JPS6051055B2 - How to detect minute defects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting flaws such as scratches or breakage in articles such as glass bottles, and more specifically, a method for detecting minute defects that are difficult to judge as good or bad using a television camera. It is related to.

Conventionally, methods for detecting minute defects in articles include methods in which a mirage lens is used to form multiple images of the article on the imaging surface of a television camera, and the number of defects in the frame is increased to detect the defects. There is a method of detecting a defect image by enlarging it by using a cross filter to make a defect image with high brightness shine in a cross shape.

However, in the former case, the light intensity of the article image on the imaging surface is reduced, and the field of view is narrowed, so there is a risk that minute defects may be overlooked. In addition, the latter method does not emit light unless the brightness of the defect image is quite high, and it is difficult to detect a defect image with low brightness, which has the problem that it is actually difficult to detect minute defects. SUMMARY OF THE INVENTION In view of the above drawbacks, it is an object of the present invention to provide a method for reliably detecting minute defects that are difficult to judge.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1a shows an example of a configuration for carrying out the method of the present invention, and 1 is a conveyance means such as a conveyor, 2 is an object to be inspected that is intermittently (or continuously) conveyed by this conveyance means 1, 3 is a television camera, and 4 is a light source. The light emitted from the light source 4 is reflected by the surface of the object 2 to be inspected, and is captured by the television camera 3 as a reflected light image of the object 2 to be inspected. 5 is a video signal from the television camera 3, which is input to the special effect generator 6.

8 is a monitor that projects an image on its screen based on the mixing signal 7 from the special effect generator 6, and is configured so that the brightness and contrast can be adjusted as appropriate.

A television camera 9 takes an image of the screen of the monitor 8, and its output, a video signal 5', is input to the special effect generator 6.

Here, the special effect generator 6 has functions such as overlapping (mixing) input video signals, dividing left and right to create separate screens, or inverting black and white. For example, there is model number WJ540 manufactured by Matsushita Tsushin Kogyo Co., Ltd.

Next, the operation of the above-described configuration will be explained with reference to FIG. 1 and FIG. 3 as well. Assuming that there is a minute defect in the object 2 to be inspected, first, the television camera 3 takes an image of the object 2 to be inspected, and the video signal 5 thereof is input to the special effect generator 6. On the other hand, a screen 8'' of a monitor 8 is imaged by a television camera 9, and its video signal 5'' is input to a special effects generator 6. Then, in the special effect generator 6, the video signal 5 (including the object to be inspected 2a and the accompanying defect image 10a) and the video signal 5'' (the screen 8 of the monitor 8
'') is mixed to form a mixed signal 7 as shown in FIG. 3a, which is input to the monitor 8 to display an image as shown at the right end of FIG. 3a. Next, the screen of the front monitor 8 is imaged by the television camera 9, and the video signal 5'' and the television camera 3 are
A special effect generator 6 mixes the video signal 5 with the video signal 5 from the monitor 8, and the mixed signal 7 is sent to the monitor 8. As shown in the right end of FIG. , 2b and defect images 10a, 10b are displayed.Furthermore, the screen 8'' of the monitor 8 is imaged by a television camera 9, and the video signal 5'' and the television camera 3 are captured.
As a result, as shown in the right end of FIG.
0b and 10c are displayed.

Thereafter, by repeating the same operations as described above, the images 8'', 8'''', 8'' on the monitor 8 become as shown in FIG. 1b, and the screen on the monitor 8 becomes A plurality of images of the object to be inspected 10a, 10b, 10c, . is emphasized by Further, by adjusting the contrast and brightness of the monitor 8, the defect image is further emphasized. Then, after an appropriate period of time has passed, the inspection object image 2
a, 2b, 2c... on the screen 8 of the monitor 8
'' is also scanned by a television camera 9, and a scanning signal 11 is sent to a determination circuit 12 to detect minute defects.
'' with the special effect generating device 6, the image of the object to be inspected 10a,
10b, 10c, etc. are adjusted so that they are superimposed, it is possible to obtain one inspected object 2'' and defect image 1'' on the screen 8'' of the monitor 8 as shown in FIG. 1C. can.

In this case, the inspected object 2'' can be enlarged and displayed to fill the monitor screen 8'', and the defect image 10'' can be enlarged by adjusting the brightness and contrast.

In this embodiment, the defect images 10a, 10b, 10
We have explained the case where the defect images 10a, 10b, 10c..., 1' are white and the defect images 10a, 10b, 10c..., 1' are displayed on the screen 8'' of the monitor 8 as white on a black background.
10c,...1'' is black, the special effect generator 6
By performing negative-positive inversion, the defect images 10a, 10b, 10c, .

Next, FIG. 2a shows another embodiment of the present invention, in which an object to be inspected 13 illuminated with light from a light source 4 and a monitor 8 are placed side by side so that a single television camera 9 can take an image. , capturing a reflected light image of the object to be inspected 13 with the television camera 9;
The screen 8 of the monitor 8 is displayed by the video signal 14 of the camera 9.
``It was constructed so that it would be projected on top.

The operation of this embodiment is almost the same as that of the previous embodiment, and will be explained with reference to FIG. 13 at the same time with the camera 9, the inspected object 13a and the defect image 15a are displayed on the screen 8'' of the monitor 8, as shown in FIG. When images of the inspection object 13 and the inspection object 13 are captured simultaneously, defect images 15a and 15b of the inspection object 13a and 13b1 are displayed on the screen of the monitor 8, as shown in FIG. 4b. Furthermore, in the third stage, the inspected objects 13a, 13b, 13c1 defect images 15a, 1 are displayed on the screen 8'' of the monitor 8.
5b and 15c are displayed.

Note that 9'' is the field of view of the television camera 9. Then, by repeating the same operations as described above, a monitor 8 and images 8'', 8'''', etc. as shown in FIG. 2b are obtained. , a plurality of consecutive test objects 13b, 13c,...
and accompanying defect images 15b, 15c, etc. are formed continuously on the screen 8'' of the monitor 8, and after an appropriate period of time, the inspected objects 13b, 13c,... are scanned by the television camera 9. The scanning signal 16 is sent to the determination circuit 12, and the determination circuit 12 detects minute defects.
In this other embodiment, the monitor 8 and the object to be inspected 13 are placed side by side, but due to the location etc., the object to be inspected 13 is placed on the monitor 8.
However, if an optical device such as a mirror is installed at the position of the inspected object 13 shown in Fig. 2a and the image of the inspected object is reflected on the optical device, the second Screen 8'' and screen 8'', 8'''' of monitor 8 similar to Figure b
... can be obtained. By the way, in any of the above embodiments, if the contrast and brightness are adjusted appropriately on the screen 8'' of the monitor 8, the defect image 10
As the operations in the above embodiment are repeated, the signals of a, . . . 15b, .
15b... is emphasized and can be easily observed. In addition, the objects to be inspected 2a..., 13b... on the screen 8'' of the monitor 8 are all reflected light images, but the light source 4 is placed in the opposite direction from the television camera 9. As explained above, the present invention makes it possible to emphasize a defect image by appropriately adjusting the contrast or brightness on the monitor screen. Since it can be displayed on multiple monitor screens, it has the advantage of being able to reliably detect minute defects that are difficult to judge.

[Brief explanation of the drawing]

FIG. 1a is an explanatory diagram showing one embodiment of the present invention, FIGS. 1b and c are monitor images, FIG. 2a is an explanatory diagram showing another embodiment of the present invention, and FIG. 2b is a monitor Image shows L1 3rd
Figures A, b, and c are explanatory views of the operation of the embodiment shown in Fig. 1a, and Figures 4A, b, and c are explanatory views of the operation of the embodiment shown in Fig. 2a. 2, 13...Object to be inspected, 2a, 2b, 2c, 1
3b, 13c... Image of the object to be inspected, 3, 9...
...TV camera, 8...Monitor, 8''...
...Monitor screen, 10a, 10b, 10c, 15b
, 15c... - Defect image.

Claims (1)

[Claims] 1 The object to be inspected is imaged with a television camera and projected on the screen of a monitor whose contrast and brightness can be adjusted, and the monitor image is imaged with the same or a separate television camera as said camera and projected on said monitor screen. A single inspected object image or a plurality of consecutive inspected object images superimposed on each other are formed on the monitor screen, the image of the defect is emphasized by adjusting the brightness and contrast, and the monitor image is captured. A method for detecting minute defects, comprising scanning the object to be inspected with a television camera to detect minute defects.