JPH11237221A - Image measuring method and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate operation for detecting protruding parts and recessed parts in a specified direction of a work image. SOLUTION: This image measuring method displays a work image 62 obtained by image-sensing a work on an image window 51, sets a rectangular detection tool 61 in the window 51, detects edges of the work image 62 by scanning it in a specified direction in the tool 61, and detects a point Pn which protrudes most in the scanning direction, out of detected edges. The tool 61 is rectangular and has sides parallel with reference axes X and Y of measurement coordinate system. A pair of facing sides desiginates the scanning direction of an edge, and a pair of the other facing sides designates a point to be detected which protrudes on either side of the edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image measuring apparatus such as a non-contact three-dimensional measuring machine, and more particularly to detecting a point of a work image obtained by imaging a work, which is most protruding or depressed. The present invention relates to a method and an apparatus for measuring images.

[0002]

2. Description of the Related Art Conventional CNC (Computer Numerical Con
trol) With a coordinate measuring machine or a manually operated coordinate measuring machine, it is necessary to detect various unique measurement points from the work image obtained by imaging the work to be measured and measure the required physical quantity. Sometimes it doesn't. For example, when the processing accuracy of the mating portion of the connector is strictly required, the width of the mating portion at the most protruding point is required for evaluating the mating dimensional accuracy and confirming the presence or absence of burrs. .

Conventionally, in order to detect such a protruding portion or a concave portion in a specific direction, an edge of a work image obtained by enlarging and imaging the work is detected, and the detected edge is detected. A straight line is set so as to be in contact with the display screen from a predetermined direction, and a required dimension value is obtained from the coordinate value of the contact point or the like.

[0004]

However, in the above-mentioned conventional measuring method, it is necessary to perform an operation of setting a straight line tangent to the detected edge and finding the coordinates of the contact point. There is a problem that the operation of finding a point is troublesome. In addition, the measurement usually needs to be performed on the basis of a work coordinate system or a machine coordinate system (hereinafter, these are collectively referred to as a “measurement coordinate system”). Since it is different from the memory coordinate system, there is also a problem that it is difficult to determine from which direction to detect an edge protrusion point.

As described above, in the conventional image measuring method, the operation for detecting a protruding portion or a concave portion of a work image in a specific direction is a complicated and time-consuming operation.

The present invention has been made in view of the above points, and an image measuring method and apparatus capable of easily performing an operation for detecting a projecting portion or a concave portion of a work image in a specific direction. The purpose is to provide.

[0007]

According to the image measuring method of the present invention, a work image obtained by imaging a work is displayed in an image window, and a rectangular tool is set in the image window. An image measurement method that scans a work image in a predetermined direction in a tool to detect an edge of the work image, and detects a point that protrudes in the scanning direction among the detected edges, wherein the tool includes: It is a rectangular shape having sides parallel to the reference axis of the measurement coordinate system. The scanning direction of the edge is designated by a pair of opposed sides, and a point protruding to any side of the edge is detected by another pair of opposed sides. It is characterized by specifying whether or not to perform.

[0008] An image measuring apparatus according to the present invention comprises: display means for displaying a work image obtained by imaging a work in an image window; and position designating means for designating an arbitrary position in the image window. A tool generating means for generating a rectangular tool in the image window based on the position specified by the position specifying means, and scanning a workpiece image inside the rectangular tool generated by the tool generating means. To detect the edge of the work image,
Protruding point detecting means for detecting a point most protruding in the scanning direction among the detected edges, wherein the tool generating means includes a rectangular tool having a side parallel to a reference axis of the measurement coordinate system. The scanning direction of the edge is specified by a pair of opposing sides, and the protruding point of the edge is specified by the other pair of opposing sides.

According to the present invention, a scanning direction for edge detection with respect to a workpiece image in a tool is designated only by setting a tool in an image window, an edge is detected by a scanning process, and the detected edge is detected. Among them, the point most protruding in the scanning direction is detected. Moreover, since the tool is set on the basis of the measurement coordinate system, the most protruding point or the depressed point can be accurately detected in the measurement coordinate system, and the evaluation of the machining accuracy of the fitting portion can be easily performed. Become.

Since the tool has a rectangular shape, it can be easily set in the image window by designating two diagonal points.

Further, a point protruding most in the scanning direction from the sequence of detected edge points in the tool is determined as a candidate point, and the continuity between the candidate point and an adjacent edge point is evaluated to obtain a true edge. The above point and noise can be distinguished, and the reliability of detection is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the overall configuration of a CNC image measuring device according to one embodiment of the present invention. The apparatus comprises a non-contact image measurement type measuring machine main body 1 and a computer system 2 which controls the driving of the measuring machine main body 1 and executes necessary measurement data processing.
And a command input unit 3 for manually operating the measuring instrument body 1 and a printer 4 for printing out the measurement results.

The measuring instrument body 1 is configured as follows. That is, the work 1 to be measured is placed on the gantry 11.
2 is mounted, and the measurement table 13 is driven in the Y-axis direction by a Y-axis drive mechanism (not shown). An upwardly extending frame 14 is fixed to the rear end of the gantry 11.
A CCD camera 16 driven by an X-axis and Z-axis driving mechanism (not shown) is attached to the inside of a cover 15 projecting from the upper part to the front so as to face the measuring table 13 from the upper part. The work 1 is located at the lower end of the CCD camera 16.
2 is provided with a ring-shaped illumination device 17 for irradiating the illumination light.

The computer system 2 includes a computer main body 21, a keyboard 22, a mouse 23, and a CRT display 24. This system centered on the computer main body 21 is configured, for example, as shown in FIG. That is, the image signal of the work 12 captured by the CCD camera 16 is converted into multi-valued image data by the AD converter 31 and stored in the multi-valued image memory 32.
The multivalued image data stored in the multivalued image memory 32 is displayed on the CRT display 24 by the operation of the display control unit 33. On the other hand, operator commands from the keyboard 22 and the mouse 23 are transmitted to an interface (I / F) 34.
Is transmitted to the CPU 35 via. The CPU 35 executes various processes such as stage movement in accordance with instructions from the operator or programs stored in the program memory 36. The work memory 37 provides a work area for various processes of the CPU 35.

An X-axis encoder 41 and a Z-axis encoder 43 for detecting the position of the CCD camera 16 in the X-axis direction and the Z-axis direction, and a Y-axis encoder 42 for detecting the position of the table 13 in the Y-axis direction. Is provided,
Outputs from these encoders 41 to 43 are taken into the CPU 35. The CPU 35 drives the CCD camera 16 in the X-axis and Z-axis directions via the X-axis drive system 44 and the Z-axis drive system 46 based on the acquired information on each axis position and the above-mentioned operator's instruction. The table 13 is driven in the Y-axis direction via the shaft drive system 45. Thus, a stage moving operation is realized. Furthermore, the lighting control unit 39
An analog command voltage is generated based on the command value generated by the PU 35 and applied to the lighting device 17.

FIG. 3 shows the CR at the time of measurement by this image measuring device.
FIG. 4 is a diagram showing a display screen of a T display 24. The display screen is a color video window (image window) 5
1, a graphics window 52, a counter window 53, a function window 54, an illumination / stage window 55, and a measurement window 56. The color video window 51 displays a color image of the work 12 captured by the CCD camera 16, that is, a work image 57. Graphics window 5
2 includes design drawing data 58 corresponding to the work 12 captured by the CCD camera 16, specifically, IGES or D
A graphics image generated based on CAD data in a standard format such as the XF format is displayed. In the counter window 53, the center coordinates (X,
(Y, Z) is displayed. Function window 54
, Icons for activating microprograms for various measurement processes and calculation of measured values are arranged. The lighting / stage window 55 is a window for various setting operations regarding the lighting device 17 and the stage. The measurement window 56 is a window for performing a measurement operation according to the measurement microprogram selected in the function window 54.

Next, a method for obtaining the maximum value / minimum value in the designated direction of the image measuring apparatus thus configured will be described. FIG. 4 is a diagram showing a work image 62 displayed in a video window 51 and a tool 61 for detecting a maximum value and a minimum value according to the present invention. When evaluating the dimensions of the protruding portion or the recessed portion, the evaluation is generally performed with reference to a measurement coordinate system (work coordinate system in this example) XY. The measurement coordinate system also corresponds to a design coordinate system (a coordinate system serving as a basis for CAD data). Therefore, in this embodiment, an example in which the tool 61 is set to be parallel to the work coordinate system XY will be described. However, regardless of the work coordinate system XY, the tool 61 is set in parallel with the video window coordinate system.
1 may be fixed. In particular, when the tool 61 is fixed at the center of the video window coordinate system, it is possible to measure the lens aberration, illumination, and the like under the best conditions.

The work coordinate system XY and the video window coordinate system xy are usually associated with each other. Now, as shown in FIG. 4, the work coordinate system XY and the video window coordinate system x
Assuming that the shift amount of the origin position of y is Δx, Δy and the inclination is θ, the coordinates (x, x, y) of the work image 62 in the video window coordinate system designated by the mouse pointer 63
The relationship between y) and the coordinates (X, Y) of the same point in the work coordinate system is associated as shown in the following Expression 1. Here, α and β are enlargement / reduction rates in the x and y directions, respectively.

[0019]

(Equation 1)

As shown in FIG. 4, a detection tool 61 set in a work image 62 is a video window coordinate system xy.
Instead, they are generated along the work coordinate system XY. The detection tool 61 is set by clicking and dragging two diagonal points with the mouse pointer 63.
Mouse click and drag operations are usually
Form a rectangle with sides that are horizontal and vertical to the display screen.
On the other hand, in the case of the detection tool 61, an inclined rectangle is generated if the work coordinate system is inclined with respect to the video window coordinate system. As described above, when the detection tool 61 is generated (parallel) along the workpiece coordinate system (measurement coordinate system), it becomes easy to intuitively grasp the scanning direction for edge detection, and the setting of the detection tool is simple and accurate. become. Note that the tool 61 can also be set by directly inputting the position coordinates and the size for setting the numerical value from a keyboard with numerical values.

In this example, of the sides constituting the detection tool 61, two opposite sides 64a and 64b and two sides 65a and 65b orthogonal to the opposite sides are set so as to be parallel to the X axis and the Y axis, respectively. Generated. Arrows are added to the sides 64a and 64b, and indicate the scanning direction at the time of edge detection. One side 65b of the sides 65a and 65b has ×
A mark is added to indicate whether the maximum value or the minimum value is detected.

Next, the processing of the CPU 35 for detecting the maximum value will be described with reference to the flowchart of FIG. First,
The detection tool 61 is set in the video window 51, and the coordinate values of each vertex P1 to P4 of the detection tool 61 in the video window coordinate system (image data coordinate system) are obtained (S1). That is, as shown in FIG. 6, if two diagonal points P1 and P2 of the detection tool 61 are input by a mouse, the coordinate values (x1, y1), (x2, y) of the points P1 and P2.
From 2), vertices P3 and P
4 are calculated (x3, y3) and (x4, y4).

[0023]

X3 = x1 + acosθ y3 = y1 + asinθ x4 = x2-acosθ y4 = y2-asinθ a = (x2-x1) cosθ + (y2-y1) sinθ

At the time of dragging the mouse (when the coordinate value of the second point is not determined), the CPU 35
The coordinate values (x2, y2) of the points are read at regular time intervals, and the coordinate values of P3 and P4 are sequentially calculated to generate a rectangular tool 61 along the work coordinates.

When the detection tool 61 is set, the number of scans n for edge detection, the scan start point (xs, ys), and the scan end point (xe, ye) are 1, (x1,
y1) and (x3, y3) are set (S2). And
As shown in FIG. 7, from (xs, ys) to (xe, ye)
The image data is scanned up to the edge point P from the luminance information.
n is detected and stored in the work memory 37, and the length Ln from the start point (xs, ys) to the edge point Pn is represented by P
n and a pair of data are stored in the work memory 37 (S3).

This edge detection processing is performed from P1-P3 to P4
Repeating at a pitch of ΔY until −P2 (S4, S5),
As shown in FIG. 7, the edge point sequence data P1, P2,.
Pn, ... are required. Next, an edge point having the largest distance from the start point, that is, a point Pn having the largest Ln is selected as a candidate point (S6). Then, the obtained candidate point Pn
Is continuity confirmed from the edge information in the vicinity of the point in order to confirm whether is not noise (S7).
For example, as shown in FIG. 8A, a candidate point Pn and its neighboring edge points Pn-3, Pn-2,..., Pn + 2, Pn
When +3 is connected by a smooth curve, it is determined that there is continuity, and as shown in FIG. 3B, the candidate point Pn and its neighboring edge points Pn-3, Pn-2,. P
If n + 3 are not connected by a smooth curve, it is determined that there is no continuity. If continuity is not confirmed (S8), the point Pn is removed as noise (S9), and then the same processing is repeated with the point Pn having the largest Ln as a candidate point. If is confirmed (S
8) Then, the point Pn is output as the maximum value, and the process ends (S10).

Although the detection of the maximum value has been described above, in the case of detecting the minimum value, the edge point Pn having the minimum Ln may be set as the candidate point. As a tool, Figure 9
As shown in (a) and (b), if a point protruding to the side where the X mark exists on the rectangle is detected, in the case of (a), the most concave point (detection of the minimum value) , (B) is the most prominent point (detection of the maximum value).

As described above, according to this apparatus, the most protruding point or the most concave point in the measurement coordinate system can be detected by simply setting the detection tool 61 in the video window 51. Evaluation of the processing accuracy of the fitting portion and the like can be easily performed.

[0029]

As described above, according to the present invention, only by setting a tool in an image window, a scanning direction for detecting an edge with respect to a workpiece image in the tool is designated, and an edge is formed by a scanning process. The detected point and the most prominent point in the scanning direction among the detected edges are detected, and the tool is set with reference to the measurement coordinate system. Can be detected, and it is easy to evaluate the processing accuracy of the fitting portion.

[Brief description of the drawings]

FIG. 1 is a perspective view of a CNC image measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a computer system and peripherals in the same apparatus.

FIG. 3 is a diagram showing a display screen of a CRT display in the device.

FIG. 4 is a diagram showing a relationship between a work image displayed in a video window and a detection tool in the apparatus.

FIG. 5 is a flowchart of a maximum value detection process in the same device.

FIG. 6 is a diagram showing coordinates of each vertex of a tool in the apparatus.

FIG. 7 is a diagram showing an edge detection process in the maximum value detection process.

FIG. 8 is a diagram for explaining evaluation of continuity in the maximum value detection process.

FIG. 9 is a diagram illustrating an example of a detection tool.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Measuring machine main body, 2 ... Computer system, 3 ... Command input part, 4 ... Printer, 11 ... Base, 12 ... Work, 1
3 ... measurement table, 14 ... frame, 15 ... cover, 1
6 CCD camera, 17 lighting device, 21 computer body, 22 keyboard, 23 mouse, 24 CR
T display, 31 AD converter, 32 multi-value image memory, 33 display controller, 34 interface, 35
... CPU, 36 ... Program memory, 37 ... Work memory, 39 ... Lighting control unit, 41 ... X-axis encoder, 42 ...
Y-axis encoder, 43: Z-axis encoder, 44: X-axis drive system, 45: Y-axis drive system, 46: Z-axis drive system.

Claims (5)

[Claims] 1. A work image obtained by imaging a work is displayed in an image window, a rectangular tool is set in the image window, and the work image is scanned in a predetermined direction within the tool to scan the work image. An image measuring method for detecting an edge of a work image and detecting a point most protruding in the scanning direction among the detected edges, wherein the tool has a rectangle having a side parallel to a reference axis of a measurement coordinate system. And a scanning direction of the edge is designated by a pair of opposed sides, and a point protruding to which side of the edge is detected by another pair of opposed sides. Image measurement method. 2. The image measurement method according to claim 1, wherein the tool is set in the image window by designating two diagonal points. 3. A point most protruding in the scanning direction is an edge point obtained by sequentially scanning the workpiece image in the tool in the scanning direction at a constant interval in a direction orthogonal to the scanning direction. 3. The image measurement method according to claim 1, wherein a candidate point is obtained from a column, and the candidate point is determined by evaluating continuity between the candidate point and an edge point in the vicinity thereof. 4. A display means for displaying a work image obtained by imaging a work in an image window, a position designating means for designating an arbitrary position in the image window, and designation by the position designating means. Tool generating means for generating a rectangular tool in the image window based on the set position, and scanning a work image inside the rectangular tool generated by the tool generating means to determine an edge of the work image. Protruding point detecting means for detecting and detecting a point most protruding in the scanning direction among the detected edges, wherein the tool generating means has a rectangular shape having a side parallel to a reference axis of a measurement coordinate system. The scanning direction of the edge is designated by a pair of opposing sides, and the point protruding to either side of the edge is detected by the other pair of opposing sides. Image measuring apparatus, characterized in that to specify whether to. 5. A method according to claim 1, wherein the most protruding point detecting means is configured to sequentially scan a workpiece image in the tool in the scanning direction at a predetermined interval in a direction orthogonal to the scanning direction. 5. The image measuring apparatus according to claim 4, wherein a candidate point is obtained, and continuity between the candidate point and an edge point in the vicinity thereof is evaluated to determine a point most protruding in the scanning direction. .