JP2006214870A - Shape measuring system, method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape measuring system, a shape measuring method, and a shape measuring program capable of calculating automatically a dimension such as a radius, a distance and an angle of a corner R in a specified portion requiring high dimensional precision. <P>SOLUTION: This shape measuring system of the present invention includes an outline shape image generating means for generating an outline shape image from a read-in outline shape data; an evaluation area setting means for setting the first evaluation area and the second evaluation area in a prescribed peripheral position of the measured objective portion found by executing geometrical pattern matching (called as PM in some cases) in the outline shape image; a measuring area setting means for setting a measuring area, using as a reference an intersection of two straight lines linear-approximated based on the outline shape data within the first evaluation area and the second evaluation area; and a shape evaluation means for finding a physical quantity of a geometric element in the outline shape data within the measuring area in response to a kind of set shape evaluation, and for executing prescribed dimension measuring processing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shape measuring system, a shape measuring method, and a shape measuring for the purpose of calculating and evaluating dimensions such as corner radius, distance, and angle at a specific portion of a piston ring material used in an internal combustion engine with high accuracy. It is about the program.

  Conventional means for measuring the dimensions of an object to be measured are disclosed in, for example, Patent Document 1 and Patent Document 2 below. According to Patent Literature 1, two oppositely arranged laser distance meters are run in the horizontal direction to measure the shape of the H-shaped steel, and the obtained four contour shape data are based on the measurement information at the same location. It is synthesized and replaced with the same spatial coordinates, and the cross-sectional dimensions such as the H-shaped steel flange width and leg length are automatically calculated from the spatial coordinates. In this method, linear approximation is used for geometric element fitting to calculate dimensions from the obtained contour shape data, and the intersection point is calculated using a linear equation obtained by linear approximation, and the H-shaped steel flange width, leg length, etc. Thus, the dimension of the portion constituted by a straight line is measured, and finally the cross-sectional dimension of the object to be measured is obtained using the obtained flange width, leg length, and the like.

According to Patent Literature 2, necessary edge points are sampled while moving independently along an edge from a set initial window position in an image to be measured, and contour shape data is obtained. . Thereafter, the operator selects a shape evaluation type corresponding to the physical quantity to be obtained. A shape evaluation type is a physical quantity of a geometric element itself such as a circle, a straight line, a peak point, a tangent, or a perpendicular line, or a physical quantity between a geometric element such as an intersection angle, a distance, a radius, or an area, and another geometric element. . Then, the operator is prompted to input a measurement region corresponding to the selected shape evaluation type or to select a geometric element. When the operator designates a measurement area with the mouse in response to this, the shape evaluation process is executed and a desired dimension can be obtained.
JP-A-8-327329 (paragraph numbers 0045 to 0047) JP 11-118444 A (paragraph numbers 0036 to 0040, 0045)

Since the piston ring material is a component used in an internal combustion engine, the shape of the surface portion that contacts the cylinder is particularly important, and high dimensional accuracy is required. However, if the method of Patent Document 1 is used to measure the piston ring material, the geometrical element is only fitted with a straight line, so that it is not possible to cope with the calculation of dimensions when R is attached as in the piston ring material. Furthermore, it cannot cope with various dimensional calculation methods such as obtaining the distance using an inflection point that changes from a straight line to a circle or an intersection of a circle and a straight line.
Further, since the method of Patent Document 2 is a method in which measurement is performed by manually inputting a measurement region, when there are many dimensions to be obtained such as a piston ring material, it is necessary to perform automatic measurement. Can not respond. Therefore, even if the operation once performed is stored and stored, and the automatic dimension measurement is performed by tracing the operation, the shape evaluation is performed using the contour shape data in the measurement region set at the same position every time. It becomes. Therefore, for example, when the R part of the piston ring material is approximated by a circle, the contour shape will change not only if the same product changes, but not only the arc portion but also the contour shape data of the straight portion within the measurement region. And there is a risk of incorrect shape evaluation. In addition, the two-dimensional best fit processing disclosed in Patent Document 2 is also a method for quantitatively evaluating the degree of matching between data given as design value data and contour shape data. Is not set. Even if the measurement area is set by the best fit, it is only a rough position detection, and it is difficult to cope with automatic measurement such as a piston ring material that requires high dimensional accuracy.

  In view of the above-described problems, the present invention provides a shape measurement system, a shape measurement method, and a shape measurement that can automatically calculate the radius, distance, angle, and other dimensions of a corner R of a specific part that requires high dimensional accuracy. The purpose is to provide a program.

  The shape measuring system according to the present invention includes a contour shape image generating means for generating a contour shape image from the read contour shape data, and geometric pattern matching (hereinafter abbreviated as PM) for the contour shape image. )), A straight line based on the evaluation area setting means for setting the first evaluation area and the second evaluation area at a predetermined position around the measurement target site and the contour shape data in the first evaluation area and the second evaluation area. Measurement area setting means for setting a measurement area based on the intersection of two approximated straight lines, and a physical quantity of a geometric element for the contour shape data in the measurement area in accordance with the set shape evaluation type, and a predetermined dimension measurement It is characterized by comprising shape evaluation means for executing processing.

  The evaluation region setting means causes a master image obtained by cutting out and registering an image of a specific part from an arbitrary contour shape image in advance to cause the contour shape image and PM to be measured in a preset search region, While searching for the measurement target region, the first evaluation region and the second evaluation region are set in a predetermined peripheral portion of the contour shape image of the measurement target region searched using the predetermined position of the master image at that time as a reference. The first evaluation area and the second evaluation area are set so as to surround a portion whose contour shape is linear.

  The shape evaluation means calculates a physical quantity of a geometric element for the contour shape data in the measurement region according to the set shape evaluation type, and executes a predetermined dimension measurement process. It is preferable to output to the display means.

  The types of shape evaluation include physical quantities of geometric elements themselves such as peak points, tangent lines, perpendicular lines, parallel lines, circles, straight lines, and other geometric elements such as intersection points, distances, intersection angles, and radii. The physical quantity calculated between and.

  In addition, the shape measurement system of the present invention includes an external storage device that stores data such as a master image, an evaluation region, a measurement region, and a shape evaluation type related to a specific region to be measured in advance for a plurality of measurement locations. Can be measured automatically in sequence, which is preferable.

  The shape measurement method according to the present invention includes a contour shape input step for reading contour shape data of a measurement target, a contour shape image generation step for generating a contour shape image from the read contour shape data, and pattern matching for the contour image. The evaluation area setting step for setting the first evaluation area and the second evaluation area at a predetermined position around the measurement target site obtained in this way, and linear approximation 2 based on the contour shape data in the first evaluation area and the second evaluation area A measurement area setting stage for setting a measurement area based on the intersection of straight lines, and a physical quantity of a geometric element is obtained for contour shape data in the measurement area according to the set shape evaluation type, and a predetermined dimension measurement process is executed. And a shape evaluation stage.

  A shape measurement program according to the present invention is a shape measurement program for measuring a dimension of a measurement target region based on contour shape data of a measurement target by a computer, and creates a contour shape image from the contour shape data. A step of generating a shape image, a step of calculating a first evaluation region and a second evaluation region at a predetermined peripheral position of a region to be measured obtained by performing pattern matching on the contour shape image, and a first evaluation region and a second evaluation region A step of calculating a measurement region based on the intersection of two straight lines approximated based on the contour shape data inside, and obtaining physical quantities of geometric elements for the contour shape data in the measurement region according to the set shape evaluation type And a step of executing a predetermined dimension measurement process.

  According to the present invention, since the shape measuring system configured as described above is used, the shape change included in the first and second evaluation regions set using pattern matching is measured when measuring the shape of the object to be measured. The measurement area is automatically set so that the part to be measured is included on the basis of the intersection of two straight lines obtained by linearly approximating a straight line part that hardly occurs, and the physical quantity of the geometric element of the part included in the measurement area Therefore, even when there is a change in the shape of the object to be measured with respect to the predetermined shape, the shape can be accurately measured.

  The present invention will be described based on the embodiments with reference to the drawings. Hereinafter, the measurement target is a piston ring attached to an engine or the like, and the geometric element indicated by reference numeral 31e in FIG. 6 on the surface where the piston ring and the cylinder are in contact is a circle and the physical quantity is the radius of the circle. An example of measuring the dimension of the corner R will be described.

  A computer apparatus according to the shape measurement system of the present invention is configured to include a computer main body, a keyboard, a mouse, and a display. For example, the computer main body is configured as shown in FIG. That is, the CPU 11, the program memory 12 containing the shape measurement system of the present invention, the work memory 13 that provides a work area for various processes in the CPU 11, and the image converted according to the program stored in the program memory 12. An image memory 14 for storing information, a display control unit 15 for displaying the image information stored in the image memory 14 on a display, an interface 16 for inputting various information such as measurement items with a mouse, etc., contour shape data and a master An external storage device 17 is provided for storing images, measurement procedures, and the like, and various types of information are exchanged via a bus.

  FIG. 1 is a functional block diagram showing the configuration of the shape measuring system stored in the program memory 12. The contour shape image generation means 21 converts the contour shape data read according to the read request from the CPU 11 into an image and stores it in the image memory 14. The evaluation area setting means 22 performs PM on the image stored in the image memory 14 to obtain a part that matches the master image, and performs the first evaluation at a relative position set in advance with reference to the part. An area and a second evaluation area are set. The measurement area setting means 23 performs straight line approximation on the contour shape data in the first evaluation area and the second evaluation area, obtains the intersection of the two straight lines, and sets the measurement area at a preset relative position from the intersection. Set. The shape evaluation unit 24 executes various arithmetic processes for the designated shape evaluation on the contour shape data in the measurement region, and displays the result on a display or outputs it to another system, for example. .

FIG. 3 is a flowchart showing the overall operation of the shape measuring system. First, the system reads various setting information such as a master image, a relative position of an evaluation area, and a relative position of a measurement area as preprocessing (S1). Next, the system reads contour shape data that outputs the number of data and contour point information in accordance with the format of FIG. 4 (S2). The contour shape image generation means 21 converts the contour shape data into an image and stores it in the image memory (S3). Next, the evaluation area setting means 22 detects a position that matches the master image by position detection by PM, and calculates a first evaluation area and a second evaluation area (S4). Subsequently, the measurement area setting means 23 calculates a measurement area (S5). When the measurement region is obtained, the shape evaluation unit 24 executes the contour shape evaluation process (S6).
Hereinafter, the configuration and operation of the evaluation region setting unit 22, the measurement region setting unit 23, and the shape evaluation unit 24 will be specifically described. Note that the contour shape image generating means 21 can be constituted by a well-known image processing means, and detailed description thereof will be omitted.

[Evaluation area setting means]
The evaluation area setting means 22 will be described with reference to FIGS. FIG. 5 is a flowchart showing the processing procedure of the evaluation area setting means 22. 6 to 9 are conceptual diagrams visually showing processing corresponding to the steps (S41 to S44) in FIG. 5. Reference numeral 31 in the drawing denotes the read contour shape data as contour shape image generation means 21. FIG. Is a workpiece outline which is an outline of an image of a piston ring obtained by converting.

  First, as shown in FIG. 6, the first ridge line 31a extending vertically of the workpiece contour 31 placed at an arbitrary position in the X, Y plane P having a predetermined size with respect to the origin G, and the horizontal An intersection of straight lines obtained by linearly approximating the second ridge line 31b extending in the straight line is obtained and set as the first reference point 34 (S41 in FIG. 5). Next, as shown in FIG. 7, the workpiece contour 31 is moved so that the first reference point 34 is located at the center of the plane P. Thereafter, for example, a workpiece contour 31 including an R ridgeline (hereinafter referred to as a measurement ridgeline) 31e of a corner to be measured so that the upper left end point of the search area 35 is positioned at preset coordinates (Ix, Iy). The search area 35 is set at a predetermined part of the left protruding end (S42). Here, the search area 35 is a rectangular area including a desired measurement site and having a predetermined size for performing PM described later.

  As shown in FIG. 8, the master image 37 is moved in the search area 35, and PM between the workpiece contour 31 and the master image 37 in the search area 35 is performed according to a predetermined rule. Then, the position (SAx, SAy) of the upper left end point of the master image 37 at the position where the master image 37 and the workpiece outline 31 most closely match is set as the second reference point 36 (S43). Here, the master image 37 of this aspect is obtained by measuring the shape of the piston ring as a reference in advance and acquiring an image of a predetermined portion corresponding to the measurement ridge line 31e obtained therefrom. As the master image, an image of design data can be used.

  Next, as shown in FIG. 9, the first evaluation area 38 is set (S44). Here, the first evaluation area 38 includes a part of the horizontal third ridge line 31c connected to the right side of the measurement ridge line 31e, and the second evaluation area 39 is connected below the measurement ridge line 31e. It is set so as to include the first ridgeline 31a. This is because the intersection of the third ridge line 31c and the straight line obtained by linearly approximating the first ridge line 31a is a reference point in the measurement of the measurement ridge line 31e. In this aspect, the first and second evaluation areas 38 and 39 are large so that the distance from the second reference point 36 to the upper left end point of the first and second evaluation areas 38 and 39 satisfies the above condition. Is set to be That is, as shown in the figure, the first evaluation area 38 is HAx and HAy in the X and Y axis directions, and the second evaluation area 39 is HBx and HBy in the X and Y axis directions. 2 The positions of the evaluation areas 38 and 39 are set. In this aspect, the first and second evaluation regions 38 and 39 are set so as to include the third ridge line 31c and the first ridge line 31a in order to measure the R dimension of the corner portion. The evaluation area may be set so as to include the ridgeline.

  As described above, the first and second evaluation areas 38 and 39 cause the measured shape of the workpiece contour 31 of the piston ring and the master image 37 to be PM according to a predetermined rule, and the predetermined point of the master image 37 positioned by PM. Is set as a reference. Therefore, even when the measured piston ring workpiece contour 31 and the piston ring contour of the master image 37 do not completely match, the first and second evaluation regions 38 and 39 are set.

[Measurement area setting means]
The measurement area setting means 23 will be described with reference to FIGS. FIG. 10 is a flowchart showing the processing procedure of the measurement area setting means 22. 11 and 12 are conceptual diagrams visually showing processing corresponding to the steps (S51 and S52) in FIG.

  First, as shown in FIG. 11, a straight line 40 obtained by linearly approximating the third ridgeline 31c included in the first evaluation region 38 is obtained. Similarly, a straight line 41 obtained by linearly approximating the third ridge line 31a included in the second evaluation region 39 is obtained. And the intersection of these two straight lines 40 and 41 is calculated | required, and it is set as the 3rd reference point 42 (S51 of FIG. 10).

  Next, as shown in FIG. 12, the measurement region 43 is set in a predetermined range with the third reference point 42 as a reference. Here, the measurement region 43 is set to include the measurement ridgeline 31e. In this aspect, the distance from the third reference point 42 to the upper left end point of the measurement region 43 is set to be P0x in the X-axis direction and P0y in the Y-axis direction (S52).

  The measurement area 43 can be set with the second reference point 36 set by PM by the above-described evaluation area setting means 22 as a reference. However, the third reference point 42 set by the measurement region setting means 23 is set with reference to the workpiece contour 31 of the piston ring actually measured. Therefore, since the third reference point 42 is a reflection of the actual shape of the workpiece contour 31, it is possible to measure the dimensions with high accuracy in response to changes in the shape of the piston ring.

[Shape evaluation means]
The shape evaluation unit 24 performs arithmetic processing on the workpiece contour 31 in the measurement region 43. The shape evaluation unit applies, for example, an arbitrary geometric element, and calculates a physical quantity of the geometric element itself and calculates a physical quantity between the geometric element and another geometric element. Here, the geometric element includes, for example, at least one of a peak point, a tangent line, a perpendicular line, a parallel line, a circle, a straight line, etc., and a physical quantity of the geometric element itself and a physical quantity between the geometric element and another geometric element. Includes, for example, at least one of an intersection, a distance, an intersection angle, a radius, and the like. In this aspect, the shape evaluation means 24 performs a circular approximation to the measurement ridge line 31e in the measurement region 43, and calculates the radius of R.

  The method of setting the measurement region 43 so as to include as many measurement ridgelines 31e forming the R as possible and approximating the circle with respect to the measurement ridgelines 31e has been described above in order to obtain the radius of the corner R. However, in the measurement area setting means 23, an inflection point can be used to obtain the radius of R.

  FIG. 13 shows an example in which inflection points are used when performing circular approximation. As shown in FIG. 13, the first measurement region 61 is set at a predetermined position along the straight line 40 extending in the horizontal direction that is linearly approximated to the third ridge line 31 c with reference to the third reference point 42. Similarly, the second measurement region 62 is set at a predetermined position along the vertical straight line 41 that is linearly approximated to the first ridge line 31a with the third reference point 42 as a reference. Next, the first point that is a predetermined distance away from the straight line 40 with respect to the workpiece contour 31 in the first measurement region 61 is defined as a first inflection point 63, and the workpiece contour 31 in the second measurement region 62. The first point away from the straight line 41 by a predetermined distance is defined as a second inflection point 64. Then, the shape evaluation means 24 approximates the circle with respect to the workpiece contour 31 existing between the first inflection point 63 and the second inflection point 64, that is, the measurement ridge line 31e, and obtains the radius of R. By obtaining the radius of R using the inflection point in this way, data other than the measurement ridge line 31e forming R can be excluded, so that the radius of R at the corner can be obtained with higher accuracy.

  Next, a method for obtaining the piston ring width 80 will be described with reference to FIG. According to the present shape measurement system, first, the third reference point of the outer corner at both projecting ends is obtained in the same manner as described above. Specifically, in one search area 35 set at the left end, one first measurement area 71 and second area based on one second reference point 36 obtained by PM using one master image 37. Measurement region 72 is set, and one third reference point 73 is obtained. Similarly, the other first measurement region 74 and the second measurement based on the other second reference point 78 obtained by PM using the other master image 77 in the other search region 79 set at the right end. A region 75 is set, and the other third reference point 76 is obtained. Then, a distance 80 between one third reference point 73 and the other third reference point 76 is obtained. In the case of obtaining the distance between two distant points, it is possible to measure the distance dimension following the shape change by dividing the search area and obtaining each point as in this example.

  The example in which the physical quantity of one geometric element has been described has been described above. For example, even when there are a plurality of shape evaluation items to be measured such as intersections, distances, intersection angles, and radii, If the location of the search area and the master image used for PM, the first evaluation area, the second evaluation area, the relative position of the measurement area, the type of shape evaluation, etc. are stored in the external storage device 17, the book shown in FIG. A plurality of set shape measurements can be automatically performed by sequentially executing the processing of the shape evaluation system.

It is a functional block diagram of the shape measurement system concerning the present invention. It is a block diagram which shows the structure of the computer apparatus incorporating the system of FIG. It is a flowchart which shows operation | movement of the system of FIG. It is a data format of the outline shape read by the system of FIG. It is a flowchart explaining the setting process method of the evaluation area | region in the system of FIG. It is a figure explaining the calculation method of the reference point in the coordinate system of an outline shape image in the flow of FIG. It is a figure explaining the method to set a search area | region in the flow of FIG. It is a figure explaining the method of detecting a position using PM in the flow of FIG. It is a figure explaining the method to set an evaluation area | region in the flow of FIG. It is a flowchart explaining the setting process method of the measurement area | region in the system of FIG. It is a figure explaining the method of calculating the reference point of a measurement area in the flow of FIG. It is a figure explaining the method of setting a measurement area | region in the flow of FIG. It is a figure explaining the circle approximation method using the inflection point in the system of FIG. It is a figure explaining the calculation method of the distance between two points in the system of FIG.

Explanation of symbols

11 CPU
DESCRIPTION OF SYMBOLS 12 Program memory 13 Working memory 14 Image memory 15 Display control part 16 Interface 17 External storage device 21 Contour shape image generation means 22 Evaluation area setting means 23 Measurement area setting means 24 Shape evaluation means 31 Work outline 32 1st edge 33 Second Ridgeline 34 First reference point 35 Search area (one search area)
36 Second reference point (one second reference point)
37 Master image (one master image)
38 First Evaluation Area 39 Second Evaluation Area 40 Approximate Line 41 Approximate Line 42 Third Reference Point 43 Measurement Area 61 First Measurement Area 62 Second Measurement Area 63 First Inflection Point 64 Second Variation Inflection point 71 One first measurement area 72 One second measurement area 73 One third reference point 74 The other first measurement area 75 The other second measurement area 76 The other third reference point 77 The other Master image of 78 The other second reference point 79 The other search area 80 Piston ring width

Claims (3)

In the shape measurement system for measuring the dimension of the measurement target part based on the contour shape data of the measurement target using a computer system,
Contour shape image generating means for generating a contour shape image from the contour shape data;
An evaluation area setting means for setting the first evaluation area and the second evaluation area at a predetermined position around the measurement target site obtained by performing pattern matching on the contour shape image;
Measurement area setting means for setting the measurement area with reference to the intersection of two straight lines obtained by linear approximation of the contour shape data in the first evaluation area and the second evaluation area;
A shape measuring system comprising shape evaluating means for obtaining a physical quantity of a geometric element for contour shape data in a measurement region in accordance with a set shape evaluation type and executing a predetermined dimension measuring process. In a method for measuring a dimension of a measurement target portion based on contour shape data of a measurement target using a computer system,
Contour shape input stage for reading contour shape data;
A contour shape image generation stage for creating a contour shape image from the contour shape data;
An evaluation area setting step for setting the first evaluation area and the second evaluation area at a predetermined position around the measurement target site obtained by performing pattern matching on the contour image;
A measurement region setting stage for setting a measurement region on the basis of the intersection of two straight lines approximated based on contour shape data in the first evaluation region and the second evaluation region;
A shape measurement method comprising: a shape evaluation step of obtaining a physical quantity of a geometric element for contour shape data in a measurement region in accordance with a set shape evaluation type and executing a predetermined dimension measurement process. A shape measurement program for measuring the dimensions of a measurement target part based on contour shape data of the measurement target by a computer,
A contour shape image generation step for creating a contour shape image from the contour shape data;
Calculating a first evaluation region and a second evaluation region at a predetermined position around the measurement target region obtained by performing pattern matching on the contour shape image;
Calculating a measurement region on the basis of an intersection of two straight lines approximated based on contour shape data in the first evaluation region and the second evaluation region;
A shape measurement program comprising: calculating a physical quantity of a geometric element for contour shape data in a measurement region according to a set shape evaluation type, and executing a predetermined dimension measurement process.

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