JPS6191547A - Defect detector - Google Patents

Abstract

PURPOSE:To judge on the propriety of the surface of metal, by arranging two detector sections which capture regularly reflected light and scattering reflected light from the surface with an image sensor to compare analog data corresponding to the density of an image with the upper and lower limit threshold data. CONSTITUTION:Camera heads 1a and 1b at detector sections A and B form images of an object 4 to be inspected on an image sensor 2 with an optical lens 3 as exposed to light from a light source. Here, at the detector section A the head 1a is so arranged as to admit scattering reflected light from the object 4 to be inspected while at the detector section B, the head 1b is arranged on the regular reflection optical axis of light from a light source. Then, comparators 5a and 5b compare analog data corresponding to the density of the images outputted from the sensor 2 with upper and lower limit thresholds preset to prepare a binary-coded data. AND gates 9a and 9b AND the data memorized into a mask pattern memory 8 and the binary-coded data and outputs the AND output as result data of the defect detection to be processed with a host computer C.

Description

Detailed Description of the Invention [Technical Field 1] The present invention relates to a method for detecting defects such as dents, scratches, and wrinkles on the surface of an inspection object having a metal surface such as a metal surface, a metal plate, or a gold PA foil laminate. This invention relates to a detection device.

[Background technology 1] Conventional devices of this type include a spot flying method using a laser and a method using an image sensor, but in addition to defects, gloss (partially shining places on the metal surface) that is a good product is detected.
It also has the disadvantage that it can also be detected.

[Objective of the Invention 1] The present invention was developed in view of the above-mentioned problems, and its object is to provide a defect detection device that can detect defects by distinguishing between gloss and defects.

[Disclosure of the Invention J Figure 1 shows a circuit configuration of an embodiment of the present invention, which includes two detection sections A and B, a precomputer 13a that processes defect detection signals of both detection sections A and B, respectively; 13b, and a host computer C that judges the data of the two virtual computers l3a, 13bh, etc. Are each detection part A and B connected to the camera? The configuration is basically the same except for the arrangement of the boards 1a and 1b, and the circuit configuration of the detection section B is omitted in the figure. Camera head shown in Figure 2
a, lb are inspection objects 4 equipped with an image sensor 2 using a CCD probe, and illuminated with light from a light source 15 of an illumination device;
is formed on the image sensor 2 by the optical lens 3. Here, the detection part A is arranged so that the optical axis is perpendicular to the inspection object 4 so that the hole 1a to the camera enters the hole-reflected light of the light irradiated onto the inspection object 4 from the light source, as shown in FIG. established,
The detection section B has a camera head 1b disposed on the optical axis of specular reflection from the light source. The comparator 5a is for comparing analog data corresponding to the brightness and darkness of the image output from the image sensor 2 with preset upper limit threshold data, and outputs an H'' signal when the threshold level La is exceeded. , if not, outputs an L'' signal to create binary data D+a. The comparator 5b is used to compare analog data corresponding to the brightness of the image output from the image sensor 2 with a preset lower limit threshold data, and when the threshold data is below the threshold level Lb, it is set to "H". If you cross the Igbo-go, press L''
This signal is output to create binary data D and b. Threshold data memories 6a and 6 are memories for storing each threshold data, and the stored data is converted into analog data by D/A converters 7a and 7b and sent to comparators 135a and 5b, respectively. . The mask pattern memory 8 stores mask pattern data as @L and @ levels at addresses corresponding to the array positions of patterns printed on the surface of the inspection object 4, and stores "H" at addresses corresponding to positions where no patterns exist. It stores level data. AND gates 9a and 9b connect the data stored in the mask pattern memory 8 and the binarized data Dl.
a.

Take the AND with D and b, and the theory J! l! The product output is output as defect detection result data Dza, Dzb. Error data pan 7a 10Aa and 10Ab are the result data D2a and D2 corresponding to even lines during image scanning.
B is taken into the error data buffer rlOBa.

10Bb is result data D, a, D corresponding to odd lines
, b. Switch means 11a111
b is for switching result data D2jL+D2b. The address circuit 12 is a circuit for creating the timing for sequentially scanning the coordinate points on the image sensor 2 and the address data of the mask pattern memory 8 corresponding to the scanning coordinates and α. The precomputers 13a and 13b are provided corresponding to each of the detection sections A and BI:N, and are used to give a start command to the counter/address circuit 12 via the interface section 14, or to read out the mask pattern memory 8. control the
Furthermore, error data buffers 10An, 10Ab, 10B
a, defect detection result data D 2a from 10Bb.

Comparison data obtained by taking in D2b and passing through each comparator 5a and 5b is sent to the host combinator C.

Thus, the camera nozzles 1a and 1b of each detection unit A%B form images on the respective image sensors 2 of the state of the surface of the inspection object 4 traveling in the direction of the arrow on the same line as shown in FIG. The test object 4 is arranged as shown in FIG. A signal such as is output as a defect detection signal.

In addition, the host computer C and the prepaid computer 13a, 1
31z may be configured with one computer.Next, the operation of this device will be explained. Now, if the inspection object 4 is moved in the direction of the arrow as shown in Fig. 2 and the measurement parts of the image sensors 2 of the throats Ia and lb are on the straight line in the middle direction of the inspection object 4, the detection is performed by each camera. In part A%B, camera head 1a,
The output level of each point of the image sensor 2 corresponding to the image of the inspection object 4 formed on the image sensor 2 of 1b is bright at a position where there is no pattern, so it is at a low level, and conversely, at a position where a pattern is present, the output level is at a low level. 1, which is at a high level, these analog data are sequentially scanned and output to comparators 5a and 5[+. Furthermore, the A/D converter 16 converts t! into a digital signal. F! and sent to the flash computer 13 via the interface section 14. The brightness computer 13 takes in this digital signal and selects the inspection object 4 according to the brightness.
The predetermined threshold digital data La, Lb shown in FIG. 3, in which the brightness of the background of It is sent to 5a and 5b.

This threshold data and the analog data from the image sensor 2 are compared. In other words, comparison n 5
In a and 5b, when the output of the image sensor 2 exceeds or falls below the threshold level La or Lb, the comparator 5a
5b generates an H'' level signal, and conversely, the upper and lower threshold levels La.

If it is between Lb, a signal of "L" and "L" is generated.

Data D1a binarized according to scanning in this way
1 data DIb will be obtained. - Corresponding to force scanning, the mask pattern memory 3 is 71:4! l: Data corresponding to the pattern is read out sequentially from the address corresponding to the point, and this data and the above binary data D, a, 'D
=b means ANDY-A match is detected at 9a and 9b. In other words, in the position where the pattern is, it is 9a, 9
The output of b becomes "L", the pattern is prevented from being detected as a defect, and the defect is detected at an unprecedented position. Here, if the defect is a dent or a deep scratch, the output S from the image sensor 2 corresponding to the defect will be thicker (, In specular reflection, the brightness of the background becomes smaller as shown in Figure 4 (b).Therefore, in detection iA, each threshold level in detection period A is compared with the output S, so that the output S is at the threshold level La. Comparator 5 to exceed
The output from the comparator 5b is H'', and the output from the comparator 5b is L''. On the other hand, in detection section B, the comparison between each threshold level and output S in detection section A shows that output S is threshold 1.
Since the voltage is smaller than the current level Lb, the output from the comparator 5a is "L" and the output from the comparator 5b is "H". In the result detection section A, the result data D2a becomes H'', and the result data D and b become L''; in the detection section A, the result data D2a becomes ``L'' and the result data D and b become ``H'', and these data The data of the detection units A and B are sent to the host combinator C via the flash computers 13 of each of the detection units A and B, and compared with various defect and gloss data stored in the host computer C in advance. Result data D2
ah'"H" and the result data D2b of the detection part B is H", it is determined that there is a defect such as a deep scratch or dent,
A determination signal indicating that the inspection object 4 is defective is output. By the way, when the defect is a shallow scratch or wrinkle, the output S corresponding to the defect of the image sensor 2 of the inspection section B, which captures specular reflection, is at the threshold level La, L as shown in FIG. 5(b).
Therefore, the outputs of the comparators 5a and 5b of the inspection section B are L'', and the result data D2a and D2b are both L''.
However, since the output S corresponding to the defect of the image sensor 2 of the inspection part A that captures the 6L reflection exceeds the threshold level La as shown in Fig. fIVJ5 (a), it The result data D,a becomes "H".The host computer C, as mentioned above, shows that the result data D2a of the test section A is "H" and the result data D of the test section B.
2t) If w D 2a are both "L", shallow scratches,
If there are wrinkles or the like, it is determined that there is a defect in the same manner as described above, and a determination signal indicating that the inspection object 4 is defective is output. Further, when the defect is a pinhole, the output S corresponding to the pinhole of the image sensor 2 of each detection unit A and B is shown in t56 (a
), as shown in (b), the threshold level Lb is checked, and the comparators 5! ) becomes H” level, and the result data D2a of the result-side inspection units A and B
are both L'', and the resulting data D21+ are both 1H''. As mentioned above, if the result data D2b of the inspection part A is "H" and the result data D and b of the inspection part B are also "H", the host computer C determines that there is a pinhole and there is a defect as described above. Then, it outputs a judgment signal indicating that the inspection object 4 has a defect.Next, although there is no defect, the surface of the inspection object 4 has a
If there is a difference, the output S" of the image sensor 2 corresponding to the gloss of the detection part A, which removes diffused reflection, becomes smaller than the underlying part, and falls below the threshold level Lb as shown in FIG. 7(a). The output of the comparator 5b becomes H''.

On the other hand, the output S' corresponding to the gloss of the image sensor 2 of the detection part B which detects specular reflection also becomes larger than the base part and exceeds the threshold level La as shown in FIG. 7(b), and the comparator The output of 5a becomes "H". As a result, the result data D2b of inspection section A becomes H'', and inspection section B
The result data D2a becomes H''.The host computer C receives the result data D2blJr'' of the inspection section A as described above.
When the result data D2a of the inspection section B is "H", it is determined that the inspection object 4 is glossy, and a determination signal is output that indicates that the inspection object 4 has no defects and is a good product.

[Effect of the Invention 1] As described above, the present invention provides an image sensor that extracts specularly reflected light from the surface of an inspection object having a metal surface, such as a metal foil, metal plate, or metal foil laminate material, irradiated by a light source. Analog data corresponding to the brightness of the image obtained by the image sensor and threshold 3 of the upper and lower limits of brightness set in advance
and a comparison means for determining whether the upper limit threshold level is exceeded or the lower limit threshold level is exceeded by comparing the detected data with the reference data. An image sensor that captures diffusely reflected light from a second detection section having a comparison means for determining whether the level is below the level, and the presence or absence of a defect on the surface of the inspection object and the type of the defect are determined based on the comparison results from the comparison means of both detection sections. Equipped with a determination means, it is possible to distinguish between gloss and defects such as scratches, wrinkles, and pinholes, and it is possible to reliably determine the quality of metal surfaces such as metal foil, metal plates, and metal foil laminates. This has the effect of allowing you to do this.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of the present invention, Fig. 2 is a layout diagram of the same as above, Fig. 3 is a waveform diagram explaining the relationship between analog data and threshold level, and Figs. 4 to 7 are operation of the same as above. 1a and 1b are camera heads, 2 is an image sensor, 4 is an inspection object, 5a and 5b are comparators, 13 is a precomputer, 15 is a light source, A and B are detection units, C is a host computer, La and Lb are threshold levels. Agent Patent Attorney Ishi 1) Ai Figure 7 Figure 4 Figure 6 Figure 5 II Figure 7

Claims (1)

[Claims] (1) An image sensor that captures the specularly reflected light from the surface of an inspection object having a metal surface such as a metal foil, metal plate, or metal foil laminate that is irradiated by a light source, and according to the brightness and darkness of the image obtained by the image sensor. a light source; a light source; and a light source. An image sensor that captures the diffusely reflected light from the surface of the object to be inspected that has been irradiated with more light is compared with analog data corresponding to the brightness and darkness of the image obtained by the image sensor and threshold data of the upper and lower limits of brightness set in advance. a second detection section having a comparison means for determining whether the detected value exceeds the upper limit threshold level or falls below the lower limit threshold level, and detects defects on the surface of the inspection object based on the comparison results from the comparison means of both detection sections. What is claimed is: 1. A defect detection device comprising determining means for determining the presence or absence of defects and the type of defects.