JPS63222244A - Surface inspector - Google Patents

Abstract

PURPOSE:To perform marking accurately at a position where a flaw is generated, by detecting a position at which an axial flaw is generated from a surface density image data and a position where a flaw in the direction of conveyance is generated from discrimination of the level of a surface density signal to input a coincidence signal thereof to a control circuit. CONSTITUTION:A surface density signal S1 obtained by scanning an object 3 to be inspected across the width thereof with a camera device 11 is applied to memories 14, 15 and 16 through an A/D converter 12 to prepare a surface density image data D. A flaw width position detecting circuit 19 generates a histogram from a surface density image data D, a peak position is detected as position at which a width-wise flaw of the object 3 being inspected is generated and a detection signal S6 thereof is applied to a flaw address generation circuit 23 to generate an address signal S7. A memory 16 has flaw position information stored with respect to the direction of conveying the object 3 being inspected corresponding to each discrimination level and a flaw position signal S8 selected with a selection circuit 25 is sent out to a shift circuit 26. A gate circuit 24 ORs the address signal S7 and the flaw position signal S8 and a coincidence signal S9 is outputted to a marker timing control circuit 22.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention automatically detects the presence or absence of defects on the surface of an object to be inspected, such as a steel plate or an aluminum plate, by inspecting the surface of the object to be inspected. This invention relates to a surface inspection device for marking.

(Prior art) As shown in FIG. 6, this type of conventional device moves at high speed on a conveying line, cuts steel plates into fixed lengths by a shear 1, and winds them up by a coil winding device 2. A surface image of a certain area of the inspected object vJJ3 is captured by an optical paper detector 4, and based on this image signal, a flaw determination processing section 5 determines whether there is a flaw on the surface of the inspected object. If there is a defect, the determination output is sent to the tracking processing unit 6.
Here, tracking is performed using a speed signal from a speed detector 8 attached to the roller 7 of the conveyance line so that the image detection position and the marking position match, and then the marking drive device 9 is driven and controlled to mark the marker. 10 is used to directly mark the surface of a moving object to be inspected.

Here, the area of the surface image captured by the paper detector 4 and subjected to flaw determination is [board width W] x
[Constant length in the transport direction], and the judgment area required for normal visual inspection is approximately 0.25 to 0! M> is required. If a flaw K exists in this area, a marking M is marked by a marker 10 on the edge portion of the object 3 to be inspected.

For this reason, it is difficult to make the accuracy of the marking M less than the resolution of the determination area WXL, and in the next eaves removal process, if the marking M exists, the determination will include a margin of about ±WX1 in consideration of tracking accuracy. It was common to remove the eaves when the dimensions were larger than the area. Particularly, in the case of a tin steel plate for food cans as the object to be inspected 3, even the slightest flaw will impede quality improvement, so the eaves are removed to provide a fairly large margin. Therefore, the area required for processing food cans, etc. is the flaw detection area WXL as shown by WxQ in Figure 7.
Despite being sufficiently small, many non-defective parts had to be removed due to the limited resolution for marking.

(Problems to be Solved by the Invention) As mentioned above, in conventional surface inspection devices of this type, the accuracy of marking for flaw determination is rough, so many non-defective parts are removed in the next flaw removal process. This resulted in a decrease in product yield.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a surface inspection device that can improve the marking accuracy for determining defects, ensure a sufficient number of non-defective parts depending on the application, and improve the yield of products.

[Configuration of the Invention (Means for Solving the Problems)] The surface inspection device of the present invention scans from one end to the other end in the width direction of a moving object to obtain a surface density signal of the object to be inspected; Based on this surface gradation signal, a surface gradation image of a constant length in the transport direction of the object to be inspected is created, and based on this surface gradation image, the type of flaw on the surface of the object to be inspected is determined, and the object to be inspected while traveling is determined. In the automatic marking of objects, the surface 81
a width direction position detection means for detecting paper position information in the width direction of the object to be inspected based on the light image; and a transport direction position detecting means for detecting paper position information in the direction of transport of the object to be inspected based on the surface gray signal. a detection means; a marking position control means for outputting a coincidence signal between the paper position information obtained by the conveyance direction position detection means and the paper position information obtained by the width direction position detection means as marking position information; and marking means for marking the determined flaw type information on a predetermined portion of the object to be inspected.

(Function) By taking such measures, the type of flaw on the surface of the inspected object is determined, and the flaw position is detected in the transport direction and width direction of the inspected object, and the flaw position of the inspected object is detected. For example, flaw type information is marked on an edge portion corresponding to the area.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the same figure, 11 is from one end in the width direction to the other end of the object 3 to be inspected, which is transported in the direction indicated by the arrow in the figure. This me device optically scans and outputs a surface density signal S1 of the object to be inspected 3, and this surface density signal S1 is output to an A/D converter 12 and converted into a digital signal S2. This digital signal S2 is passed through the switch 13 to the first . The signal is supplied to one of the second image memories 14 and 15 and also to the gray level signal level memory 16. Above 1. The second image memory 14.15 sequentially stores the digital signal S2 to create a surface gradation image for a constant length of the object 3 in the transport direction, and the created surface a>image data D is The signal is output to an image feature extraction circuit 18 and a paper width position detection circuit 19 via a signal line 17. In other words, when the counter 20 receives the pulse signals P from the speed detector 8 by the number corresponding to the fixed length of the inspection object 3 in the transport direction, it outputs the image cutout timing signal S3 to the switches 13 and 17. 17 is switched and controlled so that data is written and read out alternately in both memories 14 and 15 in response to a timing signal $3.

The image feature extraction circuit 18 extracts feature quantities such as height and width of the surface gradation image data, and this feature quantity data signal S4 is given to the flaw determination circuit 21. Flaw determination circuit 21
determines the type and class of a flaw formed on the surface of a fixed length in the transport direction of the object to be inspected 3 based on the feature amount data signal S4, and outputs the determination result to the marker timing circuit 22 as a flaw determination signal $5. .

On the other hand, one paper width position detection circuit creates a histogram based on the surface gradation image data D, for example, and detects the peak position as the flaw occurrence position in the width direction of the inspected object 3, and this flaw position detection signal S6 is the flaw address generation circuit 2
given to 3. The flaw address generation circuit 23 is the object to be inspected 3.
For example, the width direction is divided into four parts to form addresses, an address corresponding to the flaw position signal S6 is obtained, and an address signal S7 for turning on the gate of the gate circuit 24 corresponding to this address is generated. .

The gray level signal level memory 16 has, for example, a memory area a divided in the width direction corresponding to the address of the flaw address generation circuit 23, and the digital signal S2 from the A/D converter 12 is divided into a plurality of predetermined areas. By discriminating the wave height based on the discrimination level, paper position information with respect to the transport direction of the object to be inspected 3 is stored in correspondence with each discrimination level based on the pulse signal P from the speed detector 8. and is connected to the selection circuit 25. The selection circuit 25 is for selecting the paper position information of the level to be marked according to the object to be measured 3 from among the paper position information for each discrimination level stored in the gray level signal level memory 16,
The selected flaw position signal S8 is sent to the shift circuit 26. The shift circuit 26 shifts the flaw position signal S8 in synchronization with the moving speed of the object to be inspected 3 using the pulse signal P from the speed detector 8. The timing is adjusted to synchronize with the timing of occurrence.

The gate circuit 24 performs a logical product of the address signal S7 generated by the flaw address generation circuit 23 as paper position information in the width direction and the flaw position signal 88' shifted by the shift circuit 26 as paper position information in the transport direction. If the AND of both signals is established, the match signal S9 is output from the corresponding gate to the marker timing control circuit 22 as marking position information. The marker timing control circuit 22 controls the marking operation of the marking device 27 having an edge tracking function of the object to be inspected 3 in order to mark the flaw determination information from the determination circuit 21 at the etched position of the object to be inspected 3 corresponding to the marking position information. A signal 810 is output.

The marking device 27 receives the marking operation control signal 310 and marks a mark encoding the type and class of the flaw at a corresponding position on the edge portion of the object 3 to be inspected.

Next, the operation of the apparatus of this embodiment will be explained with reference to FIGS. 2 to 4. The object to be inspected 3 is traveling on the conveyance line in the direction of the arrow in FIG.
By optically scanning the object 3 in the width direction from one end to the other end, the surface density signal S1 of the object 3 to be inspected is output. Further, the speed detector 8 outputs a pulse signal P in synchronization with the moving speed of the object to be inspected 3, and this pulse signal P causes the A/D converter 12. As the illll level memory 16 and the shift circuit 26 are controlled, the count value of the counter 20 increases. When the count value of the counter 20 reaches a value corresponding to the constant length of the inspection object 3 in the transport direction, the counter 20 outputs an image cutout timing signal S3, and the switches 13 and 17 are respectively switched. In FIG. 2, if the timing signal S3 is output at time to, and this causes the switch 13 to switch to the first image memory 14 side, and the switch 17 to the second image memory 15 side, then the previous From the time when the timing signal 83 is generated to the current timing signal 8
3 occurs (time point 10), the second image memory 1
The grayscale image data D of the cutout image N formed in step 5 is output via the switch 17 to the image feature extraction circuit 18 and the paper width position detection circuit 19 with a delay of one clock.

In the image feature extraction circuit 18, features of the gray image data D are extracted by determining the height of the a-light image data D, for example, for a fixed length in the conveyance direction for each divided section in the width direction, and also performing determination in the width direction. , this wait @
The type and class of the flaw is determined by the flaw determination circuit 21 based on the distribution state of the base data.

On the other hand, in one paper width position detection circuit, for example, a histogram D' of the grayscale image data D is obtained as shown in FIG. 3, and a flaw position signal S6 corresponding to the peak position is sent to the flaw address generation circuit 23 . Then, the flaw address generation circuit 23 selects the address (in this case, address ■) of the width direction position of the object to be inspected 3 corresponding to the generation position of the paper position signal S6, and opens the corresponding gate of the gate circuit 24. Address signal S7 is generated.

Further, in the gray level signal level memory 16, as shown in FIG.
The digital signal S2 from the A/D converter 12 has a plurality of discrimination levels r1. r2. storage areas R1, R2, which are respectively discriminated by r3 and in which each discrimination data is formed for each level;
Stored in R3.

Then, the selection circuit 25 selects the paper position information stored in the level storage area for marking according to the object to be measured 3, and sends the paper position signal S8 to the shift circuit 26. Then, the paper position signal S8 is transmitted to the shift circuit 2.
6, it is shifted in synchronization with the moving speed of the object to be inspected 3,
It is sent to the gate circuit 24 as a paper position signal S8' in synchronization with the generation timing of the address signal S7. Then, the gate circuit 24 performs an AND operation between the address signal S7 and the paper position signal 88', and a matching signal S9 is output from the corresponding gate to the marker timing control circuit 22 as marking position information. Then, the marking position information and the position of the marking device 27 are tracked by the marker timing control circuit 22, and the flaw determination information from the determination circuit 21 is to be marked at the etched position of the inspected object 3 corresponding to the marking position information. , Marking operation 11 on the marking device W127. control signal 310
is output. As a result, as shown in FIG. 3, the marking device 27 codes the type of flaw, the class of the flaw, and the position in the width direction at the edge position of the object to be inspected 3 in response to the rise of the marking operation control signal S10. mark(
k53. 63) is printed out. Note that FIG. 3 shows that the selection circuit 25 selects the storage area R corresponding to the discrimination level r1.
1 is selected, and when the content of the storage area R3 corresponding to the discrimination level r3 is selected, the marking control signal becomes 810', and marking is performed at the rising edge of the signal.

As described above, according to the present embodiment, the flaw occurrence position in the width direction is detected using the surface gradation image data D for determining the type of flaw formed on the surface of the object to be inspected 3, and
By level-discriminating the digital signal of the surface density signal, the flaw occurrence position in the conveyance direction is detected, and a matching signal of these flaw occurrence information is obtained and used as a marking signal, so it is possible to reliably determine the presence or absence of flaws. At the same time, it is possible to accurately mark the location where the flaw occurs. In addition, level discrimination of the gray image signal is performed at multiple levels so that the selection can be made according to the rough measurement object 3, and the flaw occurrence position and the flaw position in the width direction and transport direction can be determined by following the etched area of the object to be inspected 3. Since the mark indicating the type 1 class can be encoded and printed out, the area to be removed from the eaves can be adjusted according to the purpose of the inspection object 3, allowing effective use of non-defective parts, and greatly reducing the size of the product. Yield can be improved. moreover,
I made the markings follow the edge parts, so
Marks are uniformly printed on the object to be inspected, and the workability of the removal process can also be improved.

Note that the present invention is not limited to the above embodiments.

For example, in the above embodiment, the image memory 14, 15 for storing the surface gradation image is used, but as shown in FIG. 5, by sequentially integrating the outputs of the A/D converter 12, Image histogram memories 31 and 32 that form long histograms are used to determine the flaw type and flaw class based on this histogram data, and a peak position detection circuit 33 detects the peak position of the histogram data to obtain flaw position information in the width direction. You can also get it.

Further, in the embodiment described above, the digital signal is discriminated using a plurality of discrimination levels in the clear signal level memory 16, but the digital signal may be discriminated using only one level using the level discrimination circuit 34.

In this case, the selection circuit 25 becomes unnecessary. Furthermore, in the embodiment, the device signal S configured by the selection circuit 25
8 may be divided into a plurality of address units in the width direction. By doing so, even if a plurality of flaws with different positions in the width direction are formed overlapping each other in the conveying direction, the position where each flaw occurs can be accurately determined. However, in this case, each gate in the gate circuit 24 needs to be arranged in a matrix. In addition, by creating histogram data in the width direction of the surface shading image and detecting the peak position, the flaw occurrence position in the transport direction is determined, and the flaw occurrence position is determined based on this position information and the histogram data of a constant length in the transport direction according to the above embodiment. The flaw occurrence position may be accurately determined by matching the position information. It goes without saying that various other modifications can be made without departing from the spirit of the invention.

[Effects of the Invention] As detailed above, the present invention provides a surface inspection device that can improve the marking accuracy for determining defects, ensure a sufficient number of non-defective parts depending on the application, and improve the yield of products. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the configuration of an apparatus according to an embodiment of the present invention, FIGS. 2 to 4 are diagrams for explaining the operation of the embodiment, and FIG. 2 is a signal waveform diagram; 3 is a diagram showing a marking example of the present invention, FIG. 4 is an explanatory diagram of a gray level signal level memory, FIG. 5 is a block diagram showing a modified example of the present invention, and FIG.
The figure shows a conventional surface inspection device, and FIG. 7 shows an example of conventional marking. 3...Object to be inspected, 8...Speed detector, 11...Image device, 14.15...1st. second image memory, 1
6... Grayscale signal level memory, 18... Image feature extraction circuit, 19... Paper width position detection circuit, 21... Flaw determination circuit, 22... Marker timing control circuit, 23.
...Flaw address generation circuit, 24...Gate circuit, 25
... selection circuit, 26 ... shift circuit, 27 ... marking device. Applicant's agent Patent attorney Takehiko Suzue. Figure 2 Figure 3 Figure 4

Claims (4)

[Claims] (1) Obtain a surface shading signal of the object to be inspected by scanning from one end to the other in the width direction of the object to be inspected while it is running, and based on this surface gradation signal, a surface gradation image of a certain length in the transport direction of the object to be inspected. In a surface inspection apparatus that automatically marks the moving object by determining the type of flaw on the surface of the object to be inspected based on the surface gradation image, width direction position detection means for detecting flaw position information in the width direction of the object; transport direction position detection means for detecting flaw position information in the transport direction of the object based on the surface density signal; marking position control means for outputting a coincidence signal between the flaw position information by the detection means and the flaw position information by the widthwise position detection means as marking position information; and marking means for marking the determined flaw type information. (2) The conveyance direction position detection means includes a memory circuit that divides the surface density signal in the width direction of the object to be inspected and stores it in correspondence with the density level, and selects and outputs the signal level of this memory circuit. A surface inspection device according to claim 1, comprising a selection circuit. (3) The width direction position detection means includes a peak position detection circuit that detects the peak position of the histogram of the surface gradation image, and an output means that outputs the width direction position of the object to be inspected corresponding to this peak position. A surface inspection device according to claim (1), characterized in that: (4) The surface inspection apparatus according to claim (1), wherein the marking means marks the flaw type information on an edge portion of the object to be inspected corresponding to the marking position information.