JPH0552768A - Surface defect inspecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a low-cost inspecting apparatus simplified in structure which can automatically detect an abnormal part and evaluate and distinguish a flaw from image signals obtained when the surface of a to-be-inspected material is photographed. CONSTITUTION:This apparatus consists of a photographing part 1 which photographs the surface of a to-be-inspected material, a recording device 5 for recording photographed two-dimensional signals, an image signal extracting part 2 for taking out, part of the two-dimensional signals, a signal processing part 3 which processes the signals of the extracting part 2 thereby to detect a defective part on the surface of the material, a timing controlling part 4 for controlling the recording timing of the recording device 5, an image processing part 6 for analyzing the defective part of the surface and a display part 7 for displaying the result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting surface defects of a moving test material such as a rolled steel plate and for judging and identifying the detected defects.

[0002]

2. Description of the Related Art (1) Visual inspection means by an operator as a technical means for inspecting a surface defect of a material to be inspected in a transfer process of a sheet-like material to be inspected such as a steel plate in a rolling line.
(2) A means for irradiating a material to be inspected with laser light or the like and detecting a defect from the reflected light, (3) A means for directly taking a two-dimensional image of the surface of the material to be inspected, such as a combination of a camera and a strobe. , Etc. are disclosed and partially put into practical use. But,
It is inhumane for the visual inspection means by the operator not only to cause individual differences in the inspection result by the operator but also to perform mental and heavy labor such as defect inspection for a long time. Further, although the means for detecting defects by reflected light such as laser light is excellent in terms of high-speed response, it has not yet been possible to determine the type and grade of the detected defects. Therefore, to automatically perform the judgment and identification of defects,
The most effective means is to analyze a two-dimensional image of the surface of the test material.

The biggest problem of the means for analyzing a two-dimensional image is that a storage device such as a large-capacity memory is required for recording a photographed image and that it takes time to process an image, which is applied to a high-speed line. There is something that cannot be done. In order to solve this problem, JP-A-2-38957 and JP-A-3-3514 are used.
Japanese Patent Publication No. 8 discloses a device that includes a detection unit that only detects defects, an image capturing unit that captures and processes a required amount of images according to a trigger signal from the detection unit, and a processing unit thereof. ing.

[0004]

However, the above-mentioned conventional apparatus requires two devices, a defect detecting section and an image capturing section, which leads to a significant increase in cost and the apparatus configuration. There was a problem that it became complicated. The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to provide a surface defect inspection apparatus capable of inspecting a surface defect with a simple configuration in a step of transferring a material to be inspected. To do.

[0005]

The present invention is to solve the above-mentioned problems and adopts the following technical means. That is, (a) a photographing unit for repeatedly photographing the surface of the material to be inspected, (a) a recording device for recording the photographed two-dimensional image signal, and (c) an image signal extracting unit for extracting a part of the two-dimensional image signal. A signal processing unit that processes the extracted signal to detect surface defects in the material to be inspected, and a trigger signal is generated in response to the defect detection signal from the O signal processing unit to set the timing at which the recording device records a two-dimensional image signal. It is characterized by comprising a timing control unit, an image processing unit for processing a two-dimensional image recorded by a recording device and analyzing a surface defect portion, and a display unit for displaying an analysis result of the image processing unit. This is a surface defect inspection device.

[0006]

According to the present invention, by detecting a part of the two-dimensional image signal of the surface of the material to be inspected obtained by the photographing unit and processing the extracted signal at high speed, it is possible to detect a flaw (surface defect portion). The timing controller generates a trigger signal. In response to the trigger signal, after the image recording unit records the image of the flaw, the image processing unit determines and identifies the flaw. That is, the present invention does not perform image processing on all transferred test materials, but the image processing unit analyzes only the image of the test material in which a flaw is present. There is a margin to execute the complicated processing required for time. The analysis result is confirmed by the operator and the inspector on the display unit. Alternatively, it is transmitted to the host computer. Further, according to the present invention, since the respective constituent elements are integrally formed, it is possible to perform the defect inspection of the material to be inspected with this single apparatus.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a structural explanatory view of an embodiment of a surface defect inspection apparatus according to the present invention. In FIG. 1, the imaging unit 1 images the surface of the material 10 to be inspected as a two-dimensional image. Shooting unit 1
For example, an electronic shutter high-speed TV camera or the like can be used. An analog signal representing a two-dimensional image is continuously output from the photographing unit 1. For example, since this analog signal is obtained by scanning a two-dimensional image like a TV screen signal, the image signal extraction unit scans the upper part of each two-dimensional image by the number of horizontal scanning lines. The signal can be taken out periodically. The signal processing unit 3 executes the abnormal portion detection processing on the extracted analog signal at high speed.

For example, as shown in FIG. 2, an analog signal 18 for one scanning line (20 indicates an abnormal portion) is supplied to a clock 2
When the signal is divided by the signal divider 22 according to one pulse and input to the integrating amplifier group 23 having the integrating amplifiers 23a corresponding to the number of the divided signals, the abnormal portion 20 in the signal, that is, the extracted two-dimensional image signal The output of the integrating amplifier corresponding to the part indicating the flaw shows a clearly different value compared to other integrating amplifiers. The output of the integration amplifier group 23 is transmitted to the comparison circuit 24, and the comparison circuit 24 receives the integration amplifier 23a.
When a certain threshold value or more is shown, the output signal 25 indicating the abnormality is generated. In this way, the signal processing unit 3 can be realized by a combination of analog circuits, and therefore, extremely high-speed processing is possible as compared with the case where image processing calculation is performed.

The timing control section 4 receives the output signal 25 indicating an abnormality transmitted from the signal processing section 3, and receives the image processing section 6
Generates a trigger signal indicating the timing at which the recording device 5 records the secondary image to be analyzed. The recording device 5 is
A preset number of two-dimensional images are recorded, and the image processing unit 6 performs image analysis according to a predetermined algorithm. For example, the size, length, width, brightness, peripheral length, and periodicity of the abnormal portion 18 are obtained to determine whether or not the detected abnormal portion 18 is a harmful flaw, and the type and grade of the flaw. The analysis result of the image processing unit 6 is output by the display unit 7.

FIG. 3 is a flow showing a flow of a series of processes necessary for defect inspection. The extraction rate of the image signal by the image signal extraction unit 2 can be determined by the moving speed of the test material 10 and the imaging speed of the imaging unit 1. For example, when the material to be inspected 10 has a speed capable of capturing the same flaw on the surface of the material to be inspected 5 by the image capturing unit 1 five times, if at least a scanning signal of 20% or more of the tip of the two-dimensional image is extracted, 1
The signal processing unit 3 has an opportunity to process a target flaw more than once. In this case, the timing control unit 4 uses the signal processing unit 3
A trigger may be generated so that the recording device 5 is activated from the image signal subsequent to the image signal processed by. In this example, the image processing unit 6 can process four images in which the same flaw is captured.

[0011]

As described above, according to the apparatus of the present invention, an abnormal portion can be detected, a flaw can be determined and identified from an image signal of a material to be inspected, so that an efficient defect inspection can be performed by one apparatus. It can be performed. That is, since high-level analysis by image processing can be performed only on a required image, not only the defect image is displayed but also the defect determination can be automated. As a result, it is possible to reduce the occurrence of defective materials in the next process, improve the product yield, shorten the process,
Effects such as automation can be obtained.

Further, the apparatus structure can be simplified, and the apparatus cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration explanatory diagram of an embodiment of a surface defect inspection apparatus according to the present invention.

FIG. 2 is a block diagram showing an example of a signal processing unit of the present invention.

FIG. 3 is a flow chart showing a signal processing procedure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photographing section 2 Image signal extraction section 3 Signal processing section 4 Timing control section 5 Recording apparatus 6 Image processing section 7 Display section 18 Analog signal 20 Abnormal section 21 Clock 22 Signal divider 23 Integrating amplifier group 23a Integrating amplifier 24 Comparison circuit 25 Output signal

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location G06F 15/62 400 9287-5L H04N 7/18 B 8626-5C

Claims (1)

[Claims] 1. A photographing unit for repeatedly photographing the surface of a material to be transferred, a recording device for recording the photographed two-dimensional image signal, and an image signal extracting unit for extracting a part of the two-dimensional image signal. A signal processing unit for processing the extracted signal to detect a surface defect portion of the test material, and a timing for generating a trigger signal according to the defect detection signal of the signal processing unit and recording the two-dimensional image signal by the recording device are set. A timing control unit for setting, an image processing unit for processing a two-dimensional image recorded by the recording device to analyze a surface defect portion, and a display unit for displaying an analysis result of the image processing unit. And surface defect inspection equipment.