JPH06337210A - Inspection of building material - Google Patents

Abstract

PURPOSE:To detect the break of a building material on the basis of the change of the luminance value of each pixel on a scanning straight line by allowing each pixel on the scanning straight line to be situated in the image area of the building material. CONSTITUTION:A plurality of the boundary coordinates (a), (b) on a lateral side La are calculated to calculated the straight line LLa passing the boundary coordinates (a), (b). The scanning segment LS preformed into the regular shape of a side LB to be inspected is set so that a reference point BP is positioned on the straight line LLa and the angle thetas formed between the scanning segment LS and the straight line LLa coincides with the angle thetam between the side LB to be inspected and the lateral side La. The distance alpha1 from the point P1 on the scanning segment LS to the side LB to be inspected is calculated and the scanning segment LS is parallelly moved to the position separated by a proper distance obtained by adding a minute distance alphaX to the distance alpha1 to be superposed on an image V to be set thereto and the change of the luminance value of each pixel along the scanning segment LS is caught to discriminate the presence of a break in the side LB to be inspected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of inspecting a building material such as a roof material such as a color vest or a roof tile, a wall material, or the like, which is manufactured to have a certain shape, for the presence or absence of a chip. .

[0002]

2. Description of the Related Art Generally, in the manufacturing process of building materials such as color vests, 40 m / min. Although the operator performed visual inspection to determine the presence or absence of a defect in the color vests sequentially conveyed in a certain degree, this is extremely inefficient and requires a high degree of skill for the operator. For this reason, recently, a method has been adopted in which the color vest is photographed by a CCD camera as a photographing device and the output thereof is subjected to image processing to determine whether or not the color vest is missing.

There are two methods, a so-called total area method and a local method. Among them, the total area method is to synchronize the conveyed color vest with a strobe and
The total area of the color vest on the image is obtained by the image processing device which receives the image output from this CCD camera, and the difference between the entire area and the actual area which is the reference area is obtained. This is a method of determining the presence or absence of color vest defects. In the local method, a plurality of cameras are prepared, the corners of the color vest are photographed in the respective visual field areas of these cameras, and the shape of the corner is measured to determine whether or not the color vest is missing. It is the one.

[0004]

However, in the above-mentioned conventional total area method, although the entire chip of the color vest can be detected, the resolution in the image processing is low and the minute chip can be detected. You cannot expect the high accuracy of. On the other hand, in the local method, the resolution in image processing is high, and it is relatively easy to detect small defects, especially corner defects, but the edges between the vertices of the color vest, especially the non-straight line It was not possible to detect with high accuracy the so-called edge chipping that exists on the edge forming the.

The present invention has been made to solve the above-mentioned conventional problems, and is capable of reliably detecting a chip existing on the side of a building material, especially on the side of a non-linear characteristic shape. The purpose is to provide the inspection method.

[0006]

In order to achieve the above object, a method of inspecting a building material according to the present invention is characterized in that an inspection target side having a non-linear shape of a building material conveyed at a constant speed is provided on one side thereof. An image is taken by a photographing device including a corner portion and adjacent sides sandwiching the corner portion, and an image output from the photographing device is subjected to image processing in an image processing device to obtain a plurality of boundary coordinates on the side portion, A straight line passing through these plural boundary coordinates is obtained, and a scanning line segment formed in advance in a regular shape of the inspection target side is formed between the scanning line segment and the straight line whose base point is located on the straight line. The angle to be set to match the angle between the side and the side to be inspected, the distance from the representative point plotted on the scanning line segment to the side to be inspected,
The scanning line is moved in parallel at a position separated by an appropriate distance obtained by adding a small distance to the distance, and the scanning line is set so as to be superposed on the image. The change in the luminance value of each pixel along the scanning line is captured to perform the inspection. It is configured to determine the presence or absence of a chip on the target side.

[0007]

According to the present invention, since the scanning line segment having the regular shape of the inspection target side is set in parallel with the inspection target side on the image, each pixel on the scanning straight line is originally a building material. , And its luminance value is uniform. Therefore, if the brightness value of each pixel located on the scanning straight line changes, it can be determined that a defect exists on the inspection target side at the location.

Since the scanning straight line is set to an appropriate distance obtained by adding the minute distance to the inspection target side in consideration of the distance from the representative point on the line segment to the inspection target side, on the image separated by the minute distance from the inspection target side. It is possible to improve the inspection accuracy without the risk of overlapping the position without fail and causing the detection omission of a minute chip on the inspection target side.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the building material inspection method of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a color vest inspection apparatus to which a building material inspection method according to an embodiment of the present invention is applied.

In FIG. 1, reference numeral 1 is a conveyer for placing a color vest M as a building material and transporting it at a constant speed, and 2A and 2B are photographing devices arranged facing the front side of the color vest M. , For example, two CCD cameras. The left half of the CCD camera 2A including the apex A of the corner Ma in the color vest M is set as a visual field area, and the other CCD camera 2B includes the right half including the apex B of the corner Mb in the color vest M. Half is set as the field of view. Inspection target side L of color vest M
B has a non-linear shape, the inspection target side LB and the side edge La are adjacent to each other across the corner Ma, and the inspection target side LB and the side edge Lb are adjacent to each other across the corner Mb. An image processing device 3 receives an image output from the CCD camera 2 and has a function of determining whether or not the color vest M is missing.

Next, an inspection method for determining whether or not the color vest M is missing from the image V shown in FIG. 2 taken by one of the CCD cameras 2A will be described. The image processing circuit 3 receives the image output from the CCD camera 2A and performs image processing. First, a plurality of boundary coordinates a and b on the side La in the image V are obtained, and a straight line LLa passing through these plurality of boundary coordinates a and b is obtained.

Next, as shown in FIG. 3, a scanning line segment LS formed in advance in a regular shape on the side LB to be inspected is set such that its base point BP is located on the straight line LLa, and further scanning is performed. The angle θs formed between the line segment LS and the straight line LLa is set to match the angle θm between the inspection target side LB and the side La. Moreover, obtains a distance alpha ₁ to said object side LB from the representative point P ₁ plotted on the scanning line LS, suitable distances summing the minute distance alpha _X to the distance alpha ₁ to (α ₁ + α _X) The scanning straight line L at the separated positions
S is moved in parallel and is set so as to be superimposed on the image V.

Then, the change in the brightness value of each pixel along the scanning line LS is captured to determine the presence or absence of the chip A _{1 on} the inspection target side LB. By the way, the representative point P ₁ set on the scanning line segment LS may be a plurality of points in order to eliminate error motion, and for simplification, an appropriate distance (α ₁ + α _X ).
Can be set to an appropriate constant value. The presence / absence of a defect on the inspection target side LB in the area photographed by the other CCD camera 2B is also determined in the same manner as described above.

[0014]

As described above, according to the present invention, since the scanning line segment having the regular shape of the inspection target side is set parallel to the inspection target side and overlapped on the image, the scanning line is originally set. The above pixels are located in the image area of the building material, and their brightness values are uniform. Therefore, if the brightness value of each pixel located on the scanning straight line changes, it can be determined that there is a defect on the inspection target side at the location, and there is a risk that a detection failure of a minute defect on the inspection target side may occur. None,
The inspection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a color vest inspection apparatus to which a building material inspection method according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram showing a method of discriminating a missing side of a color vest from a captured image of a CCD camera in the embodiment.

FIG. 3 is an explanatory diagram showing a setting state of scanning line segments in the embodiment.

[Explanation of symbols]

2A, 2B Imaging device 3 Image processing device A, B Vertices a, b Boundary coordinates M Building material Ma, Mb Corner P ₁ Representative point V Image α _X Minute distance α 1 Distance LB Inspection side La, Lb Side LS Scan line segment LLa straight line

Claims (1)

[Claims] 1. A non-linear shape inspection target side of a building material conveyed at a constant speed is photographed by a photographing device including a corner on one side and a side adjacent to the corner adjacent to the corner.
The image output from the photographing device is subjected to image processing in the image processing device to obtain a plurality of boundary coordinates on the side, and a straight line passing through the plurality of boundary coordinates is obtained to form a regular shape of the inspection target side in advance. The scanning line segment is set such that its base point is located on the straight line, and the angle formed between the scanning line segment and the straight line matches the angle between the inspection target side and the side, The distance from the representative point plotted on the scanning line segment to the inspection target side is obtained, and the scanning straight line is moved in parallel at a position separated by an appropriate distance obtained by adding a small distance to the distance, and the scanning straight line is superimposed and set on the image. Then, the method for inspecting a building material is characterized in that the presence or absence of a chip on the inspection target side is discriminated by capturing a change in the brightness value of each pixel along the scanning straight line.