, no projection error will occur between the contour data O1, O2, and O3 projected onto the projection plane PP, as shown in FIG. 8C.

[0046] Now, returning to the explanation of Fig. 4, after the projection correction, the processor 201 causes the display device 30 to display an image representing the true contour shape of the measurement object O based on the projection-corrected contour data. Furthermore, the processor 201 causes the display device 30 to display the extrusion direction. After the display is completed, the processing of Fig. 4 ends.

[0047] FIG. 9 is a diagram showing an example of a display on the display device 30. An example display screen 300 displays an image 301 in which multiple images of the contours of the measurement target O projected after projection correction are superimposed. Furthermore, an example display screen displays an estimated extrusion direction 302. The extrusion direction 302 displayed in FIG. 9 is calculated based on an estimated rotation matrix R k The projection direction vector e corresponds to the extrusion direction of ζ is expressed based on the machine coordinate system xyz.

[0048] As described above, according to the embodiment, the rotation matrix of the projection plane is optimized so as to minimize the projection error of multiple pieces of contour data corresponding to multiple cross-sectional shapes of the measurement object O. The component of the optimized rotation matrix in the normal direction of the projection plane coincides with the extrusion direction. In this way, in the embodiment, the extrusion direction is estimated with high accuracy using a simple configuration. Furthermore, projection correction can correct the contour data to contour data on a plane perpendicular to the datum axis. Therefore, each piece of contour data can become data that accurately represents the true cross-sectional shape of the measurement object O.

[0049] (Variation 1) A modified example of the embodiment will be described. In the embodiment, the measurement device 10 is a CMM in which the probe 11 is movable in three axial directions. However, the technology of the embodiment can be applied to various shape measurement devices other than a CMM in which the probe 11 is movable in three axial directions.

[0050] 10 is a diagram showing another example of the configuration of the measurement system 1. The measurement system 1 has a measurement device 40 and a control device 20. The control device 20 is configured to be able to communicate with the display device 30.

[0051] Similar to the measuring apparatus 10, the measuring apparatus 40 is a shape measuring apparatus configured to measure information related to the three-dimensional shape of the measurement object O. Here, the measuring apparatus 40 in FIG. 10 is, for example, a roundness measuring apparatus, and includes, for example, a probe 41, a probe receiving portion 42, a support member 43, a z-axis moving mechanism 44, a support member 45, a rotary table 46, and a stage 47. Here, similar to the measuring apparatus 10, a machine coordinate system is defined for the measuring apparatus 40. The x-axis of the machine coordinate system for the measuring apparatus 40 is an axis parallel to the horizontal direction of the stage 47. The y-axis of the machine coordinate system is an axis parallel to the vertical direction of the stage 47. The z-axis of the machine coordinate system is an axis parallel to the thickness direction of the stage 47.

[0052] Like probe 11, probe 41 has a ball-shaped contactor at its tip, which comes into contact with the measurement object O and generates a signal. Probe 41 is held by probe receiving part 42. Probe receiving part 42 holds probe 41 so that when the contactor of probe 41 comes into contact with the measurement object O, the contactor can move in accordance with the shape of the measurement object O. Probe receiving part 42 is supported by support member 43. Support member 43 extends in the x-axis direction and supports probe receiving part 42 so that it is fixed. Support member 43 is attached to z-axis movement mechanism 44.

[0053] The z-axis moving mechanism 44 is attached to the support member 45 so as to be able to move the support member 43 in the z-axis direction. The support member 45 holds the z-axis moving mechanism 44 so as to be able to move the z-axis moving mechanism 44 in the z-axis direction, and is fixed by the stage 47.

[0054] The rotary table 46 is attached to a stage 47 so that it can rotate about a rotation axis A that is parallel to the z-axis, and so that the contact of the probe 41 can come into contact with the measurement object O placed on the rotary table 46. The stage 47 is flat and holds the support member 43 and the rotary table.

[0055] The control device 20 rotates the turntable 46 in the θ direction around the axis A. The measurement object O placed on the turntable 46 also rotates in the θ direction. At this time, the contact of the probe 41 comes into contact with the measurement object O so as to trace the circumferential direction of the measurement object O. The contour data generation unit 22 of the control device 20 can generate contour data of the measurement object O similar to that of the measurement device 10 from the signal obtained via the probe 41.

[0056] (Other variations) In this embodiment, it is assumed that the measurement object O satisfies all of assumptions (1)-(3). If assumptions (1)-(3) are strictly satisfied, then in theory, the minimum value of the error function f(R) will be zero. However, in practice, assumptions (1)-(3) do not necessarily need to be strictly satisfied. For example, the measurement object O may be slightly deformed or twisted. If the measurement object O is deformed or twisted, the error function f(R) will not be zero. On the other hand, the normal direction vector of the rotation matrix R that minimizes the error function f(R) roughly coincides with the extrusion direction of the measurement object O. Accurate estimation of the extrusion direction is expected to enable accurate comparison of contour data between areas where deformation or twisting occurs and areas where these do not occur.

[0057] In the embodiment, an example is shown in which information about the extrusion direction is displayed on the display device 30. On the other hand, shape measurement may be performed again based on information about the estimated extrusion direction. Such shape measurement again is expected to result in more accurate contour data.

[0058] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0059] 1 Measurement system, 10 Measurement device, 11 Probe, 12 Probe receiving part, 13 Z-axis movement mechanism, 14 X-axis movement mechanism, 15 Y-axis movement mechanism, 16 Stage, 20 Control device, 21 Drive control part, 22 Contour data generation part, 23 Database, 24 Optimization calculation part, 25 Projection correction part, 26 Display control part, 30 Display device, 40 Measurement device, 41 Probe, 42 Probe receiving part, 43 Support member, 44 Z-axis movement mechanism, 45 Support member, 46 Rotary table, 47 Stage, 201 Processor, 202 ROM, 203 RAM, 204 Storage, 205 Input interface, 206 Communication device.

Claims

1. an optimization calculation unit that calculates, by an optimization algorithm using a plurality of contour data corresponding to each of a plurality of cross sections of the object to be measured, obtained by scanning and measuring the plurality of cross sections of the object to be measured using a measurement device, a direction of a projection plane that minimizes a projection error of the plurality of contour data; a correction unit that corrects each of the contour data based on the direction of the projection surface; A measurement system comprising:

2. The measurement system according to claim 1 , further comprising an output control unit that outputs a projection direction that indicates a normal to the projection plane as a push-out direction in scanning measurement of the measurement object.

3. calculating, by an optimization algorithm using a plurality of contour data corresponding to each of the plurality of cross sections obtained by scanning and measuring the plurality of cross sections of the measurement object using a measurement device, a direction of a projection plane that minimizes a projection error of the plurality of contour data; correcting each of the contour data based on the direction of the projection surface; A measurement method comprising:

4. calculating, by an optimization algorithm using a plurality of contour data corresponding to each of the plurality of cross sections obtained by scanning and measuring the plurality of cross sections of the measurement object using a measurement device, a direction of a projection plane that minimizes a projection error of the plurality of contour data; correcting each of the contour data based on the direction of the projection surface; A measurement program for causing a processor to execute the above.

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