Image measuring device

Abstract

To simplify the setup process for coordinate measurement using a touch probe and improve usability. [Solution] The image measuring device includes a setting unit that sets geometric measuring elements on a workpiece image for measurement using a touch probe, a storage unit that stores in advance the correspondence between the shape type or size of the measuring elements that can be set by the setting unit and the position and number of contact target positions of the touch probe relative to the measuring elements, and a control unit that, when performing measurement with a touch probe, identifies a plurality of contact target positions of the touch probe based on the position of the measuring elements on the workpiece image set by the setting unit, the shape type or size of the measuring elements, and the pre-stored correspondence, and moves the stage or the touch probe relative to the plurality of identified contact target positions.

Description

Technical Field

[0001] The present disclosure relates to an image measuring apparatus for measuring dimensions of a workpiece based on a workpiece image.

Background Art

[0002] Conventionally, there has been known a multi-sensor CNC image measuring apparatus including a contact probe (touch probe) configured to place a workpiece on a stage, bring a probe into contact with a desired location on the surface of the workpiece on the stage, and measure three-dimensional coordinates of the location where the probe contacts. This image measuring apparatus is provided with a joystick for moving the touch probe in an arbitrary direction in the X, Y, and Z directions. At the time of measurement setting, the user operates the joystick to specify measurement points in advance.

[0003] In addition, for example, a method has been devised in which CAD data is read, measurement points are specified from a CAD drawing, and the path generation of the touch probe is automatically performed.

[0004] In addition, for example, as disclosed in Patent Document 1, there is also known an image measuring apparatus that performs virtual probing setting using marks overlaid on a captured image of a workpiece. In the image measuring apparatus of this Patent Document 1, the user can set the target detection position of the touch probe by operating a mouse and moving a mark indicating the probe sphere of the touch probe to the measurement point.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, when the user operates a joystick to set the measurement parameters, as in the multi-sensor CNC image measuring device mentioned above, it is necessary to operate it carefully to avoid the touch probe coming into contact with areas that should not be measured, which is time-consuming and inefficient.

[0007] In this regard, as mentioned above, one could consider setting the measurement parameters on the CAD drawing, but this is not possible if the CAD data is not available.

[0008] Furthermore, while it is conceivable to set virtual probing on the captured image of the workpiece, as described in Patent Document 1, setting multiple target detection positions requires moving each mark to the measurement point one by one, which is time-consuming and impractical.

[0009] This disclosure is made in view of the above points, and its purpose is to simplify the setup process for coordinate measurement using a touch probe and improve usability. [Means for solving the problem]

[0010] To achieve the above objective, in one aspect of this disclosure, a light-emitting unit that irradiates a workpiece on a stage with detection light, an imaging unit that receives the detection light and generates a workpiece image, a touch probe for contacting the workpiece on the stage and measuring the three-dimensional coordinates of the contact point, a drive unit that moves the stage or the touch probe relative to the stage in the direction normal to the stage, in a direction parallel to the upper surface of the stage, or in a direction inclined from the normal direction, thereby bringing the touch probe into contact with the surface of the workpiece placed on the stage, a display unit that displays the workpiece image generated by the imaging unit when the touch probe is set to measure, and the workpiece image displayed on the display unit The system includes: a setting unit for setting geometric measurement elements on an image for measurement by the touch probe; a storage unit that stores in advance the correspondence between the shape type and size of the measurement elements that can be set by the setting unit and the position and number of contact target positions of the touch probe relative to the measurement elements; and a control unit that, when measurement is performed by the touch probe, identifies a plurality of contact target positions of the touch probe based on the position of the measurement elements on the work image set by the setting unit, the shape type or size of the measurement elements, and the correspondence stored in advance in the storage unit, and controls the drive unit so that the touch probe moves sequentially to the plurality of identified contact target positions. Furthermore, the system includes a measurement unit that measures the three-dimensional coordinates of the contact point where the touch probe contacts the workpiece based on a contact signal output when the touch probe contacts the workpiece due to the operation of the drive unit controlled by the control unit.

[0011] This configuration allows users to set geometric measurement elements on the workpiece image for measurement using a touch probe during the measurement setup process. The positions of the set measurement elements are identified on the workpiece image. Furthermore, the correspondence between the shape type or size of the set measurement elements and the positions and number of contact target positions for the touch probe relative to those measurement elements is stored in advance. Therefore, during measurement execution, multiple contact target positions for the touch probe are automatically identified based on the positions of the measurement elements on the workpiece image and the above correspondence. This simplifies the setup process for the user. The touch probe then moves sequentially to the identified contact target positions, and the measurement is automatically performed. The measurement elements may be set by the user, or the image measuring device may automatically read and apply measurement elements that have been stored in advance based on user settings.

[0012] Furthermore, the setting unit may be able to set feature information for identifying the position and orientation of the workpiece at the time of measurement on the workpiece image displayed on the display unit. In this case, the control unit can, at the time of measurement, identify the position and orientation of the workpiece using the feature information stored in the storage unit from the workpiece image newly generated by the imaging unit, identify the contact target position of the touch probe based on the identified workpiece position and orientation, and control the drive unit so that the touch probe moves sequentially to the identified contact target position. This makes it possible to use the information from the measurement setup when measuring a workpiece at a different position and orientation than the workpiece used during the measurement setup.

[0013] Furthermore, the control unit may be configured to allow specifying an edge extraction region for detecting the edges of a workpiece on the workpiece image displayed on the display unit. In this case, the setting unit can set the edges detected from the edge extraction region specified by the control unit as measurement elements.

[0014] Furthermore, the control unit can perform a pattern search on the workpiece image newly generated for measurement by the imaging unit to correct the workpiece position so that it corresponds to the position at the time of measurement setting. In this case, the position correction of the edge extraction region is performed to correspond to the workpiece position correction, and the edges detected from the edge extraction region after position correction can be set as measurement elements.

[0015] Furthermore, the control unit can also determine the target contact position of the touch probe according to the measurement elements detected from the edge extraction region after position correction.

[0016] Furthermore, the setting unit may be configured to allow setting the number of touch probe target positions to be placed. In this case, the storage unit can store the number of touch probe target positions set in the setting unit. When measurement is performed, the same number of contact target positions as the number stored in the storage unit can be placed, allowing measurement with the desired accuracy.

[0017] Furthermore, the setting unit may be configured to allow setting of an approach path to the contact target position of the touch probe. The storage unit can store the approach path set in the setting unit. When measurement is performed by the touch probe, the control unit can control the drive unit so that the touch probe moves according to the approach path stored in the storage unit.

[0018] Furthermore, the setting unit may be configured to allow the setting of points, in addition to geometric elements, as measurement elements for performing measurements by the touch probe on the workpiece image displayed on the display unit.

[0019] Furthermore, the support unit may be provided with an overhead image generation unit that generates an overhead image of the workpiece. In this case, the field of view of the imaging unit is set to be narrower than the field of view of the overhead image generation unit, and the control unit can detect the position of the workpiece on the stage based on the overhead image generated by the overhead image generation unit, move the stage so that the detected workpiece is within the field of view of the imaging unit, take multiple images with the imaging unit, generate a concatenated image by combining the multiple acquired images, and perform a pattern search on the generated concatenated image.

[0020] Furthermore, if the device is equipped with a main unit indicator that displays the measurement results from the measurement unit, the measurement results can be communicated externally.

[0021] Alternatively, the display unit may show a cross-sectional view of the workpiece. In this case, the setting unit can set parameters associated with the measurement elements for measurement using a touch probe on the cross-sectional view of the workpiece displayed on the display unit.

[0022] Furthermore, the setting unit may be configured to accept input of angle information near the contact target position of the touch probe. In this case, the control unit can use the angle information to identify the contact target position of the touch probe.

[0023] Furthermore, the setting unit may be configured to allow setting the approach direction of the touch probe to the target contact position. The approach direction may include a first approach direction in which the touch probe is moved from above to approach the workpiece, and a second approach direction in which the touch probe is moved in a direction normal to the slope of the workpiece. [Effects of the Invention]

[0024] As described above, it is possible to set the geometric measurement elements for measurement by the touch probe on the workpiece image. At the time of measurement execution, based on the correspondence relationship between the position of the measurement element, the shape type or size of the measurement element, and the contact target position of the touch probe, a plurality of contact target positions of the touch probe are automatically specified, and the touch probe can be sequentially and automatically moved to the plurality of specified contact target positions. Therefore, the setting work for coordinate measurement using the touch probe can be easily performed, and the usability can be improved.

Brief Description of the Drawings

[0025] [Figure 1] It is a diagram showing the overall configuration of an image measuring apparatus according to an embodiment of the present invention. [Figure 2] It is a perspective view of the apparatus main body as seen from above. [Figure 3] It is a schematic diagram when the apparatus main body is seen from the front side. [Figure 4] It is a schematic diagram when the apparatus main body is seen from the side. [Figure 5] It is a perspective view of the light receiving lens and its vicinity as seen from obliquely below. [Figure 6] It is a block diagram of the image measuring apparatus. [Figure 7] It is a longitudinal sectional view of the touch probe. [Figure 8] It is a plan view of the elastic member for forming the fulcrum. [Figure 9] It is a sectional view taken along line IX-IX in FIG. 7. [Figure 10] It is a view corresponding to FIG. 7 showing another example of the touch probe. [Figure 11] It is a perspective view of the stylus changer mechanism. [Figure 12] It is a perspective view of the stylus holding part. [Figure 13] It is a flowchart showing an example of the procedure for attaching the stylus. [Figure 14]FIG. 14A is a perspective view showing the housing positioned above the stylus holder in the mounting position, and FIG. 14B is a perspective view showing the housing lowered and the stylus attached. [Figure 15] This flowchart shows an example of the procedure for removing the stylus. [Figure 16] This flowchart shows an example of the procedure for setting up an image measuring device. [Figure 17] This is a flowchart illustrating an example of the image generation procedure. [Figure 18] This flowchart shows an example of the procedure for setting up image measurement. [Figure 19] This flowchart shows an example of the procedure for setting up coordinate measurement. [Figure 20] This is a perspective view of the work on stage. [Figure 21] This is a plan view of the stage on which the workpiece is placed. [Figure 22] This is a longitudinal cross-sectional view of the workpiece on the stage, along the Y-direction. [Figure 23] This figure shows an example of a user interface screen for setting the contact target location. [Figure 24] This figure shows an example of a user interface screen for setting the target contact position on a slope. [Figure 25] This is a flowchart illustrating an example of the procedure for measurement using a non-contact displacement sensor. [Figure 26] This figure shows an example of a user interface screen for displaying geometric elements. [Figure 27] This figure shows an example of a user interface screen for displaying geometric elements superimposed on a three-dimensional image. [Figure 28] This flowchart shows an example of a detailed procedure for the measurement operation of a touch probe. [Figure 29A] This flowchart shows an example of the initial steps involved in setting up an image measuring device. [Figure 29B]This flowchart shows an example of the latter part of the procedure when setting up an image measuring device. [Figure 30] This flowchart shows an example of a non-contact measurement procedure during measurement execution. [Figure 31] This is a diagram corresponding to Figure 6, relating to a modified example 1 having a 3-channel image sensor. [Figure 32] This is a diagram corresponding to Figure 6, relating to a modified example 2 having a single-channel image sensor and a three-channel image sensor. [Modes for carrying out the invention]

[0026] Embodiments of the present invention will be described in detail below with reference to the drawings. The following description of preferred embodiments is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0027] Figure 1 shows the overall configuration of an image measuring device 1 according to an embodiment of the present invention. The image measuring device 1 comprises a device body 2, a control unit 3 composed of a personal computer or the like, and a display unit 4. The control unit 3 processes the data acquired by the device body 2 to measure the dimensions of each part of the workpiece W, and is configured to also perform quality control of the measurement results as needed. The control unit 3 may be incorporated into and integrated with the device body 2. As will be described in detail later, the data acquired by the device body 2 includes image data of the workpiece W, data on the contact point when the touch probe 80 (described later) contacts the workpiece W, and data measured by a non-contact displacement meter 70 (shown in Figure 3).

[0028] The display unit 4 displays, for example, various setting screens, image data, measurement results, etc. The display unit 4 is composed of, for example, a liquid crystal display or an organic EL display. In this example, the display unit 4 is shown as being separate from the main unit 2 and the control unit 3, but it is not limited to this arrangement and may be incorporated into the main unit 2 or into the control unit 3.

[0029] The image measuring device 1 is further equipped with user-operated devices such as a keyboard 5 and a mouse 6. The operating devices are not limited to the keyboard 5 and mouse 6, but may also be touch panel type operating devices, etc. For example, the control unit 3 can be configured as a notebook personal computer, in which case the keyboard 5 and mouse 6 will be integrated with the control unit 3 together with the display unit 4.

[0030] The image measuring device 1 further includes a storage unit 7. The storage unit 7 can be configured as, for example, a hard disk drive or a solid-state drive, and stores various data acquired by the device body 2, user settings, images, measurement results, pass / fail judgment results, etc. The storage unit 7 may be built into the control unit 3 or provided outside the control unit 3. If the storage unit 7 is provided outside the control unit 3, it may be, for example, a cloud-type storage connected via a communication line such as the Internet.

[0031] (Configuration of the main unit 2 of the device) As shown in Figure 2, the apparatus body 2 comprises a base 20 and a stage 21 that is horizontally movable relative to the base 20. The stage 21 may also be vertically movable. Near the center of the stage 21, a mounting table 21a made of a light-transmitting material such as glass is provided, and a workpiece W can be placed on this mounting table 21a. The stage 21 is supported on the base 20 so as to be movable in the horizontal direction (the width direction of the apparatus body 2, the X direction, and the depth direction of the apparatus body 2, the Y direction). That is, the apparatus body 2 is equipped with an XY direction drive unit 23 (schematically shown in Figures 3 and 4) that drives the stage 21, and the XY direction drive unit 23 can move the stage 21 within a predetermined range in the X direction and within a predetermined range in the Y direction. In addition to moving Stage 21 in a straight line in the X direction and in a straight line in the Y direction, it is also possible to move Stage 21 so that its movement trajectory is inclined with respect to the X and Y axes in a plan view, or to move Stage 21 to trace an arbitrary curve.

[0032] The XY direction drive unit 23 has an X-direction linear scale 23a for detecting the distance traveled in the X direction and a Y-direction linear scale 23b for detecting the distance traveled in the Y direction. The X-direction linear scale 23a enables the detection of the position and distance traveled of the stage 21 in the left-right direction. The Y-direction linear scale 23b enables the detection of the position and distance traveled of the stage 21 in the depth direction.

[0033] The XY direction drive unit 23 is controlled by the control unit 3. Based on the control signals output from the control unit 3, the XY direction drive unit 23 is controlled, and the current position of the stage 21 is determined based on the detection signals of the X direction linear scale 23a and the Y direction linear scale 23b. The stage 21 is then moved to a desired position and moved so that it follows a desired movement trajectory.

[0034] In this description of the embodiment, the Z direction is sometimes referred to as the up-down direction or height direction, the X direction as the left-right direction, and the Y direction as the front-back direction. This is for the convenience of explanation and does not limit the orientation of the device body 2 when in use. Also, since the user is usually in front of the device body 2, the user side of the device body 2 is simply referred to as the front, the opposite side from the user is simply referred to as the rear, the right side from the user's perspective is simply referred to as the right side, and the left side from the user's perspective is simply referred to as the left side.

[0035] As shown in Figures 3 and 4, a transmitted light source 30 is provided in the lower part of the base 20 below the stage 21. As shown in Figure 4, the transmitted light source 30 includes a transmitted light source 31, such as a light-emitting diode; a slit 32 through which light emitted from the transmitted light source 31 passes; a mirror 33 for directing the light that has passed through the slit 32 upwards; and a lens 34 into which the light directed upwards by the mirror 33 enters. The lens 34 is a lens capable of emitting incident light as parallel light. The light emitted from the lens 34 is directed towards the mounting table 21a of the stage 21, passes through the mounting table 21a, and irradiates the workpiece W placed on the mounting table 21a from below.

[0036] As shown in Figure 2, a measurement start button 2a is provided on the front side of the base 20 of the device body 2. The measurement start button 2a is a button that the user operates when starting the measurement of the workpiece W. When performing a measurement, the measurement operation is executed by simply pressing the measurement start button 2a once.

[0037] The main body of the device 2 comprises a support section 22 and a measurement execution section 24. As shown in Figures 3 and 4, the support section 22 is connected to the rear portion of the base 20 and extends upward from the rear portion of the base 20. The measurement execution section 24 is supported on the upper portion of the support section 22. The measurement execution section 24 is equipped with a coaxial incident illumination 40, a ring illumination 45, an imaging section 50, a non-contact displacement meter 70, a lens unit 81 of a touch probe 80, and the like.

[0038] The measurement execution unit 24 is configured separately from the support unit 22 and is movable in the Z direction relative to the support unit 22. That is, the main body of the device 2 is equipped with a Z-direction drive unit 25 that drives the measurement execution unit 24, and the Z-direction drive unit 25 allows the measurement execution unit 24 to move linearly from the upper end position to the lower end position. The imaging axis of the imaging unit 50 coincides with the Z axis, and therefore the imaging axis extends in the Z direction. The measurement execution unit 24 is an example of a movable part that moves along the imaging axis of the imaging unit 50.

[0039] The Z-direction drive unit 25 has a Z-direction linear scale 25a for detecting the distance traveled in the Z-direction. The Z-direction linear scale 25a enables the detection of the height of the measurement execution unit 24, the distance traveled in the height direction, and other parameters. The Z-direction drive unit 25 is controlled by a control unit 3d of the control unit 3. The control unit 3d controls the Z-direction drive unit 25 with a control signal, determines the current position of the measurement execution unit 24 based on the detection signal from the Z-direction linear scale 25a, and moves the measurement execution unit 24 to the desired position. The movement speed of the measurement execution unit 24 can be changed in multiple steps or continuously.

[0040] The coaxial incident illumination 40 is a light-emitting unit and, as shown in Figure 4, comprises a coaxial incident illumination light-emitting element 41, which is made of, for example, a light-emitting diode, a lens 42 into which the light emitted from the coaxial incident illumination light-emitting element 41 enters, and a direction changing member 43 that directs the light emitted from the lens 42 downward. The direction changing member 43 is made of a light-transmitting member that can transmit light in the vertical direction. The light emitted from the direction changing member 43 is detection light. The detection light emitted from the direction changing member 43 is directed toward the mounting table 21a of the stage 21 and is irradiated from above onto the workpiece W placed on the mounting table 21a, i.e., the workpiece W on the stage 21.

[0041] The imaging unit 50 includes a light-receiving lens 51, a beam splitter 52, a high-magnification imaging lens 53, a low-magnification imaging lens 54, a high-magnification image sensor 55, and a low-magnification image sensor 56, which together constitute the first imaging unit. The imaging unit 50 is supported by a support unit 22 above the stage 21 in a position where the imaging direction is the normal direction (Z direction) of the stage 21.

[0042] Specifically, as shown in Figure 5, the light-receiving lens 51 of the imaging unit 50 is positioned on the lower surface of the measurement execution unit 24, with its light-receiving surface facing the upper surface of the mounting base 21a of the stage 21. Therefore, the light-receiving lens 51 can receive detection light that is irradiated from the coaxial incident illumination 40 and reflected from the surface of the workpiece W, and it can also receive light irradiated from the transmitted illumination 30.

[0043] The optical axis of the light-receiving lens 51 coincides with the Z direction. In this example, the direction changing member 43 of the coaxial incident illumination 40 is located directly above the light-receiving lens 51, so the detection light emitted from the coaxial incident illumination 40 passes through the light-receiving lens 51 and irradiates the workpiece W on the stage 21.

[0044] The beam splitter 52 is positioned above the direction changing member 43 and consists of a prism that splits the light emitted upward from the light-receiving lens 51 into two directions. For example, a cube-shaped or plate-shaped beam splitter can be used as the beam splitter 52. Compared to the plate-shaped beam splitter, the cube-shaped beam splitter is preferred because the light passing through the beam splitter does not refract, so the optical axis does not shift, and the alignment adjustment of the branching angle is easy. In this example, the light incident on the beam splitter 52 via the light-receiving lens 51 is split upward and backward. For this reason, the high-magnification imaging lens 53 is positioned above the beam splitter 52, while the low-magnification imaging lens 54 is positioned behind the beam splitter 52. The high-magnification image sensor 55 is positioned above the high-magnification imaging lens 53, and the light incident on the high-magnification imaging lens 53 is imaged at the light-receiving surface of the high-magnification image sensor 55. Furthermore, the low-magnification image sensor 56 is positioned behind the low-magnification imaging lens 54, and the light incident on the low-magnification imaging lens 54 is imaged at the light-receiving surface of the low-magnification image sensor 56.

[0045] The high-magnification image sensor 55 and the low-magnification image sensor 56 are composed of a CCD (Charge-Coupled Device) image sensor, a CMOS (Complementary MOS) image sensor, etc. The workpiece image acquired by the low-magnification image sensor 56 is a low-magnification image, and the workpiece image acquired by the high-magnification image sensor 55 is a high-magnification image with a higher magnification than the low-magnification image. In this example, in order to improve measurement accuracy, the high-magnification image sensor 55 and the low-magnification image sensor 56 are configured as single-channel image sensors to acquire high-resolution workpiece images. Therefore, the workpiece images output from the high-magnification image sensor 55 and the low-magnification image sensor 56 are monochrome images (grayscale images).

[0046] The focal position of the imaging unit 50 is adjusted by the Z-direction drive unit 25. That is, the control unit 3d can move the measurement execution unit 24 in the Z direction by controlling the Z-direction drive unit 25. Since the Z direction coincides with the imaging axis direction of the imaging unit 50, the imaging unit 50 can be moved along the imaging axis. In other words, the Z-direction drive unit 25 is a focus adjustment mechanism that adjusts the focal position of the imaging unit 50, and the focus of the imaging unit 50 can be adjusted by moving the measurement execution unit 24 in a direction along the imaging axis. When adjusting the focus, in addition to autofocus using conventionally known algorithms such as the contrast method and the phase difference method, manual focus is also possible, which is adjusted by the user performing predetermined operations.

[0047] The above-described configuration of the light-receiving lens 51 and beam splitter 52 allows for the simultaneous acquisition of high-magnification and low-magnification images without mechanically switching the optical system. Alternatively, the configuration of the beam splitter 52 can be omitted, and high-magnification and low-magnification images can be acquired by mechanically switching between the high-magnification lens and the low-magnification lens.

[0048] The ring illumination 45 is a light-emitting unit that illuminates the workpiece W on the stage 21 with monochromatic light (white light) or detection light of multiple different wavelengths. The detection light of multiple different wavelengths includes, for example, red light, green light, blue light, etc. The ring illumination 45 has a circular shape that surrounds the outer circumference of the light-receiving lens 51 and is positioned below the light-receiving lens 51 and coaxially with the light-receiving lens 51.

[0049] As shown in Figure 6, the ring light 45 includes a red light source 45a that emits red light, a green light source 45b that emits green light, and a blue light source 45c that emits blue light. The red light source 45a, green light source 45b, and blue light source 45c are each composed of light-emitting diodes or the like, and can be turned on and off individually. That is, by turning on only the red light source 45a, the workpiece W is illuminated with red light; by turning on only the green light source 45b, the workpiece W is illuminated with green light; by turning on only the blue light source 45c, the workpiece W is illuminated with green light; and by turning on all three light sources 45a, 45b, and 45c, the workpiece W is illuminated with white light.

[0050] The ring illumination 45 is equipped with a Z-direction illumination drive unit 45d, which allows the ring illumination 45 to move linearly from the upper end position to the lower end position. By moving the ring illumination 45 according to the height of the workpiece W, it becomes possible to illuminate the workpiece W with detection light from a point close to it. The Z-direction illumination drive unit 45d has a Z-direction linear scale 45e for detecting the distance of movement in the Z direction, which enables the detection of the height of the ring illumination 45, the distance of movement in the height direction, etc. In this embodiment, the ring illumination 45 is located outside the housing of the measurement execution unit 45, but the present invention is not limited to this, and it may be located inside the housing of the measurement execution unit 45.

[0051] As shown in Figure 3, the mirror 33 that guides the transmitted illumination 30 to the stage 21, the ring illumination 45, the direction changing member 43 that guides the coaxial incident illumination 40 to the stage 21, and the imaging unit 50 (for example, the high-magnification image sensor 55) are arranged in a substantially straight line in the vertical direction. The ring illumination 45, the direction changing member 43, and the imaging unit 50 are fixed to the housing of the measurement execution unit 24, which is movable vertically, and are integrally movable in the Z direction. In addition, in this embodiment, the housing 81 of the touch probe 80, which will be described later, is also fixed to the housing of the measurement execution unit 24, and the housing 81 is also integrally movable in the Z direction.

[0052] The measurement execution unit 24 includes a first stage camera 46, a second stage camera 47, and a front camera 48. Since the measurement execution unit 24 is located in the upper part of the support unit 22, the first stage camera 46, the second stage camera 47, and the front camera 48 are also located in the upper part of the support unit 22. The first stage camera 46, the second stage camera 47, and the front camera 48 each have an image sensor capable of acquiring color images. In addition, the number of pixels of the first stage camera 46, the second stage camera 47, and the front camera 48 is less than that of the high-magnification image sensor 55 and the low-magnification image sensor 56, but this is not limited to this, and they may have a similar number of pixels.

[0053] As shown in Figure 4, the first stage camera 46 and the second stage camera 47 are positioned in front of the light-receiving lens 51 and are spaced apart from each other in the left-right direction. The imaging direction (optical axis direction) of the first stage camera 46 and the second stage camera 47 is the same as the imaging direction of the imaging unit 50. The imaging fields of the first stage camera 46 and the second stage camera 47 are located in front of the imaging field of the imaging unit 50, enabling imaging of the front portion of the stage 21. The first stage camera 46 or the second stage camera 47 generates an overhead image (planar image) by imaging the entire stage 21 from directly above, and may be called an overhead image generation unit.

[0054] The front camera 48 is a second imaging unit that generates an overhead image by imaging the workpiece W above the stage 21 in an orientation different from the normal direction of the stage 21, and can also be called the overhead image generation unit. The front camera 48 is positioned in front of the light-receiving lens 51 and is positioned in front of the first stage camera 46 and the second stage camera 47 in the front-to-back positional relationship. Therefore, the front camera 48 can be said to be the camera positioned closest to the user. The imaging field of view of the front camera 48 is set to be wider than the imaging field of view of the high-magnification image sensor 55 and the low-magnification image sensor 56, and can include the imaging field of view of the high-magnification image sensor 55 and the low-magnification image sensor 56, and can also image outside the imaging field of view of the high-magnification image sensor 55 and the low-magnification image sensor 56. In this example, the front camera 48 can image the entire top surface of the stage 21. In addition, the front camera 48 is configured to be able to image in real time and is a camera that can acquire live view images.

[0055] The imaging direction (optical axis direction) of the front camera 48 is set to face the top surface of the stage 21 from diagonally above the front of the stage 21, that is, from the user's perspective, from front to back. This is to ensure that the imaging direction of the front camera 48 roughly coincides with the line of sight the user has when looking at the stage 21 during measurement. As a result, the overhead image generated by the front camera 48 corresponds to what the user can see when viewing the workpiece W from above in a natural measurement posture.

[0056] (Configuration of the non-contact displacement meter 70) The non-contact displacement meter 70 is a non-contact measuring unit that measures the height of a workpiece W on the stage 21 in a non-contact manner by emitting measurement light along the normal direction of the stage 21 and receiving reflected light from the workpiece W on the stage 21. The non-contact displacement meter 70 is a laser coaxial displacement meter, more specifically a white confocal displacement meter, and as shown in Figure 3, it comprises a lens unit 71, a light-emitting / receiving unit 72, and an optical fiber section 73 connecting both units 71 and 72. The light-emitting / receiving unit 72 is built into the base 20 and comprises a laser light source 72a, a light source optical element 72b, a phosphor 72c, and a light-receiving element 72d.

[0057] The laser light source 72a emits light of a single wavelength, preferably blue or ultraviolet light with a wavelength of 450 nm or less. In particular, if it emits blue light, it is possible to project light onto the workpiece W that is a mixture of light that has been wavelength-converted and used to excite the phosphor 72c, and light that remains blue and is not used to excite the phosphor 72c.

[0058] The phosphor 72c is excited by light from the laser light source 72a, converts it to a different wavelength, and emits light. The phosphor 72c is composed of one or more types of phosphors 72c. For example, it may be excited by blue light and converted to yellow light to emit light, or two types of phosphors 72c may be excited by blue light and converted to green light to emit light, and also excited by blue light and converted to red light to emit light.

[0059] The optical fiber section 73 is composed of one or more optical fibers. To facilitate handling, a ferrule 73a may be used at the end of the optical fiber. The core diameter of the output end, which is the end of the optical fiber section 73 on the lens unit 71 side, can be 200 μm or less, or 50 μm or less, as it affects the spot diameter formed on the workpiece W.

[0060] A phosphor 72c is fixed to the incident end of the optical fiber section 73. The phosphor 72c may be fixed in a light-transmitting medium such as resin or glass that transmits light from the laser light source 72a and light emitted by the phosphor 72c, and the light-transmitting medium may also be fixed to the incident end of the optical fiber section 73. In this case, in order to efficiently incident the light from the laser light source 72a and the light from the phosphor 72c into the optical fiber section 73, the refractive index of the light-transmitting medium is set to be less than or equal to the refractive index of the core on the incident end side of the optical fiber section 73.

[0061] The light-receiving element 72d is composed of a multi-segment PD (photodiode) or an image sensor such as a CCD or CMOS, and selectively receives light from the workpiece W according to its wavelength via a spectrometer 72e composed of a diffraction grating, prism, etc., or a color-selective optical filter, etc. The light-receiving element 72d may receive light from the workpiece W via the optical fiber section 73, or it may receive light via another optical path.

[0062] The lens unit 71 is attached to the measurement execution unit 24 and is therefore movable in the Z direction together with the imaging unit 50. The lens unit 71 is a component for focusing the light emitted from the output end of the optical fiber unit 73 toward the workpiece W, and includes an upper lens 71a and a lower lens 71b. The lens unit 71 is positioned to the right of the imaging unit 50, and its optical axis is in the Z direction.

[0063] When the lens unit 71 is configured to be at a confocal position with the exit end of the optical fiber section 73, the light from the workpiece W is separated according to wavelength by a spectrometer 72e, which is composed of a diffraction grating, a prism, etc., and the wavelength-luminance distribution of the light from the workpiece W is detected by the light-receiving position of the photodetector 72d. Signals regarding the light-receiving position and amount of light received by the photodetector 72d are transmitted to the displacement measuring unit 3c of the control unit 3.

[0064] For example, when a chromatic aberration lens is used as the lens unit 71, the displacement measurement unit 3c shown in Figure 6 evaluates that the workpiece W is closer when shorter wavelength light is detected, and that the workpiece W is farther away when longer wavelength light is detected. Similarly, when a diffractive lens is used as the lens unit 71, the displacement measurement unit 3c measures the displacement of the workpiece W by evaluating that the workpiece W is farther away when shorter wavelength light is detected, and closer when longer wavelength light is detected.

[0065] As shown in Figure 3, the focal length of the non-contact displacement meter 70 is set to be longer than the focal length of the imaging unit 50. Also, the focal height of the non-contact displacement meter 70 is set to be approximately the same as the focal height of the imaging unit 50. That is, the mounting height of the lens unit 71 of the non-contact displacement meter 70 relative to the measurement execution unit 24, and the mounting height of the imaging unit 50 relative to the measurement execution unit 24 can be set arbitrarily, but in this example, the height of the lens unit 71 and the height of the imaging unit 50 are set so that the focal height of the non-contact displacement meter 70 and the focal height of the imaging unit 50 are approximately the same. For example, the lower lens 71b of the lens unit 71 is positioned above the light-receiving lens 51 of the imaging unit 50.

[0066] In this example, the Z-direction drive unit 25 makes it possible to move the non-contact displacement meter 70. For example, by matching the focal length of the imaging unit 50 with the focal length of the non-contact displacement meter 70, it becomes possible to perform height measurement using the non-contact displacement meter 70 simply by moving the stage 21 horizontally so that the non-contact displacement meter 70 is in focus on the measurement target position at the focal length of the imaging unit 50.

[0067] (Touch probe configuration) The touch probe 80 shown in Figure 3 is a component that outputs a contact signal when it comes into contact with the workpiece W on the stage 21. In this example, since the touch probe 80 is provided on the measurement execution unit 24, the Z-direction drive unit 25 can move the touch probe 80 relative to the stage 21 in the Z direction. In addition, the stage 21 can be moved relative to the touch probe 80 in the XY direction by the XY-direction drive unit 23. In this way, the Z-direction drive unit 25 and the XY-direction drive unit 23 move at least one of the stage 21 and the touch probe 80 relative to the other, thereby enabling the touch probe 80 to come into contact with the workpiece W placed on the stage 21. Note that the stage 21 may be moved in the Z direction, or the touch probe 80 may be moved in the XY direction. The axis perpendicular to the Z axis and coinciding with the left-right direction of the device body 2 is defined as the X axis. The axis perpendicular to the Z axis and coinciding with the direction perpendicular to the X axis (the front-back direction of the device body 2) is defined as the Y axis.

[0068] The contact signal output from the touch probe 80 is transmitted to the coordinate measurement unit 3b of the control unit 3 shown in Figure 6. When the coordinate measurement unit 3b receives the contact signal output when the touch probe 80 makes contact with the workpiece W by the Z-direction drive unit 25 and the XY-direction drive unit 23, it measures the three-dimensional coordinates of the contact point where the touch probe 80 made contact with the workpiece W based on the contact signal.

[0069] For example, the X-direction and Y-direction positions of the stage 21 when a contact signal is output from the touch probe 80 can be obtained using the X-direction linear scale 23a and the Y-direction linear scale 23b, respectively. The Z-direction position of the touch probe 80 when a contact signal is output can be obtained using the Z-direction linear scale 25a. Furthermore, by pre-setting the relative positional relationship between the touch probe 80 and the workpiece W, and performing calibration of the imaging unit 50, etc., it is possible to measure the three-dimensional coordinates of the contact point based on the detection results of the linear scales 23a, 23b, and 25a.

[0070] As shown in Figure 7, the touch probe 80 comprises a housing 81, a probe shaft 82, a stylus 83, a pivot-forming elastic member (first elastic member) 84, a home-return elastic member (second elastic member) 85, and a displacement detection mechanism 86. The housing 81 is cylindrical in shape and extends in the Z direction, and as shown in Figure 5, it is fixed to the measurement execution unit 24 and positioned to the left of the imaging unit 50. Therefore, the imaging unit 50 is interposed between the touch probe 80 and the lens unit 71 of the non-contact displacement meter 70.

[0071] As shown in Figure 7, the probe shaft 82 is a rod-shaped member located inside the housing 81 and extends in the Z direction. An upper cylindrical member 82a, which has a larger diameter than the outer diameter of the probe shaft 82, is fixed to the lower end of the probe shaft 82. The stylus 83 is also a rod-shaped member that extends in the Z direction, similar to the probe shaft 82, but it is thinner than the probe shaft 82. A spherical contact portion 83b that contacts the workpiece W is provided at the lower end of the stylus 83.

[0072] The upper end of the stylus 83 is detachably attached to the lower surface of the cylindrical member 82a of the probe shaft 82. In other words, a lower cylindrical member 83a, which has a larger diameter than the outer diameter of the stylus 83, is fixed to the upper end of the stylus 83. The upper cylindrical member 82a and the lower cylindrical member 83a have approximately the same diameter, but the lower cylindrical member 83a is set to be longer in the vertical direction. Furthermore, since the probe shaft 82 is integrated with the housing 81, it can also be said that the stylus 83 is detachably attached to the housing 81.

[0073] The structure for attaching and detaching the stylus 83 to the probe shaft 82 is not particularly limited, but for example, a kinematic mount can be used. Specifically, permanent magnets (not shown) with mutually attractive polarity are fixed to the lower surface of the upper cylindrical member 82a and the upper surface of the lower cylindrical member 83a, respectively. For example, three steel balls 83c are fixed around one of the magnets on the lower surface of the upper cylindrical member 82a and the upper surface of the lower cylindrical member 83a at equal intervals in the circumferential direction, and fitting grooves (not shown) into which the steel balls 83c fit are formed around the magnet on the other surface, corresponding to the positions of the steel balls 83c. As a result, when the stylus 83 is brought closer to the probe shaft 82 from below, the stylus 83 is held in a state of attraction to the probe shaft 82 by the attractive force of the magnets fixed to the upper cylindrical member 82a and the lower cylindrical member 83a. Alternatively, when the probe shaft 82 is brought closer to the stylus 83 from above, the stylus 83 is held in place by the attractive force of the magnets fixed to the upper cylindrical member 82a and the lower cylindrical member 83a, and is attracted to the probe shaft 82. At this time, the steel ball 83c engages with the fitting groove, causing the stylus 83 to be positioned coaxially with the probe shaft 82.

[0074] To remove the stylus 83 from the probe shaft 82, either move the stylus 83 downward against the magnetic force while keeping the probe shaft 82 fixed, or move the probe shaft 82 upward against the magnetic force while keeping the stylus 83 fixed. This separates the lower cylindrical member 83a from the upper cylindrical member 82a, allowing the stylus 83 to be removed.

[0075] The fulcrum-forming elastic member 84 is connected to the housing 81 and the probe shaft 82 and is a member for forming a deflection fulcrum of the probe shaft 82, and is composed of, for example, a flat spring. Specifically, the fulcrum-forming elastic member 84 is composed of a leaf spring that extends along the radial extension of the probe shaft 82 and whose radial outer end is connected to the inner surface of the housing 81. An example of the shape of the fulcrum-forming elastic member 84 is shown in Figure 8, and the outer shape of the fulcrum-forming elastic member 84 is a circle formed to conform to the inner surface of the housing 81. An insertion hole 84a through which the probe shaft 82 can be inserted is formed in the center of the fulcrum-forming elastic member 84, and the probe shaft 82 is fixed in a state where it is inserted through the insertion hole 84a. The fulcrum-forming elastic member 84 is integrally molded with an outer part 84b, an inner part 84c in which the insertion hole 84a is formed, and three connecting parts 84d that connect the outer part 84b and the inner part 84c.

[0076] The fulcrum-forming elastic member 84 can be made of an elastic material that has axial shape recovery properties. Furthermore, the material and shape of the fulcrum-forming elastic member 84 are set so that the inner portion 84c is positioned on the axis and radial displacement is suppressed. This allows the deflection fulcrum of the probe shaft 82 to be maintained by the fulcrum-forming elastic member 84. In addition, when the stylus 83 contacts the workpiece W, the fulcrum-forming elastic member 84 deforms with a force small enough not to affect the contact resistance. Furthermore, in order to allow the probe shaft 82 to be displaced in the Z direction with a small force, the fulcrum-forming elastic member 84 is designed so that the inner portion 84c can be displaced relative to the outer portion 84b in the Z direction with a small force.

[0077] As shown in Figure 7, a support portion 81a is provided inside the housing 81 to support the outer portion 84b (shown in Figure 8) of the fulcrum forming elastic member 84 from below. Because the outer portion 84b is supported by the support portion 81a, the probe shaft 82 is held and stabilized at a predetermined height, becoming less susceptible to vibration and improving measurement accuracy.

[0078] The home-return elastic member 85 is connected to the housing 81 and the probe shaft 82 at a point axially separated from the fulcrum-forming elastic member 84, and is a member for returning the probe shaft 82 to its home position. Thus, the fulcrum-forming elastic member 84 for forming a deflection fulcrum and the home-return elastic member 85 for returning to the home position are provided separately, and each elastic member 84 and 85 is designed to satisfy different functions from each other. Specifically, the fulcrum-forming elastic member 84 is set to exert a stronger radial displacement suppression force on the probe shaft 82 compared to the home-return elastic member 85, and the home-return elastic member 85 is set to exert a stronger biasing force that biases the probe shaft 82 towards the home position compared to the fulcrum-forming elastic member 84.

[0079] The home-return elastic member 85 is located on the tip side (lower side) of the probe shaft 82 than the fulcrum forming elastic member 84. As shown in Figure 9, it consists of three or more tension springs 85a, 85b, and 85c that extend radially from the probe shaft 82 and along the radial extension of the probe shaft 82, with their outer ends connected to the housing 81. The spring forces of these three or more tension springs 85a, 85b, and 85c are balanced. In this example, the home-return elastic member 85 is composed of three tension springs 85a, 85b, and 85c, but the number of tension springs 85a, 85b, and 85c is not limited to this.

[0080] The inner ends of each tension spring 85a, 85b, and 85c are fixed to the outer surface of the probe shaft 82, and these three fixing points are arranged at equal intervals (120° intervals) in the circumferential direction. Each tension spring 85a, 85b, and 85c is positioned so that its axis is perpendicular to the axis of the probe shaft 82, and the extensions of the axes of each tension spring 85a, 85b, and 85c intersect on the axis of the probe shaft 82. The spring constants of the tension springs 85a, 85b, and 85c are the same.

[0081] Let's assume that the probe shaft 82 is displaced in one of the directions of the three tension springs 85a, 85b, and 85c. If tension spring 85a is balanced at a position where it is compressed by ΔA, the remaining tension springs 85b and 85c will have a displacement of A / 2 from the vector division. The force will act in half in the direction of tension spring 85a, and in the end, half of the spring force of tension spring 85a will be added to each other, resulting in a total force of 1.5 × ΔA acting to achieve equilibrium. Since the three tension springs 85a, 85b, and 85c have the same spring constant, the spring constant × ΔA × 1.5 becomes the only design parameter. In other words, if the same spring constant is set for tension springs 85a, 85b, and 85c, it becomes possible to create a low-pressure contact touch probe 80 even if the length required to maintain equilibrium varies.

[0082] Furthermore, since the touch probe 80 is a low-pressure contact probe, if the probe shaft 82 is subjected to an excessive stroke, it may exceed its elastic limit or deform. For this reason, it is desirable to provide a protective limit mechanism and to adopt a configuration that can withstand even stronger external forces. For example, assuming that the contact portion 83b is strongly pressed in the X direction, if the limit mechanism is located above it, the probe shaft 82 may be subjected to a force that causes it to bend, which can induce deformation of the probe shaft 82. In other words, if the home-return elastic member 85 is located above the fulcrum-forming elastic member 84, the probe shaft 82, subjected to a large external force in the X direction as described above, may be subjected to a force that causes it to bend. In this example, by positioning the home-return elastic member 85 below the fulcrum-forming elastic member 84, the probe shaft 82 is less likely to be subjected to a force that causes it to bend. It should be noted that the above-mentioned problems do not apply in all cases, so the home-return elastic member 85 can also be positioned above the fulcrum-forming elastic member 84.

[0083] Furthermore, since the probe shaft 82 is radially pulled by three tension springs 85a, 85b, and 85c having the same spring constant, relative to the balanced origin position with a predetermined extension, the displacement acting on the tension springs 85a, 85b, and 85c is reduced by the lever principle at a ratio of H1 / H2 (shown in Figure 7) relative to the amount of movement of the contact portion 83b. The difference from the equilibrium can be calculated using only the displacement and spring constant. For example, if contact with the workpiece W is to be detected with an extremely low contact pressure of about 2g, the spring constant can be derived inversely, thus establishing a very simple relationship. From this relationship, even if the tension springs 85a, 85b, and 85c are made of relatively strong springs, the resistance force at the contact portion 83b will not increase too much, and a low-pressure contact touch probe 80 can be made.

[0084] As shown in Figure 7, the displacement detection mechanisms 86A, 86B, and 86C are magnetic sensors that non-contactually detect the three-dimensional displacement of the probe shaft 82, and are provided on the base end side (upper side) of the probe shaft 82, above the fulcrum forming elastic member 84. Specifically, the displacement detection mechanisms 86A, 86B, and 86C include a Z-direction displacement detection mechanism 86A (first displacement detection mechanism) that detects displacement in the Z direction (first direction) along the axial direction of the probe shaft 82, an X-direction displacement detection mechanism 86B (second displacement detection mechanism) that detects displacement in the X direction (second direction) along the radial direction of the probe shaft 82, and a Y-direction displacement detection mechanism 86C (third displacement detection mechanism) that detects displacement in the Y direction (third direction) along the radial direction of the probe shaft 82 and perpendicular to the Z direction.

[0085] The Z-direction displacement detection mechanism 86A comprises a Z-direction detection magnet 86a and a Z-direction magnetic sensor 86b, which are arranged so that their north and south poles are aligned in the Z direction. The Z-direction detection magnet 86a is fixed to the probe shaft 82, while the Z-direction magnetic sensor 86b is fixed to the housing 81. The Z-direction magnetic sensor 86b is positioned opposite the boundary between the north and south poles of the Z-direction detection magnet 86a. Therefore, if the probe shaft 82 is displaced even slightly in the Z direction, the magnetic field detected by the Z-direction magnetic sensor 86b changes, thereby enabling non-contact detection of the Z-direction displacement of the probe shaft 82.

[0086] A magnet fixing member 82b is provided at the upper end of the probe shaft 82. The X-direction displacement detection mechanism 86B includes an X-direction detection magnet 86c and an X-direction magnetic sensor 86d, which are arranged so that the north and south poles are aligned in the X direction. The X-direction detection magnet 86c is fixed to the upper surface of the magnet fixing member 82b, while the X-direction magnetic sensor 86d is fixed to the housing 81. The X-direction magnetic sensor 86d is positioned opposite the boundary between the north and south poles of the X-direction detection magnet 86c. Therefore, if the probe shaft 82 swings even slightly in the X direction around the deflection pivot point and displaces, the magnetic field detected by the X-direction magnetic sensor 86d changes, thereby enabling non-contact detection of the X-direction displacement of the probe shaft 82.

[0087] The Y-direction displacement detection mechanism 86C comprises a Y-direction detection magnet 86e and a Y-direction magnetic sensor 86f, both arranged so that their north and south poles are aligned in the Y direction. The Y-direction detection magnet 86e is fixed to the upper surface of the magnet fixing member 82b at a location away from the X-direction detection magnet 86c, while the Y-direction magnetic sensor 86f is fixed to the housing 81. The Y-direction magnetic sensor 86f is positioned opposite the boundary between the north and south poles of the Y-direction detection magnet 86e. Therefore, if the probe shaft 82 swings even slightly in the Y direction around the deflection pivot point and displaces, the magnetic field detected by the Y-direction magnetic sensor 86f changes, thereby enabling non-contact detection of the Y-direction displacement of the probe shaft 82.

[0088] The displacement detection mechanism 86 may be a sensor other than a magnetic sensor, for example, an optical or capacitive detection sensor.

[0089] The tension springs 85a, 85b, and 85c are coated with damping grease that generates damping force. The damping grease is a high-viscosity, non-volatile paste that is applied to the tension springs 85a, 85b, and 85c so as to fill the spaces between the springs. This allows damping force to be applied repeatedly in a short time when the tension springs 85a, 85b, and 85c expand and contract, making it easier to obtain the desired damping and eliminating the need to apply excessive damping that can easily cause noise.

[0090] Furthermore, when damping the tension springs 85a, 85b, and 85c, it is possible to apply damping grease or the like at a distance where the damping effect can be easily enhanced based on the lever principle. For example, damping grease may be filled between the Z-direction detection magnet 86a and the Z-direction magnetic sensor 86b, between the X-direction detection magnet 86c and the X-direction magnetic sensor 86d, and between the Y-direction detection magnet 86e and the Y-direction magnetic sensor 86f. Alternatively, other damping members may be used to dampen the tension springs 85a, 85b, and 85c.

[0091] Figure 10 shows another example of the touch probe 80. In this example, the orientation of the X-direction magnetic sensor 86d of the X-direction displacement detection mechanism 86B and the orientation of the Y-direction magnetic sensor 86f of the Y-direction displacement detection mechanism 86C are different from the example described above. Specifically, the X-direction magnetic sensor 86d and the X-direction detection magnet 86c are arranged to face each other horizontally, and the Y-direction magnetic sensor 86f and the Y-direction detection magnet 86e are arranged to face each other horizontally.

[0092] (Stylus changer mechanism) The styluses 83 come in various shapes, such as cross-shaped, L-shaped, and T-shaped, with different diameters and sizes of the contact portion 83b at the tip, and can be used interchangeably depending on the workpiece W and measurement application. As shown in Figures 1 and 2, the support portion 22 of the device body 2 is equipped with a changer mechanism (exchange unit) 100 that holds different styluses 83A, 83B, and 83C and automatically replaces them with the desired stylus at a predetermined timing. In this example, the touch probe 80 is located on the left side of the measurement execution unit 24, so the changer mechanism 100 is located on the left side of the support portion 22 to accommodate this. If the touch probe 80 is located on the right side of the measurement execution unit 24, the changer mechanism 100 should be located on the right side of the support portion 22.

[0093] Figure 11 is a perspective view of the stylus changer mechanism 100. The changer mechanism 100 includes a stylus holding section 101 for holding one or more styluses, an arm section 102 for supporting the stylus holding section 101, a changer rotation drive section (rotating section) 103 for rotating the arm section 102, and a changer feed drive section (slider section) 104 for moving the stylus holding section 101 along the arm section 102.

[0094] As shown in Figure 12, the stylus holder 101 has first to third notches 101a, 101b, and 101c for holding different types of styluses 83A, 83B, and 83C. Each notch 101a, 101b, and 101c is open in the vertical direction and also in one of the horizontal directions, and the direction of opening is the same for all notches 101a, 101b, and 101c. Note that in Figure 12, the member constituting the upper part of the third notch 101c is removed for the purpose of explaining the internal structure, but the third notch 101c has the same shape as the first notch 101a and the second notch 101b. Note that the number of notches is not limited to three, but can be set to any number.

[0095] Retaining claws 101d for holding the stylus are provided in the vertical intermediate portions of each notch 101a, 101b, and 101c. The retaining claws 101d are made of an elastic material such as resin and are shaped to open in the same direction as the horizontal open portions of each notch 101a, 101b, and 101c. Both ends of the retaining claws 101d protrude from the inner surfaces of each notch 101a, 101b, and 101c, and both ends of the retaining claws 101d engage with grooves 83d formed on the outer circumferential surface of the lower cylindrical member 83a of the stylus 83. The vertical dimension of the grooves 83d is set to be longer than the vertical dimension of the retaining claws 101d, and this dimensional difference allows the stylus held by the retaining claws 101d to move up and down relative to the retaining claws 101d.

[0096] The distance between the ends of the retaining claw 101d is narrower than the outer diameter of the portion of the lower cylindrical member 83a where the groove 83d is formed. When holding the lower cylindrical member 83a, the portion of the lower cylindrical member 83a where the groove 83d is formed is pressed against both ends of the retaining claw 101d from the open side of the retaining claw 101d, causing the retaining claw 101d to elastically deform and widen the distance between its ends. This allows the portion of the lower cylindrical member 83a where the groove 83d is formed to enter the inside of the retaining claw 101d from between both ends of the retaining claw 101d and engage with the retaining claw 101d. When releasing the lower cylindrical member 83a held by the retaining claw 101d, the lower cylindrical member 83a is moved relative to the retaining claw 101d in the opening direction, causing the retaining claw 101d to elastically deform and widen the distance between its ends, allowing the lower cylindrical member 83a to detach from the open side of the retaining claw 101d.

[0097] The arm portion 102 shown in Figure 11 is a member for moving the styluses 83A, 83B, and 83C (reference numerals 83B and 83C are shown in Figure 2), which are held by the stylus holding portion 101, between an attachable position that allows them to be attached to the housing 81 and a retracted position that moves them away from the attachable position. The attachable position can also be called the stylus attachment preparation position, and the retracted position can also be called the stylus storage position. Specifically, the arm portion 102 is composed of a member that extends horizontally, and its base end is attached to the support portion 22 via the changer rotation drive unit 103. The changer rotation drive unit 103 is composed of an electric motor having a pivot shaft 103a that extends in the Z direction. The pivot shaft 103a is parallel to the imaging axis of the imaging unit 50, and the base end of the arm portion 102 is connected to the lower end of the pivot shaft 103a.

[0098] As shown by the dashed line in Figure 2, the changer rotation drive unit 103 is positioned above the stage 21. Figure 2 shows the state in which the styluses 83A, 83B, and 83C held by the stylus holder 101 have been moved to the retracted position. The stylus holder 101 and the styluses 83A, 83B, and 83C in the retracted position are positioned so as not to interfere with measurement setup or measurement execution, specifically so that they do not enter the movable range of the measurement execution unit 24 or the imaging field of the imaging unit 50.

[0099] The support portion 22 is provided with a canopy portion 22A that covers at least a portion above the stylus holder portion 101 when it is in the retracted position. The canopy portion 22A is formed to protrude to the left from the left wall portion of the support portion 22, and the stylus holder portion 101 can be positioned directly below the canopy portion 22A. This prevents surrounding objects from coming into contact with the stylus holder portion 101 or the styluses 83A, 83B, and 83C held by the stylus holder portion 101. The canopy portion 22A may be formed to cover the entire area above the stylus holder portion 101.

[0100] As shown in Figure 11, the arm portion 102 is provided with a changer feed drive unit 104. The changer feed drive unit 104 comprises a feed electric motor 104a, a threaded rod 104b rotated by the feed electric motor 104a, and a threaded member 104c that screws onto the threaded rod 104b. The feed electric motor 104a is fixed to the base end of the arm portion 102, and its rotational centerline is oriented in the longitudinal direction of the arm portion 102. The threaded rod 104b is arranged parallel to the arm portion 102 and is rotatably supported relative to the arm portion 102. A stylus holder 101 is fixed to the threaded member 104c.

[0101] The arm portion 102 is provided with a guide rail 102a that guides the stylus holder portion 101 in the longitudinal direction of the arm portion 102. The stylus holder portion 101 is engaged with the guide rail 102a and is immobilized, allowing it to move only in the longitudinal direction of the arm portion 102. In other words, the styluses 83A, 83B, and 83C held by the stylus holder portion 101 can be moved in a direction perpendicular to the imaging axis.

[0102] When the threaded rod 104b is rotated by the feed motor 104a, the stylus holder 101 can be moved to the tip side of the arm portion 102, as shown in Figure 11, and also, although not shown, to the base end side or near the base end of the arm portion 102. The stylus holder 101 can be stopped at any position relative to the arm portion 102. The position of the stylus holder 101 is detected by position detection means such as a rotary encoder and output to the control unit 3d.

[0103] Figure 11 shows the state in which the styluses 83A, 83B, and 83C, held by the stylus holder 101, have been moved to a position where they can be attached to the housing 81. The position of the changer swivel drive unit 103 is set so that the pivot axis 103a of the changer swivel drive unit 103 is positioned between the styluses 83A, 83B, and 83C in the attachable position and the styluses 83A, 83B, and 83C in the retracted position, and the changer swivel drive unit 103 in that position is attached to the support unit 22.

[0104] The changer rotation drive unit 103 rotates the arm portion 102 by 180° when moving the stylus holder portion 101 from the retracted position to the mountable position, and when moving it from the mountable position to the retracted position. In other words, the position of the stylus holder portion 101 can be switched significantly from the front to the rear and from the rear to the front of the changer rotation drive unit 103.

[0105] Next, the procedure for replacing the stylus will be explained. Figure 13 is a flowchart showing an example of the stylus mounting procedure. In step SA1 after the start, the control unit 3d of the control unit 3 controls the Z-direction drive unit 25 to move the measurement execution unit 24 to the upper standby position. In step SA2, the control unit 3d controls the changer feed drive unit 104 to move the stylus holding unit 101 in the longitudinal direction of the arm unit 102 so that the desired notch (let's call it the first notch 101a) among the first to third notches 101a, 101b, and 101c is positioned in a predetermined location. As a result, the stylus holding unit 101 moves outward from the space directly below the visor 22A (for example, the stylus holding unit 101 moves to near the center of the arm unit 102 and comes out to the outside of the visor 22A). In step SA3, the control unit 3d controls the changer rotation drive unit 103 to rotate the arm unit 102 and position the stylus holder 101 in a mountable position. This state is shown in FIG. 14A of Figure 14, and since the measurement execution unit 24 is in the upper standby position, the stylus 83A has not yet been mounted in the housing 81. After step SA3, the position of the stylus holder 101 may be finely adjusted along the longitudinal direction of the arm unit 102.

[0106] Next, the process proceeds to step SA4, where the control unit 3d controls the Z-direction drive unit 25 to lower the measurement execution unit 24 and move it to the mounting height. At this point, the lower cylindrical member 83a of the stylus 83A is attracted to the upper cylindrical member 82a of the probe shaft 82 by magnetic force. The state after attraction is shown in FIG. 14B of Figure 14. Then, the process proceeds to step SA5, where the control unit 3d controls the changer rotation drive unit 103 to rotate the arm unit 102 and position the stylus holding unit 101 in the retracted position. At this time, the retaining claw 101d elastically deforms and the lower cylindrical member 83a is released from the retaining claw 101d.

[0107] Next, Figure 15 shows the procedure for removing the stylus mounted on the housing 81. In step SB1 after the start, similar to step SA4, the control unit 3d of the control unit 3 controls the Z-direction drive unit 25 to move the measurement execution unit 24 to the mounting height. In step SB2, the control unit 3d controls the changer feed drive unit 104 to move the stylus holding unit 101 in the longitudinal direction of the arm unit 102 so that the desired notch (let's call it the first notch 101a) among the first to third notches 101a, 101b, and 101c is positioned in a predetermined location. At this time, the notch that does not hold the stylus is positioned in a predetermined location. Also, the stylus holding unit 101 moves outward from the space directly below the visor 22A (for example, the stylus holding unit 101 moves to near the center of the arm unit 102 and comes out to the outside of the visor 22A).

[0108] In step SB3, the control unit 3d controls the changer rotation drive unit 103 to rotate the arm unit 102 and position the stylus holder 101 in a mountable position. This flow is for removal and therefore not "mountable," but the position of the stylus holder 101 is the same as the "mountable position" in the flow shown in Figure 13, so it is also considered the "mountable position" in this flow. The "removable position" may be used instead of the "mountable position." This state is as shown in FIG. 14B of Figure 14, where the retaining claw 101d engages with the groove 83d formed in the lower cylindrical member 83a of the stylus 83A.

[0109] Next, the process proceeds to step SB4, where the control unit 3d controls the Z-direction drive unit 25 to raise the measurement execution unit 24 and move it to the upper standby position. As a result, the upper cylindrical member 82a of the probe shaft 82 moves upward relative to the lower cylindrical member 83a of the stylus 83A, and the lower cylindrical member 83a of the stylus 83A detaches from the upper cylindrical member 82a of the probe shaft 82 against the magnetic force. The state after detachment is shown in FIG. 14A of Figure 14. Then, the process proceeds to step SB5, where the control unit 3d controls the changer rotation drive unit 103 to rotate the arm unit 102 and position the stylus holding unit 101 in the retracted position.

[0110] As described above, the control unit 3d controls the changer rotation drive unit 103 and the changer feed drive unit 104 so that the stylus held in the stylus holding unit 101 is moved from the retracted position to the mountable position, and also controls the changer rotation drive unit 103 and the changer feed drive unit 104 so that the stylus held in the stylus holding unit 101 is moved from the mountable position to the retracted position. Furthermore, the control unit 3d controls the changer feed drive unit 104 so that the stylus holding unit 101 in the retracted position is positioned closer to the base end of the arm unit 102 than the stylus holding unit 101 in the mountable position.

[0111] In this embodiment, the retaining claw 101d is configured to engage with a groove 83d formed on the outer circumferential surface of the lower cylindrical member 83a, but a modified version in which this groove 83d is not formed is also conceivable. For example, a movable member (preferably an elastic member) that moves radially relative to the outer circumferential surface of the lower cylindrical member 83a (contacting or moving away from it) may be provided inside the notches 101a to 101c. This movable member may be moved by the control unit 3d. In this case, in step SA4 described above, after the lower cylindrical member 83a of the stylus 83A is attracted to the upper cylindrical member 82a of the probe shaft 82, the control unit 3d controls the movable member to move away from the outer circumferential surface of the lower cylindrical member 83a. Also, in step SB4 described above, before raising the measurement execution unit 24 to the upper standby position, the control unit 3d controls the movable member to contact the outer circumferential surface of the lower cylindrical member 83a. In this way, the detachment operation of the stylus 83A may be achieved without forming a groove 83d on the outer surface of the lower cylindrical member 83a.

[0112] (Control unit configuration) The control unit 3 shown in Figure 6 includes, for example, a CPU (Central Processing Unit), RAM, ROM, an internal bus, etc. (not shown). The CPU is connected to the display unit 4, keyboard 5, mouse 6, memory unit 7, and main unit 2 of the device via the internal bus. The control unit 3 acquires the operation status of the keyboard 5, mouse 6, measurement start button 2a, etc. of the main unit 2 of the device. The control unit 3 can also acquire image data acquired by the imaging unit 50, first stage camera 46, second stage camera 47, and front camera 48 of the main unit 2. Furthermore, the control unit 3 can display the results of calculations performed within the control unit 3, as well as the image data acquired by the imaging unit 50, first stage camera 46, second stage camera 47, and front camera 48, on the display unit 4.

[0113] Furthermore, the control unit 3 controls the Z-direction drive unit 25, XY-direction drive unit 23, coaxial incident illumination 40, ring illumination 45, illumination Z-direction drive unit 45d, imaging unit 50, non-contact displacement meter 70, touch probe 80, changer rotation drive unit 103, changer feed drive unit 104, etc. of the main unit 2 of the apparatus. Specifically, since the control unit 3 is connected to each piece of hardware via an internal bus, it controls the operation of the aforementioned hardware and also executes various software functions according to the computer program stored in the memory unit 7. For example, the control unit 3 is provided with an image measurement unit 3a that measures the dimensions of the workpiece W based on the workpiece image generated by the imaging unit 50, a coordinate measurement unit 3b that measures the three-dimensional coordinates of the contact point where the touch probe 80 contacts the workpiece W, and a displacement measurement unit 3c that measures the displacement of the workpiece W on the stage 21 based on the output signal from the non-contact displacement meter 70. Displacement measurement is also called height measurement.

[0114] The following describes in detail the functions that control unit 3 can perform, divided into two parts: the measurement setup phase before measuring workpiece W, and the measurement execution phase when measuring workpiece W.

[0115] (When setting up the measurement) Figure 16 is a flowchart showing an example of the procedure for setting up the image measuring device 1 for measurement. In step SC1 after the start, a plan view image is generated. That is, the stage 21 is imaged by the imaging unit 50. At this time, if the user places the workpiece W on the mounting table 21a of the stage 21, a workpiece image is acquired. For example, the measurement execution unit 24 can be moved by the Z-direction drive unit 25 to move the imaging unit 50 to the measurement position, and then the workpiece W on the stage 21 can be imaged by the imaging unit 50, and illumination can be provided as needed.

[0116] In step SC2, an overhead image is generated. The Z-direction drive unit 25 moves the measurement execution unit 24 to move the front camera 48 to the measurement position, and then the front camera 48 captures an image of the workpiece W on the stage 21.

[0117] When imaging the workpiece W with the front camera 48, the following control can be performed. First, the control unit 3d detects the position of the workpiece W on the stage 21 based on the workpiece image generated by the imaging unit 50. Then, based on the detected position of the workpiece W on the stage 21 and the known field of view of the front camera 48, the control unit 3d determines whether or not the workpiece W on the stage 21 is located within the field of view of the front camera 48. Next, if the workpiece W on the stage 21 is located outside the field of view of the front camera 48, the control unit 3d controls the XY direction drive unit 23 to move the stage 21 so that the workpiece W on the stage 21 is located within the field of view of the front camera 48. This ensures that the workpiece W on the stage 21 is reliably imaged by the front camera 48.

[0118] Furthermore, after capturing an image of the workpiece W on the stage 21 with the front camera 48, the control unit 3d can control the XY direction drive unit 23 to move the stage 21 and capture an image of another area on the stage 21 with the front camera 48.

[0119] The front camera 48 can capture an overhead image, and the position information of the stage 21 can be acquired using a linear scale 23a in the X direction or a linear scale 23b in the Y direction. The acquired position information of the stage 21 and the overhead image can be associated and stored in the memory unit 7. This makes it possible to determine the position of the stage 21 when the overhead image was captured.

[0120] In step SC3, a determination is made as to whether or not to generate a color work image (color image) based on the user's selection. If the user wishes to generate a color image, they select "Generate Color Image" on the user interface screen displayed on the display unit 4; otherwise, they do not select "Generate Color Image". The user's selection operation is performed using the keyboard 5, mouse 6, etc., and is received by the reception unit 3e of the control unit 3.

[0121] If the user does not wish to generate a color image, that is, if it is determined in step SC3 that a color image should not be generated, the process proceeds to step SC4, where a grayscale work image (grayscale image) is generated based on the data acquired by the imaging unit 50 under monochromatic light illumination. On the other hand, if the user wishes to generate a color image, that is, if it is determined in step SC3 that a color image should be generated, the process proceeds to step SC5, where a color image is generated.

[0122] The image generation process for steps SC4 and SC5 will be explained in detail based on the flowchart shown in Figure 17. In step SD1 after the start shown in Figure 17, the workpiece W is illuminated with transmitted light 30. In step SD2, the XY direction drive unit 23 is controlled to move the stage 21 in the X or Y direction, and the workpiece W is searched for while imaging is performed with the imaging unit 50. The stage 21 is moved in a spiral pattern, for example, from the center of both the X and Y directions. When the ratio of black pixels (pixels with a brightness value below a predetermined level) in the image captured by the imaging unit 50 exceeds a certain level, it is determined that the workpiece W is present in that region. In this way, the workpiece W is searched for, its position on the stage 21 is determined, and the size of the workpiece W, the portion of the stage 21 occupied by the workpiece W, etc., can be determined.

[0123] In step SD3, the workpiece W discovered in step SD2 is captured by the imaging unit 50. When generating a grayscale image, the red light source 45a, green light source 45b, and blue light source 45c of the ring illumination 45 are all turned on to illuminate the workpiece W with white light, and the image is captured by the imaging unit 50.

[0124] On the other hand, when generating a color image, the grayscale work image is acquired, and the color information generation unit 3f of the control unit 3 generates color information for the workpiece W based on multiple work images generated by the imaging unit 50 each time detection light of multiple different wavelengths is irradiated from the ring illumination 45. Specifically, the imaging unit 50 generates a work image under red illumination, captured by the imaging unit 50 with only the red light source 45a lit; a work image under green illumination, captured by the imaging unit 50 with only the green light source 45b lit; and a work image under blue illumination, captured by the imaging unit 50 with only the blue light source 45c lit. The color information generation unit 3f acquires hue and saturation as color information from these three work images.

[0125] The control unit 3d generates a color image by adding the color information of the workpiece generated by the color information generation unit 3f to a grayscale workpiece image. Here, an RGB image consisting of three channels (red, green, and blue) can be converted to an HSV image consisting of hue (H), saturation (S), and lightness (V). The color information corresponds to the hue (H) and saturation (S) of this HSV image. To add color information to a single-channel image, a new color image can be generated by assigning the desired color information to the hue (H) and saturation (H) of the single-channel image, using the lightness (V) as the value. In this example, the hue and saturation acquired by the color information generation unit 3f are combined with the lightness of the grayscale workpiece image to generate a color image. Note that the color space is not limited to HSV; other color spaces such as HLS can also be used.

[0126] When generating a color image, the grayscale work image, which is used directly for measurement, is a high-magnification image captured by the high-magnification image sensor 55. The work images for generating color information, i.e., the work images under red illumination, green illumination, and blue illumination, are low-magnification images captured by the low-magnification image sensor 56. Therefore, a color image is obtained by adding the color information generated based on the low-magnification image to the grayscale work image, which is a high-magnification image. Since imaging with the low-magnification image sensor 56 results in a deeper depth of field, acquiring the work image for generating color information with the low-magnification image sensor 56 allows for the acquisition of color information over a wide range and at a deep depth in a short time. The acquired color information can then be added to the work image captured by the high-magnification image sensor 55, which has a shallower depth of field.

[0127] For grayscale work images, images taken under different shooting conditions (exposure, illumination intensity, illumination type, lens magnification, etc.) than the work image used to generate color information can be used. In addition, color information may be added to work images with different illumination conditions, focus conditions, etc. Furthermore, even if the image captured in real time by the imaging unit 50 is single-channel, it is possible to add color information acquired by the color information generation unit 3f.

[0128] Next, the process proceeds to step SD4. In step SD4, it is determined whether it is necessary to image the portion adjacent to the area imaged in step SD3. During this determination, the search result from step SD2 is used, and if there is workpiece W outside the area imaged in step SD3 and it is necessary to image that portion, step SD4 is determined to be YES and the process proceeds to step SD5. In step SD5, the XY direction drive unit 23 is controlled to move the stage 21 so that other parts of workpiece W enter the imaging field of the imaging unit 50. After that, the process proceeds to step SD3, and a different portion from the one imaged the first time is imaged by the imaging unit 50. Steps SD5 and SD3 are repeated as many times as necessary, and a concatenation process is performed to concatenate the acquired workpiece images. In other words, the control unit 3d controls the XY direction drive unit 23 and the imaging unit 50 to generate multiple workpiece images of different parts of the workpiece, and concatenates the generated multiple workpiece images to produce a concatenated image that covers a wider area than the imaging field of the imaging unit 50. The color information of the workpiece generated by the color information generation unit 3f is also added to the concatenated image. This makes it possible to obtain a color concatenated image. If the result in step SD4 is NO, no further imaging is required, and this flow will be terminated.

[0129] Next, the process proceeds to step SC6 of the flowchart shown in Figure 16. In step SC6, if the control unit 3d generated a color image in step SC5, it displays the color image on the display unit 4. Conversely, if it generated a grayscale image in step SC4, it displays the grayscale image on the display unit 4. Also, if the control unit 3d generates a stitched image, it displays either a color stitched image or a grayscale stitched image on the display unit 4. Furthermore, if the control unit 3d generates a live view image, it displays either a color live view image or a grayscale live view image on the display unit 4.

[0130] In step SC6, the overhead image captured by the front camera 48 can also be displayed on the display unit 4. If the front camera 48 has captured multiple overhead images, multiple overhead images can be displayed as thumbnails on the display unit 4. That is, each overhead image is reduced in size and displayed in a predetermined direction, and when the user selects any of the reduced images, the control unit 3d displays the overhead image corresponding to the selected reduced image on the display unit 4.

[0131] In step SC7, the measurement means is determined. The measurement means includes an image measurement unit 3a that measures the dimensions of the workpiece W based on a workpiece image, a coordinate measurement unit 3b that measures three-dimensional coordinates using a touch probe 80, and a displacement measurement unit 3c that measures displacement using a non-contact displacement meter 70. The user can select any of the image measurement unit 3a, coordinate measurement unit 3b, and displacement measurement unit 3c. For example, if a selection operation for the measurement means is performed on the user interface screen displayed on the display unit 4, that selection operation is received by the reception unit 3e.

[0132] If it is determined in step SC7 that the image measurement unit 3a is selected, the process proceeds to step SC8. If it is determined that the coordinate measurement unit 3b is selected, the process proceeds to step SC9. If it is determined that the displacement measurement unit 3c is selected, the process proceeds to step SC10.

[0133] The details of the case where image measurement is selected (step SC8) are shown in the flowchart in Figure 18. In step SE1 after the start, the control unit 3d changes the imaging conditions to match the image measurement of the workpiece W. The imaging conditions include illumination, exposure time, etc.

[0134] In step SE2, the reception unit 3e receives the user's specification of the shape type. In step SE3, the reception unit 3e receives the user's specification of the edge extraction area. The edge extraction area can be an area that is extracted as an edge on the workpiece image and used for measurement. In step SE4, the imaging unit 50 images the workpiece W on the stage 21. In step SE5, multiple edge points are detected on the workpiece image acquired in step SE4. Edge points can be detected based on changes in brightness values ​​on the workpiece image. In step SE6, a fitting line passing through the multiple edge points is calculated. Then, in step SE7, the image measurement unit 3a calculates the dimensions using the fitting line. The image measurement unit 3a measures the dimensions of the workpiece W based on the high-magnification image generated by the high-magnification image sensor 55.

[0135] The details of the case when coordinate measurement is selected (step SC9) are shown in the flowchart in Figure 19. Steps SF1 to SF6 after the start are the same as SE1 to SE6 in the flowchart shown in Figure 18. Then, in step SF7, the scan lines for coordinate measurement, i.e., the scan lines of the touch probe 80, are calculated. In step SF8, the touch probe 80 performs the measurement operation, and then in step SF9 the fitting lines are calculated again, and in step SF10 the coordinate measurement unit 3b calculates the dimensions.

[0136] Here, we will explain the details of coordinate measurement with a specific example. Figure 20 is a perspective view showing the workpiece W placed on the stage 21, and Figure 21 is a plan view taken from above of the workpiece W placed on the stage 21. In Figures 20 and 21, the absolute coordinates in the three-dimensional space enclosed by the stage 21, the support part 22 (shown in Figure 2, etc.), and the imaging unit 50 are indicated by X, Y, and Z.

[0137] The workpiece W has a side surface S1 extending along the Z direction, a top surface S2 extending along the XY direction, a slanted surface S3 inclined at a predetermined angle with respect to the Z direction, and a hole H1 opening in the top surface S2 and extending along the Z direction. Alignment marks M for positioning are also provided on the top surface S2.

[0138] During measurement setup, a plan view image of the workpiece, as shown in Figure 21, is displayed on the display unit 4. The user sets, on the workpiece image displayed on the display unit 4, a first contact target position P1 which serves as a reference for contacting the side surface S1 of the workpiece W from the XY direction with the touch probe 80, a second contact target position P2 which serves as a reference for contacting the top surface S2 of the workpiece W from the Z direction, and a characteristic pattern for identifying the position and orientation of the workpiece W during measurement, relating them to each other. The setting unit 3g of the control unit 3 makes the above settings possible. Note that the "first contact target position P1" and "second contact target position P2" referred to here are concepts that include not only the contact point where the touch probe 80 contacts the workpiece W, but also the operation start position and end position, which will be described later.

[0139] In this example, the feature pattern is defined as alignment mark M. When setting the feature pattern, the user uses the mouse 6 or similar to specify an area on the work image that includes the feature pattern, as shown by the rectangular frame 200 in Figure 21. The method of setting the feature pattern is not limited to the illustrated example; the area may be specified using a free curve, or only the feature pattern may be specified. Alternatively, the feature pattern may be set by having the setting unit 3g automatically extract it.

[0140] The feature pattern may be a part of the shape, pattern, color, symbol, or characters of the workpiece W, and can also be called feature quantity information. Furthermore, the feature pattern may be any type of information that is used to identify the position and orientation of the workpiece W on the workpiece image displayed on the display unit 4 during measurement. Feature quantity information may be composed of multiple feature patterns.

[0141] In Figure 21, a third contact target position P3 and a fourth contact target position P4 are also set. The third contact target position P3 is a reference position for bringing the touch probe 80 into contact with the inner surface of the hole H1 of the workpiece W from the XY direction, and the fourth contact target position P4 is a reference position for bringing the touch probe 80 into contact with the inclined surface S3 of the workpiece W from the direction normal to the inclined surface S3. The setting unit 3g can also set the third contact target position P3, the fourth contact target position P4, and the feature pattern in relation to each other.

[0142] Multiple first contact target positions P1 can be set based on the absolute coordinates described above. As shown in Figure 21, multiple positions can be set at intervals in the Y direction, and as shown in Figure 22, multiple positions can be set at intervals in the Z direction. As shown in Figures 22 and 23, the display unit 4 can display the longitudinal section of the workpiece W. Each setting can also be performed on the longitudinal section of the workpiece W.

[0143] As shown by the frame line 201 in Figure 21, the setting unit 3g extracts and sets the side surface S1 of the workpiece W as the first edge measurement element (straight edge element) on the workpiece image. Since the first edge measurement element corresponds to the outer surface of the workpiece W, it can be extracted accurately and clearly with illumination by transmitted illumination 30. The setting unit 3g sets the first edge measurement element in association with the extracted first contact target position P1. In addition to the automatic setting described above, the edge can also be set manually by the user operating the mouse 6, etc.

[0144] For example, the control unit 3d can generate a user interface screen 210 for setting the contact target position, as shown in Figure 23, and display it on the display unit 4. The setting user interface screen 210 includes a cross-sectional display area 211 for displaying the cross-section of the workpiece W, and a parameter setting area 212. In the parameter setting area 212, multiple parameters for setting the first contact target position P1 can be set. For example, the number of measurement points in the XY direction can be set as a horizontal parameter. In this example, as shown in Figure 21, the number of measurement points in the XY direction is 2, so it is set to 2, but the number of measurement points is not limited to this. The number of measurement points set will be displayed on the display unit 4. The number of measurement points is the number of contact target positions for the touch probe 80.

[0145] The setting unit 3g can set the position in the XY direction on the workpiece image when setting the first contact target position P1. For example, the position in the XY direction of the first contact target position P1 can be set by moving the first contact target position P1 on the workpiece image using a mouse 6 or the like. Alternatively, the position in the XY direction of the first contact target position P1 can be arbitrarily set by inputting the distance from the reference position separately in the X and Y directions using a keyboard 5 or the like. Furthermore, the height position in the Z direction of the first contact target position P1 can be set in the same manner.

[0146] The horizontal parameters may include a parameter for setting the measurement direction. The measurement direction is the approach direction of the touch probe 80 to the contact target position. As shown in Figure 23, the measurement direction is from right to left, as indicated by the arrow. However, depending on the workpiece W, it may be necessary to use the opposite direction. In that case, the user checks "reverse direction" to select the reverse direction. This operation is set in the setting unit 3g and then stored in the storage unit 7 as the approach direction.

[0147] Furthermore, the approach directions include a first approach direction in which the touch probe 80 is moved from above to approach the workpiece W, and a second approach direction in which the touch probe 80 is moved in a direction normal to the slope S3 of the workpiece W. The approach direction can be arbitrarily selected by the user.

[0148] Vertical parameters include the number of measurement points in the Z direction, the starting margin, and the measurement range. In this example, the number of measurement points in the Z direction is set to 2. The starting margin is the dimension in the Z direction from the upper surface S2 of the workpiece W to the upper first contact target position P1. The measurement range is the dimension from the upper first contact target position P1 to the lower first contact target position P1.

[0149] In the parameter setting area 212, parameters related to the scanline can also be set. The scanline can be defined as the path that moves the touch probe 80 from a position where it is not in contact with the workpiece W to a position where it is in contact. The parameters related to the scanline become the path information of the touch probe 80 when it approaches the workpiece W, and the approach path of the touch probe 80 to the contact target position can become the scanline. The scanline may be straight or curved.

[0150] The starting position (start point) of the scan line is the starting position of the touch probe 80, and this starting position can be set by specific dimensions, specifying how far horizontally it should be from the edge position of the side surface S1 of the workpiece W. Similarly, the ending position of the scan line can be set by specific dimensions, specifying how far it should be from the edge position of the side surface S1 of the workpiece W toward the cross-section of the workpiece W. Even if the scan line has reached the cross-section of the workpiece W, the scan will automatically stop when the touch probe 80 makes contact with the workpiece W.

[0151] Multiple second contact target positions P2 can also be set based on the absolute coordinates described above, and as shown in Figure 21, they can be set with intervals between them in the X and Y directions. The parameters for the second contact target position P2 are different from those for the first contact target position P1, and the number of measurement points in the X direction and the number of measurement points in the Y direction are set. The setting of parameters in the vertical direction is omitted. The setting unit 3g extracts and sets the line that forms the boundary between the upper surface S2 and the inclined surface S3 of the workpiece W on the workpiece image as the second edge measurement element (straight edge element), but the second edge measurement element (the part enclosed by the frame line 202) and the second contact target position P2 are not associated with each other.

[0152] Multiple third contact target positions P3 can also be set based on the absolute coordinates described above. Multiple positions can be set at intervals around the circumferential direction of hole H1, and multiple positions can be set at intervals in the Z direction. In the case of hole H1, the starting position is defined as the position approaching the central axis from the inner surface of hole H1 in a plan view. The approach direction is the direction from the position approaching the central axis from the inner surface of hole H1 toward the inner surface of hole H1, and this direction can also be set using the user interface shown in Figure 23. In the case of hole H1, the measurement points are arranged so as to be aligned in the circumferential direction, and the number of measurement points can also be set. The parameters for the third contact target position P3 can be set in the same way as the parameters for the first contact target position P1.

[0153] The setting unit 3g extracts and sets the peripheral edge of hole H1 as a third edge measurement element (circular edge element) on the workpiece image. The setting unit 3g then associates the third contact target position P3 with the extracted third edge measurement element (the part enclosed by the frame line 203). If the workpiece W has a cylindrical portion, the measurement points for the cylindrical portion can be set in the same manner.

[0154] Multiple fourth contact target positions P4 can also be set based on the absolute coordinates described above. Figure 24 shows the user interface screen 210 for setting the contact target position relative to the slope. The horizontal parameters in the parameter setting area 212 are the same as when setting the first contact target position P1, but the settings for the slope direction parameters are different. The slope direction parameters allow setting the number of measurement points in the slope direction, the starting margin, and the measurement range. The starting margin is the dimension along the slope S3 from the second edge measurement element shown in Figure 21 to the upper fourth contact target position P4. The measurement range is the dimension from the upper fourth contact target position P4 to the lower fourth contact target position P4. The slope angle α of the slope S3 can also be set. The slope angle α of the slope S3 is the angle information near the contact target position of the touch probe 80, and this slope angle α can also be input by the setting unit 3g. Furthermore, the setting unit 3g associates the fourth contact target position P4 with the second edge measurement element (the part enclosed by the frame line 202 in Figure 21). The various setting information set in this manner is stored in the storage unit 7.

[0155] When setting up the measurement, it is also possible to set the measurement range for dimensional measurement. For example, if you want to measure only the top surface S2 of the workpiece W, you set the measurement range on the workpiece image displayed on the display unit 4 so that it encloses only the top surface S2. The reception unit 3e is configured to accept the measurement range setting made by the user. The measurement range setting information received by the reception unit 3e is also stored in the storage unit 7.

[0156] Next, the details of step SC10 (measurement using the non-contact displacement meter 70) in the flowchart shown in Figure 16 are shown in the flowchart shown in Figure 25. In step SG1 after the start, parameters for non-contact displacement measurement are set. Then, the process proceeds to step SG2, where the control unit 3d accepts the specification of the height measurement location on the workpiece image. Step SG2 is for specifying the position in the XY direction. For example, the user may look at the workpiece image displayed on the display unit 4, confirm the desired measurement location, and specify that measurement location using the mouse 6, etc., or they may specify the measurement location by numerically inputting position identification information such as coordinates. Multiple measurement locations can be specified.

[0157] After specifying the measurement location, the process proceeds to step SG3, where the control unit 3d controls the stage 21 so that the measurement light from the non-contact displacement meter 70 is shone onto the measurement location specified in step SG2. Specifically, the control unit 3d controls the Z-direction drive unit 25 and the XY-direction drive unit 23 to align the focus of the non-contact displacement meter 70 with the measurement location specified in step SG2. Then, in step SG4, the measurement light is emitted and the measurement is performed. In step SG5, the displacement measurement unit 3c calculates the dimension. At this time, the averaging process described later may be performed.

[0158] After step SC10 in the flowchart of Figure 16, proceed to step SC11. In step SC11, set the measuring tools. For example, tools for measuring the distance between lines, tools for measuring diameter, tools for measuring angle, etc., can be displayed in a list format on display unit 4, allowing the user to select the desired tool. The measuring tools selected by the user are saved.

[0159] In step SC12, the measurement results from the measurement tool set in step SC11 are superimposed on the workpiece image on the display unit 4. If a color image is acquired, the measurement results are superimposed on the color image. It is also possible to pre-configure the range for superimposing the measurement results using the reception unit 3e. When setting up the measurement, for example, if the user specifies the range on the color image displayed on the display unit 4 where they want to superimpose the measurement results, that range is accepted by the reception unit 3e and stored in the storage unit 7. When the measurement is executed, the specified range is read from the storage unit 7, and the measurement results are superimposed only within the specified range. If a live view image is acquired, it is also possible to display the measurement results on the video.

[0160] Furthermore, in step SC13, if, for example, measurement results are obtained by the image measurement unit 3a, the measurement results from the image measurement unit 3a are superimposed on the overhead image generated by the front camera 48. In step SC13, geometric elements 221 and 222 corresponding to the measurement results from the image measurement unit 3a can also be displayed on the overhead image, for example, as shown in Figure 26. Figure 26 is another example of the user interface screen 220 for displaying geometric elements 221 and 222 (shown by thick lines) on the display unit 4, where the work image and geometric elements 221 and 222 corresponding to the shapes of the measurement elements in the work image are superimposed. Geometric elements 221 and 222 may be rectangles or other shapes in addition to straight lines and circles, as long as they correspond to the shape of the measurement elements. Geometric elements 221 and 222 are set as edge measurement elements by the setting unit 3g, and include straight edges, circular edges, rectangular edges, etc.

[0161] For each measurement element, the position and number of contact target positions of the touch probe 80 can be associated. For example, different positions can be associated with geometric element 221 and geometric element 222 as the positions for which contact target positions are placed, and different numbers of contact target positions can also be associated. The correspondence between the shape type or size of the measurement element and the position and number of contact target positions of the touch probe 80 for that measurement element can be stored in the storage unit 7. The shape type, size, etc. of the geometric element can also be set on the overhead image.

[0162] While the overhead view image is generated by the front camera 48, the workpiece image from which the geometric elements 221 and 222 are extracted is generated by a different imaging unit 50 than the front camera 48. Therefore, if the geometric elements are superimposed on the overhead view image without correction, a misalignment may occur. In this example, a correction process is configured to correct the misalignment of the geometric elements relative to the overhead view image before measurement. Examples of misalignment of geometric elements include misalignment due to the optical characteristics of the camera and lens, and camera positional misalignment. The correction process may be performed at the time of factory shipment of the image measuring device 1 or after shipment. Any method of correction is acceptable, but one example is shown below.

[0163] During the correction process, a correction workpiece (not shown) having, for example, a dot chart is prepared and placed on the stage 21. The correction workpiece on the stage 21 is imaged by the imaging unit 50, and the central coordinates of each dot are detected. The front camera 48 also images the correction workpiece on the stage 21, and the central coordinates of each dot are detected. A correction table is generated as an internal parameter so that the central coordinates detected based on the image from the imaging unit 50 and the central coordinates detected based on the image from the front camera 48 can be converted. A conversion function may be used instead of a correction table. After that, the correction table is applied to the image captured by the imaging unit 50 to convert it to projected coordinates.

[0164] The correction process includes, for example, the detection of external parameters. Specifically, the correction workpiece on the stage 21 is imaged by the imaging unit 50, and the three-dimensional coordinates of the center of each dot are detected. The image from the front camera 48 is used to determine the center coordinates of each dot in projected coordinates using internal parameters. A transformation matrix is ​​calculated for these corresponding images. The positions and orientations of the imaging unit 50 and the front camera 48 are also defined in three-dimensional space. A transformation matrix is ​​calculated for the detected dots, comparing the center coordinates detected based on the image from the imaging unit 50 with the center coordinates detected based on the image from the front camera 48.

[0165] In step SC13 of the flowchart shown in Figure 16, the measurement results and geometric elements 231 and 232 may be superimposed on a user interface screen 230 capable of displaying the workpiece W in three dimensions, as shown in Figure 27.

[0166] Step SC14 determines if there are any other measurement elements. If there are other measurement elements, the process returns to step SC7. If there are no other measurement elements, the process proceeds to step SC15. Step SC15 is used to configure the pattern search. For example, as shown in Figure 21, the alignment mark M, which is a feature pattern, can be used as the search target. In this case, the user generates a frame 200 surrounding the alignment mark M and specifies the area within that frame 200 as the search area.

[0167] In step SC16, the setting information set in each process shown in this flowchart is stored in the storage unit 7. Specifically, the feature pattern (feature quantity information) set by the setting unit 3g, the relative positional relationship of the first and second contact target positions P1 and P2 with respect to the feature pattern, etc., are stored in the storage unit 7. The storage unit 7 also stores the fixed positional relationship between the imaging unit 50 and the touch probe 80, etc. The fixed positional relationship is the relative positional relationship of the touch probe 80 with respect to the imaging unit 50, and may be a relationship shown by coordinate information, or a relationship shown by the relative separation distance or separation direction, etc.

[0168] (Touch probe measurement operation) Next, the details of the measurement operation of the touch probe 80, specifically step SF8 of the flowchart shown in Figure 19, will be explained based on the flowchart shown in Figure 28. After the start, although not shown in the flowchart, the control unit 3d controls the Z-direction drive unit 25 to move the measurement execution unit 24 upward to a retracted position, and then the changer mechanism 100 attaches the desired stylus 83 to the touch probe 80. After that, the process proceeds to step SH1, and the contact portion 83b of the touch probe 80 is moved relative to the start point of the scan line set on the setting user interface screen 210 shown in Figure 23. Specifically, the control unit 3d controls the XY-direction drive unit 23 to move the stage 21 in the XY direction so that the XY coordinates of the start point of the scan line match the XY coordinates of the contact portion 83b of the touch probe 80. After that, the control unit 3d controls the Z-direction drive unit 25 to lower the measurement execution unit 24 and position the contact portion 83b of the touch probe 80 at the start point of the scan line.

[0169] In step SH2, the control unit 3d controls the XY direction drive unit 23 and the Z direction drive unit 25 to move the contact portion 83b of the touch probe 80 relative to the direction of the scan line (the direction of the arrows in Figures 23 and 24). In step SH3, it is determined whether or not the touch probe 80 has detected contact. If the touch probe 80 does not detect contact, it continues to move the contact portion 83b of the touch probe 80 relative to the direction of the scan line. When the contact portion 83b of the touch probe 80 comes into contact with the workpiece W, the movement stops, and in step SH3, it is determined to be YES, and the process proceeds to step SH4.

[0170] In step SH4, the coordinate measurement unit 3b acquires the X, Y, and Z coordinates when the contact portion 83b of the touch probe 80 contacts the workpiece W, and uses them as measured values. In step SH5, the control unit 3d controls the XY direction drive unit 23 and the Z direction drive unit 25 to return the contact portion 83b of the touch probe 80 to the starting point of the scan line. In step SH6, it is determined whether measurement has been completed for all scan lines. If measurement has been completed for all scan lines, the process proceeds to step SH7, where the control unit 3d controls the Z direction drive unit 25 to move the measurement execution unit 24 upward to the retracted position. After that, if necessary, the stylus 83 is removed by the changer mechanism 100 and stored in the retracted position.

[0171] If there are scanlines that are determined to be NO in step SH6 and measurement is not yet complete, the process proceeds to step SH8 to determine the retraction method. If the retraction method is to retract in the Z direction, the process proceeds to step SH9, where the control unit 3d controls the Z-direction drive unit 25 to move the measurement execution unit 24 upward to the retraction position. In step SH10, the control unit 3d controls the XY-direction drive unit 23 to move the contact portion 83b of the touch probe 80 relative to the start point (X,Y) of the scanline. Then, in step SH11, the control unit 3d controls the Z-direction drive unit 25 to move the contact portion 83b of the touch probe 80 relative to the start point (Z) of the scanline.

[0172] If the retraction method is a polygonal retraction method, the process proceeds to step SH12. In step SH12, the control unit 3d controls the XY direction drive unit 23 to move the center of the contact portion 83b of the touch probe 80 relative to the starting point (X,Y) of the scan line so that it forms a polygon along the circumferential direction of the measurement element.

[0173] If the device is not moved, the process proceeds to step SH13, where the control unit 3d controls the XY direction drive unit 23 to move the contact portion 83b of the touch probe 80 relative to the starting point (X,Y) of the scan line.

[0174] (During measurement execution) Figures 29A and 29B are flowcharts illustrating an example of the procedure during measurement execution by the image measuring device 1. In step SI1 after the start, setting information stored in the memory unit 7 is read. For example, the feature pattern, search area, the relative positional relationship of the first and second contact target positions P1 and P2 with respect to the feature pattern, and the fixed positional relationship between the imaging unit 50 and the touch probe 80 are read. Because of this step, the user does not need to move the touch probe 80 to set the reference coordinates each time the workpiece W is placed on the stage 21, making the measurement work easier.

[0175] In step SI1, the position of the measurement element on the workpiece image and the shape type or size of the measurement element are read from the storage unit 7. Furthermore, the correspondence between the shape type or size of the measurement element and the position and number of contact target positions of the touch probe 80 relative to the measurement element are also read from the storage unit 7.

[0176] In step SI2, the imaging unit 50 captures an image of the stage 21 from above, acquires a plan view image, and displays it on the display unit 4. In step SI2, a stitched image may be displayed, or an overhead image captured by the front camera 48 may be displayed. The imaging unit 50 may acquire the stitched image using either the high-magnification image sensor 55 or the low-magnification image sensor 56, or it may acquire stitched images using both image sensors. As described above, in this embodiment, a bifurcated optical system configuration using a beam splitter 52 is adopted, so a high-magnification image and a low-magnification image may be acquired simultaneously to obtain a first stitched image by stitching together the high-magnification images and a second stitched image by stitching together the low-magnification images.

[0177] Step SI3 determines whether or not to perform ghost display. For example, if the user selected "Show ghost" during measurement setup, step SI3 determines YES and proceeds to step SI4, where the control unit 3d displays the search area as a ghost on the display unit 4 to guide the placement of the workpiece W to the appropriate position on the stage 21. Ghost display involves superimposing the pre-set search area onto the plan view image during measurement setup. For example, the search area may be displayed fainter than the plan view image to avoid interfering with the recognition of the plan view image. If the user selected "Do not show ghost" during measurement setup, step SI3 determines NO and proceeds to step SI5. Ghost display may also be applied to linked images, overhead images, etc.

[0178] Step SI5 determines whether or not to specify a search area. That is, if the user specifies a search area for the feature pattern during measurement, step SI5 is determined to be YES and the process proceeds to step SI6. If no search area is specified, the process proceeds to step SI7. Specifying a search area is performed by the user drawing a box around a specific area on any image, such as a plan view image, a stitched image, or an overhead view image, using the mouse 6 or similar device. In this case, for example, if the entire workpiece W is captured by the imaging unit 50 (or stage cameras 46, 47 or the front camera 48) and the overhead view image is displayed on the display unit 4, the user can specify a search area on the overhead view image displayed on the display unit 4. Note that using the imaging unit 50 or stage cameras 46, 47, which capture images from directly above, makes it easier to specify the search range than using the front camera 48, which captures images from an oblique angle.

[0179] In step SI7, it is determined whether or not the measurement start button 2a has been pressed. Steps SI2 to SI7 are repeated until the measurement start button 2a is pressed, at which point the process proceeds to step SI8. In step SI8, it is determined whether or not to display the overhead image on the display unit 4. If the user selected "Display overhead image" during measurement setup, step SI8 is determined to be YES, and the process proceeds to step SI9, where the control unit 3d displays the overhead image captured by the front camera 48 on the display unit 4. If the user selected "Do not display overhead image" during measurement setup, step SI8 is determined to be NO, and the process proceeds to step SI10.

[0180] Step SI10 determines whether or not to generate a color image. If the user selected "Generate color image" during measurement setup, step SI10 is determined to be YES and the process proceeds to step SI12. In step SI12, a color image of workpiece W (a newly generated workpiece image for measurement) is generated using a process similar to step SC5 shown in Figure 16. On the other hand, if the user selected "Do not generate color image" during measurement setup, step SI10 is determined to be NO and the process proceeds to step SI11. In step SI11, a grayscale image of workpiece W (a newly generated workpiece image for measurement) is generated using a process similar to step SC4 shown in Figure 16.

[0181] Next, the process proceeds to step SI13 in Figure 29B. In step SI13, the target image for pattern search is acquired. For example, the control unit 3d can acquire a color image of the workpiece W newly generated for measurement in step SI11, or a grayscale image of the workpiece W newly generated for measurement in step SI12, as the target image for pattern search. After acquiring the target image for pattern search, the process proceeds to step SI14, where the control unit 3d identifies the position and orientation of the feature pattern from the newly generated workpiece image for measurement. At this time, if a search area has been specified by the user in step SI6, the position and orientation of the feature pattern are narrowed down to the specified search area. This improves the processing speed.

[0182] Furthermore, when a concatenated image is used as the workpiece image, the control unit 3d controls the XY direction drive unit 23 to move the stage 21 in the XY direction until the workpiece W enters the field of view of the imaging unit 50. Once the workpiece W enters the field of view, the imaging unit 50 captures the workpiece W that is within the field of view. Subsequently, the stage 21 is moved in the XY direction so that another part of the workpiece W enters the field of view, and then the imaging unit 50 captures another part of the workpiece W that is within the field of view. The concatenated image obtained by concatenating multiple images in this way becomes the workpiece image, and the position and orientation of the feature pattern are identified from the concatenated image. In this case as well, if a search area is specified by the user, the position and orientation of the feature pattern are identified by narrowing the search area to the specified area.

[0183] The process then proceeds to step SI15. In step SI15, the control unit 3d identifies a first contact target position P1 and a second contact target position P2 for measurement based on the position and orientation of the workpiece W identified in step SI14, the relative positional relationship of the first and second contact target positions P1 and P2 with respect to the feature pattern, and the fixed positional relationship between the imaging unit 50 and the touch probe 80. For example, if at least one of the position or orientation of the workpiece W based on the workpiece image newly generated during measurement differs from the position or orientation of the workpiece W used during measurement setup, the position or orientation of the workpiece W can be corrected based on the position and orientation of the workpiece W identified in step SI14. The position is identified by the X and Y coordinates, and the orientation is identified by the rotation angle around the X axis and the rotation angle around the Y axis. Correcting the position can be called position correction, and correcting the orientation can be called orientation correction, but these can be collectively referred to as position correction.

[0184] During position correction, by using the relative positional relationship between the first and second contact target positions P1 and P2 with respect to the feature pattern, the first and second contact target positions P1 and P2 can be identified in the same positions as during measurement setting, even after correction.

[0185] Furthermore, the control unit 3d can perform a pattern search on the workpiece image newly generated for measurement by the imaging unit 50 to identify edge measurement elements, extract edges from the identified edge measurement elements, and identify the first contact target position P1 and the second contact target position P2 based on the extracted edges. The third contact target position P3 and the fourth contact target position P4 shown in Figure 21 can be identified in the same manner. Since the fourth contact target position P4 is a position identified on the inclined surface S3, the inclination angle α of the inclined surface S3 can be used to identify the fourth contact target position P4. Knowing the inclination angle α allows the normal direction of the inclined surface S3 to be estimated. This allows the fourth contact target position P4 to be identified as the position where the touch probe 80 is brought into contact with the inclined surface S3 of the workpiece W from the normal direction of the inclined surface S3.

[0186] After identifying the target contact location, proceed to step SI16. In step SI16, if there are multiple measurement locations, determine the order of the measurement locations.

[0187] Steps SI17 to SI20 are the same as steps SC7 to SC10 in the flowchart shown in Figure 16. For example, when performing image measurement in step SI18, the measurement is performed only within the measurement range received by the reception unit 3e. This improves the measurement speed.

[0188] Furthermore, in step SI19, for example, the control unit 3d controls the XY direction drive unit 23 so that the touch probe 80 contacts the side surface of the workpiece W with reference to the first contact target position P1 for measurement identified in step SI15. Also, the control unit 3d controls the Z direction drive unit 25 so that the touch probe 80 contacts the top surface of the workpiece W with reference to the second contact target position P2 for measurement identified in step SI15. At this time, the touch probe 80 is moved relative to the scan line set during measurement setup, and the number of measurement points, start margin, start position, end position, approach direction, etc. are reflected.

[0189] When moving the touch probe 80 relative to the workpiece W, the control unit 3d controls the Z-direction drive unit 25 and the XY-direction drive unit 23 so that the touch probe moves according to the approach direction set in Figure 23. At this time, the relative movement speed is set to a first speed until the touch probe 80 makes contact with the workpiece W. Once contact is detected, the touch probe is moved back a predetermined distance from the contact position, and then the touch probe 80 is moved relative to the workpiece W at a second speed, which is slower than the first speed, until it makes contact with the workpiece W. The measurement result is then output based on the position where contact was made at the second speed. This enables precise measurement.

[0190] Furthermore, when bringing the touch probe 80 into contact with the inclined surface of the workpiece W, the touch probe 80 is brought close to the inclined surface of the workpiece W at a first speed, and the relative movement speed is set to a second speed when the distance between the touch probe 80 and the inclined surface of the workpiece W reaches a predetermined distance. Then, the measurement result is output based on the position where contact was made at the second speed.

[0191] Furthermore, in step S1, the control unit 3d reads the position of the measurement element on the workpiece image, the shape type or size of the measurement element, and the correspondence between the shape type or size of the measurement element and the position and number of contact target positions for the touch probe 80 relative to the measurement element. Therefore, based on the position of the measurement element on the workpiece image, the shape type or size of the measurement element, and the aforementioned correspondence, the control unit 3d can identify multiple contact target positions for the touch probe 80 and control the XY direction drive unit 23 and the Z direction drive unit 25 so that the touch probe 80 moves sequentially to the identified multiple contact target positions. In this way, multiple contact target positions for the touch probe 80 are automatically identified based on the information at the time of measurement setup, and the XY direction drive unit 23 and the Z direction drive unit 25 are automatically controlled, making the measurement work by the user easier.

[0192] In step SI20, non-contact height measurement is performed using the non-contact displacement meter 70. In this case, the non-contact displacement meter 70 may perform multiple height measurements, and an averaging process may be performed to average the multiple acquired height measurements. A specific example will be explained based on the flowchart shown in Figure 30.

[0193] In step SJ1 after the start, the control unit 3d drives the Z-direction drive unit 25 to move the measurement execution unit 24 so that the non-contact displacement meter 70's focus aligns with the measurement point. In step SJ2, it is determined whether or not a measurement value can be read from the non-contact displacement meter 70. If no measurement value can be read, the process proceeds to step SJ3 for a rough search, i.e., moving the measurement execution unit 24 to a position where a measurement value can be read from the non-contact displacement meter 70. If a measurement value can be read in step SJ2, the process proceeds to step SJ3 for a precise search. In the precise search, the measurement execution unit 24 is moved to adjust the focus so that the measurement value of the non-contact displacement meter 70 is approximately 0.

[0194] In step SJ5, it is determined whether the measurement value of the non-contact displacement meter 70 is smaller than the convergence threshold. The convergence threshold can be set to, for example, approximately 0.2 mm, but is not limited to this. If the result in step SJ5 is NO and the measurement value of the non-contact displacement meter 70 is greater than or equal to the convergence threshold, the process proceeds to step SJ6 to determine whether the number of feedback iterations has been exceeded. The number of feedback iterations can be set to, for example, 5, but is not limited to this. If the number of feedback iterations has not been exceeded, the process proceeds to step SJ4; if the number of feedback iterations has been exceeded, the process proceeds to step SJ7. In step SJ7, it is determined whether automatic adjustment is OFF. If automatic adjustment is ON, the process proceeds to step SJ8 to determine whether the second peak of the light-receiving waveform of the non-contact displacement meter 70 has been acquired. If the second peak has been acquired, the process proceeds to step SJ11, and since the workpiece W is presumed to be transparent, the transparent body mode is set. If the second peak has not been acquired, the process proceeds to step SJ12, and since the workpiece W is presumed to be opaque, the opaque body mode is set.

[0195] Next, the process proceeds to step SJ13. In step SJ13, the diameter of the folio curve used for averaging the measured values ​​is reduced during scanning. In step SJ14, the control unit 3d controls the stage 21 so that the focus of the non-contact displacement meter 70 traces a trajectory of the folio curve on the surface of the workpiece W. The figure formed by the folio curve during averaging is point-symmetric and line-symmetric. The center of the folio curve is the measurement target point. The diameter of the folio curve may be selected by the user from a predetermined range of values, such as 0.25 mm, 0.5 mm, 1 mm, etc.

[0196] The user may be given the option to choose whether or not to perform the averaging process. For example, the user interface could accept the user's choice of whether or not to perform the averaging process, and if the user chooses to perform it, the averaging process would be executed; if the user chooses not to perform it, the averaging process would not be executed.

[0197] In step SJ14, it is further determined whether the variance of the measured values ​​during scanning of the folio curve is smaller than the automatic adjustment threshold. The automatic adjustment threshold can be set to, for example, around 0.005 mm, but is not limited to this. If the variance of the measured values ​​during scanning of the folio curve is greater than or equal to the automatic adjustment threshold, the folio curve is turned ON (averaging process is executed). On the other hand, if the variance of the measured values ​​during scanning of the folio curve is smaller than the automatic adjustment threshold, highly accurate measured values ​​can be obtained without performing the averaging process, so the folio curve is turned OFF (averaging process is not executed).

[0198] Next, the process proceeds to step SJ17, where the measurement is performed, and then to step SJ18, where the dimensions are calculated. During the measurement, a folio curve is scanned to retain multiple measurement points. During the dimension calculation, the multiple measurement points are averaged to determine the output value.

[0199] After performing the measurement as described above, proceed to step SI21 in Figure 29B. In step SI21, determine whether measurement of all measurement points has been completed. If measurement points remain, proceed to step SI17; if measurement of all measurement points has been completed, proceed to steps SI22 and SI23. Steps SI22 and SI23 display the measurement results superimposed on the workpiece image, similar to steps SC12 and SC13 in the flowchart shown in Figure 16.

[0200] When measuring with the non-contact displacement meter 70, the control unit 3d may perform an extraction process to extract edge measurement elements used in image measurement from the workpiece image. If the extraction process successfully extracts the edge measurement elements, the control unit 3d performs image measurement and height measurement using the non-contact displacement meter 70.

[0201] Furthermore, when measuring with the non-contact displacement meter 70, the control unit 3d moves the stage 21 in a direction perpendicular to the imaging axis of the imaging unit 50 so that the focus of the non-contact displacement meter 70 coincides with the measurement location, then performs height measurement with the non-contact displacement meter 70 and determines whether or not a height measurement value is obtained. If a height measurement value is not obtained, the control unit 3d may move the non-contact displacement meter 70 along the imaging axis using the Z-direction drive unit 25 until a height measurement value is obtained. In this way, by using the Z-direction drive unit 25, which adjusts the focal position of the imaging unit 50, to move the non-contact displacement meter 70 together with the imaging unit 50 in the imaging axis direction, the measurement time can be shortened when performing high-precision height measurement using the non-contact displacement meter 70.

[0202] (indicator) As shown in Figure 6, the main body of the device 2 is provided with an indicator 2c. The indicator 2c is located on the side of the main body of the device 2 facing the user and is controlled by the control unit 3. The indicator 2c displays the measurement result and is composed of, for example, a light-emitting part and a display part. The control unit 3 controls the indicator 2c so that it displays differently depending on whether the measurement result meets or does not meet predetermined conditions. The predetermined conditions are set in advance by the user and stored in the memory unit 7, etc. For example, if the measurement result is above a certain value, it is displayed in red, indicating a defect, and if the measurement result is below a certain value, it is displayed in green, indicating a good product.

[0203] (modified version) Figure 31 shows a modified example 1 in which the high-magnification image sensor 55 and the low-magnification image sensor 56 of the imaging unit 50 are 3-channel image sensors. That is, since the high-magnification image sensor 55 and the low-magnification image sensor 56 are composed of 3-channel image sensors consisting of RGB, a color work image can be generated by emitting only one color of white light from the ring illumination 45.

[0204] In the modified example 1, the control unit 3 is equipped with a conversion unit 3h. The conversion unit 3h is the part that converts a color work image generated by the imaging unit 50 into a grayscale work image, and this conversion can be performed by a conventionally known method. The image measurement unit 3a is configured to measure the dimensions of the workpiece W based on the grayscale work image converted by the conversion unit 3h.

[0205] Furthermore, the color information generation unit 3f generates color information for the workpiece W based on the color workpiece image generated by the imaging unit 50. The control unit 3d generates a color image by adding the color information for the workpiece W generated by the color information generation unit 3f to the grayscale workpiece image converted by the conversion unit 3h. As a result, the display unit 4 can display the color image, which is the workpiece color information generated by the color information generation unit 3f added to the grayscale workpiece image converted by the conversion unit 3h, and can also superimpose the results of the dimensional measurement by the image measurement unit 3a onto the color image.

[0206] Next, a modified example 2 shown in Figure 32 will be described. Modified example 2 has a first imaging unit 50A which has a single-channel image sensor and receives detection light to generate a grayscale work image, and a second imaging unit 50B which has a three-channel image sensor consisting of RGB and receives detection light to generate a color work image. The first imaging unit 50A is composed of a single-channel high-magnification image sensor 55 and a low-magnification image sensor 56. The image measurement unit 3a is configured to measure the dimensions of the work W based on the work image generated by the first imaging unit 50A.

[0207] The color information generation unit 3f generates color information for the workpiece W based on the workpiece image generated by the second imaging unit 50B. The control unit 3d generates a color image by adding the color information for the workpiece W generated by the color information generation unit 3f to the grayscale workpiece image generated by the first imaging unit 50A. The display unit 4 displays the color image generated by the control unit 3d and also displays the results of the dimensional measurement by the image measurement unit 3a superimposed on the color image.

[0208] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. [Industrial applicability]

[0209] As described above, this disclosure can be used to measure the three-dimensional coordinates of a workpiece placed on a stage. [Explanation of Symbols]

[0210] 1. Image measuring device 3a Image measurement unit 3b Coordinate measurement section 3c Displacement measurement section 3D control unit 3g settings section 4 Display section 7 Memory section 21 stages 23 XY Direction Drive Unit 25 Z-direction drive unit 30 Transmitted illumination (light source) 40 Coaxial incident illumination (light source) 45 Ring lighting (light source) 50 Imaging Unit 80 Touch Probes

Claims

1. A stage on which the workpiece is placed, A light-emitting unit that irradiates detection light onto the workpiece on the aforementioned stage, An imaging unit that receives the aforementioned detection light and generates a workpiece image, A touch probe for contacting a workpiece on the aforementioned stage and measuring the three-dimensional coordinates of the contact point, A drive unit that moves the stage or the touch probe relative to the stage in the direction normal to the stage, in a direction parallel to the upper surface of the stage, or in a direction inclined from the normal direction, thereby bringing the touch probe into contact with the surface of a workpiece placed on the stage. When setting the measurement of the touch probe, a display unit is provided to display the workpiece image generated by the imaging unit, A setting unit for setting geometric measurement elements for measurement by the touch probe on the workpiece image displayed on the display unit, A storage unit that pre-stores the correspondence between the shape type and size of the measurement element that can be set by the setting unit, and the position and number of contact target positions of the touch probe for the measurement element, When measurement is performed by the touch probe, the control unit identifies a plurality of contact target positions for the touch probe based on the position of the measurement element on the workpiece image set by the setting unit, the shape type or size of the measurement element, and the correspondence relationship stored in advance in the storage unit, and controls the drive unit so that the touch probe moves sequentially to the plurality of identified contact target positions. A measuring unit measures the three-dimensional coordinates of the contact point where the touch probe contacts the workpiece based on a contact signal output when the touch probe contacts the workpiece due to the operation of the drive unit controlled by the control unit, Equipped with, The setting unit sets feature information on the workpiece image displayed on the display unit to identify the position and orientation of the workpiece during measurement. The memory unit stores the feature information, The image measuring apparatus is characterized in that, during measurement execution, the control unit identifies the position and orientation of a workpiece using the feature information stored in the storage unit from a workpiece image newly generated by the imaging unit, identifies the contact target position of the touch probe based on the identified workpiece position and orientation, and controls the drive unit so that the touch probe moves sequentially to the identified contact target position.

2. In the image measuring device according to claim 1, The control unit is configured to be able to specify an edge extraction region for detecting the edges of a workpiece on the workpiece image displayed on the display unit. The image measuring device is characterized in that the setting unit sets the edges detected from the edge extraction region specified by the control unit as the measurement elements.

3. In the image measuring device according to claim 2, The control unit performs a pattern search on a workpiece image newly generated for measurement by the imaging unit to correct the workpiece position so that the workpiece position corresponds to that at the time of measurement setting, and also performs a position correction of the edge extraction region to correspond to the workpiece position correction, and sets the edges detected from the edge extraction region after position correction as the measurement elements.

4. In the image measuring device according to claim 3, The image measuring device is characterized in that the control unit identifies the contact target position of the touch probe according to the measurement element detected from the edge extraction region after position correction.

5. In the image measuring device according to claim 1, The setting unit is configured to allow setting the number of contact target positions for the touch probes. The image measuring device is characterized in that the storage unit stores the number of contact target positions of the touch probe set in the setting unit.

6. In the image measuring device according to claim 1, The setting unit is configured to enable setting of the approach path to the contact target position of the touch probe. The storage unit stores the approach path set by the setting unit, The image measuring apparatus is characterized in that the control unit controls the drive unit so that the touch probe moves according to the approach path stored in the storage unit when measurement is performed by the touch probe.

7. In the image measuring device according to claim 1, The image measuring device is characterized in that the setting unit is configured to allow setting of points, lines, or arbitrary shapes as measurement elements for measurement by the touch probe on the workpiece image displayed on the display unit.

8. In the image measuring device according to claim 3, A support portion above the stage, which supports the imaging unit in a position where the imaging direction is the normal direction of the stage, The support portion includes an overhead image generation unit that generates an overhead image by imaging a workpiece in a position where the imaging direction is the normal direction of the stage or a position different from the normal direction, above the stage, The field of view of the imaging unit is set to be narrower than the field of view of the overhead image generation unit. The image measuring apparatus is characterized in that the control unit detects the position of a workpiece on the stage based on the overhead image generated by the overhead image generation unit, moves the stage so that the detected workpiece is within the field of view of the imaging unit and takes multiple images of it, generates a concatenated image by concatenating the multiple acquired images, and performs the pattern search on the generated concatenated image.

9. In the image measuring device according to claim 1, An image measuring device characterized by having a main unit indicator that shows the measurement result from the aforementioned measuring unit.

10. In the image measuring device according to claim 1, The display unit displays the longitudinal section of the workpiece. The image measuring device is characterized in that the setting unit is configured to allow setting of parameters associated with the measurement element for performing measurement by the touch probe on the vertical cross-section of the workpiece displayed on the display unit.

11. In the image measuring device according to claim 1, The setting unit is configured to accept input of angle information near the contact target position of the touch probe, The control unit is characterized by identifying the contact target position of the touch probe using the angle information.

12. In the image measuring device according to claim 1, The setting unit is configured to allow setting the approach direction of the touch probe to the target contact position. The storage unit stores the approach direction set by the setting unit, The image measuring apparatus is characterized in that the control unit controls the drive unit so that the touch probe moves according to the approach direction stored in the storage unit when measurement is performed by the touch probe.

13. In the image measuring device according to claim 12, The image measuring apparatus is characterized in that the approach direction includes a first approach direction in which the touch probe is moved from above to approach the workpiece, and a second approach direction in which the touch probe is approached in a direction normal to the slope of the workpiece.

Images