JPS63106508A - Method and apparatus for inspecting mounting state - Google Patents

Abstract

PURPOSE:To certainly inspect the mounting state of an object to be detected, by a method wherein the predetermined object containing the object to be detected is irradiated with light from a diagonally upward side and the side opposite to the object to be detected to generate shades on the side surface of the object to be detected and the side surface thereof on the opposite side thereof and unnecessary information is removed from the image informations obtained by said irradiation to perform the matching of shaded patterns with a standard pattern. CONSTITUTION:A plurality of circuit parts 3a-3d are mounted to the required places of a circuit substrate 1 having a required pattern 2 formed thereon. An image pickup camera 6 is arranged above the board 1 and the predetermined region of the board 1 present within the visual field of the camera 6 is separately irradiated with the lights from light irradiation devices 7a, 7b arranged at diagonally upward parts on both sides of the camera 6. The image informations picked up by the camera 6 are converted by an A/D converter circuit 9 to be respectively recorded on the first and second image memories 10a, 10b. The difference between the image informations of the memories 10a, 10b on the same coordinates is calculated by a subtractor circuit 11 and the matching of the shaded patterns of the image informations with a preset standard pattern is taken by a pattern matching circuit 13 inputting the output from a binarization circuit 12 to inspect the mounting state of the parts 3a-3d.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is a mounting state inspection that detects the presence or absence of detection objects such as electronic components mounted on a circuit board, and the mounting state such as a positional deviation chart. The present invention relates to a method and an apparatus thereof.

(Prior Art) In recent years, as electronic devices have become thinner, thinner, and smaller, the mounting density of circuit components has also become higher. Further, although considerable progress has been made in automating and speeding up the mounting of electronic components, post-mounting inspections still rely on humans. This is because the object to be detected is in a complex background (for example, in the case of a circuit board, it is mixed in wiring patterns, prints, and characters) and cannot be detected using conventional thinking and methods. In addition, due to high density,
Decreased reliability and increased fatigue in conventional human testing are also becoming problems.

(Point m during which the invention attempts to solve the problem) The present invention was made in consideration of the problems with the inspection accuracy and inspection efficiency of the mounting state of circuit components, which are becoming increasingly dense in recent years. An object of the present invention is to provide a mounting state inspection method and apparatus that can reliably inspect the mounting state of a detected object.

[Structure of the invention]

(Means and effects for solving the problem) In the method and apparatus for recognizing the detected object by processing image information obtained by imaging a predetermined area including the detected object, After irradiating light from above to generate a shadow on the side of the object to be detected to image a predetermined area, irradiating light onto the predetermined area from diagonally above, opposite to the above-mentioned light irradiation, to A shadow is generated on the side of the object to be detected in the opposite direction to the shape, and a predetermined area is imaged, and the image information obtained from these images is processed to obtain image information of the shadow part in each image information. Then, based on the projection information obtained by projecting the image information of this shadow area, pattern matching is performed with preset standard image data to recognize the detected object on the abstract. By this,
It is possible to reliably inspect the attachment state of the required object to be detected.

(Embodiments of the Invention) Hereinafter, an explanation will be given based on a mounting condition inspection device according to an embodiment of the present invention with reference to the drawings. Fig. 1 shows parts attached to a circuit board which is an embodiment of the present invention. The configuration of the recognition wearing state inspection device is shown. As shown in this drawing, a circuit board (1) has a required wiring pattern (2) on its board surface.
is formed, and multiple types of circuit components (3a
) -(3d) is attached. Accordingly, the device includes an imaging camera (6) placed on the circuit board (1) and having an optical lens (5) attached to the front face facing the circuit board (1) 17; A pair of light irradiation devices (7a) and (7b) are provided on both sides of the camera to separately irradiate light from diagonally above to predetermined areas of the circuit board (1) within the field of view of the imaging camera (6). There is. The imaging camera (6) is equipped with the light irradiation device (7a) or (7b).
) A/
The D conversion circuit (9) is connected, and this person/D conversion circuit (9)
) stores the human/D-converted image information. Second image memories (10a) and (10b) are connected. Of the pair of image memories (10a) and (10b), the first image memory (10a) is the light irradiation device (7a).
), the second image memory (10b) is a memory that stores image information captured under light irradiation of the light irradiation device (
7b) is a memory that stores image information captured under the light irradiation. These first. 2nd image memory (ioa)
, (tab) contains these image memories (ioa),
A subtraction circuit (11) that calculates the difference between signals on the same coordinates is connected to the image information stored in the (iob), and this subtraction circuit (11) is sequentially connected to a binarization circuit (1
A pattern matching circuit (to which 13 is connected) performs matching of the signal binarized by the binarization circuit α2 of 3 and 2 with preset standard image data of the component. In addition to calculating the matching amount obtained from the pattern matching circuit α■, the light irradiation device (7a),
An arithmetic control circuit 1e is connected which controls the timing of the light irradiation switching operation (7b) through a timing circuit (one).The arithmetic processing result of the pattern matching described above is The information is displayed at η on a display device such as a printer connected to the control circuit +if9.

Next, a method for inspecting the wearing condition of this embodiment using the wearing condition inspection apparatus having the above-mentioned configuration will be described.

First, the circuit board (1) or the imaging camera (6) and the pair of light irradiation devices e (7a), (7b) are moved together, and the imaging camera (6) is placed over a predetermined area of the circuit board (1). , that is, for example, as shown in FIG.
) is positioned on the area including the circuit component (3a) located approximately in the center of the area. Then, in response to a command from the arithmetic and control circuit (1e), the light irradiation device (7a) is first turned on to irradiate the predetermined area with light, and the irradiation area is illuminated by the imaging camera (6).
). The image information obtained by this imaging is sent to the first image memo IJ via the human/D conversion circuit (9).
(10a) Next, the arithmetic control circuit (
Light irradiation device (7a) according to instructions from le.

(7b), the light irradiation device (7b) irradiates the same area as the irradiation area of the light irradiation device (7a), and images this irradiation area in the same manner as above. The obtained image information is stored in the first image memory J (10b) via the λ/D conversion circuit (9).

By the way, when the light is irradiated from the light irradiation device (7a) located diagonally above the predetermined area as described above, as shown in FIG.
3a) produces a shadow (20a) on the side opposite to the light irradiation according to its protruding height. Therefore, the imaging camera (6
) captures an image including this shadow (20a), so image information including this shadow (20a) is stored in the first image memory (10a). Similarly, when the same area is irradiated with light from the light irradiation device (7b), the light irradiation device (7b) disposed on the opposite side of the light irradiation device (7a) will be affected as shown in FIG. ) As shown in the figure, a similar shadow (20b) is produced on the opposite side, and a second
Image information including this shadow (20b) is stored in the image memory (iob). So, this first one. The image information stored in the second image memories (10a) and (10b) is called to the subtraction circuit (11), and the difference between them is calculated for each signal at the same coordinates. When the values are binarized, as shown in Figure 3 (A), the image data of the circuit component (3a), the substrate material, the wiring pattern (2), etc. are converted to "0", the shadows (20a), (20b), etc. However, on the 0th floor of the pattern matching circuit, the standard pattern corresponding to the shadow of the part prepared in advance + 23 (3rd (see figure (B)) and image information C2υ, that is, the standard pattern @ is moved one pixel in each of the X and Y directions within a predetermined area within the image information Cυ. Find the X and Y coordinates of the location where both match. By processing the XY coordinates obtained by this pattern matching in the arithmetic control circuit C1e, the circuit component (
It is possible to recognize the presence or absence of 3a), the positional shift of two parts, the difference in the inclination of two parts, etc.

Next, other embodiments will be described.

In the above embodiment, when processing the image information obtained from the subtraction circuit, the image information is binarized, but it is also possible to process the image information as a digital signal having gray levels.

Further, in the above embodiment, a pair of light irradiation devices are used to selectively irradiate a predetermined area, but the number of light irradiation devices may be limited to two as long as they produce shadows in different directions. There are many things that can be done. Further, in the above embodiment, the image information obtained from the imaging camera is once transferred to the first and second cameras.
Although the image information was stored in the image memory, especially image information obtained later is not stored in the image memory, but is sent to the subtraction circuit in real time, and the r! ii image information may be calculated. Furthermore, the standard pattern may be a part of the shadow, a part of the part, or a combination of the shadow and the part. Alternatively, a standard pattern showing the shape of the component itself as shown in FIG. 3(C) may be used as the standard pattern.

Although the above embodiment describes recognition of circuit components on a circuit board, the present invention can also be applied to recognition of other detected objects.

〔Effect of the invention〕

A predetermined area including the object to be detected is irradiated with light from above the can to generate a shadow on the side of the object to be detected, and then light is irradiated from the opposite side of the irradiation of light to create a shadow on the side of the object to be detected. After creating a shadow on the side of the image and using the two image information obtained under these two types of illumination to delete unnecessary information, pattern matching with the standard pattern was performed. Since this is done, it is possible to reliably inspect the attachment state of the target object to be detected.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a recognition wearing state inspection device according to an embodiment of the present invention, and FIGS. 2 and 3 are explanatory diagrams of a mounting state inspection method according to an embodiment of the present invention. ...Circuit board, (3a) to (3d)...
Circuit components (object to be detected). (6)...Imaging camera (imaging means), (7a)
, (7b)...Light irradiation device (illumination means), αυ...
- Subtraction circuit (shadow extraction means). (13... Pattern matching circuit (means). (20a), (20b) -... Shadow of circuit component. 4... Standard pattern of shadow, @... Standard pattern of component.

Claims (2)

[Claims] (1) A first step of irradiating light from diagonally above onto a predetermined region on which a detected object is attached to generate a shadow of the detected object on the side of the detected object to image the predetermined region; The predetermined region is imaged by irradiating light onto the predetermined region from diagonally above, opposite to the light irradiation, to generate a shadow of the object to be detected on the side of the object to be detected in a direction opposite to the shadow. a second step; a third step of extracting shadow information of the detected object by calculating the difference on the same coordinates between the image information obtained in the first and second steps; and a third step of extracting shadow information of the detected object, and a shadow indicated by the shadow information. a fourth step of determining the mounting position of the object to be detected by performing pattern matching processing between the pattern and a standard pattern set in advance; and detecting the mounting state of the object to be detected based on the determined mounting position; A mounting state inspection method characterized by having the following. (2) illumination means for generating a shadow of the object by irradiating a predetermined area on which the object to be detected is mounted from obliquely upper positions facing each other; and illumination means for illuminating the predetermined area from each of the above positions an imaging means that takes an image and outputs a first and second image signal; A shadow extraction means that outputs a shadow extraction signal performs pattern matching between the shadow pattern indicated by the shadow extraction signal and a preset standard pattern to determine the mounting position of the object to be detected, and detects the mounting position of the detected object. and pattern matching means for detecting the mounting state of the object to be detected based on the following.