JPS6029895B2 - surface inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for continuously inspecting the surface quality of an object to be inspected that moves at high speed.

The applicant has developed a device for detecting the surface eaves of objects to be inspected that move at high speed, such as steel plates on a hot rolling line.
It was proposed in No. 387 (Special Publication No. 57-35788).

This surface inspection device is described in detail in the specification of the application, and its outline is as follows. That is, as shown in FIG. 1, the surface of the object to be inspected 1 such as the rolled steel plate is momentarily irradiated with a flash light source 2 such as a strobe device, and a still image thereof is captured by an imaging device 4 such as a high-resolution television camera. The output video signal of the camera 4 is sent on the one hand to a defect detection circuit 7 for detecting defects, that is, surface irregularities 5, and on the other hand is input to a memory device 8 for storage. The memory device 8 includes screen memories 14a to 14c for one field, as shown in FIG.
, 17a to 17c, a memory selection circuit 13, an output image selection circuit 15, and a channel selection circuit 16. camera 4
The video signal sent from the memory selection circuit 13 is sequentially written into the memories 4a, 14b, and 14c screen by screen, and after writing, these memories are read and send the video signals to the selection circuit 15, and are then erased and sent to the next screen. Prepare for writing. The defect detection circuit 7 processes the video signal, detects the left and right edges of the steel plate 1 as points of large amplitude change, sets an inspection range as a slightly narrower area within the left and right edges than the inside of the steel plate, and detects the video signal within the inspection range. Habit 5 is detected as a point of large change in signal amplitude. When the defect detection circuit 7 detects a defect,
The defect signal is sent to the control device 3, which gives an output command 18 to the selection circuit 15, and the selection circuit sends the signal of the screen in which the defect is detected to the channel selection circuit 16, which circuit 16 sends the signal of the screen in which the defect is detected to the memory 17a. The signal is inputted to those of 17c whose erasure has been completed. The one-screen memory in which this image signal has been written is outputted to the television monitor device 9 for a time set by the output time setting device 22 according to the command signal 19 from the control device 3, and the monitor device Display the screen with 5. In this proposed device, as described above, the output video signal of the camera 4 is written into the memories 4a-14c and erased, and is not displayed on the monitor device 9 unless a defect is detected.

However, the defects detected by the defect detection circuit 7 need to be larger than a certain level, and if the threshold level is lowered to be able to detect even the smallest defects, it will also detect dirt and other surface deposits other than the eaves. A detection signal will be emitted, reducing reliability. Therefore, the screen displayed by the monitor becomes a screen with large irregularities beyond a certain extent, and there is a problem in that it is not possible to detect or judge minute irregularities.
There is a method in which the surface of the object to be inspected is periodically displayed on a television monitor and eaves detection is performed, but this method has the disadvantage that surface inspection is performed only on selected samples and the entire surface cannot be checked.

In view of this, the present invention provides a surface inspection device that is capable of inspecting the entire surface of an object to be inspected and also capable of detecting minute defects.

The present invention provides an imaging device that images an object to be inspected, a flash light source that irradiates the surface of the object to be inspected, a defect detection device that detects a defective part of the object to be inspected using a video signal output from the imaging device, and In a surface inspection apparatus that includes a memory device that stores video signals and a monitor device that displays information stored in the memory device, the memory device is composed of a memory for periodic inspection and a memory for automatic inspection; means for writing the output video signal of the camouflage layer into a memory for protocol periodic inspection at relatively large cycles; means for displaying the playback output on a monitor device; writing the video signal into the memory for automatic inspection at relatively short cycles. and a means for stopping writing to and erasing from the memory for automatic inspection when the defect detection circuit detects a defect; Write and discuss in the memory, display the output on a monitor device, and when a defect is detected by the defect detection circuit, display screen information including the defect written in the automatic inspection memory. This feature is characterized in that it is prioritized and displayed on the monitor device, and this will be explained in detail below with reference to embodiments. FIG. 3 shows an embodiment of the present invention, in which numerals 2, 4 and 9 are the above-mentioned strobe device, television camera and monitor device.

Reference numerals 8a and 8b are memory devices, and in this example, the former is for automobile inspection, and the latter is for periodic inspection.

10 is an abnormality detector, 11 is an edge detector, 12 is a detection range setting circuit, and 13 is an AND gate, which constitute the aforementioned defect detector 7, the configuration and operation of which are related to the application filed by the present applicant. Special Publication No. 51-87017 (Special Publication No. 55)
-41077) etc., and gate 1
3 outputs a defect signal on the surface of the object to be inspected.

14 to 17 and 29 are flip-flops, 18 is a synchronization signal generator that generates a vertical synchronization signal VD and horizontal synchronization signal HD, 19 is a cycle setter consisting of a counter, etc., 20 is a pulse generation circuit, 21 is a strobe drive unit, 22 is a sliding door, 23 to 28 are gate circuits, and 30 and 31 are inverters.

The operation of this circuit will be explained with reference to the waveform diagram in FIG. 4. The vertical synchronization signal VD generated by the synchronization signal generator 18
A horizontal synchronizing signal HD is applied to the television camera 4 to control its vertical and horizontal synchronization, and a vertical synchronizing signal VD is also applied to flip-flops 16 and 17 and a gate circuit 28.

The flip-flops 16 and 17 are arranged in two stages with 1/
The frequency is divided by 4, and the AND gate 23 receives the Q terminal outputs of the flip-flops 16 and 17, so the signal VD is divided by 4.
produces an output that is 1 at a rate of 1 for each. This output signal S2 is applied to the pulse generation circuit 20 and the strobe device 2
Therefore, as shown in FIG. 4, the light emission is performed once every four vertical synchronizing signals VD in FIG. 1. The period of light emission is determined by the television camera 4 that operates every time light is emitted.
be selected so that the entire surface of the object to be inspected can be imaged. Signal S
2 is also applied to the inhibit terminals of AND gate 24 for writing and inhibit gate 25 for erasing, and the Q output of flip-flop 15 input to the other terminals of these gates 24 and 25 is now "1". Therefore, the signal S
During one field period when 2 becomes 1, the AND gate 24 outputs a write signal WP, as shown in FIG. 4, to the automatic inspection screen memory 8a having a capacity for one field.
Image A, image B, etc. are written sequentially. During the next three field periods of the write cycle, the gate 25 outputs the erase signal EP, as shown in FIG. ing. The period setting circuit 19 divides the S2 signal by an appropriate frequency division ratio, and when the output S3 of the circuit 19 with an arbitrary period T and the signal S2 become 1, the AND gate 26 divides the signal S2 as shown in FIG. A write signal WP2 is generated to cause a heavy video signal S to be written into the fixed periodic inspection screen memory 8b having a capacity for one field.

The write pulse WP2 also has one field, so the video signal writing to the memory 8b is for one screen (1 field).
field). In this example, the screen written to the memory 8b is image A. The memory 8b is repeatedly read from the next vertical synchronizing signal period onwards, and the read output is inputted to the monitor device 9 through the switch 22, where the image A is displayed as shown in FIG. 4. Erasing is signal S2
, S3 is input to the output EP of the inhibit gate 27.
2, as shown in FIG. 4, during the three field periods before the writing is performed, the next is the image after the period T. In this example, E is written to the memory 8b and the defect must be detected. The image E of the cigarette is then displayed by the monitor device 9. When a defect is detected and the AND gate 13 outputs a defect signal S4 as shown in FIG. This is read and reset at the falling edge, and the Q output signal S5 is set to 0 as shown in FIG. 7.

This signal S5 switches the switch 22 so that the one-field screen memory 8a for automatic inspection is connected to the monitor device 9, and also closes the writing and erasing gates 24 and 25. Therefore, writing and erasing of the memory 8a is not performed, and the stored video signal of the screen where the habit has been detected is outputted and inputted to the monitor device 9 through the switch 22, and the habit screen is displayed on the monitor device. indicate. The operator looks at this, determines the habit, takes appropriate measures such as a recording alarm, and after completing such processing, closes the switch SW, the flip-flop 29 is reset at the rising edge of the signal shown in FIG. 4, and the flip-flop 14 is also reset. It will be reset immediately. Thereafter, at the falling edge of the signal shown in FIG.
Switch to the b side, raise the gates 24 and 25, and return to the initial steady state. As explained above, in the present invention, the image of the object to be inspected is displayed on the monitor device at regular intervals, and the operator can visually observe this to discover minute eaves and other defects. It can be confirmed that the shared video system is operating normally.

Further, as soon as an eaves is detected, the eaves screen is displayed, and if this is accompanied by an alarm, the operator can visually observe it as soon as he/she notices it. If only a regular periodic inspection system is used, there is a risk that irregular screens may not be sampled because the system's screen switching is performed at a relatively slow cycle (visual observation is difficult if the cycle is too fast).
Furthermore, even if the sample is sampled, there is a risk that the screen display may be delayed. In this regard, if you use a periodic inspection system and an automatic inspection system together, you can quickly display the habit screen, discover minute habits that are difficult to detect automatically,
Effects such as being able to determine whether the surface inspection device is normal or abnormal can be obtained.

[Brief explanation of drawings]

1 and 2 are block diagrams showing the configuration of a previously proposed surface inspection apparatus, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 4 is an explanatory diagram of the operation of FIG. 3. In the drawings, 4 is an imaging device, 1 is an object to be inspected, 2 is a flash light source,
7 is a defect detector, 8 is a memory device, 9 is a monitor device, 8
A is a memory for automatic inspection, and 8b is a memory for periodic inspection. Figure 1 Figure 2 Figure 3 Figure Dimensions

Claims (1)

[Claims] 1. An imaging device that images an object to be inspected, a flash light source that illuminates the surface of the object to be inspected, a defect detection device that detects a defective part of the object to be inspected using a video signal output from the imaging device, and a defect detection device that detects a defective part of the object to be inspected using a video signal output from the imaging device. In a surface inspection apparatus that includes a memory device for storing information and a monitor device for displaying information stored in the memory device, the memory device includes a memory for periodic inspection and a memory for automatic inspection, and the output of the imaging device means for writing the video signal into the memory for fixed periodic inspection at a relatively large cycle; means for displaying the playback output on a monitor device; means for writing the video signal into the memory for automatic inspection at a relatively short cycle; and means for stopping writing to and erasing from the automatic inspection memory when the defect detection circuit detects a defect, and writing the video signal to the periodic inspection memory during a period in which the defect detection device does not detect a defect. and displaying the readout output on a monitor device, and when a defect is detected by the defect detection circuit, reading screen information including the defect written in the automatic inspection memory and monitoring it. A surface inspection device characterized in that priority display is given to the device.