JPH10171991A - Pattern density checking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern density checking method which coincides a decision result with a feeling that is seen with eyes and also quickly checks. SOLUTION: In a pattern density checking method for a seal pattern which consists of a character and a symbol, an image of a seal pattern to be checked is picked up, a part where a representative scan line that is provided in prescribed intervals in each character and symbol is continuously overlapped in an outline of each character and symbol is set as a run 1, a central pixel of each set run 1 is made plural representative pixels 1a that represent seal density of the character and symbol, an average value of plural representative pixels 1a in each character and symbol is calculated, and when an average value of the calculated density values in each character and symbol is out of the allowable density range that is preliminarily set, the seal density of the character and symbol is decided as a failure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor and an IC
Product names, properties, quantities, etc. applied to electronic parts, chemicals, etc.
The present invention relates to a method of inspecting a seal pattern of a character or symbol for displaying a date or the like, and particularly to a pattern density inspection method of inspecting the density of each character or symbol of the seal pattern.

[0002]

2. Description of the Related Art Previously, a method of inspecting a character / symbol marking pattern for displaying a product name, a characteristic, an amount, a date, etc. applied to electronic components such as capacitors and ICs, chemicals, and the like, is based on a method of inspecting a stamped character / sign. It was to determine whether the sign was correct.

However, recently, even if characters and symbols indicating the product name, characteristics, quantity, date, etc. applied to electronic parts such as ICs, chemicals, etc., are imprinted correctly, If there is uneven printing density between characters / symbols or within each character / symbol, the user will feel inferior. Therefore, inspection to detect uneven printing density between these characters / symbols or within each character / symbol. Demands for methods have begun to emerge, and furthermore, not only are these characters and symbols correct, and there is no such unevenness in the printing density, but also the printing density of these characters and symbols is not too high or too low and is within a certain range. An inspection method is required to make sure that it is included.

[0004] A conventional example of a pattern density inspection method for inspecting the imprint density of each character / symbol of an imprint pattern performed based on the above demand will be described with reference to FIG.

In the conventional inspection method, each character or symbol of a seal pattern to be inspected is imaged, and the obtained video information is
As shown in FIG. 5, after the stamping portion of each character / symbol is cut out by binarization processing, the average density of all the pixels in the cut out stamping portion is averaged on a computer to obtain the average density of all pixels. The average density of all pixels is
It is inspected as the symbol concentration.

[0006]

However, in the configuration of the above-mentioned conventional example, even in the outline of the stamped portion obtained by cutting out the stamped pattern of the stamped character / symbol, the peripheral portion thereof is generally shown in FIG. As shown in the figure, it is not appropriate to determine the printing density based on the average of the image densities of all the pixels including the image density of the thin portion, and the determination result does not match the visual feeling. There's a problem. Further, there is a problem that it takes time to calculate for all pixels.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and to provide a pattern density inspection method in which the judgment result matches the feeling of the eyes and which can be inspected quickly.

[0008]

According to a first aspect of the present invention, there is provided a method for inspecting a pattern density of a seal pattern comprising characters and symbols.
The seal pattern to be inspected is imaged, and a plurality of representative pixels representing the seal density of the character / symbol are set in the outline of the character / symbol for each character / symbol, and the plurality of representative pixels are set for each character / symbol. Calculate the average value of the density values of the representative pixels, and if the average value of the calculated density values for each character / symbol deviates from a preset allowable density range, the printing density of the character / symbol is determined to be defective. It is characterized by determining.

As described above, according to the present invention, a seal pattern to be inspected is imaged, and a plurality of representative pixels representing the seal density of the character / symbol are set for each character / symbol within the outline of the character / symbol. Calculating the average value of the density values of the plurality of representative pixels for each character / symbol, and when the average value of the calculated density values for each character / symbol deviates from a preset allowable density range. Since the printing density of the character / symbol is determined to be defective, the number of pixels used in the calculation is extremely reduced and the time required for the inspection is reduced as compared with the conventional example in which calculation is performed for all the pixels.

As a representative pixel, a pixel other than a portion having a low printing density just inside the outline of a character or a symbol and having a printing density of a character or a symbol as seen by the eyes can be selected. It is possible to match the judgment result with the feeling seen by eyes.

In particular, as a representative pixel, a portion where a representative scanning line provided at a predetermined interval for each character / symbol continuously overlaps the outline of each character / symbol is set as a run. Selecting the center pixel simplifies the process and further shortens the required inspection time. Since the representative pixel is located on the center line within the outline of each character / symbol, the inspection result and visual feeling are better. Matches.

As a representative pixel, for each character / symbol,
When the pixel of the skeleton point selected on the skeleton line for the outline of each character / symbol is selected within the outline of each character / symbol, the representative pixel is located on the center line within the outline of each character / symbol.
The test results and the visual feeling better match.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the pattern density inspection method of the present invention, in order to make the inspection result coincide with the visual feeling and to perform the inspection quickly, an image of a seal pattern to be inspected is taken, and each character / symbol is printed. For each character / symbol, set a plurality of representative pixels in the outline of the character / symbol representing the marking density of the character / symbol, calculate the average value of the density values of the plurality of representative pixels for each character / symbol,
If the average of the calculated density values for each character / symbol falls outside the preset allowable density range,
It is characterized in that the marking density of the symbol is determined to be defective.

The pattern density inspection method of the present invention is generally performed following a normal pattern inspection method for inspecting whether or not a seal pattern is correct. Data on a contour obtained by a pattern inspection method (contour data is obtained by binarizing an image) can be used.
In addition, the seal pattern to be inspected separately is imaged, and
The outline of the character / symbol may be detected for each character / symbol by the value conversion process.

Hereinafter, a first embodiment of the present invention using a representative pixel 1a, which is a center point of a run 1 shown in FIG. 3 described later, as the representative pixel will be described with reference to FIGS.

As shown in FIG. 3, in the present embodiment, a seal pattern to be inspected is imaged, the outline of each character / symbol is determined, and a representative interval is set for each character / symbol at a predetermined interval. A portion where the scanning line continuously overlaps the outline of each character / symbol is set as a run 1, and the center pixel of each set run 1 is used as a representative pixel 1a.

FIGS. 1 and 2 show each character / symbol of a seal pattern to be inspected, binarize the obtained video information, cut out the seal part of each character / symbol as an outline, and then cut out. Image density of all pixels within the contour line
9 is a histogram obtained for image densities of all detected pixels.

FIG. 1 shows the above-mentioned histogram when the printing density is appropriate for the visual feeling, and FIG. 2 shows the above-mentioned histogram when the printing density is too light for the visual feeling.

In FIGS. 1 and 2, as shown in FIG. 6 described above, the printing density of the peripheral portion P is generally low in the outline of the printing portion obtained by cutting out the printing pattern of the printed character / symbol. Therefore, the histograms shown in FIGS. 1 and 2 show the left peak indicating the thin printing density at the peripheral portion in the outline of FIG. 6 and the right peak indicating the printing density near the center line in the outline of FIG. There is.

In FIGS. 1 and 2, the average density of all the pixels in the conventional example is indicated by a broken line, and is significantly different from the image density at the center of the right mountain, which is the impression density as seen with the eyes. It is not appropriate to use it as a criterion. Also, calculating the density of all pixels takes time and reduces productivity.

In FIGS. 1 and 2, the density range of the plurality of representative pixels 1a is between two dashed lines, and the average density of the plurality of representative pixels 1a is at the position indicated by the two-dot chain line. That is, as the image density of each character / symbol, a plurality of representative pixels 1
When the average density of a is used, the number of the plurality of representative pixels 1a to be calculated is extremely small, so that a quick inspection can be performed, and a judgment that matches well with the visual feeling can be performed.

In the actual measurement examples shown in FIGS. 1 and 2, the average value of the density values of the representative pixels 1a of the characters and symbols having the proper density shown in FIG. 1 is 158, and the representative pixel 1a having the too low density shown in FIG.
Is 143. Therefore, if the allowable density range of the average value of the density values of the representative pixels 1a of characters and symbols is set in advance, it is possible to inspect the printing density of the printing pattern.

Next, a second embodiment of the present invention using pixels of a plurality of skeleton points set at predetermined intervals on the skeleton line 2 as the representative pixels 2a will be described with reference to FIG.

In FIG. 4, reference numeral 2 denotes a skeleton line formed of skeleton points at which the shortest distance from the outline of each character / symbol is maximum within the outline of each character / symbol. It is a representative pixel that is a pixel of a plurality of skeleton points set on the skeleton line 2 at predetermined intervals. Note that the shortest distance from the contour to the skeleton point is greater than the shortest distance from the contour to its neighboring points.

Since the representative pixel 2a shown in FIG. 4 is located on the center line within the outline of each character / symbol, it has the same properties as the representative pixel 1a which is the pixel at the center point of the run 1 in the first embodiment. Having. Therefore, the representative pixel 1a in the description of the first embodiment may be replaced with the representative pixel 2a, and the description is omitted.

In the first and second embodiments, the representative pixel 1a which is the pixel at the center point of the run 1 and the representative pixel 2a selected by the skeleton line 2 are used. The same result can be obtained by using a pixel near the center line in the outline of each character / symbol as a representative pixel.

[0027]

According to the pattern density inspection method of the present invention, a marking pattern to be inspected is imaged, and a plurality of marks representing the marking density of the character / symbol are included in the outline of the character / symbol for each character / symbol. A representative pixel is set, and the average value of the density values of the plurality of representative pixels is calculated for each character / symbol.
If the average value of the calculated density values for each symbol is out of the preset allowable density range, the printing density of the character / symbol is determined to be defective. , The number of pixels used in the calculation is extremely reduced, and the time required for the inspection is shortened. In addition, the representative pixel can be selected at the center of the outline of each character / symbol. The effect is that the eye feels well matched.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a histogram of density values of all pixels of characters and symbols having a proper density of a seal pattern and a density of a representative pixel of the present invention.

FIG. 2 is a diagram illustrating a relationship between a histogram of density values of all pixels of characters and symbols of a seal pattern that are too light and a density of a representative pixel of the present invention.

FIG. 3 is a diagram illustrating positions of representative pixels according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating positions of representative pixels according to the second embodiment of the present invention.

FIG. 5 is a diagram showing an operation of a conventional pattern density inspection method.

FIG. 6 is a diagram illustrating a general density distribution of characters and symbols of a seal pattern.

[Explanation of symbols]

 1 run 1a representative pixel 2 skeleton line 2a representative pixel

Claims (3)

[Claims] In a method for inspecting the pattern density of a seal pattern composed of characters and symbols, an image of a seal pattern to be inspected is taken, and for each character and symbol, the seal density of the character or symbol is printed in the outline of the character or symbol. A plurality of representative pixels are set as representatives, an average value of the density values of the plurality of representative pixels is calculated for each character / symbol, and the average value of the calculated density values is set in advance for each character / symbol. A pattern density inspection method characterized in that when the density is out of a certain allowable density range, the printing density of the character / symbol is determined to be defective. 2. A representative pixel is set for each character / symbol as a run where a representative scanning line having a predetermined interval continuously overlaps within the outline of the character / symbol. 2. The pattern density inspection method according to claim 1, wherein the pattern density is a central pixel. 3. The method according to claim 1, wherein the representative pixel is a pixel of a skeleton point selected for each character / symbol within the outline of each character / symbol on a skeleton line for the outline of each character / symbol. Pattern density inspection method.