JPH07151702A - Inspection equipment - Google Patents

Abstract

PURPOSE:To exactly position an inspection window by moving the window for the distance corresponding to the error when the error exists between the reference position of an window for position correction and the detected position of brightness changing part. CONSTITUTION:The window setting part sets a window 120 for position correction in the image 110 of an object to be inspected 100. At this moment, it detets the boundary 111 of brightness which is generated by the shadow 102 at the level difference part 101 of the object 100. The darkness of each pixel in the window 120 is integrated in y-axis direction to produce darkness signal 140. When there is an error between the specific position 121 of the window 120 and the low level part 141 of the signal 140, the window 120 is moved to x-axis direction for the distance (d) corresponding to the error and this difference is made 0. As the result, the boundary 111 agrees to the part 141 and the window setting part 22 positions the window 120 to the point set in advance against the object 100. A properness judgment part 23 judges good or bad of the object 100 based on the image of the inspection window 130 by the window setting part 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article inspection apparatus for determining the quality of an object to be inspected.

[0002]

2. Description of the Related Art Some of the inspection devices for articles use image processing technology to judge the quality of an inspection object. Using this inspection device, it is possible to detect an unpainted portion of the inspection object, detect a defective appearance, detect a chip, and the like.

This inspection apparatus generally performs image processing on an image of an object to be inspected taken by a camera to judge pass / fail. At this time, the inspection device determines the position of the inspection target object with respect to the camera, and uses the image photographed after that for determining the quality. For positioning, a positioning device using a limit switch or the like is provided.

However, in order to improve the positioning accuracy and improve the inspection accuracy, the structure of this device becomes complicated and the cost becomes high. Therefore, there is an inspection method for performing positioning by software. This method is disclosed in JP-A-3-166666.
No. 3 publication.

The inspection apparatus using this method, as shown in FIG. 7, takes an image of the object 100 to be inspected with the camera 50 and determines an image 61 from the camera 50 when determining the quality of the object 100 to be inspected, for example. Is displayed on the monitor 60. A position correction window 62 is set for this image 61, and the center of gravity P1 is calculated from the level value of the data of the image 61. When there is an error between the center of gravity P1 and the reference value preset in the position correction window 62, the position correction window 62 is moved by the amount of this error, and the error is set to zero.

After that, the inspection device determines the quality of the inspection object 100 based on the image of the inspection window 63 set at a predetermined position with respect to the image 61.

[0007]

In the inspection apparatus using the soft positioning method, the center of gravity P1 is calculated from the level value of the data of the image 61. At this time, for example, when a large-area chipping occurs on the inspected object 100 as a defect, the position of the original center of gravity P1 of the inspected object 100 and the center of gravity P2 obtained from the image of the inspected object 100 having a defect. Is different from. As a result, the inspection window 63 cannot always be set at the same position with respect to the image 61 of the inspection object 100. For this reason, there are times when this chipping is not detected, and the reliability of the inspection accuracy of the inspection object 100 becomes poor.

An object of the present invention is to eliminate the above drawbacks and to provide an article inspection apparatus which enables accurate positioning of an inspection window.

[0009]

In order to achieve the object, the present invention comprises image input means for generating an image of an object to be inspected, and the quality of the object to be inspected is determined based on the image of the image input means. In the device for inspecting an article, the position correction window is set in the image from the image input means, and the light / dark change portion at the predetermined position of the inspection object is detected from the image in the position correction window, If there is an error between the stored reference position of the position correction window and the position of the detected light / dark change portion, the position correction window is moved by a distance corresponding to this error, and the position correction window is displayed. On the other hand, it has an inspection means for determining the quality of the inspection object from the image in the inspection window set at a predetermined position.

[0010]

In this invention, the object to be inspected has a stepped portion or a pattern at a predetermined position. Image input means
When the object to be inspected is photographed, an image with light and darkness is generated in the step portion and the pattern portion.

The inspection means sets a position correction window on the image from the image input means. From the image in the position correction window, the light / dark change portion of the inspection object is detected. When there is an error between the detected position of the changed portion of brightness and the reference position stored in advance, the position correction window is moved by a distance corresponding to this error. Then, the quality of the object to be inspected is determined from the image in the inspection window set at a predetermined position with respect to the position correction window.

[0012]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. This inspection apparatus for articles determines the quality of the inspection object 100 having the step portion 101.

This article inspection apparatus is composed of image input means 10
And an inspection unit 20 and an output unit 30. The image input means 10 includes a light source unit 11 and a TV camera 12,
The inspection unit 20 includes an A / D (analog / digital) conversion unit 21, a window setting unit 22, and a pass / fail judgment unit 23.

The light source section 11 of the image input means 10 is provided with a light source 11A inside, and the stepped portion 101 of the inspection object 100 is provided.
In order to generate a shadow 102 at
Illuminate 0 at an angle. As the light source 11A, there is a halogen lamp or the like.

The TV camera 12 photographs the object 100 to be inspected from the side where the step portion 101 is located. Then, an image signal representing the photographed image of the inspection object 100 is output.
This image signal is an analog quantity. As the TV camera 12, there is a CCD (charge coupled device) area sensor or the like.

In the image input means 10, the light source section 11 and the TV
The camera 12 is arranged as shown in FIG. That is, the distance from the light source unit 11 to the measuring table 201 is H1, and the distance from the lens 12A of the TV camera 12 to the measuring table 201 is H2. In addition, the optical axis 202 of the light source unit 11
The angle of intersection between the optical axis 203 and the optical axis 203 of the TV camera 12 is θ.
The distances H1 and H2 and the angle θ are values set in advance in order to bring the shadow 102 of the inspection object 100 into an optimum state at the time of measurement.

The A / D converter 21 of the inspection means 20 is a TV
The analog image signal from the camera 12 is converted into a digital image signal.

As shown in FIG. 3, the window setting unit 22 sets a rectangular position correction window 120 in the image 110 of the inspection object 100 represented by the image signal from the A / D conversion unit 21. . In addition, the window setting unit 22
Sets the rectangular inspection window 130 in a predetermined positional relationship with the position correction window 120.

The window setting unit 22 sets the position correction window 120 on the image 110 at a predetermined position. At this time, the shadow 102 generated in the step portion 101 of the inspection object 100 is used. That is, shadow 1
A bright / dark boundary 111 generated by 02 is detected. The boundary 111 corresponds to the step portion 101 of the inspection object 100. Further, the boundary 111 is the position correction window 12
The image input means 10 is preset so as to be positioned in a direction parallel to the 0 side 120A, that is, parallel to the y-axis direction.

The window setting section 22 integrates the density values of each pixel in the position correction window 120 in the y-axis direction to generate a density signal 140. The density signal 14
A portion having the highest density of 0, that is, a portion 141 having a low level in the density signal 140 is determined as the boundary 111.

When there is an error between the predetermined position 121 of the position correction window 120 and the low-level portion 141 of the density signal 140, the window setting section 22 moves the position correction window by a distance d corresponding to this error. 12
The position correction window 120 is moved in the direction parallel to the side 120B of 0, that is, the x-axis direction, and this error is set to zero. As a result, as shown in FIG. 4, the boundary 111 and the low-level portion 141 coincide with each other, and the window setting unit 22
Displays the position correction window 120 on the inspection object 100.
Position it at a preset position with respect to.

The pass / fail judgment unit 23 is a window setting unit 22.
Based on the image of the inspection window 130, the quality of the inspection object 100 is determined. Therefore, the characteristic amount of the non-defective object 100 to be inspected is stored in advance. And
From the image of the inspection window 130, the characteristic amount such as the area and variance of the inspection target object 100 is measured, and the measured characteristic amount is compared with the stored characteristic amount, and the inspection target object 10 is measured.
The quality of 0 is judged.

The output unit 30 displays the quality judgment result of the quality judgment unit 23, the settings of the position correction window 120 and the inspection window 130 on a monitor device (not shown).

Next, the operation of this embodiment will be described.

Here, for example, the roof tile 300 shown in FIG. 5 is used as the inspection object 100. And this example
It is placed after the roof tile 300 manufacturing line to determine whether the roof tile 300 is chipped or unpainted. At this time, the roof tile 300 is
It is pre-positioned in the y-axis direction by a positioning device (not shown).

When the roof tile 300 comes under the TV camera 12, the TV camera 12 photographs the roof tile 300 and sends an image signal to the A / D converter 21. The A / D conversion unit 21 converts an analog image signal into a digital image signal and sends it to the window setting unit 22.

Upon receiving the image signal, the window setting section 22 performs the processing shown in FIG. That is, when the window setting unit 22 receives the image signal (step S1),
Position correction window 1 for the image 110 of the roof tile 300
20 is set (step S2). This state is displayed on the monitor 31 of the output unit 30.

After step S2, the window setting unit 22
The density value of each pixel in the position correction window 120 is integrated to generate a density signal 140, the boundary 111 is checked from the density signal 140, and the step portion 301 of the roof tile 300 is measured (step S3).

At this time, if there is an error between the low-level portion 141 of the density signal 140 and the predetermined position 121 of the position correction window 120, the position correction window 120 is moved in the x-axis direction to move the roof tile 300. On the other hand, the position correction window 120 is located at a predetermined place.
When the position of the position correction window 120 is determined, the window setting unit 22 sets the inspection window 130 for the image 110 of the roof tile 300 (step S4).

When the inspection window 130 is set, the pass / fail judgment unit 23 causes the image 110 in the inspection window 130 to be displayed.
A is binarized (step S5), and a feature amount such as an area is measured based on the binarized image (step S5).
6). After that, the quality determination unit 23 determines the quality of the roof tile 300 by comparing with the feature amount stored in advance (step S7).

In this way, according to this embodiment, the setting position of the inspection window 130 can be accurately determined for the image 110 of the roof tile 300 having the step portion 301, so that the inspection accuracy of the roof tile 300 can be improved. .

Although the quality of the roof tile 300 is determined in this embodiment, the object to be inspected is not particularly limited to this.
What has a stepped portion may be used. Further, the position may be determined by using the lightness and darkness of the pattern printed on the inspection object instead of the stepped portion.

Further, in this embodiment, the inspection window 130 is set by detecting the specific step portion 301 of the roof tile 300. However, since the roof tile 300 has a plurality of steps,
If the inspection window 130 is set so as to maintain a predetermined positional relationship with each step, it is possible to determine whether the step is detected or not.

Further, in this embodiment, the roof tile 300 is photographed by using one image input means 10, but the invention is not particularly limited to this. For example, two devices of this embodiment may be prepared and each half of the roof tile 300 may be inspected.

[0036]

As described above, according to the present invention, when the quality of an object to be inspected having a light and darkness at a predetermined position is determined, the inspection window is set with reference to the changed portion of the light and dark. It is possible to accurately determine the inspection position of the object. Thereby, the inspection accuracy of the inspection object can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between a light source unit and a TV camera.

FIG. 3 is a diagram showing a position correction window and an inspection window.

FIG. 4 is a diagram showing a position correction window and an inspection window.

FIG. 5 is a perspective view showing an example of an object to be inspected.

FIG. 6 is a diagram showing processing in a window setting unit and a quality determination unit.

FIG. 7 is a schematic view showing a conventional inspection device.

[Explanation of symbols]

 10 image input means 20 inspection means 100 object to be inspected

Claims (1)

[Claims] 1. An inspection apparatus for an article, comprising image input means for generating an image of an object to be inspected, and determining whether the object to be inspected is good or bad based on the image of the image input means. The position correction window is set in the image of the position correction window, the change portion of the lightness and darkness at the predetermined position of the inspection object is detected from the image in the position correction window, and the reference position of the position correction window is stored in advance. When there is an error in the position of the detected change in brightness and darkness, the inspection window is moved by a distance corresponding to this error and is set at a predetermined position with respect to the position correction window. An inspection device for articles, comprising inspection means for determining whether the object to be inspected is good or bad from the image inside.