JPH0571934A - Surface defect inspection device - Google Patents

Abstract

PURPOSE:To enable scratches at all angles to be detected as a bright point, presence/absence, position deviation, front/rear, etc., of an object to be inspected, and defects such as a scratch and an impression which are generated on metal parts which are punched by a press to be inspected. CONSTITUTION:A title item is provided with a ring-shaped fiber light guide 6 which lights an object 1 to be inspected from a direction of entire periphery and a CCD camera 4 which reads a reflection light which enters a light guide center part. Further, it is provided with an image-processing means which enables an input image data of the CCD camera to be binary-coded, a positive reflection light at a peripheral part of the object to be inspected to be identified by a binary-coded image data, presence/absence and/or position deviation of the object to be inspected to be judged, and a defect which is located within a certain position from a peripheral part to be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface defect inspection device for inspecting defects such as scratches and dents generated on the surface of a metal part punched by a press.

[0002]

2. Description of the Related Art As an apparatus for inspecting a surface defect of a metal part punched by a press, a large number of apparatuses in which a CCD camera and an image processing apparatus are combined have been announced. In this device, a ring-shaped fluorescent lamp is used for illumination, the illumination is performed obliquely, and a flaw is detected as a bright spot.

[0003]

However, the prior art has the following disadvantages. That is, since the accuracy of detecting scratches changes depending on the angle of illumination, when a ring-shaped fluorescent lamp is used, since it is illuminated from each direction, it is possible to detect flaws in a considerable angular range. However, since the light source is U-shaped and cannot be illuminated from the entire circumference, the flaw detection accuracy at some angles deteriorates.
In addition, since a bright spot is not detected in a normal inspection object having no flaw, there is an inconvenience that the inspection object is displaced when there is no inspection object.

The present invention has been made on the basis of the above background, and its object is to detect flaws at all angles as bright spots, and further to check the presence / absence of the inspection object, the positional deviation, and the front and back. It is to provide a surface defect inspection device capable of performing such as

[0005]

A surface defect inspection apparatus according to the present invention comprises a ring-shaped optical fiber light guide for illuminating an inspection object at an incident angle θ from the entire circumferential direction, and at least the center of the ring-shaped optical fiber light guide from the inspection object. From the CCD camera that reads the reflected light incident on the part and the image data input to the CCD camera are binarized, and the inclination of the surface is substantially θ / 2 at the peripheral part of the upper, lower, left, or right of the inspection object. An image processing means for identifying the specular reflection light from the binarized image data, determining presence / absence and / or positional deviation of the inspection object, and detecting a defect within a certain position from the peripheral portion. It is what

[0006]

The present invention having the above-described structure operates and operates as follows. Illumination is performed at a substantially constant angle from the entire circumference of the ring-shaped optical fiber light guide, and flaws at all angles are detected as bright spots. The inspection product punched by the press is
There is an inclination in the peripheral part, and this part is used to detect the presence or absence of the inspection object or to detect the positional deviation. When illuminated by a ring-shaped optical fiber light guide at an incident angle θ, if the surface is tilted at an angle of half the incident angle, that is, substantially θ / 2, the specularly reflected light is received by the CCD camera. Even a normal inspection object with no flaws can detect the peripheral part as a bright spot. Therefore, by performing bright point detection in one of the upper, lower, left, and right areas corresponding to the peripheral portion of the inspection object, the presence or absence of the inspection object, or
Positional deviation can be determined. With respect to the central part of the inspection object that needs inspection, if the defect within a certain range from the position corresponding to the peripheral part is detected, the inspection range can be corrected even if the inspection object is misaligned. .

[0007]

The present invention will be described in detail below with reference to examples.

FIG. 1 is a schematic diagram showing the structure of an example of a device according to the present invention. The surface defect inspection apparatus of this embodiment shown in the drawing has a ring-shaped optical fiber light guide 6 that illuminates the inspection object 1 from the entire circumferential direction at an incident angle θ, and a reflection that is incident from the inspection object 1 to the center of the ring-shaped optical fiber light guide. The lens 5 for reading light, the CCD camera 4, and the input image data of the CCD camera are binarized, and the specular reflection light from the peripheral part having a surface inclination of θ / 2 at the peripheral part of the upper, lower, left, or right of the inspection object is generated. The image processing means 3 discriminates from the binarized image data, determines presence / absence and / or positional deviation of the inspection object, and detects a defect in a certain range from the peripheral portion. Further, in the mode of this embodiment, the monitor TV 8 connected to the image processing device, the light source 7 of the ring-shaped light guide,
A transport system 2 that transports an inspection object by a control signal from and to the image processing device is provided.

In the apparatus of this embodiment, the surface defect inspection is carried out by the following procedure. The inspection objects 1 are set to the inspection position one by one by the transport system 2. The inspection object 1 in this example is the following IC chip terminal. a) Size 1-2 mm b) Shape Square, hexagonal, circular, etc. with sagging around the surface. c) Material Aluminum is plated with aluminum.

When set at the inspection position, the conveyance system 2 outputs an inspection start signal to the image processing apparatus 3.

The ring-shaped optical fiber light guide 6 illuminates the inspection object 1 with light from the light source 7 at an incident angle θ from the entire circumference. In addition, as the lens 5 of the CCD camera, a 5 × to 10 × objective lens is attached to a C mount adapter. The CCD camera does not receive reflected light from a portion without defects such as scratches and dents through the lens, and reflects from a defective portion and a portion with a θ / 2 surface inclination around the inspection object. Receive light. In this way, the CCD camera 4 inputs an image. In this example, the ring-shaped optical fiber light guide 6 is a PR55 manufactured by Mitsubishi Rayon Co., Ltd.
-1000 type (trade name) was used. As the light source 7, Mitsubishi Rayon Co., Ltd. ELI-100 type (trade name)
It was used.

In the image processing apparatus 3, the input image is binarized with a preset value, and the peripheral portion of the defect and the inspection object is set to “white” and the other portions are set to “black”. As the image processing device 3, an optical area checker FSC-100 type (trade name) manufactured by Mitsubishi Rayon Co., Ltd. was used. Since the binarization condition changes depending on the brightness of the illumination, the aperture of the lens, etc., input a blank paper image with uniform reflected light and set it so that the white area ratio after binarization is 50%. did. With this method, the binarization level can be easily set with an accuracy of 1/256 or less.

The number of “white” pixels is counted with any one of the upper, lower, left, and right ranges corresponding to the peripheral portion of the inspection object as the inspection range. Actually, the inspection ranges were set at two places on the left and above. The coordinates of each inspection range are as follows. a) Leftward direction Start point (80,192) Range (37,4)
1) b) Upward direction Start point (204,44) Range (37,4)
1) Here, when the inspection object is set normally, the number of "white" pixels is within a certain range (200 or more), but in the following abnormal cases, the number of "white" pixels is significantly large. Less. a) When there is no inspected object b) When the displacement of the inspected object is outside the inspection range c) When the inspected object is the back surface and there is no inclination of the peripheral part such as the front surface d) The inspected object is The film is removed after punching with a press, but this film was not removed

The defect in the central portion of the inspection object 1 is detected for the one determined to be normal. a) Inspection range is starting point (132, 104) range (16
9, 217). b) As a rough inspection, the number of "white" pixels in the range of a) above was counted, and a case of 300 or more was judged to be defective. c) The presence or absence of “white” in the designated pixels (10) or more was measured for those which were not determined to be defects in b) above.

When it is determined as a defect in the above,
The NG signal is output to the carrier system 2. The image and the measurement result are output to the monitor TV8.

In the transport system 2, the O of the image processing device 3
The normal and defective products are sorted according to the K and NG signals.

FIG. 2 is a view showing an arrangement example of the image input section of the apparatus of the embodiment shown in FIG. The optical fiber emitting end 9 of the ring-shaped optical fiber light guide 6 has a diameter of 61 mmφ,
73mm above the inspection surface. At the optical fiber emitting end 9, 0.5 mmφ optical fibers are arranged in a line. As the optical fiber, esca manufactured by Mitsubishi Rayon Co., Ltd. is used. Since the Esca's NA is 0.5, it will be illuminated in the range of 60 °. However, since the 5 × objective lens 11 is mounted below the C mount adapter 10, the illumination is restricted to 47 ° (incident angle 23.5 °). In the portion of the inspection object 1, the light condensing part has a diameter of 3 mm and the inspection object 1 is set in this. Further, the peripheral portion of the inspection object 1 is detected as a bright spot at a portion having an inclination of 11.75 °.

3 to 7 are images showing the screen of the monitor TV 8, which are images input by the CCD camera or images showing the screen of the inspection result. FIG. 3 is a grayscale image input from the CCD camera. Defects in the peripheral portion and the central portion are detected as bright spots.

FIG. 4 shows the result of inspecting the input image of the CCD camera of FIG. The inspection time in this example is 460 ms as displayed in the upper left. This determination result was NG as displayed on the third line on the left.
Regarding the position of the inspection object, the number of “white” pixels in the peripheral portion (upper part) is 551 as shown in the fourth line to the left.
It is a pixel (40.4%). The number of “white” pixels in the peripheral portion (left side) is 259 as shown in the sixth line on the left side.
It is a pixel (19.0%). 200 for each of the above
Since the number of pixels is greater than or equal to the number of pixels, it is determined that the inspection object 1 is normally set. Rough Inspection The number of “white” pixels in the central portion is 271 pixels (0.8%), as displayed in the eighth row to the left. Since the inspection condition is less than 300 pixels, the rough inspection is OK.
It has been determined. Detailed inspection As for the set of “white” with 10 or more pixels in the center, as shown in the 10th row on the left side, 5 pieces, the total number of pixels is 145,
The average number of pixels is 29 and the variation is 169.
It is judged as NG.

FIG. 5 shows the inspection result when there is no inspection object. As can be seen from this figure, the number of "white" pixels in the peripheral part (left, upper) is 0, and it is determined to be NG at this stage. FIG. 6 shows the inspection result when the position of the inspection object is displaced. In this example, FIG.
Similarly to the above, the number of “white” pixels in the peripheral portion (left and upper) is 0, and it is determined to be NG at this stage.

FIG. 7 shows the inspection result when the inspection object is the back surface. As you can see from this figure, the periphery (upper)
The number of pixels of "white" is 0 and the number of pixels of "white" in the peripheral portion (on the left side) is 1, and it is determined to be NG at this stage. As demonstrated by the above-described examples, flaws at all angles can be detected as bright spots, and the presence or absence of the inspection object, the positional deviation, and the front and back can be surely checked.

[0022]

Industrial Applicability According to the present invention, flaws at all angles can be detected as bright spots, and the presence / absence of an inspection object, positional deviation, front / back checking, etc. can be performed. The effect as a surface defect inspection device for inspecting defects such as scratches and dents generated on the surface is great.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a device configuration of the present invention.

FIG. 2 is a diagram showing an arrangement example of an image input unit of the apparatus example shown in FIG.

FIG. 3 is a monitor T input from a CCD camera.
It is an image figure of V screen.

FIG. 4 is an image diagram of a monitor TV screen of an inspection result in which a defective defective product is determined.

FIG. 5 is an image view of a monitor TV screen of an inspection result determined that there is no inspection object.

FIG. 6 is an image diagram of a monitor TV screen of an inspection result in which it is determined that the position of the inspection object is displaced.

FIG. 7 is an image view of a monitor TV screen of an inspection result in which it is determined that the inspection object is the back surface.

[Explanation of symbols]

 1 inspection object 2 conveyance system 3 image processing device 4 CCD camera 5 lens 6 ring-shaped optical fiber light guide 7 light source 8 monitor TV 9 Optical fiber emitting end 10 C mount adapter 11 Objective lens

Claims (1)

[Claims] 1. A ring-shaped optical fiber light guide that illuminates an inspection object at an incident angle θ from the entire circumferential direction, and a CCD camera that reads reflected light that is incident on at least the central portion of the ring-shaped optical fiber light guide from the inspection object, The input image data of the CCD camera is binarized, and specular reflection light from the peripheral portion having a surface inclination of θ / 2 at any of the peripheral portions of the upper, lower, left, and right sides of the inspection object is identified from the binarized image data. An image processing unit that determines the presence or absence and / or positional deviation of the inspection object and detects a defect in a certain position from the peripheral portion.