JP6442627B2 - Image measuring instrument - Google Patents

Description

  The present invention relates to an image measuring instrument, and more particularly, to an improvement of an image measuring instrument that extracts an edge in a workpiece image obtained by photographing a workpiece and measures the dimension of the workpiece.

  An image measuring device is a device that captures a workpiece, acquires the workpiece image, extracts an edge in the workpiece image, and measures the size and shape of the workpiece (for example, Patent Documents 1 to 5). Usually, the workpiece is placed on a movable stage movable in the X, Y and Z axis directions. The workpiece image is focused by moving the movable stage in the Z-axis direction, and the position of the workpiece in the visual field is adjusted by moving in the X- or Y-axis direction.

  Since the workpiece image is a very accurate similar shape to the workpiece regardless of the position of the movable stage in the Z-axis direction, the actual dimensions on the workpiece can be determined by determining the distance and angle on the workpiece image. Can be detected. Edge extraction is performed by analyzing the brightness change of the workpiece image, detecting edge points, and fitting geometric shapes such as straight lines, circles, and arcs to the detected edge points, and the boundary between the workpiece and the background Then, an edge indicating the unevenness on the workpiece is required. The dimensions of the workpiece are measured as the distance and angle between the edges determined in this way, and the center position and diameter of the circular edge. In addition, a quality determination is performed by comparing a difference (error) between the measured dimension value and the design value with a tolerance.

  When measuring the external shape of a workpiece using such an image measuring device, transmitted illumination that irradiates illumination light to the workpiece on the stage from the opposite side of the camera is often used. On the other hand, when measuring a non-through hole, a step, and an unevenness on a workpiece, epi-illumination that illuminates the workpiece on the stage from the same side as the camera is used.

JP 2012-32224 A JP 2012-32341 A JP 2012-32344 A JP 2012-159409 A JP 2012-159410 A

  In conventional image measuring instruments, when measuring the dimensions using epi-illumination, textures on the workpiece surface, that is, processing traces, patterns, and fine irregularities may be erroneously extracted as edges. In comparison, there was a problem that dimensional measurement was difficult to stabilize. Therefore, depending on the shape and material of the workpiece, various types of illumination devices are used properly or the irradiation position of illumination light is adjusted.

  However, selection of illumination type and adjustment of irradiation position require abundant knowledge based on skilled technology and experience, and in dimension measurement using epi-illumination, the performance of the device is sufficiently improved unless it is an expert. There was a problem that it was difficult to demonstrate. In particular, even if it is the same workpiece, if the position of the measurement target location is different, the appropriate illumination type and irradiation position also change, so appropriately setting the illumination type and irradiation position according to the measurement target location is There was a problem that it would be difficult for non-experts.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image measuring instrument that can sufficiently exhibit the performance of the apparatus even if it is not an expert. In particular, an object of the present invention is to provide an image measuring device that can automatically adjust illumination conditions such as the type of illumination device and the irradiation position of illumination light in accordance with the measurement target location.

  An image measuring device according to a first aspect of the present invention includes a stage for placing a workpiece, an illumination device that illuminates the workpiece on the stage, a camera that photographs the workpiece on the stage and generates a workpiece image, Based on a user operation, the measurement target location specifying means for specifying the measurement target location for the work image, the illumination condition storage means for holding two or more illumination conditions, the camera and the illumination device are controlled, and Any of the imaging control means for acquiring two or more work images photographed sequentially with different illumination conditions, the work image display means for displaying the plurality of acquired work images, and any of the displayed work images A work image selecting means for selecting one of them, an illumination condition determining means for determining the illumination condition based on the selected work image, and the determined illumination condition. In based on the captured the workpiece image to extract an edge of the position to be measured, based on the extracted edge, constituted by a dimension calculation means for calculating a dimension of the position to be measured.

  In this image measuring device, when a measurement target location is designated, two or more workpiece images that are sequentially photographed with different illumination conditions are acquired and displayed. If any one of the displayed work images is selected, the illumination condition is determined based on the selected work image, so that the performance of the apparatus can be sufficiently exerted even if it is not an expert. . In particular, it is possible to automatically adjust the illumination conditions such as the type of the illumination device and the illumination light irradiation position in accordance with the measurement target location simply by selecting the displayed work image.

  In addition to the above-described configuration, the image measuring instrument according to the second aspect of the present invention includes two or more measurement target locations designated for the same workpiece image by the measurement target location designation means, and the illumination for each of these measurement target locations. Measurement setting storage means for holding the illumination conditions determined by the condition determination means as measurement setting information, wherein the measurement setting storage means holds the illumination conditions in association with the measurement target location, and the imaging control means However, in the continuous measurement in which the measurement setting information is specified, acquiring the work image photographed under the illumination condition held as the measurement setting information is repeated while changing the measurement target portion, and the dimension calculation is performed. The means extracts an edge for each of the measurement object locations held as the measurement setting information for a plurality of workpiece images acquired in the continuous measurement. Configured to perform.

  According to such a configuration, since the illumination condition is stored in the measurement setting storage unit in association with the measurement target location, the illumination condition suitable for measuring the measurement target location is specified by specifying the measurement setting information. Can be identified. In continuous measurement in which measurement setting information is specified, a workpiece is photographed under illumination conditions suitable for measuring a measurement target location, and edge extraction is performed on the obtained workpiece image. For this reason, even if the shape or material of the workpiece changes, it is possible to perform stable dimension measurement only by specifying measurement setting information.

  In the image measuring device according to the third aspect of the present invention, in addition to the above-described configuration, the dimension calculation means obtains a dimension between edges extracted from two or more workpiece images having different illumination conditions and different positions of the measurement object. Configured as follows. According to such a configuration, since the dimension between the edges is obtained using two or more workpiece images photographed under illumination conditions suitable for measuring the measurement target portion, the dimension between the edges is accurately identified. be able to.

  An image measuring instrument according to a fourth aspect of the present invention includes, in addition to the above configuration, a diffusing illumination device that irradiates the workpiece on the stage from above with a diffusing illumination device as the illumination device, and the illumination light from below on the workpiece on the stage. The illumination condition is configured to include the type of the illumination device.

  According to such a configuration, the diffuse illumination device and the transmission illumination device can be used properly according to the shape and material of the workpiece. Further, it is possible to select a type of illumination device suitable for measuring a measurement target location by simply selecting the displayed work image.

  In addition to the above-described configuration, the image measuring instrument according to the fifth aspect of the present invention, as the illumination device, irradiates the workpiece on the stage from the side with illumination light composed of parallel light or illumination light having a divergence angle close to parallel light. A side illumination device is further provided. According to such a structure, according to the shape and material of a workpiece | work, a diffused illuminating device, a transmitted illuminating device, and a side illuminating device can be used properly.

  An image measuring instrument according to a sixth aspect of the present invention is a ring-shaped light source that surrounds the imaging axis of the camera as the illumination device in addition to the above configuration, and can be turned on every two or more blocks divided in the circumferential direction. A ring illumination device having a light source is provided, and the illumination condition includes a lighting position of the ring illumination device.

  According to such a configuration, the lighting position of the ring illumination device can be adjusted according to the shape and material of the workpiece. Moreover, the lighting position of the ring illumination device suitable for measuring the measurement target location can be selected simply by selecting the displayed work image.

  In addition to the above configuration, the image measuring device according to the seventh aspect of the present invention adjusts the relative position of the illuminating device with respect to the stage by moving the stage or the illuminating device in the photographing axis direction of the camera. Means for configuring the illumination condition to include the relative position.

  According to such a configuration, the relative position of the illumination device with respect to the stage can be adjusted according to the shape and material of the workpiece. Moreover, the relative position of the illuminating device suitable for measuring a measurement object location can be selected only by selecting the displayed work image.

  In addition to the above-described configuration, the image measuring instrument according to the eighth aspect of the present invention uses, as the measurement target location, the measurement target location specifying means that takes an area on the work image photographed by irradiating the diffused light of the diffuse illumination device. Configured to specify. According to such a configuration, by using the work image taken by irradiating the diffused light, it is possible to specify the measurement target portion while confirming the whole image of the work.

  An image measuring device according to a ninth aspect of the present invention includes an illumination condition designating unit that designates the illumination condition based on a user operation in addition to the above configuration. According to such a configuration, it is possible to arbitrarily specify illumination conditions according to the shape, material, and position of the measurement target portion of the workpiece.

  In the image measuring device according to a tenth aspect of the present invention, in addition to the above configuration, the work image selecting means selects any one of the displayed work images based on a change in luminance in the measurement target portion. Configured. According to such a configuration, a work image suitable for measuring a measurement target portion is automatically selected from two or more work images that are sequentially photographed with different illumination conditions, and the illumination condition is set. Can be determined.

  In the image measuring instrument according to an eleventh aspect of the present invention, in addition to the above configuration, the dimension calculating unit extracts the edge of the measurement target portion from the plurality of acquired workpiece images, and the workpiece image displaying unit acquires A plurality of the above-mentioned work images displayed in a list, the extracted edges are displayed on the corresponding work images, and the work image selecting means designates a work image designated by the user from among the displayed work images Configured to select.

  According to such a configuration, it is possible to compare work images displayed in a list and arbitrarily select a work image having an illumination condition suitable for measuring a measurement target location by using an edge displayed on the work image. it can.

  An image measuring instrument according to a twelfth aspect of the present invention is the image measuring device according to the present invention, wherein, in addition to the above-described configuration, the dimension calculating means determines the dimension of the measurement target location based on the edges extracted from the measurement target location for the plurality of acquired workpiece images. In other words, the workpiece image display means is configured to display the determined dimension on the corresponding workpiece image.

  According to such a configuration, it is possible to compare the work images displayed in a list and select a work image having an illumination condition suitable for measuring the measurement target location based on the edges and dimensions displayed on the work image. it can.

  An image measuring instrument according to a thirteenth aspect of the present invention is configured so that, in addition to the above-described configuration, when the work image display means extracts two or more edges from the work image photographed under the same illumination conditions, these edges are extracted. Is displayed on the corresponding work image, and further comprises an edge selection means for selecting any one of the plurality of edges displayed on the work image based on a user operation. According to such a configuration, it is possible to select a work image and an appropriate edge under illumination conditions suitable for measuring a measurement target location by using a plurality of edges displayed on the work image.

  An image measuring instrument according to a fourteenth aspect of the present invention, in addition to the above configuration, performs edge extraction based on an edge designated by a user from a plurality of edges extracted from the workpiece image photographed under the same illumination conditions. Edge extraction parameter adjustment means for adjusting the edge extraction parameter for this purpose. According to such a configuration, since the edge extraction parameter is automatically adjusted to a value suitable for extracting a desired edge from the measurement target location, the stability of edge extraction can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is not an expert, the image measuring device which can fully exhibit the performance of an apparatus can be provided. In particular, it is possible to provide an image measuring device that can automatically adjust illumination conditions such as the type of illumination device and the illumination light irradiation position according to the measurement target location by simply selecting the displayed work image. it can. In addition, it is possible to provide an image measuring device capable of suppressing erroneous extraction of the texture of the workpiece surface as an edge in dimension measurement using epi-illumination.

It is the perspective view which showed one structural example of the image measuring device 1 by embodiment of this invention. It is explanatory drawing which showed typically the structural example of the measurement unit 10 of FIG. 1, and the cut surface at the time of cut | disconnecting the measurement unit 10 by the perpendicular | vertical surface parallel to an imaging | photography axis | shaft is shown. It is the block diagram which showed an example of the function structure in the control unit 20 of FIG. FIG. 2 is a diagram showing an example of the operation of the image measuring device 1 of FIG. 1, and shows a measurement setting screen 40 displayed on the display device 11 of the measurement unit 10. It is the figure which showed an example of operation | movement of the image measuring device 1 of FIG. 1, and the four workpiece | work images 2 image | photographed on mutually different illumination conditions are shown. It is the figure which showed an example of operation | movement of the image measuring device 1 of FIG. 1, and the four workpiece | work images 2 image | photographed on mutually different illumination conditions are shown. FIG. 2 is a diagram showing an example of the operation of the image measuring device 1 in FIG. 1, and shows an edge extraction setting screen 50 displayed on the display device 11. 3 is a flowchart showing an example of an operation at the time of measurement setting in the image measuring device 1 of FIG. 1. 3 is a flowchart showing an example of an operation at the time of dimension measurement in the image measuring device 1 of FIG. 1.

<Image measuring device 1>
FIG. 1 is a perspective view showing a configuration example of an image measuring instrument 1 according to an embodiment of the present invention. The image measuring instrument 1 is a dimension measuring apparatus that extracts an edge in a workpiece image obtained by photographing a workpiece and measures the dimension of the workpiece, and includes a measuring unit 10, a control unit 20, a keyboard 31, and a mouse 32. The workpiece is a measurement object whose shape and dimensions are measured.

  The measurement unit 10 includes a display device 11, a movable stage 12, an XY adjustment knob 14 a, a Z adjustment knob 14 b, a power switch 15, and an execution button 16, and irradiates the work on the movable stage 12 with detection light composed of visible light, The transmitted light or reflected light is received to generate a work image. The workpiece is placed in the detection area 13 of the movable stage 12. Further, the measurement unit 10 displays the work image on the display screen 11 a of the display device 11.

  The display device 11 is a display device that displays work images and measurement results on the display screen 11a. The movable stage 12 is a mounting table for mounting a work, and is provided with a detection area 13 through which detection light is transmitted. The detection area 13 is a circular area made of transparent glass. The movable stage 12 can be moved in the Z-axis direction parallel to the shooting axis of the camera and in the X-axis direction and the Y-axis direction perpendicular to the shooting axis.

  The XY adjustment knob 14a is an operation unit for adjusting the position in the X-axis direction and the Y-axis direction by moving the movable stage 12 in the X-axis direction or the Y-axis direction. The Z adjustment knob 14b is an operation unit for adjusting the position in the Z-axis direction by moving the movable stage 12 in the Z-axis direction. The power switch 15 is an operation unit for switching the main power supply of the measurement unit 10 and the control unit 20 between an on state and an off state. The execution button 16 is an operation unit for starting dimension measurement.

  The control unit 20 is a controller unit that controls photographing and screen display by the measurement unit 10, analyzes a work image, and measures the dimensions of the work, and is connected to a keyboard 31 and a mouse 32. After the power is turned on, if the work is placed in the detection area 13 and the execution button 16 is operated, the dimensions of the work are automatically measured.

<Measurement unit 10>
FIG. 2 is an explanatory view schematically showing a configuration example of the measurement unit 10 of FIG. 1, and shows a cut surface when the measurement unit 10 is cut by a vertical plane parallel to the imaging axis. The measurement unit 10 includes a display device 11, a movable stage 12, a housing 100, a stage adjustment unit 101, a lens barrel unit 102, an illumination position adjustment unit 103, cameras 110 and 120, a coaxial incident illumination unit 130, a ring illumination unit 140, and The transmitted illumination unit 150 is used.

  The stage adjustment unit 101, the lens barrel unit 102, the cameras 110 and 120, the coaxial incident illumination unit 130, and the transmission illumination unit 150 are disposed in the housing 100. The stage adjustment unit 101 moves the movable stage 12 in the X, Y, or Z axis direction based on the drive signal from the control unit 20 to adjust the position of the workpiece in the X, Y, and Z axis directions.

  The camera 110 is an imaging device with a low imaging magnification, and includes an imaging element 111, an imaging lens 112, a diaphragm plate 113, and a light receiving lens 114. The image sensor 111 receives the detection light and generates a work image. The image sensor 111 is disposed with the light receiving surface facing downward. The imaging lens 112 is an optical member that images the detection light on the image sensor 111. The diaphragm plate 113 is an optical diaphragm that limits the amount of transmitted detection light, and is disposed between the imaging lens 112 and the light receiving lens 114. The light receiving lens 114 is an optical member that condenses the detection light from the workpiece, and is disposed to face the movable stage 12. The imaging lens 112, the diaphragm plate 113, and the light receiving lens 114 are arranged around a central axis extending in the vertical direction.

  The camera 120 is an imaging device having a high shooting magnification, and includes an imaging device 121, an imaging lens 122, a diaphragm plate 123, a half mirror 124, and a light receiving lens 114. The image sensor 121 receives the detection light and generates a work image. The image sensor 121 is disposed with the light receiving surface facing in the horizontal direction. The imaging lens 122 is an optical member that images the detection light on the image sensor 121. The diaphragm plate 123 is an optical diaphragm that limits the amount of detection light transmitted, and is disposed between the imaging lens 122 and the half mirror 124. The light receiving lens 114 is common to the camera 110. The detection light transmitted through the light receiving lens 114 is bent in the horizontal direction by the half mirror 124 and forms an image on the image sensor 121 through the diaphragm plate 123 and the imaging lens 122.

  For the imaging elements 111 and 121, an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) is used. As the light receiving lens 114, a telecentric lens having a property that the size of the image is not changed even if the position in the vertical direction, that is, the photographing axis direction is changed, is used.

  The coaxial epi-illumination unit 130 is an epi-illumination device that irradiates the workpiece on the movable stage 12 with illumination light from above, and makes the optical axis of the illumination light coincide with the imaging axis. The coaxial incident illumination unit 130 includes a light source 131 arranged in the horizontal direction and a half mirror 132 that bends the illumination light emitted from the light source 131 downward.

  The imaging lenses 112 and 122, the diaphragm plates 113 and 123, the half mirrors 124 and 132, and the light receiving lens 114 are disposed in the lens barrel portion 102.

  The transmission illumination unit 150 is a transmission illumination device that irradiates the work on the movable stage 12 with illumination light from below, and includes a light source 151, a mirror 152, and a condenser lens 153. The light source 151 is arranged in the horizontal direction. The illumination light emitted from the light source 151 is reflected by the mirror 152 and emitted through the condenser lens 153. The illumination light is transmitted through the movable stage 12, a part of the transmitted light is blocked by the work, and the other part is incident on the light receiving lens 114.

  The ring illumination unit 140 is an epi-illumination device that irradiates the workpiece on the movable stage 12 with illumination light from above or from the side, and has a ring shape that surrounds the imaging axes of the cameras 110 and 120. The ring illumination unit 140 includes a diffuse illumination device 141 that irradiates the workpiece on the movable stage 12 from above or from the side, and a side illumination device 142 that illuminates the workpiece on the movable stage 12 from the side. Is an illuminating device arranged coaxially.

  The diffuse illumination device 141 includes a ring-shaped light source that surrounds the imaging axes of the cameras 110 and 120. This light source can be turned on every two or more blocks divided in the circumferential direction. The side illuminating device 142 can irradiate parallel light or illumination light having a divergence angle close to parallel light to illuminate the periphery of the workpiece from the side.

  An LED (light emitting diode) or a halogen lamp is used as a light source of the illumination units 130 to 150. The illumination position adjustment unit 103 is a relative position adjustment unit that adjusts the relative position of the ring illumination unit 140 with respect to the movable stage 12 by moving the ring illumination unit 140 in the imaging axis direction. As a method for illuminating the workpiece, one of transmission illumination, ring illumination, and coaxial epi-illumination can be selected.

<Control unit 20>
FIG. 3 is a block diagram showing an example of a functional configuration in the control unit 20 of FIG. The control unit 20 includes an illumination condition storage unit 21, an imaging control unit 22, a work image storage unit 23, a measurement target location specifying unit 24, a measurement setting storage unit 25, a work image display unit 26, a work image selection unit 27, and an illumination condition. The determination unit 28, the dimension calculation unit 29, the edge extraction parameter adjustment unit 30, and the edge selection unit 33 are configured.

  The illumination condition storage unit 21 holds two or more illumination conditions registered in advance. Here, it is assumed that two or more illumination conditions are fixed values. Illumination conditions include illumination type, illumination position, lighting position, irradiation intensity, and combinations thereof. The illumination type is a type of illumination device, and is specified from four types of coaxial epi-illumination, diffuse illumination, side illumination, and transmitted illumination. The illumination position is a relative position of the ring illumination unit 140 with respect to the movable stage 12, and is specified within a predetermined range. By adjusting the illumination position, the illumination angle of the illumination light can be changed. The lighting position is the position of the block to be lit in the diffuse lighting device 141, and is specified from two or more lighting patterns. The irradiation intensity is the emission intensity of the lighting device and is specified within a predetermined range.

  The imaging control unit 22 controls the cameras 110 and 120, the illumination position adjustment unit 103, and the illumination units 130 to 150 based on a user operation, acquires a work image from the camera 110 or 120, and stores it in the work image storage unit 23. Store.

  The measurement target location specifying unit 24 specifies the measurement target location for the work image based on a user operation. For example, the measurement target location designating unit 24 designates an area on the work image photographed by irradiating the diffused light from the diffuse illumination device 141 as the measurement target location. By using a work image taken by irradiating diffused light, it is possible to designate a measurement target location while confirming the entire image of the work. In the measurement setting storage unit 25, position information and measurement type indicating a measurement target location are held as measurement setting information.

  In addition, as a specific method of specifying the measurement target portion, a method of moving the mouse cursor near the edge to be extracted and performing a click operation, and a touch panel function for the display device 11 to detect a touch operation on the display screen 11a are provided. If there is, there is a method of tracing the vicinity of the edge to be extracted. Further, there are a method for specifying the start point and end point of the edge to be extracted, and a method for covering the edge extraction range with a rectangle or a circle, and these methods can be arbitrarily selected. Further, the geometric figure to be extracted can be selected from straight lines, circles, arcs, and arbitrary curves.

  The imaging control unit 22 acquires two or more work images that are sequentially photographed with different illumination conditions for a plurality of illumination conditions registered in advance in the illumination condition storage unit 21. The two or more workpiece images are workpiece images obtained by photographing the same workpiece. The work image display unit 26 displays a plurality of work images acquired by the imaging control unit 22 on the display device 11 in order to determine an illumination condition. The work image selection unit 27 selects any one of the work images displayed by the work image display unit 26 in order to determine the illumination condition. The illumination condition determination unit 28 determines the illumination condition based on the work image selected by the work image selection unit 27.

  The illumination condition determined by the illumination condition determination unit 28 is stored as measurement setting information in the measurement setting storage unit 25 in association with the measurement target location. The imaging control unit 22 acquires a work image that is captured under the illumination condition determined by the illumination condition determination unit 28. The dimension calculation unit 29 extracts the edge of the measurement target location based on the work image photographed under the illumination condition determined by the illumination condition determination unit 28, and obtains the dimension of the measurement target location based on the extracted edge. , Output the measurement results.

  In the measurement setting storage unit 25, two or more measurement target locations designated for the same workpiece image by the measurement target location designation unit 24, and the illumination determined by the illumination condition determination unit 28 for each of these measurement target locations Conditions are stored as measurement setting information.

  The imaging control unit 22 repeats acquiring a workpiece image photographed under the illumination condition held as the measurement setting information in the continuous measurement in which the measurement setting information is specified while changing the measurement target portion. In addition, the dimension calculation unit 29 performs edge extraction for each measurement target location held as measurement setting information for a plurality of workpiece images acquired in continuous measurement.

  In continuous measurement in which measurement setting information is specified, a workpiece is photographed under illumination conditions suitable for measuring a measurement target portion, and edge extraction is performed on the obtained workpiece image. For this reason, even if the shape or material of the workpiece changes, it is possible to perform stable dimension measurement only by specifying measurement setting information.

  The dimension calculation unit 29 obtains a dimension between edges extracted from two or more workpiece images having different illumination conditions and positions of measurement target positions. With this configuration, the dimension between the edges is obtained using two or more workpiece images photographed under illumination conditions suitable for measuring the measurement target location, so that the dimension between the edges can be accurately identified. Can do.

  Measurement results such as dimension values are displayed on the display device 11. Further, the control unit 20 creates measurement setting data for continuous measurement for continuously measuring the workpiece. The measurement setting data includes positioning information, measurement setting information, and information indicating design values and tolerances for each measurement target location. The positioning information is information for analyzing the workpiece image and detecting the position and posture of the workpiece.

  The dimension calculation unit 29 extracts the edge of the measurement target part from the plurality of workpiece images acquired by the imaging control unit 22 to determine the illumination condition, and obtains the dimension of the measurement target part based on the extracted edge. . As an edge extraction method for determining the illumination condition, there are a method for obtaining one likely edge using a predetermined edge extraction parameter and a method for calculating two or more edges as candidates.

  When calculating two or more edges as candidates, an edge point is extracted from an image region designated by the user as a measurement target location or an enlarged region obtained by enlarging the image region by several pixels, and two or more extracted edge points are extracted. Group into groups. For edge point grouping, edge point position information is used to classify edge points that are close to each other into the same group, or based on edge characteristics, that is, edge direction or strength. There is a way to group points. Also, the edge points can be grouped according to the matching degree with respect to the geometric figure designated as the edge extraction target.

  The work image display unit 26 displays a list of a plurality of work images acquired by the imaging control unit 22 in order to determine the illumination condition, and the workpiece corresponding to the extracted edge of the measurement target portion and the obtained dimension. Display on the image. In the list display of work images, for example, the display screen 11a is divided into two or more display areas, and a plurality of work images photographed under different illumination conditions are displayed in each display area. In addition, a thumbnail image obtained by reducing the work image is created, and two or more thumbnail images are displayed in each display area. If any one of the thumbnail images is selected, the original work image corresponding to the thumbnail image is displayed. Is done.

  The work image selection unit 27 selects a work image designated by the user from the list of work images displayed. The workpiece images displayed in a list can be compared, and a workpiece image having an illumination condition suitable for measuring the measurement target location can be arbitrarily selected based on the edges and dimensions displayed on the workpiece image. Moreover, it is possible to automatically adjust the illumination conditions such as the type of illumination device and the illumination position in accordance with the measurement target location by simply selecting the displayed work image.

  The work image selection unit 27 selects any one of the displayed work images for determining the illumination condition based on the luminance change in the measurement target portion. For example, the contrast in the vicinity of the edge of the measurement target location is obtained, and a work image optimal for edge extraction is selected based on the obtained contrast. If comprised in this way, the illumination condition is determined by automatically selecting a workpiece image suitable for measuring the measurement target location from two or more workpiece images photographed sequentially with different illumination conditions. can do.

  When two or more edges are extracted from a work image taken under the same illumination condition, the work image display unit 26 displays these edges on the corresponding work image. If comprised in this way, the workpiece | work image of a lighting condition suitable for measuring a measurement object location and a suitable edge can be selected with the some edge displayed on the workpiece | work image. The edge selection unit 33 selects any one of a plurality of edges displayed on the work image based on a user operation.

  The edge extraction parameter adjustment unit 30 adjusts an edge extraction parameter for edge extraction based on an edge designated by the user from among a plurality of edges extracted from a work image photographed under the same illumination condition. The edge extraction parameters include parameters indicating edge strength, scan direction, edge direction, and priority designation.

  The edge strength is a differential value of luminance in the luminance distribution composed of the pixel position in the linear direction and the luminance value of each pixel, and an upper limit value and a lower limit value can be designated as the edge strength parameter. The edge intensity is higher as the pixel position has a sharp change in luminance. At pixel positions with low edge strength, noise components may be erroneously extracted as edges. However, by extracting only edge points within the range specified by the edge strength parameter, stable edge extraction becomes possible. .

  The scan direction is the search direction when searching for an edge, and as a scan direction parameter, either the left direction or the right direction, or the upward direction or the downward direction, as viewed from the user, with respect to the measurement target location Alternatively, no designation can be selected. The edge direction is a changing direction when the luminance value changes, and when the luminance distribution is scanned in the scanning direction, whether the luminance value changes from the low luminance side to the high luminance side as an edge direction parameter, or the luminance It is possible to select whether the value changes from the high luminance side to the low luminance side or not specified. Usually, since the edge points constituting a specific edge are in the same direction, it is possible to suppress erroneous extraction of edges in the reverse direction by designating the edge direction.

  Priority designation is to designate which edge point is to be adopted when two or more edge points satisfying the edge extraction conditions specified by the parameters of edge strength, scan direction and edge direction are detected on the same straight line. It is. For example, when scanning the luminance distribution in the scanning direction, whether to use the edge point detected first or the edge point closest to the center or center line of the measurement target location depends on the priority designation parameter. It is specified. Further, it is possible to designate the priority distribution parameter to scan the luminance distribution from the side with less noise component and adopt the edge point detected first. Such priority designation can improve the stability of edge extraction.

  By automatically adjusting the above-described edge extraction parameter to a value suitable for extracting a desired edge from a measurement target location, the stability of edge extraction can be improved. The edge extraction parameter is adjusted by obtaining the edge intensity distribution and the edge direction for the edge points constituting the edge designated by the user.

<Measurement setting screen 40>
FIG. 4 is a diagram illustrating an example of the operation of the image measuring device 1 of FIG. 1, and shows a measurement setting screen 40 displayed on the display device 11 of the measurement unit 10. The measurement setting screen 40 is an editing screen for creating measurement setting data, and includes a preview area 41, a search execution button 42, a thumbnail display area 43, and an illumination condition display area 44.

  In the preview area 41, the photographed work image 2 and the work image 2 corresponding to the thumbnail image selected in the thumbnail display area 43 are displayed. The search execution button 42 is an operation icon for executing continuous shooting for sequentially shooting the workpiece on the movable stage 12 while changing the illumination condition.

  The thumbnail display area 43 displays a list of a plurality of thumbnail images created from the work image 2 acquired by continuous shooting. The thumbnail image is a reduced image obtained by reducing the work image 2 by pixel thinning processing or the like. In this example, three thumbnail images are displayed in the thumbnail display area 43, and the edge 3 extracted from the measurement target portion is displayed on the thumbnail image.

  Any one of the thumbnail images in the thumbnail display area 43 can be arbitrarily selected, and the work image 2 corresponding to the selected thumbnail image is displayed in the preview area 41. Each time the thumbnail image to be selected is changed, the work image in the preview area 41 is switched. The selected thumbnail image is added with a colored rectangular frame and can be easily identified. In the illumination condition display area 44, an illumination condition associated with the selected thumbnail image is displayed. For example, the selected illumination unit is the diffuse illumination device 141 of the ring illumination unit 140, and the position of the ring illumination unit 140 in the Z-axis direction is the upper limit value, that is, 0 mm.

  The user confirms the edges on the thumbnail images displayed as a list in the thumbnail display area 43 and the edges on the work image 2 displayed in the preview area 41, so that the work image 2 photographed under an appropriate illumination condition is displayed. You can choose.

  FIG. 5 is a diagram showing an example of the operation of the image measuring device 1 in FIG. 1, and shows four work images 2 photographed under different illumination conditions. This figure shows a case where four work images 2 photographed under different illumination conditions are displayed as a list in the preview area 41 of the measurement setting screen 40. Moreover, in this figure, the through-hole formed in the center part of the workpiece | work is designated as a measurement object location.

  In the preview area 41, the work image 2 photographed under the illumination conditions “diffuse illumination a”, “diffuse illumination b”, “side illumination”, and “transmission illumination” is displayed. In the illumination condition “diffuse illumination a”, the diffuse illumination device 141 of the ring illumination unit 140 is used as an illumination device, and when the illumination light is irradiated from above, the workpiece image 2 is received by receiving the reflected light from the workpiece. Generated. Under the illumination condition “diffuse illumination b”, the diffused illumination device 141 is moved in the Z-axis direction so that illumination light is irradiated obliquely from above, for example, from 45 °.

  In the illumination condition “side illumination”, the side illumination device 142 of the ring illumination unit 140 is used as an illumination device. When illumination light is irradiated from the side, the workpiece image is received by receiving reflected light from the workpiece. 2 is generated. Under the illumination condition “transmission illumination”, the transmission illumination unit 150 is used as an illumination device, and when the illumination light is irradiated from below, the workpiece image 2 is generated by receiving the transmission light transmitted through the workpiece.

  Each workpiece image 2 displays a dimension value of a measurement target portion. By checking the dimension value displayed on the work image 2, the user can easily identify the work image 2 photographed under optimum illumination conditions. In this example, the design value of the measurement target location is 3.000, and the dimension value “3.000” is displayed for the work image 2 photographed by the transmitted illumination. It turns out that it is a condition.

  FIG. 6 is a diagram showing an example of the operation of the image measuring device 1 in FIG. 1, and shows four work images 2 photographed under different illumination conditions. In this figure, a circular step formed on the workpiece surface is designated as a measurement target location. In this example, the design value of the measurement target portion is 10.000, and the dimension value “10.000” is displayed for the work image 2 photographed by the diffuse illumination a. Therefore, the diffuse illumination a is optimal. It can be seen that the lighting conditions are appropriate.

<Edge extraction setting screen 50>
FIG. 7 is a diagram showing an example of the operation of the image measuring device 1 of FIG. 1, and shows an edge extraction setting screen 50 displayed on the display device 11. This edge extraction setting screen 50 is an operation screen for designating or automatically adjusting an edge extraction parameter, and includes an automatic adjustment button 51, a reset button 52, a scan direction input field 53, an edge direction input field 54, and priority designation. The input field 55 is configured.

  The automatic adjustment button 51 is an operation icon for executing automatic adjustment of edge extraction parameters. The reset button 52 is an operation icon for resetting the current edge extraction parameter and returning the edge extraction parameter to a predetermined initial value or default value. The scan direction input field 53 is an input field for specifying a scan direction parameter. The edge direction input field 54 is an input field for specifying an edge direction parameter. The priority designation input field 55 is an input field for designating a priority designation parameter.

  As the edge strength parameter, either automatic designation or threshold designation for individually designating an upper limit value and a lower limit value can be selected. In the automatic specification of the edge strength parameter, an upper limit value and a lower limit value appropriate for extracting the edge of the measurement target portion are automatically specified. In the threshold specification of the edge strength parameter, the user can arbitrarily specify an upper limit value or a lower limit value within a predetermined range.

  Steps S101 to S112 in FIG. 8 are flowcharts showing an example of an operation at the time of measurement setting in the image measuring device 1 in FIG. First, the control unit 20 accepts a user operation, and if a measurement target location is specified for the work image (step S101), the illumination condition is selected and the work on the movable stage 12 is photographed to obtain the work image. (Steps S102 and S103). Next, the control unit 20 extracts the edge of the measurement target location based on the acquired workpiece image, and calculates the dimension value of the measurement target location based on the extracted edge (steps S104 and S105).

  The control unit 20 repeats the processing procedure from step S102 to step S105 while changing the illumination condition (step S106). If workpiece images are acquired for all the illumination conditions registered in advance, the acquired workpiece image is obtained. Are displayed as a list on the display device 11 (step S107).

  Next, the control unit 20 accepts a user operation, and if any one of the work images being displayed in the list is selected (step S108), the control unit 20 determines the illumination condition based on the selected work image, and sets the measurement settings. Information is stored (steps S109 and S110).

  If there are other measurement target locations, the control unit 20 repeats the processing procedure from step S101 to step S110 (step S111), and creates measurement setting data if the illumination conditions are determined for all measurement target locations. This process is then terminated (step S112).

  Steps S201 to S211 in FIG. 9 are flowcharts showing an example of the operation at the time of dimension measurement in the image measuring device 1 in FIG. First, the control unit 20 receives a user operation and selects measurement setting data corresponding to a workpiece to be continuously measured (step S201).

  Next, when the execution button 16 of the measurement unit 10 is operated (Step S202), the control unit 20 reads the measurement target portion held as the measurement setting data (Step S203), specifies the illumination condition, and moves the movable stage. 12 is photographed to obtain a work image (steps S204 and S205).

  The control unit 20 extracts the edge of the measurement target location based on the acquired workpiece image (step S206), and calculates the dimension value of the measurement target location based on the extracted edge (step S207). The control unit 20 repeats the processing procedure from step S203 to step S207 if there are other measurement target locations (step S208), and measures the edges and dimension values when the dimension measurement is completed for all measurement target locations. The result is displayed on the display device 11 (step S209), and the measurement result is stored (step S210).

  If there is another workpiece to be continuously measured, the control unit 20 repeats the processing procedure after step S202, and if there is no other workpiece to be continuously measured, the control unit 20 ends this processing (step 211).

  According to the present embodiment, since the lighting condition is determined by selecting any one of the displayed work images 2, the performance of the apparatus can be sufficiently exhibited even if it is not an expert. it can. In particular, it is possible to automatically adjust the illumination conditions such as the type of the illumination device and the irradiation position of the illumination light according to the measurement target location simply by selecting the displayed work image 2. In addition, since the illumination condition is automatically adjusted according to the measurement target location, it is possible to suppress erroneous extraction of the texture on the workpiece surface as an edge in dimension measurement using epi-illumination.

  In this embodiment, an example in which two or more illumination conditions registered in advance are fixed values has been described. However, the present invention specifies two or more illumination conditions registered in advance based on a user operation. There may be provided lighting condition designating means.

  In the present embodiment, an example in which the relative position of the ring illumination unit 140 with respect to the movable stage 12 is adjusted by the illumination position adjustment unit 103 adjusting the position of the ring illumination unit 140 in the Z-axis direction will be described. However, the present invention does not limit the configuration of the relative position adjusting means. For example, the relative position of the ring illumination unit 140 with respect to the movable stage 12 is adjusted by moving the movable stage 12 in the Z-axis direction or by moving the movable stage 12 and the ring illumination unit 140 in the Z-axis direction. It may be a configuration.

DESCRIPTION OF SYMBOLS 1 Image measuring device 10 Measurement unit 11 Display apparatus 11a Display screen 12 Movable stage 14a XY adjustment knob 14b Z adjustment knob 15 Power switch 16 Execution button 100 Case 101 Stage adjustment part 102 Lens barrel part 103 Illumination position adjustment part 110, 120 Camera 130 Coaxial epi-illumination unit 140 Ring illumination unit 141 Diffuse illumination device 142 Side-illumination device 150 Transmission illumination unit 20 Control unit 21 Illumination condition storage unit 22 Imaging control unit 23 Work image storage unit 24 Measurement target location designation unit 25 Measurement setting storage unit 26 Work image display unit 27 Work image selection unit 28 Illumination condition determination unit 29 Dimension calculation unit 30 Edge extraction parameter adjustment unit 31 Keyboard 32 Mouse 40 Measurement setting screen 50 Edge extraction setting screen 2 Work image 3 Edge

Claims (12)

A stage for placing the workpiece;
An illumination device that illuminates the workpiece on the stage;
A camera that shoots the workpiece on the stage and generates a workpiece image;
Based on a user operation, with respect to the work image, a measurement target location specifying means for specifying a measurement target location;
Illumination condition storage means for holding two or more illumination conditions;
Imaging control means for controlling the camera and the illuminating device, and acquiring two or more workpiece images taken sequentially while varying the illumination conditions;
Work image display means for displaying a plurality of the obtained work images;
Workpiece image selection means for selecting any one of the displayed workpiece images;
Illumination condition determination means for determining the illumination condition based on the selected work image;
Based on the work image photographed under the determined illumination conditions, the edge of the measurement target location is extracted, and based on the extracted edge, the size calculation means for obtaining the dimension of the measurement target location, and
The dimension calculation means extracts the edge of the measurement target location for the plurality of acquired work images,
The workpiece image display means displays a list of the plurality of acquired workpiece images, displays the dimension value calculated based on the extracted edge on the corresponding workpiece image,
The image measuring instrument, wherein the workpiece image selecting means selects a workpiece image designated by a user from among the workpiece images displayed in a list. Two or more measurement target locations specified for the same workpiece image by the measurement target location specifying means and the illumination conditions determined by the illumination condition determination means for each measurement target location are stored as measurement setting information. Measurement setting storage means for
In the measurement setting storage means, the illumination condition is held in association with the measurement target location,
The imaging control unit repeatedly obtains a work image photographed under the illumination condition held as the measurement setting information in continuous measurement in which the measurement setting information is specified while changing the measurement target portion. ,
2. The image according to claim 1, wherein the dimension calculation unit performs edge extraction for each of the measurement target portions held as the measurement setting information, with respect to a plurality of workpiece images acquired in the continuous measurement. Measuring instrument.   The image measuring device according to claim 2, wherein the dimension calculating unit obtains a dimension between edges extracted from two or more workpiece images having different illumination conditions and positions of the measurement target portions. The illumination device includes a diffusion illumination device that irradiates the workpiece on the stage with diffused light from above, and a transmission illumination device that irradiates the workpiece on the stage with illumination light from below,
The image measuring device according to claim 1, wherein the illumination condition includes a type of the illumination device.   5. The illumination apparatus according to claim 4, further comprising a side illumination apparatus that irradiates the workpiece on the stage from the side with illumination light composed of parallel light or illumination light having a divergence angle close to parallel light. The image measuring instrument described in 1. As the illuminating device, a ring-shaped light source that surrounds the imaging axis of the camera, and includes a ring illuminating device having a light source that can be turned on every two or more blocks divided in the circumferential direction,
The image measuring device according to claim 1, wherein the illumination condition includes a lighting position of the ring illumination device. A relative position adjusting means for adjusting the relative position of the illumination device with respect to the stage by moving the stage or the illumination device in the direction of the photographing axis of the camera;
The image measuring device according to claim 1, wherein the illumination condition includes the relative position.   The image according to claim 4 or 5, wherein the measurement target location specifying means specifies a region on the work image photographed by irradiating the diffused light of the diffuse illumination device as a measurement target location. Measuring instrument.   The image measuring device according to claim 1, further comprising an illumination condition designating unit that designates the illumination condition based on a user operation.   The image according to claim 1, wherein the work image selection unit selects any one of the displayed work images based on a luminance change in the measurement target portion. Measuring instrument. The work image display means displays two or more edges on the corresponding work image when two or more edges are extracted from the work image photographed under the same illumination condition.
The image measurement according to claim 1, further comprising an edge selection unit that selects any one of a plurality of edges displayed on the workpiece image based on a user operation. vessel.   Edge extraction parameter adjustment means for adjusting an edge extraction parameter for edge extraction based on an edge designated by the user from among a plurality of edges extracted from the work image photographed under the same illumination conditions The image measuring device according to claim 11.