JP2021085772A - Image measuring device - Google Patents

Abstract

To allow a measurement point to be determined automatically, rapidly, and with a high reproductivity by simple operations.SOLUTION: An image measuring device includes: an acquisition unit 33e for acquiring the position of a measurement point specified on a workpiece image displayed in a display unit and illuminance information of peripheral pixels including the measurement point; a position/illuminance information storage unit 35b for storing the position of the measurement point and the illuminance information; and a processing unit 33f for acquiring an illuminance distribution of the workpiece image generated in an operation and determining a measurement point on a newly generated workpiece image on the basis of the position of the measurement point and the illuminance information.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image measuring device capable of measuring two-dimensional dimensions using an image obtained by capturing an image of a work.

Conventionally, as a device for measuring the dimensions of a work, the work placed on a mounting table is illuminated by an illuminating device, the work in the illuminated state is imaged by an imaging device, and the dimensions of each part are measured using the obtained work image. A measurable image measuring device is known (see, for example, Patent Document 1).

In the image measuring apparatus of Patent Document 1, it is possible to acquire the brightness value of each pixel in the work image obtained by imaging the work, and extract the point where the change in brightness is large as the measurement point indicating the outline of the work. You can do it. By using such an image measuring device, the user can easily acquire the dimensions between these measuring points by, for example, selecting two measuring points.

JP-A-2010-169584

However, when the work in the state of being illuminated from above is imaged by the imaging device, the shadow of the work may be reflected in the acquired work image. In such a case, the work is affected by the reflected shadow. The change in brightness near the contour in the image becomes small, and it may not be extracted well as a measurement point. In addition, the contour of the work is often rounded, and even when such a work is imaged, the change in brightness near the contour in the work image becomes small, and it cannot be extracted well as a measurement point. There is.

When the measurement points could not be extracted, the user was forced to manually specify the measurement points in the work image one by one to measure the work. Since the user visually performs the work of designating the measurement points, there is a problem that it is complicated for the user and the reproducibility is low when a plurality of works of the same type are continuously measured.

The present invention has been made in view of the above points, and an object of the present invention is to automatically and at high speed as a measurement point a portion that has not been extracted as a measurement point by the prior art, although it is a simple operation. Moreover, it is to make it possible to make a decision with high reproducibility.

In order to achieve the above object, the first invention mounts the work in an image measuring device that measures a two-dimensional dimension of the work with reference to a measurement point in the work image acquired by imaging the work. A mounting table to be placed, an illuminating unit for irradiating the work mounted on the above-mentioned pedestal with light from above, and light emitted from the work by the illuminating unit and reflected on the surface of the work. An imaging unit for receiving light and generating a work image, a display unit for displaying the work image generated by the imaging unit, and a display unit displayed on the display unit at the time of setting the image measuring device. Acquires an operation unit for designating and operating an arbitrary position on the work image as the measurement point, the position of the measurement point designated by the operation unit, and brightness information of peripheral pixels including the measurement point. An image measuring device that measures a two-dimensional dimension of a work different from the work at the time of setting, the acquisition unit, the storage unit that stores the position of the measurement point acquired by the acquisition unit, and the brightness information. At the time of operation, the brightness distribution of the work image newly generated by the imaging unit is acquired, and the newly generated work is based on the position of the measurement point stored in the storage unit and the brightness information. It is provided with a processing unit that executes a process of determining a measurement point on the image.

According to this configuration, when the change in the brightness near the contour in the work image generated at the time of setting the image measuring device is small and the measurement point cannot be successfully extracted only by the information based on the change in the brightness, the work image is selected. By displaying the image on the display unit, the user can specify an arbitrary position on the work image as a measurement point by using the operation unit. Since the user knows the shape of the actual work, even if the change in brightness near the contour in the work image displayed on the display unit is small, the point to be measured can be specified almost accurately. The point specified by the user becomes the measurement point desired by the user, and the position of the measurement point and the luminance information of the peripheral pixels including the measurement point are stored in the storage unit.

When operating the image measuring device, that is, when measuring the two-dimensional dimension of another work different from the work at the time of setting, the processing unit acquires and stores the brightness distribution of the work image newly generated by the imaging unit. The position of the measurement point and the brightness information stored in the unit are read, and the measurement point is determined on the newly generated work image based on the information.

That is, if the position is fixed, the brightness information of the peripheral pixels including the measurement point at a certain position does not change so much between the same type of workpieces and is almost the same. Therefore, the position of the measurement point and the peripheral pixels thereof Based on the brightness information of, it is possible to find a measurement point at a position similar to the measurement point specified at the time of setting on a new work image with high accuracy. Since this process is automatically executed in the image measuring device, the user's work is not complicated and is executed at high speed.

The second invention is characterized in that the acquisition unit determines a line segment passing through the measurement point designated by the operation unit and acquires the luminance information of the pixel located on the line segment.

According to this configuration, by acquiring the luminance information of the pixels on the line segment defined so as to pass through the measurement point, it is possible to surely acquire the luminance information of the peripheral pixels including the measurement point.

A third aspect of the invention is characterized in that the acquisition unit is configured to generate a luminance profile of pixels located on the line segment.

According to this configuration, it is possible to acquire in detail the change in the brightness of the pixels on the line segment defined so as to pass through the measurement point. At this time, the line segment may be a line segment composed of pixels arranged in one dimension, or may be a line segment composed of pixels arranged in two dimensions, that is, a line segment having a certain width.

In the fourth invention, the operation unit is configured to be able to specify and operate a plurality of the measurement points, and when the acquisition unit draws a measurement line connecting the measurement points designated by the operation unit, the measurement is performed. Each point is characterized in that the line segment extending so as to intersect the measurement line is defined, the brightness profile of the pixel located on each line segment is generated, and a plurality of brightness profiles are acquired. To do.

According to this configuration, by designating a plurality of measurement points, it is possible to draw a measurement line connecting these measurement points. If a line segment extending so as to intersect the measurement line is determined for each measurement point, a plurality of line segments can be obtained, and by generating a brightness profile of pixels located on these line segments, a plurality of brightness can be obtained. Since the profile is acquired, it is possible to sufficiently obtain the luminance information of the peripheral pixels of the measurement point.

A fifth aspect of the present invention is characterized in that the acquisition unit uses a master profile including a brightness profile obtained by averaging a plurality of the brightness profiles as brightness information of peripheral pixels.

According to this configuration, it is possible to acquire a wide range of luminance profiles in the area including the measurement line.

A sixth aspect of the present invention is characterized in that the acquisition unit uses a master profile composed of an averaged edge profile as brightness information of peripheral pixels after differentiating a plurality of the brightness profiles.

According to this configuration, the edge profile of the work can be obtained by differentiating the brightness profile and obtaining the absolute value.

In the seventh invention, the processing unit sets a seek line in the newly generated work image by matching the work image generated at the time of the setting with the newly generated work image. It is characterized in that the measurement point is determined by a normalized correlation between the luminance profile on the seek line and the master profile.

According to this configuration, the measurement point is detected in the newly generated work image by the normalization correlation between the brightness profile on the seek line set in the newly generated work image and the master profile acquired at the time of setting. Therefore, the position of the measurement point becomes accurate.

In the eighth aspect of the present invention, when a plurality of the measurement points are detected in the newly generated work image, the processing unit approximates the detected measurement points by the method of least squares to measure the measurement points. It is characterized in that it is configured to determine.

According to this configuration, when the processing unit detects a plurality of measurement points, a plurality of new measurement points can be determined separately from the detected measurement points.

In the ninth aspect of the present invention, the processing unit establishes a measurement line connecting the measurement points detected in the newly generated work image and the new measurement points determined by approximation by the least squares method. It is characterized in that it is configured to generate.

According to this configuration, the measurement line can be displayed in the work image newly generated at the time of operation, and this measurement line becomes the outline of the work.

According to the present invention, by designating an arbitrary position on the work image displayed on the display unit as a measurement point when the image measuring device is set, the position of the designated measurement point and the peripheral pixels including the measurement point are specified. Brightness information and can be obtained. At the time of operation, the brightness distribution of the newly generated work image can be acquired, and the measurement points can be determined on the newly generated work image based on the position and the brightness information of the measurement points acquired at the time of setting. Therefore, the measurement point can be automatically determined at high speed and with high reproducibility while being a simple operation for the user.

It is a figure which shows the whole structure of the image measuring apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the structure of the image measuring apparatus which concerns on embodiment of this invention. It is a block diagram of the image measuring apparatus which concerns on embodiment of this invention. It is a top view of the work. FIG. 4A is a cross-sectional view taken along the line AA in FIG. 4A. It is a figure which shows the example of the image which imaged the work. It is a flowchart which shows an example of the process from the setting mode to the operation mode of an image measuring apparatus. It is a figure which shows the case where an arbitrary area on a master image is designated operation as a measurement point extraction area. It is a figure which shows the case which acquires the brightness change of the measurement point extraction area on a master image. It is a figure which shows the case where the extracted measurement point is superimposed and displayed on the master image. It is a figure which shows the case where the measurement line connecting a plurality of measurements is generated and superposed on the master image. It is a figure which shows the case where the user has designated operation by designating an arbitrary position on a master image as a measurement point. It is a figure which shows the case which the user specified and operated the peripheral area including a measurement point. It is a figure which shows the case where the measurement line connecting a plurality of measurement points specified by a user is generated and superposed on the master image. It is a figure which shows the set seek line. It is a figure which shows the case where two measurement lines are designated. It is a flowchart which shows an example of the generation process of a master edge profile. It is a figure which shows typically the generation process of a master edge profile. It is a flowchart which shows an example of the processing in operation mode. It is a figure which shows an example of an input image. It is a figure which shows how the measurement point extraction area is detected in the input image. It is a figure which shows the case where the measurement line connecting a plurality of measurement points and a plurality of measurement points is detected. It is a figure which shows the case where the seek line is detected. It is a figure explaining the method of determining a measurement point by a normalization correlation of a seek line luminance profile and a master profile. It is a figure which shows the case where the measurement point is detected by the normalization correlation. It is a figure which shows the case where the measurement line is detected by approximating a plurality of measurement points by the least squares method. It is a schematic diagram which shows the state which determined the new measurement point and the measurement line, and performed the measurement of the two-dimensional dimension. It is a flowchart which shows an example of the validity determination process of a master profile.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is essentially merely an example and is not intended to limit the present invention, its application or its use.

FIG. 1 is a diagram showing the overall configuration of the image measuring device 1 according to the embodiment of the present invention, and FIG. 2 is a schematic diagram showing the configuration of the image measuring device 1. As shown in FIG. 1, the image measuring device 1 has a main body portion 2 and a control unit 3, and the image data of the work W acquired by the main body portion 2 is calculated and processed by the control unit 3 to work. Measure the dimensions of each part of W. For example, the image measuring device 1 can measure the two-dimensional dimensions of the work W with reference to the measurement points in the work image acquired by imaging the work W.

(Structure of main body part 2)
As shown in FIG. 1, the main body portion 2 includes a base portion 20 and a stage 21 provided so as to be able to move up and down with respect to the base portion 20. A mounting table 21a made of a member that transmits light is provided in the vicinity of the central portion of the stage 21, and the work W can be mounted on the mounting table 21a. The stage 21 is configured to be movable not only in the ascending / descending direction (Z direction) but also in the horizontal direction (X direction which is the width direction of the main body portion 2 and Y direction which is the depth direction of the main body portion 2). Although the stage 21 can be moved by an electric actuator or the like, the stage 21 may be manually moved by the user.

An operation panel 2a as an example of the operation unit is provided on the front side of the main body portion 2. The operation panel 2a has various switches, buttons, and the like, and is for the user to operate the image measuring device 1 and perform various settings.

The main body portion 2 includes a support arm 22 extending upward from the rear side of the base portion 20, and an imaging execution unit 23 and a display unit 28 supported on the upper side of the support arm 22. The height (position in the Z direction) of the imaging execution unit 23 can be changed by an electric actuator or the like, and can also be changed by the user by operating a dial or the like. The image pickup execution unit 23 is provided with an image pickup unit 24, a light receiving lens unit 25, and the like. By placing the work W on the mounting table 21a and accepting the designation of the desired operation on the operation panel 2a, the work W is imaged by the imaging unit 24 arranged above the work W, and the work W is acquired thereby. The work image, the measurement result of the two-dimensional dimensions of the work W, and the like are displayed on the display unit 28.

As shown in FIG. 2, the main body portion 2 is provided with an epi-illumination unit 26 for irradiating the work W mounted on the mounting table 21a with light from above when the work W is imaged. There is. The epi-illumination unit 26 is attached to the light receiving lens unit 25, and can be configured in a ring shape, for example. The light emitted to the work W by the epi-illumination unit 26 is reflected by the surface of the work W and returns to the light receiving lens unit 25. This makes it possible to image the shape of the work W, the unevenness and pattern of the surface of the work W, and the like.

Further, below the stage 21, a transmission illumination unit 27 that illuminates the work W from below is installed. The transmission illumination unit 27 is composed of at least a light source 27a, a reflection mechanism 27b, and a lens 27c. The light emitted from the light source 27a is reflected by the reflection mechanism 27b toward the stage 21 side, and the lens 27c reflects the light with respect to the stage 21. Converts to parallel light in directions that are substantially orthogonal to each other. As a result, only the light at the position where the work W does not exist can be transmitted through the mounting table 21a and imaged by the imaging unit 24.

The light receiving lens unit 25 includes a light receiving lens 25a, a beam splitter 25b, a high magnification side imaging lens unit 25c, and a low magnification side imaging lens unit 25d. The high-magnification side imaging lens unit 25c is composed of a high-magnification side slit 25e for imaging and a high-magnification side imaging lens 25f, and the low-magnification side imaging lens unit 25d includes a low-magnification side slit 25g for imaging. It is composed of a low magnification side imaging lens 25h. The beam splitter 25b is a prism that splits the light from the light receiving lens 25a in two directions. For example, a cube type or plate type beam splitter can be used. Compared to the plate type, the cube type beam splitter is preferable because the light passing through the beam splitter is not refracted, so that the optical axis does not shift and the alignment adjustment of the branch angle is easy.

In FIG. 2, the light emitted by the epi-illumination unit 26 and reflected by the work W and the light emitted from the transmission illumination unit 27 and transmitted through the mounting table 21a of the stage 21 are transferred to the high-magnification side imaging lens unit 25c and the low-magnification side. An example of guiding to the imaging lens unit 25d is shown. The bidirectional light branched by the beam splitter 25b is directed to both the low magnification side imaging lens unit 25d and the high magnification side imaging lens unit 25c.

The image pickup unit 24 has a high magnification side image pickup unit 24a and a low magnification side image pickup unit 24b. The high-magnification side image pickup unit 24a forms an image of the light guided to the high-magnification side imaging lens unit 25c by an image pickup element 24c such as a CCD or CMOS, and transmits it to the control unit 3 as high-magnification image data. Similarly, the low-magnification side image pickup device 24b forms an image of the light guided to the low-magnification side imaging lens unit 25d by an image pickup element 24d such as a CCD or CMOS, and transmits it to the control unit 3 as low-magnification image data. That is, the imaging unit 24 generates a work image by receiving the light that is irradiated on the work W and reflected on the surface of the work W.

With the configuration of the bifurcated optical system by the light receiving lens 25a and the beam splitter 25b described above, high magnification image data and low magnification image data can be acquired at the same time without mechanically switching the optical system. Both image data can be electronically switched and displayed on one screen, or can be displayed separately on two screens at the same time.

It should be noted that the configuration of the bifurcated optical system by the beam splitter 25b may be omitted, and the high-magnification image data and the low-magnification image data may be acquired by mechanically switching between the high-magnification lens and the low-magnification lens. ..

(Configuration of control unit 3)
FIG. 3 is a block diagram showing a configuration of a control unit 3 of the image measuring device 1 according to the embodiment of the present invention. The control unit 3 can be composed of, for example, a personal computer provided with an operation device such as a keyboard 40 or a mouse 41, which is an example of an operation unit. The control unit 3 of the image measuring device 1 according to the embodiment connects at least a CPU (central processing unit) 33, a RAM 34, a storage device 35 including a hard disk drive, a solid state drive, or the like, a communication device 37, and the above-mentioned hardware. It is composed of an internal bus 38. The CPU 33 is also connected to the operation panel 2a, the keyboard 40, the mouse 41, the image pickup unit 24, and the display unit 28 via the internal bus 38, and the operation status of the operation panel 2a, the keyboard 40, and the mouse 41 can be acquired. At the same time, the image data acquired by the imaging unit 24 can be acquired. Further, the result of calculation in the CPU 33, the image data acquired by the imaging unit 24, and the like can be displayed on the display unit 28.

Since the CPU 33 is connected to each hardware constituting the control unit 3 via the internal bus 38, it controls the operation of the hardware described above and variously according to the computer program stored in the storage device 35. Performs software functions. The details of the functions that can be executed by the CPU 33 will be described later, but the measurement point extraction unit 33a for detecting the contour of the work W, the measurement unit 33b for measuring the two-dimensional dimensions of the work W, and the display unit 28 for measuring the measurement results are displayed. Display control unit 33c, posture / position specifying unit 33d, acquisition unit 33e for acquiring measurement point position and brightness information of peripheral pixels, processing unit 33f for determining measurement points based on measurement point position and brightness information of peripheral pixels. Can be configured by arithmetic processing of the CPU 33. Each of these parts may be configured by a combination of hardware and software, or may be configured by an arithmetic processing device or the like different from the CPU 33.

The RAM 34 is composed of, for example, a volatile memory such as SRAM or SRAM, and a load module is expanded when the computer program is executed to store temporary data or the like generated when the computer program is executed. The storage device 35 includes an image storage unit 35a that stores the master image data and the work image data acquired by the imaging unit 24, a position / brightness information storage unit 35b that stores the position of the measurement point and the brightness information of the peripheral area, which will be described later. It can be configured by a measurement setting storage unit 35c that stores information on geometric dimensions and allowable tolerances between measurement points that the user wants to measure. Although not shown, the storage unit 35 stores a computer program, and can also store measurement results, various setting information, and the like.

The communication device 37 is connected to the internal bus 38, is connected to the image pickup unit 24 via a communication line, and receives image data captured by the high magnification side image pickup unit 24a and the low magnification side image pickup unit 24b. Further, by connecting to an external network such as the Internet, LAN, WAN, etc., it becomes possible to transmit / receive data to / from an external computer or the like.

(Explanation of work W)
Here, an example of the work W will be described based on FIGS. 4A and 4B. This work W has a box shape with an open upper portion, and has a bottom plate portion W1 and a side plate portion W2 extending upward from the peripheral edge portion of the bottom plate portion W1. In such a work W, a plurality of locations for measuring two-dimensional dimensions are assumed. For example, FIG. 4A shows the outer dimensions of the wide portion indicated by the dimension line 100, the outer dimensions of the wide portion indicated by the dimension line 101, the outer dimensions of the narrow portion indicated by the dimension line 102, the inner dimensions of the narrow portion indicated by the dimension line 103, and the like. is assumed.

The outer dimensions shown by the dimension lines 100, 101, and 102 can be obtained relatively easily by illuminating the work W with the transmission illuminating unit 27 that illuminates the work W from below. That is, when the work W is illuminated from below by the transmission illumination unit 27, the light is blocked at the portion where the work W exists, and the light passes through the mounting table 21a and reaches the image pickup unit 24 at the other portions. The change in brightness occurs sharply at the contour portion (edge) of the work W. Therefore, the accuracy of detecting the contour due to the change in brightness is high, and it can be detected with high accuracy as a measurement point by designating the measurement point extraction region described later in FIG. 6A.

On the other hand, regarding the inner dimension shown by the dimension line 103, since the transmission illumination unit 27 is blocked by the bottom plate portion W1 and it is impossible to detect the inner contour as a measurement point, the work W is used by using the epi-illumination unit 26. Needs to be illuminated from above. However, in the work image captured by the imaging unit 24, the inner surface of the bottom plate portion W1 may be reflected on the inner wall of the side plate portion W2. In such a case, the side plate in the work image is affected by the reflected bottom plate portion W1. The change in brightness near the contour of the inner wall of the portion W2 becomes small, and the contour inside the work W may not be extracted well as a measurement point. Further, the work W often has a rounded outline. Even in the work W as shown in FIG. 4A, the connecting portion between the side plate portion W2 and the bottom plate portion W1 may be formed of a curved surface, or the upper end surface of the side plate portion W2 may be curved. Even when a large work W is imaged, the change in brightness near the contour in the work image becomes small, and the contour inside the work W may not be successfully extracted as a measurement point. Further, when the work W is a casting, the draft of the mold may be set to be very small on the side plate portion W2, and this draft may also be a factor that the inner contour cannot be extracted well as a measurement point. Further, in the case of the machined work W, traces of machining may appear in the work image, which may be a factor of reducing the change in brightness. As an example, a work image obtained by capturing the work W is shown in FIG. 4C. In FIG. 4C, since the bottom plate portion W1 is reflected on the inner wall of the side plate portion W2, the change in brightness near the contour of the inner wall of the side plate portion W2 is gradual, and the contour is blurred. In such a case, it cannot be detected well as a measurement point by designating the measurement point extraction area described later.

If the contour cannot be successfully extracted as a measurement point by specifying the measurement point extraction area, the user is forced to manually specify the measurement point in the work image one by one to measure the work W. However, since the user visually performs the work of designating the measurement points, it is complicated for the user and the reproducibility is low when a plurality of works W of the same type are continuously measured. Such a problem is not limited to the work W described above, and may occur in a work having various shapes.

In this embodiment, such a conventional problem can be solved, and a specific configuration and processing thereof will be described below. First, as shown in FIG. 5, the image measuring device 1 is roughly divided into a setting mode in which the user sets various settings of the image measuring device 1 before measurement and an operation mode in which the work W is measured after the setting mode. It is configured to be switchable between the two. For example, it may be configured to automatically shift to the setting mode when the image measuring device 1 is started up, or it may be configured to shift to the setting mode after accepting a mode selection operation by the user. It may be configured to automatically shift to the operation mode when the setting mode ends, or it may be configured to shift to the operation mode after accepting a mode selection operation by the user.

(Setting mode)
The flowchart shown in FIG. 5 is started when the mode shifts to the setting mode, but the setting processing described below is a part of the setting mode, and other processing can be performed during the setting mode. The setting mode is roughly divided into two steps: a step of setting the measurement point extraction region (steps SA1 to SA3) and a step of designating the measurement point and the peripheral region (steps SB1 to SB3). First, the steps (steps SA1 to ST2) for setting the measurement point extraction region will be described.

In step ST1, the master image is acquired. That is, after the work W to be the master is placed on the mounting table 21a by the user, the work W is imaged by the imaging unit 24 to acquire a work image. The image obtained by imaging the work W to be the master is called a master image. There may be a plurality of master images, for example, a master image captured with the work W illuminated from below by the transmission illumination unit 27 and a master image captured with the work W illuminated from above by the epi-illumination unit 26. And may be included. The master image can be stored in the image storage unit 35a of the storage device 35 shown in FIG.

FIG. 4C shows an example of the master image 200 displayed on the display unit 28. In step ST2 shown in FIG. 5, the user first determines whether or not the points that the user wants to measure in the master image 200 are likely to be extracted as measurement points in steps SA1 to SA3 described later. The process is branched into steps SA1 to SA3 and steps SB1 to SB3 according to the user's judgment. Note that step ST2 may be performed after step SA3. In this case, the user will try steps SA1 to SA3 and then proceed to the steps SB1 to SB3. In step SA1, as shown in FIG. 6A, the user performs an operation of designating an arbitrary position on the master image 200 displayed on the display unit 28 as a measurement point extraction area (area indicated by diagonal lines). This designation operation can be performed by the operation panel 2a, the keyboard 40, the mouse 41, or the like, and can be specified by, for example, a drag operation of the mouse 41. Specifically, when the drag operation is performed by moving the pointer PT from the upper and left ends to the lower and right ends of the portion to be designated as the measurement point extraction region, the acquisition unit 33e moves the position and width (width and length) of the region. ) Is acquired and the area is set as the measurement point extraction area. In step SA2 shown in FIG. 5, the acquisition unit 33e acquires the brightness change in the direction of the arrow shown in FIG. 6B for the measurement point extraction region designated in step SA1. As a result, pixels with a steep change in brightness are extracted as measurement points.

The extracted measurement points are superimposed and displayed on the master image 200 as shown in FIG. 6C. At this time, as shown in FIG. 6C, the outer wall of the side plate portion W2 having a clear outline is extracted as the measurement points PA1 to PA4, but the contour of the inner wall of the side plate portion W2 is not extracted as the measurement point. In step SA3 shown in FIG. 5, a measurement line is generated by performing a least squares approximation of the points extracted as measurement points in step SA2. For example, as shown in FIG. 6D, a measurement line LA1 connecting a plurality of measurement points PA1 is generated and superimposed and displayed on the master image 200. In step SA4 shown in FIG. 5, steps SA1 to SA3 are repeated until the user finishes designating an arbitrary measurement point extraction region.

In step SA5, as shown in FIG. 6D, the user specifies the geometric dimension between the measurement point and the measurement line that he / she wants to measure. In the example of FIG. 6D, the distance between the measurement lines LA1 and LA3, LA2 and LA4, and the angle between the measurement lines LA1 and LA2 are specified. This designated operation can be performed by the operation panel 2a, the keyboard 40, the mouse 41, or the like. In addition, a permissible tolerance can be specified for each of the specified geometric dimensions. In step ST3 shown in FIG. 5, the relative position (position, width and length) in the master image of the measurement point extraction region specified in steps SA1 to SA5 and the geometric dimension and allowable tolerance specified by the user are stored in the measurement setting. It is stored in the part 33c. In step ST6, which will be described later, the geometric dimension specified is automatically calculated based on the information stored in the measurement setting storage unit 33c.

Subsequently, the steps (steps SB1 to ST3) for designating the measurement points will be described. As described above, in the steps SA1 to SA3, the contour portion desired to be measured by the user may not be extracted as a measurement point. Such a location is manually designated as a measurement point by the user in the step SB1.

In step SB1 shown in FIG. 5, as shown in FIG. 7A, the user performs a designated operation by designating an arbitrary position on the master image displayed on the display unit 28 as a measurement point. This designated operation can be performed by the operation panel 2a, the keyboard 40, the mouse 41, or the like.

For example, the display control unit 33c superimposes and displays the pointer PT that can be operated by the mouse 41 or the like on the display unit 28, and the user moves the pointer PT to a portion that is presumed to be a contour by the mouse 41 or the like. After that, the measurement point can be specified by, for example, clicking the mouse 41. The operation of designating the measurement point is not limited to this, and may be performed by the operation panel 2a or the keyboard 40.

Since the user grasps the shape of the actual work, even if the change in brightness near the contour in the master image 200 displayed on the display unit 28 is small, the portion to be measured can be specified almost accurately. The measurement points specified by the user are not limited to a plurality of points, but may be one point. Further, the number of measurement points specified by the user may be a plurality or one.

The position of the measurement point designated in this way can be specified as a relative position with respect to a characteristic portion such as an outer contour or outer shape of the work W as a reference. The position of the measurement point specified as the relative position is acquired by the acquisition unit 33e and stored in the position / luminance information storage unit 35b together with the master image.

In step SB1 shown in FIG. 5, the user can also individually specify the peripheral region B1 including the measurement point PB1 and the peripheral region B2 including the measurement point PB2 as shown in FIG. 7B. The peripheral area B1 sets an area for acquiring the luminance information of the peripheral pixels including the measurement point PB1. The peripheral area B1 can be specified, for example, by dragging the mouse 41. Specifically, when the drag operation is performed from the upper and left ends to the lower and right ends of the portion to be designated as the peripheral region B1, the acquisition unit 33e acquires the position and width (width and length) of the region, and the region Is set as the peripheral area B1. The acquired position and width information of the peripheral area B1 is stored in the position / luminance information storage unit 35b together with the master image. The method of designating the peripheral area B1 may be an operation using the keyboard 40 in addition to the drag operation, or a method of designating the peripheral area B1 by inputting the position coordinates, width, and length. Further, the shape is not limited to a quadrangle, and may be a line segment when there is only one measurement point. The peripheral region B2 defines an region for acquiring the luminance information of the peripheral pixels including the measurement point P2, and can be designated in the same manner as the peripheral region B1.

Peripheral areas B1 and B2 may be automatically specified by the acquisition unit 33e without being specified by the user. For example, when the measurement point PB1 is set, a predetermined range preset to include the measurement point PB1 can be set as the peripheral region. In step SB2, as shown in FIG. 7C, a measurement line LB1 connecting a plurality of measurement points PB1 designated by the user and a measurement line LB2 connecting a plurality of measurement points PB2 are generated.

Then, the process proceeds to step SB3 shown in FIG. In step SB3, a master profile is generated. The master profile includes a master edge profile and a master luminance profile, and only one of them may be generated or both may be generated.

(Master edge profile generation process)
First, the master edge profile generation process will be described with reference to the flowchart shown in FIG. In step SC1 after the start, as shown in FIGS. 7D and 9, a plurality of seek lines SL1 to 3 are set, and the brightness profile of each seekline SL1 to 3 is acquired. For convenience of explanation, a case where three seek lines are set will be described, but the number of seek lines is not limited.

FIG. 9 shows an enlarged part of the side plate portion W2 of the work W to which the measurement point PB1 is designated. In this figure, a plurality of measurement points PB1, a measurement line LB1 connecting these measurement points PB1, and a peripheral region B1 including the measurement points PB1 are displayed. The user can view such an image through the display unit 28.

Seeklines SL1 to SL3 can be obtained as follows. First, the acquisition unit 33e determines a line segment passing through the measurement point PB1. Specifically, when a measurement line BL1 connecting a plurality of measurement points PB1 is drawn, a line segment extending so as to intersect the measurement line BL1 is defined for each measurement point PB1, and each line segment becomes a seek line SL1 to 3. .. The seek lines SL1 to SL3 can be composed of line segments orthogonal to the measurement line BL1. The shape of the seek line may be determined according to the shape of the peripheral region.

The acquisition unit 33e generates a luminance profile of the pixel located on the seek line SL1. That is, as shown in the central portion in the left-right direction of FIG. 9, the pixels (pixels) arranged on the seek line SL1 are taken on the horizontal axis, and the luminance value is taken on the vertical axis. A brightness profile can be generated. This luminance profile corresponds to the luminance information of the pixels located on the seek line SL1. Similarly, the brightness profile of the pixel located on the seek line SL2 and the brightness profile of the pixel located on the seek line SL3 are also generated. Since the luminance profile can be generated for each measurement point PB1 in this way, a plurality of luminance profiles can be acquired. The same applies to the measurement point PB2.

After that, the process proceeds to step SC2 of FIG. 8, and the luminance profiles of the seek lines SL1 to 3 are differentiated to obtain the absolute value. Thereby, the edge profile of each seek line SL1 to SL3 can be acquired.

Then, the process proceeds to step SC3, and the edge profiles of all the seek lines SL1 to SL3 are averaged to generate a master edge profile. In FIG. 7D, it is simply expressed as a master profile. When generating the master edge profile, it may be generated only by the brightness values of the pixels arranged in one dimension, or the brightness values of the pixels arranged in two dimensions in the longitudinal direction of the seek lines SL1 to 3 and the direction orthogonal to the longitudinal direction. May be generated using.

(Master brightness profile)
It is also possible to generate a master luminance profile instead of or in conjunction with the master edge profile described above. Regarding the master luminance profile generation process, the luminance profile is averaged without going through the step of differentiating the luminance profile in step SC2 of FIG.

When generating the master brightness profile, it may be generated only by the brightness values of the pixels arranged in one dimension, or the brightness of the pixels arranged in two dimensions in the longitudinal direction of the seek lines SL1 to 3 and in the direction orthogonal to the longitudinal direction. It may be generated using a value. Hereinafter, the master luminance profile is simply referred to as the master profile.

(Memory processing)
As shown in FIG. 7D, the master edge profile and the master luminance profile generated as described above are stored as the luminance information of the peripheral pixels including the measurement point PB2 together with the relative position of the measurement point PB2 on the seek line. Is stored in the position / luminance information storage unit 35b. The position of the measurement point PB1 and the luminance information of the peripheral pixels thereof are also stored in the same manner.

Subsequently, the process proceeds to step SB4 in FIG. In step SB4, steps SB1 to SB3 are repeated until the user has specified all the measurement points. In step SB5, similarly to step SA5, the geometrical dimension between the measurement point and the measurement line that the user wants to measure is specified. You may also enter the tolerance of the specified geometric dimensions. In the example of FIG. 7E, the distance between the measurement lines LB1 and LB2 is specified as shown by the dimension line 103. In step ST2 shown in FIG. 5, the master profile generated in steps SB1 to SB5, the geometric dimension specified by the user, the allowable tolerance, and the like are stored in the measurement setting storage unit 33c. In step ST5, which will be described later, the geometric dimension specified is automatically calculated based on the information stored in the measurement setting storage unit 33c.

(Operation mode)
Next, the operation mode of the image measuring device 1 will be described. The operation mode is from step ST3 shown in FIG. There are two operation modes: a step of measuring based on the measurement points extracted by designating the measurement point extraction area (steps SA6 to SA8, ST6) and a step of measuring using the master profile (steps SB6 to SB8, ST6). It is roughly divided into two. Steps ST4 to ST5 are common.

Hereinafter, the operation mode processing will be specifically described based on the flowchart shown in FIG. This flowchart starts after the setup mode is complete.

All the user has to do in the operation mode is to install the new work W on the mounting table 21a and press the measurement button in the operation panel 2a. That is, the user simply presses the measurement button in step SD1, and steps SD2 to SD6 are all performed automatically. In step SD2, the mounted work W is imaged to generate a work image (hereinafter, the work image is referred to as an input image). The work W to be imaged at this time is different from the work W of the master, and is a work W to be measured during the operation of the image measuring device 1. FIG. 11A shows an example of the input image 300. As described above, the orientation of the work W may be different from the orientation of the work W in the master image 200 shown in FIG. 6A or the like. In step SD3, the posture / position specifying unit 33d shown in FIG. 3 specifies the position and posture of the work W in the master image 200 acquired at the time of setting, and when the input image 300 is input, in the input image 300. The position and posture of the work W are called from the master image stored in the image storage unit 35a, and the posture of the input image is specified by matching with the input image. In step SD4, input is performed in either the steps SE1 to SE3 or the steps SF1 to SF4 based on the information stored in the measurement setting information storage unit 35c and the position / brightness information storage unit 35b in step ST3 in FIG. It is automatically determined whether the measurement point should be detected in the image 300.

Next, steps SE1 to SE3 will be described. In step SE1, the region corresponding to the measurement point extraction region specified in step SA1 in FIG. 5 is detected. This is step SD3, since the location of the measurement point extraction area set on the master image 200 in the setting mode is read from the measurement setting storage unit 33c in the work W, the work W in the master image 200 is read. By matching the work W in the input image 300 with the work W, the measurement point extraction region can be detected on the input image 300 in correspondence with the position of the measurement point extraction region on the master image 200. FIG. 11B shows a measurement point extraction region detected in the input image. The position and width (width and length) of the measurement point extraction area specified by the user in the master image 200 correspond to the measurement point extraction area in the input image. In steps SE2 and SE3, as shown in FIG. 11C, a plurality of measurement points and a measurement line connecting the plurality of measurement points are detected.

Subsequently, steps SF1 to SF4 will be described. In step SF1, a region corresponding to the measurement point or the peripheral region specified in step SB1 in FIG. 5 is detected. In step SD3 in FIG. 10, since the position / luminance information storage unit 35b reads where the measurement point specified by the user on the master image 200 is located in the work W in the setting mode, the work W in the master image 200 is read. When matched with the work W in the input image 300, the corresponding seek line can be detected on the input image 300 as shown in FIG. 12A, corresponding to the position of the peripheral region B1 on the master image 200. .. Similarly, the seek line on the master image 200 can be detected on the input image 300.

On the input image 300, the seek line is set by expanding the width from the peripheral area set on the master image. For example, on the input image 300, a seek line having twice the length of the seek lines SL1 to 3 set on the master image 200 shown in FIG. 7D can be used. A seek line is a line segment that passes through a measurement point. The length of the seek line set on the input image 300 is set to be equal to or longer than the length of the seek lines SL1 to 3 set on the master image 200, and the length of the seek line set on the input image 300 is set to the sea. It can be 1.5 times or more the length of Klein SL1 to 3. As a result, the search can be executed in a wider range than the peripheral area on the master image 200.

After setting the seek line on the input image 300, the process proceeds to step SF2 in FIG. In step SF2, the acquisition unit 33e acquires the brightness distribution of the newly generated input image 300, and obtains the position of the measurement point specified by the user on the master image 200 and the brightness information of the peripheral pixels including the measurement point. Based on the above, a process of determining a measurement point is executed on the newly generated input image 300.

Specifically, first, the processing unit 33f generates a luminance profile of a pixel on each seek line set in the input image 300.

Then, as shown in FIG. 12B, the measurement point is determined by the brightness profile of each seek line and the normalization correlation of the master profile. The master profile may be either a master edge profile or a master brightness profile. Hereinafter, a specific example of this determination method will be described. For example, suppose that the master profile is represented by a waveform as shown in the right figure of FIG. 12B, and the measurement point PB1 is defined. Further, it is assumed that a luminance profile having a waveform as shown in the center of FIG. 12B is generated on the seek line set in the input image 300. As shown in the lower figure of FIG. 12B, the correlation between the two profiles is examined while sliding the master profile in the pixel arrangement direction on the luminance profile (profile generated during operation) on the seek line. The lower figure of FIG. 12B shows a case where the brightness profile on the seek line generated during operation has a strong correlation with the master profile. Search for a position where the correlation between the two profiles is strong, and identify a position where the correlation is strong.

That is, the brightness information of the peripheral pixels including the measurement point PB1 at a certain position is almost the same between the same type of work W if the position is fixed. Therefore, the position of the measurement point PB1 and the brightness information of the peripheral pixels thereof. Based on the above, it is possible to find a measurement point at a position similar to the measurement point PB1 specified at the time of setting on the new work image with high accuracy. Since this process is automatically executed in the image measuring device 1, the user's work is not complicated and is executed at high speed.

In step SF2 in FIG. 10, as shown in FIG. 12C, the position of the measurement point PB1'on the master profile is detected as a measurement point on the seek line at a position where the correlation between the two profiles is strong. At this time, after detecting a plurality of measurement points, the measurement lines are detected by approximating the plurality of detected measurement points by the least squares method as shown in FIG. 12D. The measurement point can be determined based on the approximated measurement line (measurement point PB1a shown in FIG. 12D). The measurement point PB2a shown in FIG. 12D can be determined in the same manner.

When steps SE1 to SE3 and SF1 to SF4 are completed, as shown in FIG. 13, all the measurement points extracted and designated in the steps ST1 to ST5 in FIG. 5 are superimposed and displayed on the input image 300. In step SD5 in FIG. 10, the geometric dimensions specified in steps SA5 and SB5 in FIG. 5 and stored in the measurement setting storage unit 33c are measured by the measurement unit 33b and superimposed and displayed on the input image 300.

In step SD6, it is determined whether or not all the work W has been measured. If the measurement of all the work W is not completed, the process proceeds to step SD1, the steps SD1 to SD5 are repeated, and if the measurement of all the work W is completed, this process is terminated.

(Master profile validity judgment processing)
Next, the process of determining the validity of the master edge profile and the master luminance profile generated by the flowchart shown in FIG. 8 will be described with reference to the flowchart shown in FIG. This process can be executed by the processing unit 33f. The flowchart shown in FIG. 14 can be started by a user's instruction, or can be automatically started after the processing of the flowchart shown in FIG. 8 is completed.

In step SH1, a measurement line is specified for the master image 200, a plurality of luminance profiles of pixels located on a line segment passing through each measurement line are acquired, and a master profile is generated based on these luminance files.

After that, the process proceeds to step SH2, and the measurement point is detected for the master image 200 itself by using the master profile. Then, the process proceeds to step SH3, and the difference between the detected measurement point and the master profile is calculated. After calculating the difference, the process proceeds to step SH4, and the difference is displayed on the display unit 28 according to the magnitude of the difference. For example, if the difference is larger than a predetermined threshold value, it can be determined that the effectiveness of the master profile is low, while if the difference is equal to or less than the predetermined threshold value, it can be determined that the effectiveness of the master profile is high. it can.

(Modification example 1)
The master image does not have to be one, and a plurality of master images may be generated. At the time of setting, for example, a plurality of work Ws to be masters are prepared, and a plurality of master images can be generated by sequentially imaging these work Ws. Then, by learning a plurality of master images, the detection accuracy of the measurement points can be improved. For example, if 10 work Ws to be masters are sequentially imaged to generate 10 master images, 10 master profiles can be generated, so that 10 sets of measurement points can be determined. The detection accuracy can be improved by excluding those measurement points having a large dissociation.

(Modification 2)
As a method of generating a plurality of master images, it is not necessary to prepare a plurality of work Ws to be masters. For example, by preparing one work W to be a master and imaging by changing the imaging conditions. Multiple master images can be generated. Changing the imaging conditions includes, for example, changing the type of illumination (epi-illumination, transmitted illumination), changing the brightness of the illumination, changing the exposure time, changing the lens magnification, changing the focus, and the like. .. By learning the plurality of master images generated in this way, the detection accuracy can be improved. In addition, the modification 1 and the modification 2 may be combined.

Further, the input image can also be imaged under a plurality of imaging conditions, and measurement points can be generated by using the images captured under the same conditions. Among the measurement points generated in this way, the one with the smallest dissociation is adopted.

(Modification example 3)
In the operation mode, a plurality of work Ws are measured continuously, and it is assumed that the position of the measurement point is inappropriate. If the position of the measurement point is inappropriate, the user can operate an operation unit such as the mouse 41 to manually correct the position of the measurement point. The processing unit 33f grasps the correction result, feeds back the correction content, and can change the detection rule of the measurement point at the time of the subsequent measurement of the work W.

(Action and effect of the embodiment)
As described above, according to this embodiment, the user specifies an arbitrary position on the work image displayed on the display unit 28 when the image measuring device 1 is set as the measurement point, so that the designated measurement point is specified. And the brightness information of the peripheral pixels including the measurement point can be acquired. After that, when the image measuring device 1 is in operation, a work image is generated by newly imaging the work, the brightness distribution of the generated new work image is acquired, and the position and brightness information of the measurement points acquired at the time of setting are acquired. The measurement point can be determined on the work image based on the above. As a result, the measurement point can be automatically determined at high speed and with high reproducibility while being a simple operation for the user.

The above embodiments are merely exemplary in all respects and should not be construed in a limited way. Furthermore, all modifications and modifications that fall within the equivalent scope of the claims are within the scope of the present invention.

As described above, the image measuring device according to the present invention can be used when measuring two-dimensional dimensions from work images obtained by capturing images of various workpieces.

1 Image measuring device 2a Operation panel (operation unit)
21a Mounting stand 24 Imaging unit 26 Epi-illumination unit 28 Display unit 33e Acquisition unit 33f Processing unit 35a Position / brightness information storage unit 35c Measurement setting storage unit 40 Keyboard (operation unit)
41 Mouse (operation unit)

Claims (9)

In an image measuring device that measures the two-dimensional dimensions of the work based on the measurement points in the work image acquired by imaging the work.
A mounting table on which the work is placed and
An illuminating unit for irradiating the work placed on the above-mentioned pedestal with light from above,
An imaging unit for generating a work image by receiving light that is irradiated on the work by the illumination unit and reflected on the surface of the work.
A display unit for displaying the work image generated by the imaging unit, and a display unit.
An operation unit for designating and operating an arbitrary position on the work image displayed on the display unit as the measurement point at the time of setting the image measurement device.
An acquisition unit that acquires the position of the measurement point designated by the operation unit and the brightness information of peripheral pixels including the measurement point.
A storage unit that stores the position of the measurement point acquired by the acquisition unit and the luminance information, and a storage unit.
During the operation of the image measuring device that measures the two-dimensional dimensions of a work different from the work at the time of the setting, the brightness distribution of the work image newly generated by the imaging unit is acquired and stored in the storage unit. An image measuring device including a processing unit that executes a process of determining a measurement point on the newly generated work image based on the position of the measurement point and the brightness information. In the image measuring apparatus according to claim 1,
The acquisition unit is an image measuring device configured to determine a line segment passing through the measurement point designated by the operation unit and acquire brightness information of pixels located on the line segment. In the image measuring apparatus according to claim 2,
The acquisition unit is an image measuring device configured to generate a luminance profile of pixels located on the line segment. In the image measuring apparatus according to claim 3,
The operation unit is configured so that a plurality of the measurement points can be designated and operated.
When the acquisition unit draws a measurement line connecting the measurement points designated by the operation unit, the acquisition unit determines the line segment extending so as to intersect the measurement line for each measurement point, and positions the line segment on each line segment. An image measuring device configured to generate a brightness profile of a pixel to be used and acquire a plurality of brightness profiles. In the image measuring apparatus according to claim 4,
The acquisition unit is an image measuring device that uses a master profile including a brightness profile obtained by averaging a plurality of the brightness profiles as brightness information of peripheral pixels. In the image measuring apparatus according to claim 4,
The acquisition unit is an image measuring device that uses a master profile composed of an averaged edge profile as brightness information of peripheral pixels after differentiating a plurality of the brightness profiles. In the image measuring apparatus according to claim 5 or 6.
The processing unit sets a seek line in the newly generated work image by matching the work image generated at the time of the setting with the newly generated work image, and the brightness on the seek line. An image measuring device configured to determine the measurement point by a normalized correlation between the profile and the master profile. In the image measuring apparatus according to claim 7,
When a plurality of the measurement points are detected in the newly generated work image, the processing unit is configured to approximate the detected plurality of measurement points by the least squares method to determine the measurement points. Image measuring device that has been used. In the image measuring apparatus according to claim 8,
The processing unit is configured to generate a measurement line connecting the measurement points detected in the newly generated work image and the new measurement points determined by approximation by the least squares method. Image measuring device.

Images