JPH05180638A - Building-material inspecting method - Google Patents

Abstract

PURPOSE:To discriminate the chipped defect of a building material such as a colored bestos automatically by image processing and to improve the discriminating accuracy of the chipped defect without the effect of external light. CONSTITUTION:An inspection reference value X is determined based on the measured illuminance value of an illuminance meter 15, which is provided at an inspecting position of a building material M and a database wherein the inspection reference values X are accumulated for every illuminance value L. Then, a threshold value Y is obtained. The data are compared with the detected value data, which are obtained by image processing, and the presence or absence of the chipped defect is discriminated.

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 roofing material or a wall material which has a mounting hole like a color vest or a roof tile and which is manufactured in a certain shape. It is about.

[0002]

2. Description of the Related Art Generally, in a manufacturing process of building materials, for example, color vests, an operator visually checks the color vests sequentially conveyed at a rate of about 40 m / min to determine the presence or absence of a chip. However, this is extremely inefficient and requires skill for the operator. Therefore, a method for automatically detecting the lack of the color vest has been developed with the configuration shown in FIG.

In FIG. 3, reference numeral 1 is a CC as a photographing device.
It is a D camera and is 40 m when it is placed on the belt conveyor 2.
It is set so as to photograph the color vest M that is conveyed at a speed of about / minute. An image processing device 3 receives the image output from the CCD camera 1 and performs image processing, and compares the number of pixels forming the image of the color vest M with a reference number of pixels to determine the presence or absence of a defect. Reference numeral 4 is a strobe that emits light from the back side of the color vest M in synchronization with the photographing operation, 5 is a strobe controller that drives the strobe 4, and 6 is a synchronizing circuit that synchronizes the light emitting operations of the CCD camera 1 and the strobe 4. . Further, 6a is a limit switch, which sends a timing signal for determining the timing at which an image from the CCD camera 1 is input to the synchronizing circuit 6.

In such a structure, the color vest M conveyed by the belt conveyor 2 is photographed by the CCD camera 1 in synchronization with the strobe 4. The image processing device 3 that receives the image output from the CCD camera 1 compares the number of pixels forming the image of the color vest M with the reference number of pixels to determine whether or not the color vest M is missing.

[0005]

However, according to the above-mentioned conventional method, it is necessary that the illuminance at the inspection position is kept constant when the color vest M is photographed by the CCD camera 1, and the external light or the like is not emitted. In a changing environment, the illuminance changes due to the influence of this external light, the inspection standards vary, and high discrimination accuracy cannot be expected.

For this reason, there is a method which adopts an automatic threshold value setting method of setting a threshold value at an intermediate point between two peak values of the number of pixels which changes with a change in illuminance, but with respect to a slight change in external light. The inspection standard cannot be followed accurately.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for inspecting a building material, which enables highly accurate discrimination without being affected by the influence of external light or the like. .

[0008]

In order to achieve the above object, the method for inspecting a building material according to the present invention is such that the building material is placed on a carrier and is conveyed at a constant speed in one direction while the main surface side of the building material is being conveyed. While shooting with a shooting device from, the building material inspection method of irradiating the building material with light in synchronization with the shooting operation, image processing the image output from the shooting device to determine the presence or absence of the building material on the image, From the illuminance measurement value by the illuminometer provided at the inspection position of the building material and the database in which the inspection reference value is accumulated for each illuminance value, the inspection reference value of the illuminance at that time is determined, and the inspection reference value A threshold value is obtained, and this data is compared with the image-processed detection value data to determine the presence or absence of a defect.

[0009]

According to the present invention as described above, the inspection reference value is determined according to the illuminance measurement value from the illuminance meter provided at the inspection position of the building material, and the threshold value is obtained. Even if it slightly changes due to the above, since the determination is performed under the inspection standard corresponding to this, it is possible to perform highly accurate determination of the defect.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing a construction material inspection method according to an embodiment of the present invention applied to a color vest inspection. The same parts as those of the conventional example shown in FIG. Is omitted.

In FIG. 1, reference numeral 12 is a conveyor, for example, a conveyor belt, on which a color vest M as a building material is placed and which is conveyed in one direction at a constant speed.
2 is composed of a translucent material. Reference numeral 13 is a strobe storage box made of a translucent material such as acrylic, which is designed to emit light from the strobe 4 for irradiating the color vest M with light. The light irradiation means 14 is constituted by 4 and. On the inspection position of the color vest M, for example, on the upper surface of the strobe storage box 13, a plurality of illuminometers 15 (15A, 15B, 15) for measuring illuminance in the vicinity thereof are provided.
C, 15D) are attached, and the illuminance measurement value of each illuminance meter 15 is sequentially input to the image processing device 3.

When inspecting the color vest M, the image processing apparatus 3 is provided with a database in which inspection reference values are stored for each illuminance value at the inspection position. This database, for example, as shown in FIG. 2, for each measurement value (average value) (L) from each illuminance meter 15 due to a change in illuminance, sets the number of pixels forming the image of the color vest M to the inspection reference value (X ) Is obtained experimentally and tabulated.

In this state, the color vest M is placed on the conveyor belt 12 and conveyed in one direction at a speed of about 40 m / min. When it reaches a predetermined position, the CCD camera 1
While the main surface side of the color vest M is photographed, the strobe 4 emits light in synchronization with this photographing operation, and the light becomes surface emission on the upper surface of the strobe storage box 13 to illuminate the color vest M from the rear surface side. .

At this time, a plurality of illuminometers 15 measure the illuminance of the surroundings including the external light, and the respective measured values are sequentially taken by the image processing device 3.
In the image processing device 3, the average value of the plurality of illuminance measurement values at this time is obtained, and this is taken as the illuminance at that time, and the inspection reference value (number of pixels) (X) corresponding to this is determined. At the same time, the threshold value at the inspection reference value X is obtained by automatic threshold value setting. In this state, the image processing device 3 is operated by the CCD
The detection value A in the image output from the camera 1, that is, the data of the number of detected pixels of the color vest M and the data of the inspection reference value X are compared to determine whether or not the color vest M is missing. For example, when the measured illuminance value (L) at this time is 190, the inspection reference value (X) is determined to be 12000 as shown in FIG. 2, and if the allowable value at this time is 500, (X)-
Since the threshold value is obtained from 500, (X) −500 ≦ A
The quality is determined from ≦ (X).

Since the inspection reference value and its threshold value are selected in accordance with the illuminance in this manner, the optimum inspection reference value is automatically maintained even if there is a change in external light, and whether or not the color vest M is missing. Can be determined with high accuracy.

In the above embodiment, the belt conveyor 12 made of a translucent material is used to irradiate the light from the back side of the color vest M. However, the light is radiated from the main surface side of the color vest M. It can also be applied to what is irradiated.

[0017]

As described above, according to the present invention, the illuminance is measured by the illuminometer provided at the inspection position of the building material, and the inspection reference value is accumulated for each illuminance value and the illuminance measurement value is used. The inspection standard value is determined and the threshold value is obtained, and the quality is determined by comparing these data with the detection data on the image of the building material, so even if the external light changes, the inspection standard can be optimized accordingly. You can follow the value,
Therefore, it is possible to improve the discrimination performance and the discrimination accuracy.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a database stored in the image processing apparatus.

FIG. 3 is a configuration diagram showing a conventional building material inspection method applied to an inspection of a color vest.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photographing apparatus 3 Image processing apparatus 12 Carrier 14 Light irradiation means 15A, 15B, 15C, 15D Illuminance meter A Inspection value L Illumination value X Inspection reference value

Claims (1)

[Claims] 1. A building material is placed on a carrier and is photographed by a photographing device from the main surface side of the building material while being conveyed in one direction at a constant speed, and the building material is irradiated with light in synchronization with the photographing operation. In the method for inspecting a building material for determining the presence or absence of a building material on the image by image processing the image output from the photographing device, the illuminance measurement value by an illuminometer provided at the inspection position of the building material, and for each illuminance value From the database that stores the inspection reference value, determine the inspection reference value for the illuminance at that time, determine the threshold value for that inspection reference value, and compare this data with the inspection value data on the image to check for missing A method for inspecting building materials, which is characterized by determining the presence or absence.