JP3213866B2 - Work surface smoothness inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the smoothness of a work surface such as a painted surface of the work.

[0002]

2. Description of the Related Art Conventionally, as a method for inspecting whether or not a convex portion due to adhesion of dust or the like exists on a painted surface of a work, Japanese Unexamined Utility Model Publication No. 5-14902 discloses a method for inspecting a work surface A as shown in FIG. Using an optical inspection device including a light projecting means 1 for irradiating the detection light toward the light source and an imaging means 2 for receiving the reflected light from the work surface A, and converting the reflected light image data formed on the imaging means 2 into image data. One that detects a convex portion B of a work surface A based on the same is known.

The light projecting means 1 comprises a light source 10 and a condensing optical system 11 such as a Fresnel lens for irradiating the light from the light source 10 toward the work surface A. The reflected light is converged toward the image pickup means 2 by the light condensing action of the detection light, and the effective inspection range of the work surface A where the image pickup means 2 can receive the reflected light can be expanded.

The image pickup means 2 is composed of a CCD camera, and an optical inspection device is arranged so that reflected light converges toward the center of the light input section 20 composed of a lens of the image pickup means 2 for inspection. It is carried out.

Here, if the work surface A has a convex portion B,
The reflected light Rb from the convex portion B is not incident on the light incident portion 20, and a portion corresponding to the convex portion B of the image of the imaging means 2 becomes a dark portion,
The presence of the convex portion B can be detected from this dark portion.

[0006]

However, in the above-described conventional inspection method, if the convex portion B of the work surface A does not become a certain size or more, the reflected light from the convex portion B enters the imaging means 2. The light is incident on the light portion 20 and the reflected light is imaged on a portion corresponding to the convex portion B of the image, and this portion does not become a dark portion. Therefore, even if minute irregularities such as undulations due to uneven coating are generated on the work surface, no dark portion corresponding to the irregularities appears in the image of the imaging means, and it is difficult to accurately inspect the smoothness of the work surface. In view of the above, it is an object of the present invention to provide a method capable of accurately inspecting the smoothness of a work surface using the above-described optical inspection device.

[0007]

In order to achieve the above object,
The present invention includes light projecting means for irradiating detection light toward the work surface, and image pickup means for receiving light reflected from the work surface, so that the reflected light converges on the light projecting means toward the image pickup means. In a method of inspecting the smoothness of a work surface using an optical inspection device that incorporates a condensing optical system that condenses detection light, reflected light converges toward an end of a light incident portion of an imaging unit. The optical inspection apparatus is arranged as described above, and in this state, the inspection is performed based on the image data of the reflected light imaged on the imaging means.

[0008]

[Function] Even if the unevenness of the work surface is minute, the light reflected from the unevenness deviates from the end area of the light incoming portion of the imaging means where the reflected light from the flat work surface converges and enters the light incoming portion. And a dark part appears in a region that is originally a bright part of the image of the imaging means. Thus, the smoothness of the work surface can be accurately inspected based on the image data of the imaging means.

[0009]

FIG. 1 shows a work surface A using an optical inspection device.
2 shows a state in which the smoothness of the image is inspected. The basic configuration of this inspection apparatus is the same as that of the inspection apparatus shown in FIG. 3, and the same members are denoted by the same reference numerals as those used in FIG. 3, and description thereof will be omitted.

This optical inspection apparatus is mounted on the operating end of a robot (not shown) so that the relative positional relationship between the light projecting means 1 and the imaging means 2 is kept constant. In the inspection of the convex portion due to, for example, the inspection device is positioned with respect to the workpiece so that the reflected light from the workpiece surface A converges on the central portion of the light entrance 20 of the imaging means 2 as shown in FIG. In the inspection of the smoothness of A, the inspection device is tilted from the state of FIG. 3 so that the reflected light converges on the end of the light entrance 22 as shown in FIG.

According to this, of the unevenness existing on the work surface A, the reflected light RC from the unevenness portion C located on the end side of the light incident portion 20 can receive the reflected light RC even if the unevenness portion C is minute. 22
On the other hand, the reflected light Rd from the concave / convex portion D located on the side of the light incident portion 22 away from the end portion is incident on a portion outside the normal reflected light incident area, and the image of the imaging means 2 The reflected light Rd is imaged in a portion outside the normal reflected light imaging region.

Therefore, if the work surface A is smooth, the image of the imaging means 2 has a bright area corresponding to the irradiation area of the detection light and a dark area corresponding to the non-irradiation area, as shown in FIG. Although the region clearly appears, if the surface roughness of the work surface A is poor, as shown in FIG.
Are not scattered in the bright portion region due to the light not entering the light incident portion 22, and the bright portions are scattered in the dark portion region due to the imaging of the reflected light Rd from the uneven portion D. Become.

Thus, by setting a plurality of windows W in the image of the image pickup means 2 and performing image processing such as counting the number of windows W of 100% of the bright portion or 100% of the dark portion, the work surface A can be smoothed. The degree can be inspected quantitatively, which is very useful for controlling the quality of the painted skin.

[0014]

As is apparent from the above description, according to the present invention, fine irregularities on the work surface can be detected, and the smoothness of the work surface can be optically accurately inspected.

[Brief description of the drawings]

FIG. 1 is a diagram showing an inspection state of a work surface smoothness according to the present invention.

2A is a diagram illustrating an image when the work surface is smooth, and FIG. 2B is a diagram illustrating an image when the surface roughness of the work surface is poor.

FIG. 3 is a diagram showing a normal inspection state of a work surface;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projection means 2 Imaging means 20 Light entrance part A Work surface

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01N 21/84-21/958

Claims (1)

(57) [Claims] A light projecting means for irradiating the work surface with detection light; and an image pickup means for receiving reflected light from the work surface, wherein the reflected light converges toward the image pickup means. In the method of inspecting the smoothness of the work surface using an optical inspection device that incorporates a condensing optical system that collects the detection light, the reflected light converges toward the end of the light entrance of the imaging means A method for inspecting the smoothness of a workpiece surface, wherein an optical inspection device is arranged so as to perform inspection based on image data of reflected light imaged on an imaging means in this state.