JPS63196992A - Character reader - Google Patents

Abstract

PURPOSE:To improve the read accuracy of a character by detecting a signal for showing a mention degree at every prescribed bit in the mention direction of a character area, and extracting a character pattern by compressing or enlarging it, while scanning the character area shown by the signal. CONSTITUTION:A normalizing circuit 11 detects weight of a colored part of a character to a character mention direction 17 of 'shi (city)' of an inputted character pattern, obtains its weight function 21 and outputs it to a scanning circuit 13. The circuit 13 executes compression or enlargement corresponding to the weight function 21, while scanning 'shi' by the weight function 21 from the circuit 11 and a digital image signal of an image memory 9, obtains a character pattern 'shi' being similar to a standard character pattern and outputs it to a recognizing part 7. The recognizing part 7 recognizes 'shi' by detecting and collating 'shi' inputted from the circuit 13, and a similar candidate detected from a standard character pattern registered in a dictionary, and outputs a character signal to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a character reading vR device for reading characters such as addresses written on mail etc. in an automatic reading sorting machine.

(Prior Art) Conventionally, an optical character reader I (OCR) or the like has been used to read, for example, the postal code of mail.

This optical character reading device irradiates the postal code of a mail item with light, converts the reflected light from the mail item into an electrical signal, detects the converted electrical signal at one character position from the character area, and converts it into a fixed ratio. A postal code is recognized by comparing a so-called normalized character pattern to be compressed or expanded with a letter 8 in which standard character patterns are registered in advance. It was not easy for this device to recognize handwritten characters.

(Problems to be Solved by the Invention) Conventional devices recognize postal codes, etc. by irradiating light onto mail items, normalizing the character pattern obtained by the reflected light from the mail item, and comparing it with a standard character pattern. It was something to do.

However, for example, when recognizing the postal code of a mail item (not shown in Fig. 5), since the postal code is written within the frame, the postal code pattern obtained by normalizing the character area obtained from the reflected light and the standard postal code pattern are used. The accuracy of recognizing a postal code by comparing it with a dictionary stored in numerical patterns is good, but on the other hand, when reading the handwritten address information 31 of a mail piece 29,
As shown in Figure 4, the average character width 23 and cutout character height 25 of written addresses and other characters differ depending on each character, and when written in continuous characters, for example, "
When reading and matching character candidates similar to "Kawasaki" from a dictionary based on a normalized character pattern that is compressed or expanded at a certain ratio when "Kawasaki" is written continuously in one line 27, There was a risk that the characters might be recognized as different characters from ``Kawasaki,'' and a countermeasure was desperately needed.

This invention was made in view of the above, and its purpose is to provide a character reading system that can improve the reading rate of characters written on an object to be read.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, there is provided a reading means for reading characters on an object to be read and outputting a reading signal, and a reading means for reading individual characters from a reading port of the reading means. a signal calculating means for detecting a signal indicating a writing degree for each predetermined pit in a writing direction of a character area outputted from the cutting means in a character reading device having a cutting means for extracting, and converting this signal to [1]; The present invention further comprises a scanning extraction means for extracting a character pattern by scanning and compressing or enlarging a character area indicated by the signal based on the signal calculated by the signal calculation means.

(Operation) When recognizing characters written on an object to be read using a character reading device having the above configuration, the characters are output from the cutting means for extracting individual characters from the reading signal obtained by reading the characters of the object to be read. A signal indicating the writing direction of the character area is detected for each predetermined bit, and based on the result of calculating this signal, the character area indicated by the signal is scanned and compressed or enlarged to extract the character pattern. , it is possible to improve character reading accuracy.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram showing the structure of an embodiment in which the character reading device of the present invention is applied to, for example, an automatic mail reading and sorting machine (not shown).

The configuration of this embodiment includes a photoelectric conversion unit 1 that irradiates light onto a postal item (an object to be read) and converts the reflected light from the postal item into an electrical signal.
1 from the character area indicated by the electrical signal from the photoelectric conversion unit 1
A character detection and cutting unit 3 that detects and cuts out characters in character units; a normalization unit 5 (signal calculation means, scanning extraction means) that normalizes the characters cut out from the character detection and cutting unit 3; The recognition unit 7 compares the character pattern normalized by the unit 5 with a dictionary to determine the character pattern.

The photoelectric conversion unit 1 is equipped with a photoelectric conversion element such as a COD line image sensor, and scans the mail pieces taken into the automatic mail reading and sorting machine while irradiating them with light, converting the reflected light from the mail pieces into digital data. After converting it into an image signal, it is output to the character detection and cutting section 3.

The character detection cutting unit 3 detects and cuts out one character from the character area indicated by the digital image signal supplied from the photoelectric conversion unit 1, and converts the character area of each character indicated by the digital image signal into X-Y coordinates. The reading area of each character is detected and cut out using an X mask signal indicating the projection in the X direction and a Y mask signal indicating the projection in the Y direction, and an image signal is output to the normalizing section 5. Here, as a method of inspecting the character area, the area where the characters are colored is used as a label and the two-dimensional i! There are a labeling method that treats the image as 111m, and a method that detects and cuts out changes in the diagonal pattern in the X direction and Y direction of the digital image signal.

The normalization unit 5 includes an image memory 9. The normalization circuit 11 has a scanning circuit 13 and a buffer 15.

The image memory 9 is composed of, for example, a RAM, and stores image signals of the reading area of each character of one character width supplied from the character detection and cutting section 3.

The normalization circuit 11 detects the image signal of each character supplied from the character detection cutout section 3 bit by bit in the character writing direction 17, and detects "" corresponding to a black pixel when a character is written.
1” signal, “0” which corresponds to the white pixel if not listed
'' signal is calculated, and the signal ``1'' is added to calculate a weighting function, which is information indicating the degree of description, which will be described later. That is, the projection in the direction perpendicular to the writing direction of the characters is used as a weighting function.

The scanning circuit 13 scans each predetermined bit of the digital image signal based on the digital image signal inputted from the image memory 9 and the weighting function inputted from the normalization circuit 11, and scans the digital image signal every predetermined bit using the weighting function. Compress or expand. Then, the compressed or enlarged character pattern is read as Il! in response to a request from the recognition unit 7. It is output directly to the recognition section 7 or to the buffer 15.

The buffer 15 temporarily stores the character pattern input from the scanning circuit 13.

The recognition unit 7 detects candidates similar to the character pattern input from the normalization unit 5 from a dictionary in which standard character patterns predefined by JIS standards etc. are registered, and sequentially performs matching to select the candidate with the highest degree of matching. It recognizes highly standard character patterns as characters written on mail items.

FIG. 2 is a diagram showing the weighting function described above.

When the character ``city'', for example, which has been cut out by the character detection and cutout section 3, is input to the normalization circuit 11 of the normalization section 5, the colored portion of the character is colored for each predetermined bit, for example, with respect to the writing direction 17 of the character. Detect the degree of coloring, detect the colored part as a "1" signal, and add this signal to obtain the weight function song m21 shown in FIG. 2, which corresponds to the weight shown in this song 1921. The scanning circuit 13 performs compression or expansion. In other words, a portion with a high degree of weight has a high magnification rate, and a portion with a low degree of weight has a low magnification rate, so that a character pattern close to a standard character pattern registered in the dictionary is obtained.

On the other hand, as shown in FIG. 3, if compression or expansion is performed at a fixed ratio in the character writing direction 17, the entire character becomes the same size as the standard character pattern registered in the dictionary, but the pattern indicated by the character is likely to be different from the standard character pattern. That is, by using the m-mirror function shown in FIG. 2, the character pattern input from the normalization unit 5 becomes close to the standard character pattern registered in the dictionary.

Next, the operation of this embodiment will be explained.

First, after turning on the power to the automatic mail reading and sorting machine, the mail 29 is transferred from the supply section of the sorting machine to the photoelectric conversion unit 1 of the character reading device.
transported to. When the mail piece 29 is conveyed to the photoelectric conversion unit 1, the photoelectric conversion unit 1 irradiates the mail piece 29 with light to convert the mail piece 2
For example, the reflected light of "city" from 9 is received by the photoelectric conversion element and converted into a digital image signal, and then the character detection cutout section 3
Output to. When the digital image signal is output, the character detection and cutting section 3 extracts individual characters of the character pattern "city" from the character area of "city" indicated by the digital image signal for each character by using, for example, an X mask signal and a Y mask signal. After performing detection and cutting processing, the image memory 9 of the normalization unit 5
and output to the normalization circuit 11. Character pattern "city"
When the character pattern is output, the image memory 9 stores the character pattern at a predetermined address. At the same time, the normalization circuit 11 detects the weight of the colored portion of the character with respect to the character writing direction 17 of the input character pattern "city", obtains a weight function 21, and outputs the weight function 21 to the scanning circuit 13. The scanning circuit 13 scans ``city'' using the weighting function 21 from the normalization circuit 11 and the digital image signal from the image memory 9, and performs compression or expansion corresponding to the weighting function to create a character pattern ``city'' that is close to the standard character pattern. is obtained and output to the recognition unit 7. Then, the recognition unit 7 detects similar candidates from the standard character pattern registered in the dictionary and recognizes it as "city" and sends the character signal to the external Output to.

As a result, the curve 21 indicated by the weighting function of "city" read from the mail item 29 is calculated and compression or expansion corresponding to this weighting function is performed, so that the reading becomes close to the standard character pattern registered in the dictionary. accuracy can be improved.

Also, the weighting function is calculated from white pixel to black pixel J3 for each scanning line.
It is also possible to calculate the number of change points from black pixels to white pixels. Furthermore, the weighting function can also use both the count value of the number of black pixels for each scanning line and the count value of the change point.

[Effects of the Invention] As explained above, according to the present invention, the writing direction of the character area outputted from the cutting means for extracting individual characters from the reading signal obtained by reading the characters of the object to be read is determined for each predetermined bit. A signal indicating the degree of writing is detected, and based on the result of decoding this signal, the character area indicated by the signal is scanned while the pressure,
Since the character pattern is extracted by reducing or enlarging it, the reading accuracy of characters written on the object to be read can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a character reading device of the present invention, FIG. 2 is a diagram explaining a weighting function, FIG. 3 is a diagram showing an example compressed or enlarged to a certain ratio, and FIG. 4 is a diagram showing handwritten characters. FIG. 5 is a diagram showing mail. 1...Photoelectric conversion section 3...Character inspection section 5...Normalization section 7...Recognition section 9...Image memory 11...Normalization circuit 13...Scanning circuit 15...・Buffer 17...Character writing direction 19...Enlargement ratio 21...Weighting function

Claims (1)

[Scope of Claims] A character reading device comprising a reading means for reading characters on an object to be read and outputting a reading signal, and a cutting means for extracting individual characters from the reading signal of the reading means, the cutting means A signal calculation means for detecting a signal indicating the writing direction of the character area for each predetermined bit and calculating this signal, and a character area indicated by the signal based on the signal calculated by the signal calculation means. A character reading device comprising: scanning extraction means for compressing or enlarging a character pattern while scanning it and extracting a character pattern;