JPH09147108A - Method and device for inspecting print character - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspecting method for print characters which is given flexibility when it is judged whether the quality of the characters is good or not. SOLUTION: Character image data obtained by photographing a reference character with a camera device 11 are inputted to expanding and reducing process circuits 16 and 17 to generate expanded character image data and reduced character image data by expanding and reducing the reference character image data. Then, a decision circuit 20 compares those expanded character image data and reduced character image data with print characters 3 on an inspected body 2 to judge whether or not the quality of the print characters is good or not.

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 printed characters in the field of factory automation (FA).

[0002]

2. Description of the Related Art Factory automation (FA)
In the field, for example, in an automatic production line in a factory, an article is automatically printed by a printing device such as an inkjet printer, and whether the printed characters have defects such as missing characters, faint marks, and stains. Something is being inspected.

Conventionally, when the print character is inspected, the print character is captured as image data by a camera device, and the captured character image data is subjected to pattern matching with the correct character image data stored in advance. It was done and the quality was judged.

[0004]

As described above, according to the pattern matching between the captured character image data and the correct character image data, even if the characters are harmless to human eyes, the pattern matching by the computer is not possible. There were cases where it became defective, and there was a problem in economic efficiency.

Therefore, it is an object of the present invention to provide a method and an apparatus for inspecting a printed character, which has flexibility in determining the quality of the character.

[0006]

In order to solve the above problems, the method for inspecting printed characters according to the present invention is based on the character image data obtained by photographing this reference character and inflates the reference character image data. The inflated character image data and the reduced character image data reduced from the reference character image data are created, and the created inflated character image data and the reduced character image data and the printed characters of the inspection object are photographed. This is a method of comparing the print character image data obtained by the above with the quality of the print character.

Further, in the above inspection method, the expansion rate and / or the contraction rate can be changed. In order to solve the above-mentioned problems, a printed character inspection device of the present invention is a camera device for photographing a character, and expanded character image data expanded from the reference character image data of the reference character obtained by the camera device. And a conversion processing unit that creates reduced character image data that is reduced from the reference character image data, and the converted inflated character image data and reduced character image data and the camera device that captures the printed characters of the inspection object. The print character image data obtained as a result is input and a determination unit for comparing and determining the degree of overlap is formed.

Further, the above-mentioned inspection apparatus is provided with a conversion rate setting device capable of changing the expansion rate and / or the reduction rate in the conversion processing section. According to each of the above configurations, a large expanded character image data and a small reduced character image data of a reference character to be inspected are created in advance,
When comparing and determining the converted character image data and the character image data obtained by actually photographing the printed characters of the object to be inspected, it is possible to give a range to the determination range. The degree of determination can be made more flexible than in the case of determination as a print character. Further, since the expansion rate and / or the reduction rate in the conversion processing unit can be changed, the inspecting side can freely adjust the criterion for determining the quality of the printed character.

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. First, a printing character inspection device will be described with reference to FIG.

That is, the inspection device 1 is provided with the inspection object 2
A video camera device 11 for photographing the printed characters 3 printed on the surface of the device, and an A / D converter 12 for converting a video signal photographed by the camera device 11 into a digital signal.
And a binarization processing circuit 13 for binarizing the digital signal converted by the A / D converter 12,
A character inclination detection circuit 14 for inputting character image data obtained by binarization in the binarization processing circuit 13 and detecting the inclination of the character.
And the character inclination data detected by the character inclination detection circuit 14 and the character image data input from the binarization processing circuit 13 to input the character image along a predetermined reference line (eg, horizontal line). An affine transformation circuit 15 for performing rotation and / or movement processing on the input, and character image data which has been subjected to the affine transformation processing and is horizontal, and at the same time expands the character image data to obtain expanded character image data. Conversion processing circuit (conversion processing unit) 16
Similarly, the character image data from the affine transformation circuit 15 is input, and at the same time, the character image data is reduced (also referred to as thinning) to obtain reduced character image data, and a conversion processing circuit 17 for creating these conversions. First and second storage units 1 for storing the converted character image data
8 and 19 and the respective converted character image data stored in the respective storage units 18 and 19, and the inflated character image data and the reduced character image data and the inspection object 2 input from the affine conversion circuit 15 are input. Determination circuit (determination unit) 20 for comparing and determining the print character image data of the print character 3 of
And a display unit (for example, a display device) 21 that displays the quality determination result obtained by the determination circuit 20, and the conversion rate (parameter) in each of the processing circuits 16 and 17, that is, the expansion rate and the reduction rate are changed and set. And a conversion rate setting device 22 for performing the operation.

Next, a method of inspecting printed characters will be described. First, the reference character of the character to be inspected is photographed by the camera device 11. The photographed reference character image data is processed by the A / D converter 12 and the binarization processing circuit 1.
3 is input to the character inclination detection circuit 14, where the inclination of the reference character is detected, and is input to the affine transformation circuit 15 to rotate and / or rotate the reference character so as to be aligned along a reference line, for example, a horizontal line. The move is done.

Next, the reference character image data subjected to the affine transformation is expanded and reduced processing circuits 16 and 17.
2, and the expanded character image data and the reduced character image data are expanded and reduced with the respective conversion rates, as shown in FIG. Then, these converted character image data are stored in the storage units 18 and 19, respectively.

Next, when actually inspecting the print character 3 printed on the inspection object 2, the print character 3 is photographed by the camera device 11. This captured video signal is A /
The D converter 12 converts it into a digital signal, and the binarization processing circuit 13 binarizes it to obtain character image data. Then, as in the case of the reference character, the conversion processing is performed along the horizontal line by the affine conversion. To be done.

As shown in FIG. 2, the converted character image data 31 is input to the determination circuit 20, and the expanded character image data 32 and the reduced character image input from the storage units 18 and 19 are input. Comparison with image data 33,
For example, comparison by superposition is performed.

More specifically, as shown in FIG. 3A, when the character image data (indicated by diagonal lines) of the print character 3 of the inspection object 2 is out of the range of the expanded character image data, It can be seen that the printed characters are misaligned, and conversely, as shown in FIG. 3B, the reduced character image data is the character image data of the printed characters 3 of the inspection object 2 (indicated by diagonal lines). If it is out of the range (shown), it can be seen that the printed characters are missing.

That is, when the character image data of the print character 3 covers all the reduced character image data and does not extend from the expanded character image data, the print character 3 is printed.
Is printed correctly and is judged to be a good product.

Then, the determination result is displayed on the display unit 21. In this way, the reference character to be inspected
Since a large expanded character image data and a small reduced character image data are created so that the judgment range has a predetermined width, when it is judged as an accurate printed character as in the conventional case. In comparison, the degree of determination can be made flexible, and therefore economical determination can be performed.

Further, when determining the image character data, each image character data is detected by the character inclination detection circuit 14 to detect the inclination of the character data, and the affine conversion circuit 15 follows the predetermined reference line, for example, a horizontal line. Since the rotation and / or movement processing is performed on, accurate determination can be performed.

Further, since the expansion rate and the reduction rate can be changed by the conversion rate setting device 22, the user can freely adjust the criteria for judging the quality of the printed characters.

[0020]

As described above, according to the configuration of the present invention, the expanded character image data having a large reference character to be inspected and the reduced character image data having a small reference character are created in advance, and these converted character image data are created. Since the judgment range can be widened when the judgment is made by comparing with the character image data obtained by actually photographing the printed characters of the inspected object, it is possible to perform accurate printing as in the past. The degree of determination can be made more flexible than in the case of determining that it is a character, and therefore economical determination can be performed.

Further, since the expansion rate and / or the reduction rate can be changed, it is possible for the inspection side to freely adjust the criteria for judging the quality of the printed characters.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an inspection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state of expansion and contraction of character image data according to the same embodiment.

FIG. 3 is a diagram illustrating a method of determining character image data according to the same embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspection device 2 Inspected object 3 Printed character 11 Camera device 15 Affine conversion circuit 16 Expansion processing circuit 17 Reduction processing circuit 18 1st memory | storage part 19 2nd memory | storage part 20 Judgment circuit 22 Conversion rate setting device

Claims (4)

[Claims] 1. Expanded character image data expanded from the reference character image data based on character image data obtained by photographing a reference character, and reduced character image data reduced from the reference character image data. To determine the quality of the printed characters by comparing the created expanded character image data and the reduced character image data with the printed character image data obtained by photographing the printed characters of the inspection object. A method for inspecting printed characters, which is characterized in that 2. The method for inspecting printed characters according to claim 1, wherein the expansion rate and / or the reduction rate can be changed. 3. A camera device for photographing a character, expanded character image data expanded from the reference character image data of a reference character obtained by photographing with the camera device, and a reduced character reduced from the reference character image data. Input the conversion processing unit that creates image data, the converted inflated character image data and the reduced character image data, and the print character image data obtained by photographing the print characters of the inspection object by the camera device. An inspection device for printed characters, comprising: a judgment unit for judging the degree of overlap between the characters. 4. The printed character inspection apparatus according to claim 3, further comprising a conversion rate setting device capable of changing an expansion rate and / or a reduction rate in the conversion processing unit.