JPH0693776B2 - High-precision appearance video inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is preset by calculating video signals obtained from two video cameras without selecting and discriminating between the front and back of an object to be inspected. The present invention relates to a high-accuracy appearance video inspection method capable of inspecting the appearance of an object to be inspected with high accuracy at an inspection level.

(Prior art) For example, if a stamped tablet (with an identification mark) or a printing tablet (with an identification mark) that is a solid drug is an object to be inspected, an optical illumination system is used for these appearance inspections. There is a method to inspect with the influence of markings as small as possible,
Especially for printing tablets, coordinate conversion and masking methods have been adopted (see, for example, Japanese Patent Publication No. 56-67567).

(Problems to be Solved by the Invention) However, in the above-described conventional inspection method, the sensitivity setting is limited to the video signal level by marking or printing (hereinafter, referred to as mark). There is a problem that the inspection sensitivity on the unmarked surface side is low, and it is not possible to discriminate even if an unengraved tablet or an unprinted tablet without an identification mark is mixed.

Therefore, there is a method of inspecting by making the inspection level of the mark side and the inspection level of the non-mark side different.
For that purpose, it is necessary to determine in advance whether the surface to be inspected is a mark surface or a non-mark surface. However, usually,
Since tablets flow randomly on the line in the production process, it is extremely difficult to determine whether they are marked or unmarked beforehand and arrange them, and the mechanism for implementing them becomes complicated. .

The present invention has been made in view of the above problems, and the object thereof is to perform a visual inspection of the front and back of an object to be inspected with high accuracy without requiring a special detection operation for front and back discrimination. To provide high precision appearance video inspection method.

(Means for Solving the Problems) In order to achieve the above object, the present invention is provided with two video cameras for photographing the front and back surfaces of an object to be inspected, each of which has a mark on one of the front and back surfaces. For the inspection of the mark surface of an object, the area where the mark should exist and the area where the mark does not exist are divided by masking, and the inspection level corresponding to each of the divided areas is set in advance. The inspection level to be the same level is set in advance, and the inspection as the mark surface and the unmarked surface on both the front and back sides is set to each inspection level from the inspection video signal of the inspection object obtained from the two video cameras. The inspection results of the front surface and the back surface are passed, and the inspection results of the front surface and the back surface are output according to each inspection level. However, when only one of the inspection results is defective and the other inspection results are good, the inspected object is determined to be a good product, and the defective position is determined from the pattern of the other inspection results. .

(Operation) In the high-sensitivity appearance video inspection method configured as described above,
Two video cameras are provided for photographing the front and back surfaces of an object to be inspected, each of which has a mark on one of the front and back surfaces. For inspection of the mark surface of the object to be inspected, an area where a mark should exist and an area where no mark exists Are divided by masking, inspection levels corresponding to the respective divided areas are set in advance, and inspection of the unmarked surface is set to the same level over the entire surface in advance. From the inspection video signal of the object to be inspected obtained on both sides, the inspection as the mark surface and the unmarked surface is performed in duplicate based on each inspection level. The inspection result is output, the inspection results of the front surface and the back surface are collectively logically operated, and only one of the inspection results is defective and the other inspection results are good. In this case, the object to be inspected is judged to be non-defective, and the defective position is judged from the pattern of the inspection result other than that. Therefore, both the front and back surfaces of the object to be inspected are inspected as a mark surface and a non-mark surface. It is not necessary to unify the direction of the mark surface.

(Example) Below, the Example of this invention is described based on an accompanying drawing.

FIG. 1 is a diagram showing an outline of an inspection system for carrying out the method of the present invention, FIG. 2 (a) is a plan view of the mark surface of the engraved lock, and FIG. 2 (b) is a video signal image obtained on the mark surface side. FIG. 3A is a plan view of the unmarked surface side of the engraved lock, and FIG. 3B is a diagram showing a video signal image obtained on the unmarked surface side.

As shown in FIG. 1, a first camera X and a second camera Y are installed at the same location or different locations above and below the moving direction of the marking lock 1 as the inspection object. In addition to the first and second cameras X and Y, signals obtained from a light source (not shown) that irradiates strobe light on the engraved lock 1 and the first and second cameras X and Y are shown in FIG. Also, an image processing machine (not shown) for converting into an image as shown in FIG. 3B is installed, and these constitute a video inspection machine.

By the way, a second surface is formed on one surface (mark surface) of the engraved lock 1.
Although a mark "K" is engraved as shown in FIG. 9A, the circular area surrounding the character K on the mark surface side is defined as the mask inner area a and the other area is defined as the mask outer area b. Thus, on the mark surface side, as shown in FIG. 2B, video signal images having different levels are obtained in the masked area a surrounding the character K.

On the other hand, on the surface (unmarked surface) opposite to the engraved lock 1,
No marking is given as shown in FIG. 9A, and a video signal image of the same level as shown in FIG. 9B is obtained on this unmarked surface.

As for the video signal images obtained by the first and second cameras X and Y, as shown in FIG. 2B, the inspection level is set to Ma for the in-mask area a of the mark surface.
At the same time as the sensitivity is set, the inspection level is set to Mb sensitivity for the out-of-mask area b to perform masking with different inspection levels. On the other hand, as shown in FIG. The N sensitivity is set so that the inspection level is the same over the entire surface. The normal Mb sensitivity and the N sensitivity are almost at the same level.

Thus, the inspection level can be optimally set according to the difference between the front surface and the back surface of the stamped tablet 1 as the object to be inspected and the area of the surface (the area a in the mask a and the area b outside the mask). Under the settings, the inspection video signals obtained from the two first and second cameras X and Y are used to inspect both the front and back sides as the mark surface and the non-mark surface based on the respective inspection levels. Appearance inspection of the engraved lock 1 is performed by producing good and bad inspection results for each back surface at each inspection level, logically computing the inspection results of the front surface and the back surface, and collating the operation results with preset judgment criteria. Can be performed with high precision.

The following table shows the inspection results and the judgment results of the quality of the stamped tablet 1 as a whole for each case (Case 1 to Case 5). In addition, in the same table, the inspection result is good, and NG is bad.

For example, considering Case 1, the first camera X (for example, the camera on the mark surface side. However, the mark surface side does not always come to the first camera X side although it is a good product in this case. ) Occurs in the N sensitivity of the video signal image obtained in (.) Because the mark of the letter K exists. In addition, considering Case 5, in this case C
Considering the results of ase1 together, occurrence of G in all means that predetermined marks are not attached on both surfaces of the engraved tablet 1. The same can be considered for the other Cases 2 to 4. In this embodiment, in addition to masking, the N sensitivity of the same level is set over the entire surface of the engraved lock 1.
It can be determined that the side where NG occurs is the mark surface side.

As described above, sensitivity settings are individually set (Ma sensitivity, Mb, Mb
Sensitivity and N-sensitivity), both the front and back surfaces are inspected as a mark surface and an unmarked surface based on their respective inspection levels. Out and logically operate the inspection results of the front surface and the back surface together, and if only one of the inspection results is defective and the other inspection results are good, the inspected object is determined to be a good product, and the other inspection results Since the defective position is determined from the pattern, it is possible to set the criterion for judging the quality of the stamped lock 1 as the inspection object as a whole so that it can be applied to the stamped lock 1 that has been transferred with the front and back surfaces being different. Since it is not necessary to arrange the engraved locks on the front and back sides in advance, the appearance of the engraved locks can be inspected with high accuracy even if the front and back of the engraved locks are not discriminated.

In the above, only the inspection method of the engraved lock has been particularly mentioned, but the appearance inspection of the printed lock can be similarly performed with high accuracy by providing the determination standard based on the so-called number of pixels.

(Effects of the Invention) As is apparent from the above description, according to the present invention, two video cameras for respectively photographing the front and back surfaces of an object to be inspected having marks on either the front or back surface are provided, and the object to be inspected is provided. For the inspection of the mark surface, the area where the mark should exist and the area where the mark does not exist are divided by masking, and the inspection level corresponding to each of the divided areas is set in advance. The inspection level to be the same level is set in advance, and the inspection as the mark surface and the unmarked surface on both the front and back sides is performed based on each inspection level from the inspection video signal of the inspection object obtained from the two video cameras. Repeatedly, the inspection results of good and defective are obtained for each of the front and back sides at each inspection level, and the front and back inspection results are collectively logically calculated,
When only one of the inspection results is defective and the other inspection results are good, the inspected object is determined to be a non-defective item, and the defective position is determined from the pattern of the other inspection results. Both the back and back sides are inspected as a mark surface and an unmarked surface, there is no need to unify the orientations of the marked surface and the unmarked surface, and no special detection operation is required to distinguish between the front and back surfaces. The appearance of the back surface can be inspected with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an inspection system for carrying out the method of the present invention, FIG. 2 (a) is a plan view of a mark surface of an engraved lock, and FIG. 2 (b) is a video signal obtained on the mark surface side. Figure showing the image, Figure 3 (a) is the unmarked surface side plan view of the engraved lock,
FIG. 11B is a diagram showing a video signal image obtained on the same non-marked surface side. Explanation of reference numerals 1 ... Engraved lock, a ... Area inside mask b ... Area outside mask X, Y ... First and second cameras

Claims (1)

[Claims] 1. A two video camera for photographing the front and back surfaces of an object to be inspected, each of which has a mark on one of the front and back surfaces, and an area where the mark should exist for inspection of the mark surface of the object to be inspected. An area where no mark exists is divided by masking, an inspection level corresponding to each of the divided areas is set in advance, and an inspection level that sets the same level over the entire surface for inspection of an unmarked surface is set in advance, From the video signals for inspection of the object to be inspected obtained from the two video cameras, both the front surface and the back surface are inspected as a mark surface and an unmarked surface based on the respective inspection levels. The inspection result of the good and the defective by the above is output, and the inspection results of the front surface and the back surface are collectively logically operated. Only one of the inspection results is defective and the other inspection is performed. Fruit is judged to be good test objects when a good, highly accurate appearance video inspection method characterized by determining a defect location from the pattern of the other test results.