JPH0367201B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to plate materials (board materials) such as building materials used for walls, ceilings, floors, etc. The present invention relates to an appearance inspection device that automatically inspects defects such as chipped parts. From the viewpoints of safety, durability, aesthetics, etc., such board materials are required to have no defects such as depressions, protrusions, and scratches on their surfaces.

[Prior art and its problems]

Generally, building materials are made of various materials such as wood, plastic materials, plaster, and cement, and usually have irregular patterns formed on their surfaces. Therefore, it is difficult to detect scratches, chipped edges, dirt, protrusions, dents, etc. on the board in such irregular patterns.
Currently, most of the inspections rely on human visual inspection. That is, although flying spot inspection devices using a laser beam or the like or automatic inspection devices using a linear array camera are known, these devices require that the surface be free of patterns. However, visual inspection has its limitations, and therefore, it has been desired to develop a device that can automatically perform this type of inspection.

[Purpose of the invention]

The present invention has been made under these circumstances, and provides an inspection device that can accurately detect the various defects described above with a simple and inexpensive configuration, especially when a pattern is formed on the surface of a board. The purpose is to

[Key points of the invention]

This invention relates to a plate-shaped material (plate material) to be inspected.
A conveyance means which consists of an upper pressure roller and a lower roller which hold down the plate material downward with a constant pressure, and conveys the plate material by sandwiching it between these rollers, and an illumination means which illuminates the vicinity of the contact area between the surface of the plate material and the upper pressure roller. and an imaging means for taking an image of the vicinity of the contact portion from the side opposite to the illumination means that sandwich the upper pressing roller, the imaging means takes an optical image of a defect in the plate material, and based on this taken image, the image is taken. It is characterized by conducting an inspection.

[Embodiments of the invention]

Fig. 1 is a configuration diagram showing an embodiment of this invention;
The figure is an explanatory diagram for explaining the imaging device. In FIG. 1, 1 is a plate-like material, 2 is a drive roller,
3 is a pressure roller, 4 is a light source, 5 is a contact portion, 6 is a television camera, and 7 is a determination device.

The plate material 1 is moved by the drive roller 2, for example in the direction of arrow F.
conveyed in the direction. The rotation direction of the roller 2 at this time is indicated by an arrow R. Press roller 3
holds the plate 1 downward in the figure with constant pressure and rotates in the direction of arrow R. Note that the structure is such that adjustment of the pressing force of the pressing roller 3, adjustment of the gap between the pressing roller 3 and the driving roller 2, etc. can be done as appropriate. On the other hand, a light source 4 is arranged on one side of the roller 3 in the vicinity of the contact portion 5 between the plate material 1 and the pressing roller 3, and the contact portion vicinity 5 is illuminated by this. Light source 4 is a highly directional light,
For example, a laser beam is generated to illuminate the contact portion. An industrial television camera (ITV camera) 6 is placed on the opposite side of the light source 4 that sandwiches the roller 3.
An image is taken of the vicinity 5 of the contact portion between the plate material 1 and the pressing roller 3. As this ITV camera, not only one using an image pickup tube such as a vidicon, a solid-state camera using a semiconductor, or a two-dimensional sensor type, but also a one-dimensional sensor type linear array camera, etc. can be used. A video signal obtained through this camera 6 is expressed as shown in FIG. 2, for example.

In FIG. 2, A is an example in which a plate material has a recess (indentation) and light leaks through the gap formed by this recess. Note that reference numeral 11 represents an image formed by the plate material, 12 represents an image formed by the recess, and 13 represents an image formed by the pressing roller.

Similarly, B is an example in which the plate material has a protrusion (projection) and the pressure roller is pushed upward to form a gap. Note that numeral 14 indicates an image formed by a protrusion, and numerals 11 and 13 are the same as A. In addition, in both cases A and B, the gap formed by the concave or convex portions is generally narrow, so due to the pinhole effect due to light diffraction,
The width of the image actually captured by the camera is wider than the actual width, which makes it possible to reliably capture images caused by defects.

The determination device 7 can detect the presence or absence of a defect by processing the optical image formed in this manner. When a defect is detected, a signal DE to that effect is output, and based on this signal DE, the plate material is automatically removed or a warning is issued. Therefore, the determination device 7 includes well-known image processing such as binarizing the captured image, extracting various feature quantities based on the binarized image, and comparing these with reference values. If the defect is basically detectable based on the optical image,
Any material may be used.

〔Effect of the invention〕

According to this invention, it is not only possible to automatically inspect the surface of a board with a pattern, but also to stably detect small irregularities that are difficult to judge visually, which is useful for improving the quality of the board. be.
Of course, automation also brings about labor-saving effects, allowing continuous operation 24 hours a day.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of this invention;
The figure is an explanatory diagram for explaining a captured image. Explanation of symbols 1... Plate material, 2... Drive roller, 3... Press roller, 4... Light source, 5... Contact portion, 6... Camera (imaging device), 7... Judgment device,
11... Image by plate material, 12... Image by recess, 13... Image by pressing roller, 14...
...Image by protrusion.

Claims (1)

[Claims] 1. A conveying means consisting of an upper pressing roller and a lower roller that hold down the plate material to be inspected (plate material) downward with a constant pressure, and conveying the plate material by sandwiching it between these rollers, and an upper pressing member on the surface of the plate material. An illumination means for illuminating the vicinity of the contact part with the roller, and an imaging means for taking an image of the vicinity of the contact part from the side opposite to the illumination means sandwiching the upper pressing roller, and the imaging means can detect defects caused by defects in the plate material. 1. An appearance inspection device for a plate material, which captures an optical image and performs inspection based on the captured image.