JPH0238953A - Surface defect inspection device - Google Patents

Abstract

PURPOSE:To perform high-accuracy inspection at high speed by making a primary decision on the kind and grade of a surface defect by a computer, then moving a projector and a camera in the width direction of an object material of surface defect inspection and obtaining a still image by photography, and making a secondary decision. CONSTITUTION:A steel plate 10 and a detector 12 project light on the surface and detect its reflected light, and the computer 16 decides (primary decision) on the kind and grade of the surface defect through a defect detecting circuit 14 and also calculates the lateral position of the defect. A control circuit 22 drives a moving device 21 according to the lateral position information of the defect from the computer 16 and moves the stroboscopic device 18 and camera 20, thereby setting a photographic point. Further, the control circuit 22 makes the stroboscopic device 18 emits light when the surface defect reaches the photographic point Xa of the camera 20 to photograph the surface defect and an inspector makes the secondary decision on a surface defect image displayed on a monitor 30 as the still image.

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD 1 This invention relates to an improvement in a surface defect inspection device that can efficiently and accurately inspect surface defects on a moving test material such as a rolled steel plate. [Prior Art] Inspection of surface defects on materials to be inspected during transportation, such as steel plates on a rolling line, has conventionally been carried out by visual inspection by an operator, by irradiating the surface of the material to be inspected with laser light, etc., and using the reflection. For example, as disclosed in Japanese Patent Application Laid-open Nos. 53-12383, 118289-1980, and 14984-1984, a method of inspecting the material to be inspected for defects using a camera and strobe is disclosed. There are methods such as capturing a still image of the surface and performing defect inspection based on it.

[Problems to be Solved by the Invention] The above-mentioned visual inspection has a problem in that when the line speed of the material to be inspected exceeds a certain value, the number of missed inspections increases and the inspection becomes close to an uninspected state. Additionally, defect inspection equipment that uses reflection of laser light, etc. does not necessarily show a superior match rate compared to visual inspection, depending on the type of surface defect on the material being inspected, and may allow a certain degree of misjudgment. There is a problem in that it has to be used while In addition, with the surface defect inspection method using a camera and a strobe, it is unclear whether there are defects on the surface of the material to be inspected. There is a problem in that it is not possible to extract only a certain part and perform a surface defect inspection. [Purpose of the Invention] This invention has been made in view of the above-mentioned conventional problems, and has made it possible to inspect surface defects of moving steel plates and other materials to be inspected at high speed and with high precision. The purpose of the present invention is to provide a surface defect inspection device. (Means for Solving the Problems) The present invention provides a detector that irradiates the surface of a moving test material with a light beam and detects surface defects of the test material based on the state of reflection, and a detector that detects surface defects of the test material based on the state of reflection of the light beam. A calculator for calculating the type, grade, and position of the surface defect in the width direction of the specimen based on the detected surface defect detection signal, and a computer for calculating the type and grade of the surface defect output from the 11i machine ,
Based on a floodlight that irradiates light onto a defect that needs to be photographed, a camera that photographs the defect at the timing of the irradiation, and a position signal of the surface defect in the width direction of the material to be inspected from the computer,
The above object is achieved by configuring a surface defect inspection apparatus by the projector and a moving device for moving the camera to the position. [Operation] In this invention, first, the surface defect of the material to be inspected is detected by a detector, and the type and grade of the surface defect is first determined by a computer based on the detection signal, and then photography is required. For surface defects only, the projector and camera are moved to the position of the corresponding surface defect in the width direction of the material to be inspected, and the defect is photographed to obtain a still image, and based on this still image, the inspector makes a secondary judgment.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this embodiment includes a light emitter/receiver that irradiates the surface of a steel plate 1o in a rolling line with a laser or light and receives the reflected light. A detector 12 for detecting surface defects, a defect detection circuit 14 for processing the surface defect detection signal obtained by this detector 12 in a hardware manner, and a signal from the defect detection circuit 14 is taken in and processed in a software manner. A calculation tool 16 that processes the surface defects, determines the type and grade of the surface defects, and calculates the position of the surface defects in the width direction of the steel plate 10, and this total! [1
A strobe 1 that irradiates light to defects that need to be photographed based on the type of surface defect and grade signal output from 6.
8 and a camera 2 that photographs the defect at the irradiation timing.
0, a moving device 21 that moves the strobe 18 and camera 20 in the width direction based on a width direction position signal of the defective steel plate 10 from the computer 16, and an i! 1
1Jtl] and a defect inspection device 24 including a denunciation circuit 22 that performs the following. The defect inspection device W124 also includes an image processing circuit 26.
, image input/output circuit 28, timing! 11 control circuit 18A
and 2OA, a monitor 30 and a keyboard 32. As shown in FIG. 2, the moving device 21 includes a truck 37 on which the strobe 18 and camera 20 are placed, a motor 38 attached to the truck 37, and a motor 38.
The pinion 40 attached to the output shaft of
It is comprised of a rack 42 arranged and fixed in the width direction and horizontal direction of the steel plate 10 so as to mesh with the pinion 40, and a pulse generator 44 that outputs a pulse signal in accordance with the rotation speed of the binion 40. That is, the moving device 21 moves the moving unit 40 by the motor 38.
The steel plate 1 is rotated along the rack 42.
The trolley 37 moves in the width direction of the steel plate 10, and drives the strobe 18 and camera 20 in the width direction of the steel plate 10. The computer 16 includes a CRT 16A for displaying information on surface defects determined in the calculation 8116, and this CRT.
A keyboard 16B is connected to the keyboard 16B for the inspector to input whether or not the surface defect information displayed on the screen 16A should be inspected by the defect inspection device 24. Further, the calculation 1116 is configured to receive a pulse signal output from the pulse generator 34 as an input. This pulse generator 34 is connected to a roll 36 that rolls into contact with the steel plate 10 so as not to cause slip, and outputs a pulse signal in accordance with the rotational speed of the roll 36. Museum defect inspection system! The #JI11 circuit 22 seen in 24 is
Surface defect information input from calculation 1116 and total amount of $1
8116 determines the timing based on the timing signal that the detected surface defect has reached the strobe 18 and camera 20 position by tracking the detected surface defect to the detector 12 based on the pulse signal from the pulse generator 34. The strobe 18 and camera 20 are operated via the control circuits 18A and 2OA. Also, ill'f
The a circuit 22 moves the moving device 21 based on the position signal of the surface defect in the width direction of the steel plate 10 inputted from the computer 16.
is moved to a photographing point in the width direction of the steel plate 10 by the camera 20. The image input/output circuit 28 takes in image information of surface defects on the steel plate 10 obtained by the camera 20. Further, the image processing circuit 26 performs image processing such as defect determination based on the image signal taken in by the image input/output circuit 2, and displays the defective image on the monitor 30 as a still image. The keyboard 32 performs a secondary judgment such as the pIM grade of the surface defect based on the defect image displayed on the monitor 30, and then transmits the judgment result to the computer 16 by the inspector via the image processing circuit 26 and the control circuit 22. This is what you have to input. Next, the steel plate 10 is inspected by the surface defect inspection apparatus according to the above embodiment.
The process of inspecting for surface defects will be explained. While the steel plate 10 is moving to the left in FIG. 1 on the rolling line, the inspection hanger 12 projects a laser or light onto its surface, and receives the reflected light with a light receiver. Defects on the surface of the steel plate 10 are detected from the reflected state, and surface defect information is outputted to the total 1i 1116 via the defect detection circuit 14. The computer 16 processes the signal from the defect detection circuit 14,
The type and grade of the detected surface defect is determined (first determination), and the position of the surface defect in the width direction of the steel plate 10 is calculated. Here, as shown in FIG. 2, the position of the surface defect in the steel plate width direction from the calculator 16 is calculated in units of 1001 m from one end of the steel plate 10 in the width direction, for example, the edge 10P of the operator 11I. do. That is, 100 (i-1>n~1
If surface defects occur in the range of 00(i)n,
The widthwise position of the surface defect is set as the i-th position, and a position signal thereof is output. On the other hand, in the calculation method 16, the surface defect detected by the detector 12 is calculated based on the pulse signal inputted by the pulse generator 34.
From the detection point Xo to the shooting point of the camera 20) (tracking for a distance
Taking into consideration the timing adjustment time of the strobe 18, a timing signal is output to the control circuit 22 in the defect inspection device 24 when the surface defect arrives a little before the photographing point xa. Here, the surface defect information that has been primarily determined by the computer 16 is displayed on the CRT 16A, and is sent from the computer 16 based on the conditions set in advance by the inspector using the keyboard 16B for the surface defect information displayed on the CRT 16A. The signal is sent to the control circuit 22. The control circuit 22 drives the moving device 21 based on the position signal of the surface defect in the width direction of the steel plate 10 inputted from the computer 16, and moves the strobe 18 and the camera 20 to correspond to the width direction 1 of the surface defect. to set the shooting point. As described above, the width direction position signal of the surface defect outputted from the computer 16 to the control circuit 22 is the i-th signal. Therefore, the control circuit 22 moves the truck 37 based on the i-th position signal, and the moving layer of the truck 37 receives a pulse signal from the pulse generator 44 that detects the rotation speed of the binion 40. By feeding back the strobe 18 and camera 20, the strobe 18 and camera 20 are set at predetermined positions in the width direction. Furthermore, based on the timing signal input from the computer 16, the circuit 22 causes the strobe 18 to emit light via the timing control circuits 18A and 2OA when the surface defect reaches the photographing point Xa of the camera 20. At the same time, the surface defects of the steel plate 10 are photographed by the camera 20. Here, if the distance mx from the detection point Xa by the detector 12 to the photographing point xa is too short, the corresponding Since surface defects may pass through the photographing point Xa, the line speed of the steel plate 10, the moving speed and moving distance of the trolley 37, and the distance llI×
By adjusting the surface defects, the photographing point) (a
The table 1 [37 is set in advance so that it moves to a predetermined position in the width direction before reaching the position. The surface defect information of the steel plate 10 that is shadowed by the camera 20 is taken in as an image into the image input/output circuit 28, and the image taken into this image input/output circuit 28 is transferred to the image processing circuit 26.
Image processing such as defect determination is performed at , and the surface defect is further displayed as a still image on the monitor 30 . In this way, the surface defect image 'displayed as a still image on the monitor 30 is subjected to secondary determination of the type, grade, etc. of the surface defect by the inspector. The inspector inputs the result of the secondary determination into the computer 16 again from the keyboard 32 as accurate surface defect information. This input surface defect information is processed in advance by the computer 16.
Next, a comparison is made with the determined surface defect information. The primary determination result of the computer 16 is displayed on the CRTl 6A, as shown in FIG. 3, for example. In other words, the matrix in Figure 3 has the defect grade on the vertical axis,
The defect seed layer is displayed on the horizontal axis, and Y in the matrix
ES and No indicate whether the detected defect is outputted from the calculation 1fi16 to the defect inspection device 24 using the camera 20 and the strobe 18 (YES) or not (No). In the display example of FIG. 3, the determination made by the calculation 1116 is that the point defect is I, the defect grade is 01, and the defect information is output according to the matrix (YES). Here, the YES or NO determination in the matrix is set to match the visual determination result by the inspector. For example, if everything in the matrix is set to YES, information on all surface defects detected by the detector 12 is sent to the control circuit 22, photographed by the camera 20, and displayed on the monitor 30. Conversely, all numbers in the matrix are No.
If this is set, all defect information will not be sent and will not be photographed by the camera 20. Here, in the above embodiment, as an example of defect grades in the matrix shown in FIG. 3, minor defects to major defects are displayed in the order of A- and -E.
In general, major defects can be almost detected by the primary judgment of the computer 16 based on the detection of the detector 12 and the defect detection circuit 14, and the judgment of the computer 16 is also relatively accurate. Therefore, in the case of such a serious defect where appearance standards are relatively lenient, it is possible to reduce the frequency of secondary judgment by ordinary inspectors. However, in the case of strict appearance standards, such as minute defects, grade A and 8 minor defects in the matrix of FIG. As a reference, a secondary judgment by the inspector is ultimately required. Therefore, in such a case, if the CRT 16A is set up as shown in the matrix in FIG. 3, defect images will be taken for defects that have a lot of ambiguity in the primary judgment made by the computer 16, and the second judgment will be made by the inspector. An inspection can be performed with the next determination result as the final determination. Furthermore, in this embodiment, the inspector's secondary judgment result is displayed on the keyboard 3 based on the defect image displayed on the monitor 30.
2 to the computer 16 via the control circuit 22,
By comparing this with the primary determination result, it is possible to improve the primary determination result through online learning. In the above embodiment, the cart 37 in the moving device 21 is moved in the width direction with the operator side edge 10P of the steel plate 10 as a reference, but this is based on the lower live end a end m1oo on the opposite side. Furthermore, if the center line in the width direction of the steel plate 10 is used as a reference, the moving distance of the cart 37 is at most half the width of the plate. Further, in the embodiment described above, the pulse generator 44 is used to detect the position of the steel plate 10 in the width direction of the cart 37. For example, a photo sensor is attached to the cart 37, and the photo sensor detects the position of the steel plate 10. It is also possible to start counting after detecting one side edge and move to the position where the defect detected by the detector 12 occurs in the width direction. Further, in the above embodiment, the cart 37 uses only the rack 42 as a guide, but if linear guides are provided above and below the rack 42 and the cart 37 is moved by resting on these linear guides, the movement of the cart 1r37 will be improved. The reliability of movement in the width direction can be increased. Furthermore, in the above embodiment, the strobe 18 and the camera 2
0 is a stand driven by a rack and unit mechanism *37
However, the present invention is not limited to this, and the moving mechanism 21 moves the strobe 18 and camera 20 in the width direction of the steel plate 10. Anything that can be moved is fine. Therefore, other moving means may be used, such as, for example, a chain and bracket wheel mechanism, a linear moving link mechanism, a swing arm mechanism, an air cylinder mechanism, etc. Further, although the above embodiment is for inspecting the surface defects of steel f10 in a rolling line, the present invention is not limited to this, and the present invention is not limited to this, and the present invention is not limited to this. It is generally applied when inspecting.

【Effect of the invention】

Since the present invention is configured as described above, it is sufficient to take an image of a surface defect using a projector and a camera only when defect information is output from a computer, and the inspector inspects this image, thereby achieving efficient inspection. In addition, since inspectors only check still images showing surface defects, restrictions on the line speed that can be inspected can be lifted;
The secondary judgment is based on still images by the inspector (not only can accurate surface defect inspection be obtained, but also the accuracy of the primary judgment by computer can be improved, and a projector and camera are It is possible to reduce equipment costs compared to the case where a This has the excellent effect of improving the accuracy and making defect determination more precise.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the surface defect inspection device according to the present invention, Fig. 2 is a perspective view showing the relationship between the moving mechanism and the steel plate in the embodiment, and Fig. 3 is a diagram of the computer in the embodiment. It is a line diagram showing a determination result. 1o... Steel plate, 14... Defect detection circuit, 16... Total 1i 1 machine, 16B... Keyboard, 2o... Camera, 22... Sub circuit, 24... Defect detection device, 26... Image processing circuit, 28... Image input/output circuit, 30... Monitor television, 32... Keyboard, 34... Pulse generator.

Claims (1)

[Claims] (1) A detector that irradiates the surface of a moving test material with a light beam and detects surface defects of the test material based on the state of reflection;
Based on the surface defect detection signal obtained by this detector,
A calculator for calculating the type, grade, and position of the surface defect in the width direction of the material to be inspected, and irradiating light onto the defect that needs to be photographed based on the type and grade signal of the surface defect output from this computer. It has a projector and a camera that photographs the defect at the irradiation timing thereof, and a moving device that moves the projector and camera to the position based on a position signal of the surface defect in the width direction of the inspected material from the computer. Surface defect inspection equipment.