JPS6160184A - Optical character reader - Google Patents

Abstract

PURPOSE:To recognize characters accurately by using a means which separates ruled lines from a character pattern to decide whether or not the character pattern is partially eliminated by the ruled lines and referring to a table of character prepared separately in case the character pattern is partially eliminated. CONSTITUTION:Binary-coded image signals are stored in an image buffer 11, and the positions of ruled lines are detected by a ruled line detecting circuit 12. The ruled lines are separated from the image and a character pattern is stored in a character buffer memory 15. A pattern processing circuit 16 decides whether the character pattern is equal or not to a lacking pattern which had contact with the ruled lines. Then the result of said decision is outputted to a discriminating circuit 22. The patterns also undergo matching through a normal pattern dictionary 19 and a lacking pattern dictionary 20. The characters are recognized by a discriminating circuit 21. When a lacking pattern is decided from the above-mentioned deciding process, the final answer is outputted with reference to a group of characters having high misreading factors and stored in a warning character table 23.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical character reading device that reads forms with ruled lines.

[Technical Background of the Invention and Problems Therein Generally, in optical character reading devices, various restrictions are placed on forms to be read. Among these restrictions, in particular, when writing characters within black ruled lines printed on a form, there are restrictions such as requiring a predetermined margin between the ruled lines and the characters. This is because if a character touches a ruled line, it becomes difficult to recognize the character.

In order to eliminate such restrictions, a method can be considered that utilizes the difference in spectral characteristics between ruled lines and a writing instrument for writing characters. That is, this is a method in which ruled lines are printed in advance on a form using a dropout color or the like. However, in such a method, there are practical problems such as the colors used when printing ruled lines are significantly limited, and the design of the form is restricted to be thick and narrow.

[Purpose of the Invention] The present invention has been made in view of the above points, and its purpose is to reliably recognize characters even if they touch the ruled lines on a form, thereby greatly reducing constraints on form design. It is an object of the present invention to provide an optical character reading device that can be relaxed.

[Summary of the Invention] The present invention is provided with a character pattern extracting means for scanning an image memory means storing a character pattern including ruled lines, detecting the position of the ruled line, and separating the ruled line from the character pattern. The deletion determination means determines whether the character pattern extracted by the character pattern extraction means is a deletion pattern in which a portion of the character pattern is deleted by the ruled line. The matching processing means performs matching processing between the character pattern extracted by the character extraction means and a regular pattern or deletion pattern prepared in advance, and outputs the matching result.

Here, if the character pattern is a deletion pattern according to the deletion determination means, the final recognition result is determined from the matching result of the matching means by referring to a character table prepared in advance that has a high misreading rate due to deletions. Identification means are provided.

With this configuration, when writing characters on a form, even if the characters come into contact with ruled lines printed on the form in advance, the characters can be reliably recognized.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing the configuration of an optical character reader (OCR) according to one embodiment. In FIG. 1, a quantization circuit 10 converts an image signal obtained by scanning a form by a photoelectric conversion circuit (not shown) into a binary signal and outputs the binary signal.

This binary signal is a signal corresponding to the character pattern and ruled lines recorded on the form. The image buffer 11 stores the binary signal output from the quantization circuit 10,
For example, one line of character patterns and ruled lines recorded on a form are stored. A ruled line detection circuit 12 detects the position of a ruled line stored in the image buffer 11 based on format control data stored in advance in the FC memory 13. The FC memory 13 stores in advance format control data including positional information of character patterns and ruled lines recorded on a form. Based on the detection result of the ruled line detection circuit 12 and the format control data of the FC memory 13, the address calculation circuit 14 calculates
The address of the image buffer 11 corresponding to the ruled line is calculated and obtained.

The character buffer memory 15 stores a character pattern for one character extracted from the image buffer 11. At this time, a control device (not shown) (C) a control device that controls all overall CR operations) extracts only character patterns excluding the ruled lines from the image buffer 11 based on the ruled line addresses calculated by the address calculation circuit 14. and stores it in the character buffer memory 15.

The pattern processing circuit 16 performs processing such as normalization on the character pattern stored in the character buffer memory 15 and then outputs the result to both the matching circuit 17 and the deletion determination circuit 18 . The matching circuit 17 performs matching processing on the character pattern output from the pattern processing circuit 16 with the regular pattern or deletion pattern stored in advance in the regular pattern dictionary memory 19 or the deletion pattern dictionary memory 20, respectively. The matching result is output to the first identification circuit 21. The first identification circuit 21 includes a matching circuit 17
Based on the matching result, the identification result for the character pattern is output.

On the other hand, the deletion determination circuit 18 determines whether the character pattern output from the pattern processing circuit 16 is a deletion pattern in contact with a ruled line. If the character pattern is a deletion pattern according to the determination result of the deletion determination circuit 18, the second identification circuit 22 refers to the warning character table from the recognition result of the first identification circuit 21 and determines the final answer. Output. The warning character table is a table consisting of a group of characters with a high misreading rate when the character pattern is a deletion pattern, and is stored in advance in the warning character table memory 23.

-〇- In the OCR having such a configuration, the operation according to one embodiment will be explained. Suppose that ruled lines 24 and characters 25 as shown in FIG. Suppose that Next, the ruled line detection circuit 12 detects the position of the ruled line stored in the image buffer 11. in this case,
The ruled line detection circuit 12 scans the inside of the image buffer 11 and detects the position of the ruled line based on the format control data of the FC memory 13. Further, based on the detection result of the ruled line detection circuit 12, the address calculation circuit 14 calculates the address of the ruled line in the image buffer 11.

Using the address of the ruled line obtained in the address calculation step 114, the image buffer 11 is stored, for example, as shown in FIG.
Only the character patterns shown in the figure are detected and cut out character by character and stored in the character buffer memory 15. The character pattern stored in the character buffer memory 15 is subjected to processing such as normalization in a pattern processing circuit 16 and then output to a matching circuit 17.

The matching circuit 17 performs matching processing between the regular patterns and deletion patterns stored in each of the dictionary memories 19 and 20, and the character pattern. Here, the regular pattern is a normal standard character pattern, and the deletion pattern is a character pattern in which part of the character pattern is deleted due to contact with a ruled line. In the first identification circuit 21, the matching circuit 1
7, the pattern with the highest degree of similarity is output as the identification result.

For example, if the character pattern is a pattern "1" without deletions as shown in FIG. 2(b), the first identification circuit 21 outputs a regular pattern corresponding to the number "1" as the identification result. Since the character pattern is not a deletion pattern, the second identification circuit 22 outputs the identification result of the first identification circuit 21 as the final answer.

At this time, the deletion determination circuit 18 determines whether the character pattern is a deletion pattern.

, When the deletion determination circuit 18 detects that a part of the character pattern output from the pattern processing circuit 16 is in contact with a ruled line in the image buffer 11,
5. It is determined that the character pattern is a deletion pattern. In this case, since a part of the character pattern is continuous with the ruled line, it is determined that the character pattern and the ruled line are in contact with each other. Further, the deletion determination circuit 18 checks the line width of the ruled line corresponding to the corresponding character pattern, and determines that the character pattern and the ruled line are in contact if the line width is undefined.

Here, the character pattern extracted to the character buffer memory 15 is, for example, "2" to "5" as shown in FIG. 2(b).
If the deletion pattern corresponds to , the deletion determination circuit 18 outputs the determination result to the second identification circuit 22 . The matching circuit 17 outputs matching results based on the deletion patterns in the deletion pattern dictionary memory 20 to the first identification circuit 21 .

The second identification circuit 22 determines the final answer from the identification result of the first identification circuit 21, but at this time the deletion determination circuit 18
Based on the determination result, it is recognized that the character pattern is a deletion pattern. Thereby, the second identification circuit 22 refers to the warning character table and determines the final answer from the identification result from the first identification circuit 21. The warning character table consists of a group of characters that have a high misreading rate when a part of the character pattern is omitted due to a ruled line. For example, if part of the number 17 is omitted, it is likely to be misread as the number 1. For this reason, the warning character table contains, for example, the number "7".
” deletion pattern is included in advance.

In this way, when a character written on a form comes into contact with a ruled line, a character pattern with a portion removed by the ruled line is stored in the character buffer memory 15.

Then, the character pattern stored in the character buffer memory 15 is matched with the deletion pattern stored in the dictionary memory 20 in advance by the matching circuit 17. As a result, the identification result with the highest degree of similarity is output, but in the case of a deletion pattern with a high misreading rate, the second identification circuit 22 determines the final answer. That is, the second identification circuit 22
Therefore, the rejection level is set higher for deletion patterns than for normal character patterns.

Therefore, since a character pattern with a part missing due to the ruled lines can be reliably identified, restrictions on writing characters on a form with ruled lines can be largely eliminated.

[Effects of the Invention] As described in detail above, according to the present invention, even characters that touch ruled lines on a form can be reliably recognized. Therefore, restrictions on writing characters on a form with ruled lines can be significantly relaxed. Therefore, as a result, constraints on form design can be significantly relaxed, and the range of objects to be read by the optical character reading device can be expanded.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an optical character reading device according to an embodiment of the present invention, and FIG. 2(a). (b) is a diagram for explaining the operation of the same embodiment. DESCRIPTION OF SYMBOLS 11... Image buffer, 12... Ruled line detection circuit, 14... Address calculation circuit, 15... Character buffer memory, 17... Matching circuit, 18... Deletion determination circuit, 20... - Deletion pattern dictionary memory, 22... second identification circuit, 23... warning character table memory.

Claims (1)

[Claims] an image memory means for storing a character pattern including ruled lines; a character pattern extraction means for scanning the image memory means to detect the position of the ruled line and separating the ruled line from the character pattern; Deletion determining means for determining whether or not the extracted character pattern is a deletion pattern in which a portion of the extracted character pattern is deleted by the ruled line, and the character pattern extracted by the character extracting means and a regular pattern prepared in advance. or a matching processing means that performs matching processing with the deletion pattern and outputs the matching result, and if the character pattern is not a deletion pattern by the deletion determination means, outputs a recognition result based on the matching result of the matching means. When the character pattern is determined to be a deletion pattern by the deletion determination means, a first identification means is used to determine the final result from the matching result of the matching means by referring to a character table prepared in advance that increases the misreading rate due to deletions. An optical character reading device comprising: second identification means for determining a recognition result.