JPH0650735A - Mark inspection device - Google Patents

Abstract

PURPOSE:To automatically inspect whether the color and size of a mark which is coated on a pulley is proper or not. CONSTITUTION:A pulley 1 where a plurality of marks with different colors are coated is shot by a color camera 23 of a shooting device 20. The color camera outputs three types of color signals R, G, and B. An image processing device 32 of a control panel 30 processes the color signals R, G, and B individually to judge the color and size of the marks. Further, the position and spacing pitch of an instrumentation area formed in a screen obtained by the image processing device 32 are compensated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mark inspection device,
It is possible to automatically determine whether or not the color and size of the mark on the peripheral surface of the inspection object are appropriate.

[0002]

2. Description of the Related Art As shown in FIG. 14, among pulleys of automobile parts, for example, a pulley 1 attached to a crankshaft has a mark M on its peripheral surface for timing adjustment.
Has been applied. Among the marks M, those indicated by M _W are white, those indicated by M _Y are yellow, and those indicated by M _O are orange. These marks M are formed by applying the marks M in a predetermined size with a predetermined color at a predetermined mark position by hand. When this pulley 1 is incorporated in an automobile engine, the phase of other pulleys is matched with the position of the mark M of a specific color as a reference according to the characteristics of the engine.

[0003]

By the way, since the mark M is applied by hand, it is necessary to inspect whether the mark M is applied correctly. Conventionally, this inspection was performed by a human. That is, it was visually inspected whether or not a mark of a predetermined color was applied in a predetermined size at a predetermined mark position. For this reason, fatigue was great, and there was a risk of making an inspection error.

In view of the above-mentioned prior art, the present invention provides a mark inspection apparatus capable of automatically and accurately inspecting whether the color and size of the mark are proper.

[0005]

The structure of the present invention for solving the above-mentioned problems is to determine whether or not the color and size of the marks of a work having a plurality of marks of different colors on its peripheral surface are good. A mark inspection device for inspecting a mark, the image of a mark in a color camera that photographs the mark and outputs three kinds of color signals, and in each of the three kinds of images obtained by binarizing the three kinds of color signals. The measurement area is generated at the position where the mark is formed, and the position and interval pitch of the measurement area are corrected based on the position of the mark image so that the mark image enters the measurement area. A processing device that determines the size of the mark by counting the number, determines the color of the mark based on which color pixel exists in each measurement area, and determines whether the color is good or bad. Characterized by .

[0006]

In the present invention, the color of the mark can be determined by image-processing the three types of signals individually, and it can be inspected whether this color is the set color. The size of the mark can be inspected by counting the number of pixels. Moreover, the mark image enters the measurement area by correcting the position and interval pitch of the measurement area.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, the configuration and operation of the mark inspection apparatus 10 according to the embodiment of the present invention will be described based on FIG. 1, and then the image processing procedure will be described. As shown in FIG. 1, the mark inspection device 10 has a photographing device 20 and a control panel 30.

In the photographing device 20, a light shielding case 2 is provided on the top of a camera stand 21 whose lower portion is anchored to the floor.
2 is provided. The light shielding case 22 is separable from the camera stand 21. A CCD color camera 23, an illumination lamp 24, and a proximity sensor 25 are installed in the light shielding case 22. The color camera 23 can slide in the α direction as shown in FIG. 2 or can move to the upper position as shown by the dotted line. Further, the pulley 1 is conveyed into the light shielding case 22 by the conveyor 26 through the window 22a formed on the lateral surface.

When the proximity sensor 25 detects that the pulley 1 has reached the inspection position in the light shielding case 22, the conveyor 26 stops and the position of the pulley 1 is fixed by a jig (not shown). The pulley 1 is illuminated by 24, and the color camera 23 photographs the mark applied to the peripheral surface of the pulley 1. The color image signal output from the color camera 23 is the cable 2
It is sent to the control panel 30 via 7. Details will be described later,
The control board 30 inspects the suitability of the mark based on the color image signal.

When the mark suitability inspection is completed, the pulley 1
The jig that fixed the
Starts to move, the tested pulley 1 is carried out of the light shielding case 22, and another new pulley 1 is carried into the light shielding case 22.

The upper surface of the light-shielding case 22 is a maintenance lid 22b, which is normally closed, but can be opened when adjusting the posture of the color camera 23 or performing maintenance.

On the other hand, the control panel 30 includes an image processing device 32, a notebook personal computer 33, a monitor 34, a display / setting device 3 in a control case 31 having casters with a brake.
5 and the like. The image processing device 32
The personal computer 33 plays a central role in processing the color image signal and inspecting the mark for suitability. Further, the display / setting device 35 sets data for inspection. As the data setting, a program indicating which color mark is applied at which mark position, or the like is set, or a threshold value for determination is set.

The configuration and function of the image processing device 32 will be described with reference to FIG. In FIG. 3, 51 is a video selector, 52 is an A / D converter, 53 is a binarization circuit, 54 is a binarization memory, 55 is a mask memory, 56 is a histogram generator, 57 is a grayscale memory, and 58 is a CP.
U and 59 are A / D converters. Video selector 51
Selects one of the red signal R, the green signal G, the blue signal B, and the monochrome signal Video sent from the CCD color camera 23. The selected signal is sent to the A / D converter 5
2 converts it into an 8-bit digital signal d (256 levels of gray level). The digital signal d is stored in the density memory 57, binarized by the binarizing circuit 53, and stored in the binary memory 54. The histogram generator 56 generates a histogram from the data of the density memory 57, and the application amount is obtained from this histogram.

Next, a method of determining mark suitability by image processing will be described. First, when the pulley 1 enters the light shielding case 22 and reaches the inspection position, the pulley 1 is clamped by the jig 2 as shown in FIG. As a result, the position of the pulley 1 in the vertical direction (Y direction) accurately matches the specified position.
In this state, the color camera 23 photographs the mark M, and the three primary color signals, that is, the red signal R, the green signal G, and the blue signal B
And output the black and white signal Video.

The control panel 30 receives the color signals R, G, B and performs image processing to determine whether the mark M is good or bad. The processing includes “teaching” and “inspection”. Therefore, the overall procedure of the process will be described with reference to FIG. 5, the “teaching” process will be described with reference to FIG. 6, and the “inspection” process will be described with reference to FIGS.

The entire flow is carried out according to the procedure shown in FIG. That is, initial setting is performed, data is input (steps 1 and 2), and the program is called (step 3). At this time, when a teaching command is issued from the display / setting device 35, teaching is performed (step 4).

In order to inspect, the program number is set in step 5 and the product number of the pulley 1 is set. It should be noted that the inspection is not performed when the instruction is not given (step 6). When the call completion lamp is turned on and the inspection start switch is turned on to capture data (steps 7 and 8), the inspection is started (step 9), the inspection lamp is turned on (step 10), and the inspection is executed (step 11). ). The various lamps and various switches described above are provided in the display / setting device 35. After all, it is understood from the main flow shown in FIG. 5 that "teaching" is performed first and then "inspection" is performed.

Next, the procedure of "teaching" will be described with reference to FIG. First, a teaching menu is displayed for parameter setting (steps 21 and 22). Then, in step 23, the respective binarization levels for the respective color signals R, G, B are set, and in step 24, the measurement areas A1 to A12 are set.
Set the position and size (see FIG. 7) and step 25
Set the program number and set pulley 1. Further, the judgment value of the number of pixels (area) (the size of the coating area) is set in step 26, and the position correction lines H _X1 , H _X2 , H _X3 , H _X4 , and H _Y (see FIG. 8) are set in step 27. To set. The "teaching" is mainly performed by the personal computer 33.

Next, the procedure and method of "inspection" will be described.
At the time of inspection, first, correction measurement is performed. That is, as shown in FIG. 4, since the pulley 1 is held by the jig 2, the position in the Y direction is accurate, but there is a possibility of lateral sliding or rotation. Directional correction is required. Therefore, as shown in FIG. 8, the image processing device 32 generates a plurality of position correction lines H _X1 , H _X2 , H _X3 , H _X4 extending in the X direction on the image. Change points P ₁ , P ₂ , ... Of these position correction lines H _{X1 to} H _X4
.. P ₁₂ is detected, and a position correction line H _Y extending in the Y direction is generated at a position inside a few pixels from the change point P ₁ .
The coordinates (x, x) of the intersection of the position correction lines H _X2 and H _Y
y) is taught as correction coordinates. Furthermore, the change point P ₁ ,
The pitch interval between the marks M is detected from P ₂ , ... P ₁₂ . When performing this correction measurement, the red signal R is used. By using the R signal, it is possible to detect the white mark M _{W, the} yellow mark M _Y, and the orange mark M _O.

When the above-mentioned correction measurement is performed, the results and the results are used to correct the positions and pitch intervals of the measurement areas A1 to A12. That is, regarding the position, the position correction line H _X2 ,
The positions of the measurement areas A1 to A12 are shifted by the correction coordinates (x, y) that are the intersections of H _Y. Therefore, as shown in FIG. 9, even if the pulley 1 is misaligned and held, the image of the mark enters the measurement areas A1 to A12.

The correction of the pitch intervals of the measurement areas A1 to A12 will be described with reference to FIGS. 10 (a), 11 (a) and 12 (a) show the pulley 1
FIG. 10 (b), FIG. 11 (b), FIG.
(B) shows an image processing screen.

As shown in FIG. 10A, the optical axis 23a of the color camera 23 is fixed when the pulley 1 is fixed by a jig.
On the other hand, when the numbers of the marks M arranged on the left and right are almost equal,
As shown in FIG. 10B, even if the pitch intervals of the measurement areas A1 to A12 remain the same, the images of the markers M all fall within the measurement areas A1 to A12.

By the way, as shown in FIGS. 11 (a) and 12 (a), when the pulley 1 is positionally fixed in a state of being rotated in the circumferential direction and the number of the marks M arranged on the optical axis 23a becomes uneven, When the pitch intervals of the measurement areas are equal, the mark M is displaced from the measurement area A as shown in FIG. Such a situation is more likely to occur as the diameter of the pulley 1 is smaller. This deviation occurs even if the position where the mark M is added is normal, and the position where the mark M is added is not abnormal. Therefore, in the present invention, FIG.
As shown in (b), the pitch intervals of the measurement areas A1 to A12 along the x direction are corrected so that all the images of the mark M enter the measurement areas A1 to A12. As described above, the pitch intervals are corrected according to the pitch intervals of the change points P1 to P12 (see FIG. 8).

As described above, according to the present invention, even if the position of the pulley 1 is fixed by the jig while being rotated in the circumferential direction, the area can be corrected according to the rotation.

When the correction measurement and the area correction are completed, the number of pixels is individually counted for each color signal R, G, B. That is, first, the red signal R is binarized and the measurement areas A1 to A12 are set as shown in FIG. Each of the measurement areas A1 to A12 is set in a portion where an image of the mark M is generated, corresponding to the size of the mark, and the position is shifted by the correction coordinate (x, y), and the pitch interval of the area is It has been corrected. And each measurement area A1-A
The number of pixels in 12 is counted. Similarly, for the green signal G and the blue signal B, the measurement areas A1 to A12 are also performed.
Count the number of pixels in.

If the color of the mark M is white, the measurement area A
All the pixels of R, G, B exist inside, and if the color of the mark M is yellow, the pixels of R and G exist inside the measurement area A, and if the color of the mark M is orange, the measurement area A R in
There are pixels of. The peripheral surface of the pulley 1 is black. Therefore, the color of the mark M can be discriminated by inspecting which color pixel exists in each measurement area A. By comparing the color of this mark with the color of the mark taught in advance, it can be determined whether or not the mark M of the correct color is applied.

Further, by comparing the count number of pixels in each measurement area A with a value taught in advance, it is possible to determine whether or not the size of the mark M is proper.

Next, the overall procedure of the inspection will be described with reference to FIG. First, the parameters are set by the program number (step 31), it is confirmed that the work (pulley) is present and the inspection is not completed, and the color signals R, G, B are checked.
Is captured as an image (steps 32 to 37). In the inspection, the number of R, G, and B pixels is counted after the correction measurement is performed (steps 38 to 40). The color and size of the mark are judged, and the quality is judged (steps 41 and 42). If the mark is normal, the next pulley is inspected, and if the mark is abnormal, the buzzer sounds (step 44).

When the mark is abnormal, the inspection is performed again (steps 45 to 48). If it is determined to be normal by the re-inspection, the next pulley is inspected, and if abnormal, the mark is determined to be abnormal and the buzzer is stopped (steps 49, 5).
0).

[0031]

According to the present invention as specifically described in connection with the above embodiments, it is possible to automatically, accurately and promptly inspect the quality of the color of the mark and the size of the mark.

Further, according to the present invention, even if the work is rotated and fixed in the circumferential direction, the position of the measurement area and the interval pitch are corrected, so that the mark inspection can be accurately performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a mark inspection device according to an embodiment.

FIG. 2 is a configuration diagram showing a photographing device.

FIG. 3 is a block diagram showing an image processing apparatus.

FIG. 4 is an explanatory view showing a state in which a pulley is held.

FIG. 5 is a flowchart showing a main operation of the embodiment.

FIG. 6 is a flowchart showing the teaching operation of the embodiment.

FIG. 7 is an explanatory diagram showing a measurement area.

FIG. 8 is an explanatory diagram showing a position correction line.

FIG. 9 is an explanatory diagram showing a state in which a pulley is held.

FIG. 10 is an explanatory diagram showing mark positions and image states.

FIG. 11 is an explanatory diagram showing mark positions and image states.

FIG. 12 is an explanatory diagram showing mark positions and image states.

FIG. 13 is a flowchart showing the inspection operation of the embodiment.

FIG. 14 is a perspective view showing a pulley with a marker.

[Explanation of symbols]

1 Pulley 2 Jig 10 Mark Inspection Device 20 Imaging Device 21 Camera Stand 22 Shading Case 22a Window 22b Maintenance Lid 23 Color Camera 24 Lighting Lamp 25 Proximity Sensor 26 Conveyor 27 Cable 30 Control Panel 31 Control Case 32 Image Processing Device 33 Personal Computer 34 monitor 35 display and setting device _{M, M W1, M Y,} M O mark A1~A12 measurement area _{H X1, H X2, H X3} , H X4, H Y position correction line

Claims (1)

[Claims] 1. A mark inspection apparatus for inspecting whether or not the color and size of a mark of a work having a plurality of marks of different colors on its peripheral surface are inspected. A color camera that outputs three types of color signals, and a measurement area is formed at a position where a mark image is formed in each of the three types of images obtained by binarizing the three types of color signals, and the mark image Corrects the position and interval pitch of the measurement area based on the position of the mark image so as to enter the measurement area, and determines the size of the mark by counting the number of pixels indicating the mark in each measurement area, A mark inspection apparatus comprising: a processing device that determines the color of a mark based on which color pixel exists in each measurement area and determines whether the color is good or bad.