JPS6166952A - Inspecting method of outward surface of article - Google Patents

Abstract

PURPOSE:To perform accurate image picking-up and inspection by interposing a polarizing filter between a light source and an object of inspection. CONSTITUTION:Objects G of inspection such as tablets are conveyed through a belt conveyor 1 at constant intervals. Those objects G are conveyed at least in plural arrays and a camera 4 is installed beside the objects G. Further, the polarizing filter 6 is provided between the light source 5 and objects G and a polarizing filter 7 is provided nearby the camera 4 so as to prevent halation due to reflected light from an object G. Therefore, when the objects 5 have a curved surface, the light from the light source 5 is polarized by the polarizing filter at the side of the light source 5 into light in a constant oscillation direction and scattered partially even when reflected by the surface of the object 5 to obtain polarization width. Then the halation is removed completely by the polarizing filter 7 at the side of the camera 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a device that shines a light beam onto the outer surface of tablets, capsules, and other articles and images them with a TV camera, sensor, etc. to determine quality. The present invention relates to a method for optically inspecting the outer surface of an article without causing scratches even if the surface of the article is shiny.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, tablets punched out from a tablet press are visually inspected by an inspector along the conveyance line. However, people's intuitive judgment ability fluctuates depending on their physical condition and degree of fatigue, and testing standards change, making it difficult to expect accurate and complete testing. there were. For this reason, an automatic inspection method using a TV camera has been proposed. This TV
The method using a camera is to shine a light beam from a light source onto the tablet being transported (other objects to be inspected, hereinafter referred to as tablets, etc.), take an image of its outer surface with a TV camera, sensor, etc., and send this to an electric circuit. However, if the whole or part of the outer surface of a tablet, etc. is glossy or the printed surface is glossy, the light rays emitted from the light source will be This direct reflection from the outer surface of the tablets, etc. causes scratches, and when captured by a TV camera, etc., it becomes a false image of a white spot, making it impossible to accurately judge whether the tablets, etc. are good or bad.To prevent this, Although indirect lighting may be used, it is impossible to completely prevent damage from damage.

Means for Solving Problems In the present invention, there is a
A polarizing filter is interposed between one or both of the cameras, and the light from the light source is turned into a certain vibration direction by the polarizing filter, and the polarized light reflected from the surface of the object to be inspected is applied to the TV camera with a 7% laser beam. Embodiments The present invention will be described below based on embodiments shown in the drawings.

Test objects such as tablets manufactured by a tablet press or other manufacturing machine are conveyed at regular intervals via a belt conveyor 1 or a feed alignment drum 2 to a drum 3 having a tablet suction mechanism on its outer circumferential surface. This drum may have a stepped outer circumferential surface with multiple steps. The tablets shall be conveyed in at least two or more rows, preferably in several rows, and with respect to the direction of travel, that is, the direction of conveyance, the intervals between the tablets and their rows shall be such that they do not overlap each other when viewed from the diagonal direction of the tablet travel direction. It shall be left open. Cameras are installed on the sides of the objects being transported in multiple rows at predetermined intervals as a means for inspecting them in place of the workers. This camera uses a solid-state image sensor, a so-called COD camera 4, a sensor, and other TV cameras, in order to be able to image a subject moving at high speed, considering its ability to detect minute defects, good resolution, and processing power. . Furthermore, since the subject does not rotate and is simply transported in the same posture, a TV camera 4 or multiple sensors are usually used to cover the entire outer circumferential surface of the subject, but this is difficult in the direction of movement of the subject. To enable imaging of a subject from a predetermined direction in an oblique direction.

Therefore, each camera is photographed from a different angle so that the subjects in each row do not overlap when viewed from the TV camera, and the subjects adjacent to each other in the front and back in the direction of travel do not overlap. Make sure that the entire outer circumferential surface of the subject is covered. In addition, the number of TV cameras used can be reduced and multiple isthmus images can be captured using one or two TVs using mirrors and prisms placed at different angles to cover the entire outer circumferential surface of the subject G being transported at high speed. A method of taking an image with a camera is also considered. Further, in order to capture a still image of the subject being transported at high speed and to enable accurate imaging, a light source, ie, a light emitter 5 such as a strobe is used. The image captured by this TV camera is applied to an inspection circuit, and this imaged pattern is compared with a prescribed pattern stored in advance to determine whether the tablet is good or bad.

In addition, in the present invention, a polarizing filter 6 is preferably inserted between the light source (light emitter) 5 and the subject G, preferably close to the light source, to prevent light reflection from the subject G. A polarizing filter 7 is preferably inserted between the specimen G and the TV camera close to the TV camera, or furthermore, polarizing filters 6 and 7 are installed close to both the light source and the TV camera, respectively. . When inserting a polarizing filter between the subject and the light source, first the light from the light source is made to vibrate in a certain direction using the polarizing filter, and then the reflected polarized light from the subject surface prevents it from entering the camera. If a polarizing filter is inserted between the two, the polarized reflected light from the object surface is cut by the polarizing filter.

When inserting a polarizing filter into either the light source or the TV camera, it is possible to almost completely remove the polarizing filter with a flat plate, but not completely with a curved plate.

This is because the polarized light ++7 is widely scattered with δ polarization.0 In the case of a subject with such a curved surface, if a polarizing filter is inserted between the subject and the light source and between the subject and the camera at the same time, the polarizing filter on the light source side Even if the light source light is first polarized into light with a constant vibration direction and then reflected by the surface of the object, it will be partially scattered, resulting in polarized light.

Next, this halation can be completely removed using a polarizing filter on the camera side.

-Although the above example describes the case where the outer surface of a tablet is optically inspected, it can also be applied to inspecting the surface of other parts with large halation, such as capsules, film molded products, resin processed products, metal processed products, etc. It is possible.

Effects of the Invention According to the present invention, when a test object with a curved outer surface or a smooth and glossy surface is irradiated with light and imaged with a TV camera or the like to determine pass/fail, a polarizing filter is used. This has the advantage that the reflected light from the subject is polarized and accurate imaging and inspection can be performed without causing halation.

[Brief explanation of drawings]

FIG. 1 is an example diagram using a belt conveyor, FIG. 2 is an example diagram using a drum, and FIG. 6 is an explanatory diagram using a polarizing filter. 1 is a belt conveyor, 2.6 is a drum, 4 is a camera, 5
is the light source, 6.7 is the polarizing filter, G is the object,

Claims (3)

[Claims] (1) In equipment that uses a TV camera, etc. to optically image and inspect objects with curved surfaces that easily reflect irradiated light or objects with smooth luster, there is a An article other than an article characterized in that a polarizing filter is inserted to make the light source light vibrate in a certain direction, and the polarized light reflected from the surface of the object is imaged by a TV camera without the reflected light entering. Surface inspection method. (2) In a device that uses a TV camera, etc., to optically image and inspect a subject with a curved surface that easily reflects irradiated light or a smooth, shiny subject, between the subject and the TV camera. A method for inspecting the outer surface of an article, characterized in that a polarizing filter is inserted into the surface of the object, and the reflected light that is irradiated with the light source light and polarized on the surface of the object to be inspected is removed by the polarizing filter. (3) In a device that optically images and inspects an object with a curved surface that easily reflects irradiated light or a smooth, shiny object with a TV camera, etc., the light source, the object, and the object are Insert a polarizing filter between each TV camera,
A method for inspecting the outer surface of an article, characterized in that reflected light is removed.