JPH07271898A - Character recognition device - Google Patents

Abstract

PURPOSE:To make it possible to correctly recognize also characters which are extremely similar to each other. CONSTITUTION:An object to be read out, e.g. a character on a postal matter P, is optically read out and the read character is recognized by collating the read character pattern A with a 1st reference pattern stored in a memory 61. Provided that when there are plural recognized results, a specific area corresponding to the mutual combinition of respective recognized results for the read charater pattern A is specified and a prescribed 2nd reference pattern corresponding to the mutual combination of respective recognized results is specified out of the contents registered in a memory 63. The read charcter is recognized again by collating the pattern in the specified specific area with the specified 2nd reference pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character recognition device for recognizing a character written on a mail piece, for example.

[0002]

2. Description of the Related Art There is a mail sorting machine for automatically sorting mail by reading a zip code, a destination address, etc. from the mail.
This mail sorting machine is equipped with a character recognition device for recognizing the characters on the mail. This character recognition device optically reads on a mail piece, detects a character pattern for one character from this read image and cuts it out, and collates the cut out character pattern with the reference pattern of the reference character,
The character to be read is recognized based on the matching condition of both patterns.

[0003]

[Problems to be Solved by the Invention] By the way, there are very similar characters such as "king" and "ball" and "claw" and "melon". Even if these characters are recognized by the above pattern matching method, correct recognition cannot be obtained due to the influence of noise on the paper.

The present invention takes the above circumstances into consideration,
It is an object of the invention to provide a highly reliable character recognition device capable of correctly recognizing characters that are similar to each other.

[0005]

A character recognition device according to a first aspect of the present invention comprises a reading means for optically reading a character on an object to be read,
The recognition unit includes a recognition unit that recognizes a read character by collating a part of the character pattern read by the reading unit with a reference reference pattern.

The character recognition device of the second aspect of the invention comprises a reading means for optically reading a character on an object to be read, and a read character by collating the character pattern read by the reading means with a first reference pattern for reference. Recognizing means, a specifying means for specifying a specific area for the character pattern read by the reading means when there are a plurality of recognition results by the first recognizing means, and a specific area specified by the specifying means. And a second recognition means for recognizing the read character by collating the pattern with the second reference pattern.

In the character recognition device of the third invention, the reading character for optically reading the character on the object to be read and the read character by collating the character pattern read by the reading means with the first reference pattern for reference. And a specifying means for specifying a specific area corresponding to a mutual combination of the recognition results for the character pattern read by the reading means when there are a plurality of recognition results by the first recognizing means. Second recognition means for recognizing the read character by collating the pattern of the specific area designated by the designation means with the second reference pattern for reference.

In the character recognition device of the fourth invention, the first dictionary means in which the first reference pattern corresponding to the whole image of the reference character is registered and the second reference pattern corresponding to the partial image of the reference character are provided. The registered second dictionary means, the reading means for optically reading the characters on the object to be read, and the read character by collating the character pattern read by the reading means with the first reference pattern in the first dictionary means. And a first recognition means for recognizing a plurality of recognition results of the first recognition means, and a specific area corresponding to a mutual combination of the recognition results is designated for the character pattern read by the reading means, and Of the registered contents of the second dictionary means, a designation means for designating a predetermined second reference pattern according to the mutual combination of the recognition results and a pattern of the specific area designated by the designation means are designated. Second And a second recognizing means for recognizing a character reading by matching the quasi pattern.

[0009]

In the character recognition device according to the first aspect of the invention, the character on the object to be read is optically read, and the read character is recognized by collating a part of the read character pattern with the reference reference pattern. It

In the character recognition device of the second invention, the character on the object to be read is optically read, and the read character is recognized by collating the read character pattern with the first reference pattern for reference. . However, when the recognition result is plural, a specific area is designated for the read character pattern, and the read character is recognized again by collating the pattern of the specific area with the second reference pattern for reference.

In the character recognition device of the third invention, the character on the object to be read is optically read and the read character is recognized by collating the read character pattern with the first reference pattern for reference. . However, when there are a plurality of recognition results, a specific area corresponding to the mutual combination of the recognition results is designated for the read character pattern. The read character is recognized again by collating the pattern of the specified specific area with the second reference pattern for reference.

In the character recognition device of the fourth invention, the character on the object to be read is optically read and the read character is checked by collating the read character pattern with the first reference pattern in the first dictionary means. Be recognized. However, when there are a plurality of recognition results, a specific area corresponding to the mutual combination of the recognition results is designated for the read character pattern, and the mutual combination of the recognition results among the registered contents of the second dictionary means is specified. A predetermined second reference pattern corresponding to the above is designated. The read character is recognized again by collating the pattern of the designated specific area with the designated second reference pattern.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 2 shows the configuration of a mail sorting machine according to the present invention. FIG. 2 is a front view of the mail sorting machine.

The postal sorter 1 is provided with a supply unit 3 from which postal items P, such as postcards and sealed letters, are supplied collectively and in a standing position. The postal matter P supplied from the supply section 3 is conveyed to the take-out section 5. The take-out section 5 takes out the postal matter P one by one and conveys it to the take-in conveyance path 7. The take-in / conveyance path 7 is composed of a belt and a plurality of rollers, and nips and conveys the postal matter P.

An address recognition device 9 is installed on the upstream side of the take-in / transport path 7. The address recognition device 9 is a character recognition device of the present invention to which a word recognition function and an address discrimination function are added. The address recognition device 9 reads the characters of the address information described on the mail P, recognizes the read contents, and classifies them. Output specified data. The details of the address recognition device 9 will be described later.

The postal matter P passing through the address recognition device 9 is then conveyed to the sorting section 11. The sorting unit 11 is composed of, for example, a plurality of sorting boxes 13 ... Divided according to addresses and postal codes. Mailboxes P are sorted and accumulated in the sorting boxes 13 ... In accordance with the sorting designation data from the address recognition device 9 described above.

The postal matter P is transported to the sorting boxes 13 ... By the sorting transport paths 15a, 15b ,. The configuration of the address recognition device 9 is shown in FIG.

The address recognition device 9 comprises a character recognition device 20, a word recognition circuit 30, a word dictionary 31, an address recognition circuit 40, and an address dictionary 41 of the present invention. Character recognition device 2
Reference numeral 0 includes a photoelectric conversion unit 21, a binarization circuit 22, an address area detection unit 23, a selection circuit 24, a character detection / cutout circuit 25, a normalization circuit 26, a character recognition circuit 27, and a character dictionary 28.

The photoelectric conversion unit 21 irradiates the postal matter P with light by a light source (not shown), receives the reflected light from the postal matter P, and converts it into an electric signal. The output signal of the photoelectric conversion unit 21 is input to the binarization circuit 22.

The binarization circuit 22 binarizes the output signal of the photoelectric conversion unit 21 (a read signal corresponding to the image of the entire surface of the postal matter P) with a predetermined threshold value. The output signal (binarization signal) of the binarization circuit 22 is input to the address area detection unit 23 and the selection circuit 24.

The address area detection unit 23 specifies the address area of the image of the mail P by coordinates by the projection method or the like,
To detect. After the detection, a signal indicating that the predetermined range is the address area is output. The output signal of the address area detection unit 23 is input to the selection circuit 24.

The selection circuit 24 receives the binary data from the binarization circuit 22.
Among the binarized signals, the binarized signal corresponding to the addressed area is selected and output according to the detection result of the addressed area detection unit 23. The character detection / cutout circuit 25 performs line detection and cutout on the binarized signal of the address area input from the selection circuit 24,
Further, a character pattern for one character is detected and cut out based on the estimated pitch. The character pattern detected and cut out by the character detection / cutout circuit 25 is sent to the normalization circuit 26.

The normalization circuit 26 is a character detection / cutout circuit 25.
The character pattern sent from is normalized to a certain size. The character pattern normalized here is sent to the character recognition circuit 27.

In the character dictionary 28, a first reference pattern corresponding to the whole image of the reference character and a second reference pattern corresponding to the partial image of the reference character are registered. The character recognition circuit 27 includes the following functional means [1] to [3].

[1] First recognition means for recognizing a read character by collating the input character pattern with the reference first reference pattern registered in the character dictionary 28. [2] When there are a plurality of recognition results of the first recognition means, a specific area corresponding to the mutual combination of the recognition results is specified for the input character pattern, and each recognition result of the registered contents of the character dictionary 28 is specified. Specifying means for specifying a predetermined second reference pattern according to the mutual combination of

[3] Second recognition means for recognizing the read character by collating the pattern of the specific area designated by the designating means with the second designated reference pattern. Then, the recognition result of the character recognition circuit 27 is sent to the word recognition circuit 30.

The word recognition circuit 30 collates the combination of read characters successively recognized by the character recognition circuit 27 with the word data registered in the word dictionary 31, and recognizes the word by the combination of the read characters. . This recognition result is sent to the address recognition circuit 40.

The address recognition circuit 40 collates the word recognized by the word recognition circuit 30 with the address data registered in the address dictionary 41, and recognizes the address represented by the word. This recognition result is output as classification designation data. This sorting designation data is used for sorting and stacking the sorting boxes 13 in the mail sorting machine 1 as described above.

A specific example of the character recognition circuit 27 and the character dictionary 28 is shown in FIG. In FIG. 1, A is a character pattern normalized by the normalization circuit 26. The sample pattern processing unit 51 first applies blurring processing to the character pattern A. The character pattern that has passed through the sample pattern processing unit 51 is matched by the matching processing units 52, 5
Sent to 4.

The matching processing unit 52 stores a character pattern and a reference first reference pattern (corresponding to the entire image of the reference character) registered in the first memory (first dictionary means) 61 of the character dictionary 28. The read character is recognized by collating.

Further, the matching processing section 52 has two output systems, and if there is one recognition result, it outputs the first output system.
Output from the output end, if there are multiple recognition results,
Output from the output end. The recognition result (one) output from the first output end is effectively output as the recognition result of the character recognition circuit 27. The plurality of recognition results output from the second output end are
It is sent to the area / pattern designation unit 53.

The area / pattern designating section 53 reads the designating data from the second memory 62 of the character dictionary 28 based on the mutual combination of a plurality of recognition results. This designation data is sent to the matching processing unit 54.

As shown in FIG. 4, the designation data is the first candidate data corresponding to the first recognition result, the second candidate data corresponding to the second recognition result, the area designation code, and the pattern designation. It consists of an address. A large number of this designation data are registered in the second memory 62.

The area designating code is applied to the character pattern that has passed through the sample pattern processing section 51, for example, as shown in FIG. 5, widths X ₁ and X _{2 in the} horizontal direction and widths Y ₁ and Y in the vertical direction.
_This is for designating any one of the regions divided by ₂ as the specific region, and when designating a region surrounded by the broken line in the figure, it becomes "X ₂ , Y _2. " As shown in FIG. 6, the horizontal widths X ₁ , X ₂ , X ₃ , X ₄ and the vertical width Y are shown.
_The area may be divided by ₁ , Y ₂ , Y ₃ , and Y ₄ . The size and number of divisions can be set appropriately.

The matching processing section 54 extracts a specific area of the character pattern (character pattern sent from the sample pattern processing section 51) based on the area specifying code of the specifying data, and also based on the pattern specifying address of the specifying data. A predetermined second reference pattern (corresponding to the partial image of the reference character) is read from the third memory (second dictionary means) 63 of the character dictionary 28. The matching processing unit 54 then reads the extracted pattern of the specific region and the read second region.
The read character is recognized by collating with the reference pattern.

Next, the operation of the above configuration will be described. The image on the postal matter P is optically read. A portion of the read image corresponding to the address area is detected, and a character pattern for one character is detected and cut out from the image of the address area. The cut-out character pattern is normalized to a certain size.

The normalized character pattern A is subjected to blurring processing in the sample pattern processing unit 51 and sent to the matching processing units 52 and 54. Matching processing unit 52
Then, the input character pattern A and the first reference pattern in the first memory 61 (corresponding to the whole image of the reference character)
And are collated, and the read character is recognized from the similarity between both patterns.

If there is one recognition result, it is effectively output as the recognition result of the character recognition circuit 27. However, if there are multiple recognition results, each recognition result
It is sent to the pattern designation unit 53.

For example, when reading the character "ball" shown in FIG. 1, the recognition result "ball" and
There is a possibility that the recognition result of "king" will be obtained. Also,
When reading the character "nail", the recognition result "nail" and the recognition result "melon" may be obtained.

When the two recognition results of "ball" and "king" are obtained, the designation data with both of them as the first candidate and the second candidate is read from the second memory 62 to the area / pattern designating unit 53. It The read designation data includes the area designation code and the pattern designation address.

The area designating code designates the area in the lower right part, which is the difference between "ball" and "king", as the specific area. That is, in the example of FIG. 5, the width X ₂ and the width Y surrounded by broken lines
_{There are two} areas. The pattern designating address is the second corresponding to the "," in the lower right part, which is the difference between "tama" and "king".
Specify the reference pattern.

The area designation code and the second reference pattern are sent to the matching processing section 54. The matching processing section 54 extracts the lower right area from the character pattern A based on the area designation code. Then, the extracted pattern in the lower right portion is collated with the second reference pattern corresponding to ",", and the read character is recognized from the similarity between both patterns. That is, one of the “ball” and the “king” becomes the recognition result of the character recognition circuit 27.

The recognition result is sent to the word recognition circuit 30, where word recognition is performed. Further, the address recognition circuit 40 recognizes the address based on the result of the word recognition.
If there is no designation data that fits the first candidate and the second candidate in the second memory 62, the process ends with a reject.

As described above, the character pattern A is first recognized as a whole, and if there is one recognition result, it is output. If there are a plurality of recognition results, the character pattern A is output.
By re-recognizing the partial areas of, it is possible to correctly recognize even characters that are similar to each other.

In particular, which area of the character pattern A is set for partial recognition, and what kind of pattern the partial recognition is made to, is selected from the mutual combination of the respective recognition results. Therefore, high recognition accuracy can be secured.

In the above embodiment, the partial area is recognized after the entire character pattern A is recognized. However, only the partial area may be recognized from the beginning. A certain level of recognition rate can be maintained.

[0047]

As described above, the character recognition device of the first invention optically reads a character on an object to be read, and collates a part of the read character pattern with a reference reference pattern. Since it is configured to recognize the read character, it is possible to accurately recognize even characters that are similar to each other, which is highly reliable.

The character recognition device of the second invention optically reads a character on the object to be read, collates the read character pattern with the reference first reference pattern, and recognizes the read character. When there are a plurality of recognition results, a specific area is designated for the read character pattern, and the pattern of the specific area is collated with the second reference pattern for reference to perform the recognition again. Even for similar characters, it is highly reliable and can be recognized correctly.

The character recognition device of the third invention optically reads a character on the object to be read, collates the read character pattern with the first reference pattern for reference, and recognizes the read character. When there are a plurality of recognition results, a specific area corresponding to the mutual combination of the recognition results is specified for the read character pattern, and the pattern of the specified specific area is collated with the second reference pattern for reference. Since it is configured to perform the recognition again, the reliability is high so that the characters that are similar to each other can be correctly recognized.

The character recognition apparatus of the fourth invention optically reads a character on the object to be read, and collates the read character pattern with the first reference pattern in the first dictionary means to recognize the read character. However, when there are a plurality of recognition results, a specific area corresponding to the mutual combination of the respective recognition results is designated for the read character pattern, and the mutual recognition of the respective recognition results among the registered contents of the second dictionary means is performed. Since a predetermined second reference pattern corresponding to the combination is designated and the pattern of the designated specific area is collated with the designated second reference pattern to perform the recognition again, it is very similar to each other. The character is also highly reliable and can be recognized correctly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a specific configuration of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a mail sorting machine according to the embodiment.

FIG. 3 is a block diagram showing the overall configuration of the same embodiment.

FIG. 4 is a diagram showing a format of designation data in the embodiment.

FIG. 5 is a diagram showing an example of specifying a region for a character pattern in the same embodiment.

FIG. 6 is a diagram showing a modification of FIG.

[Explanation of symbols]

1 ... Mail sorter, P ... Mail, 21 ... Photoelectric converter, 2
5 ... Character detection / cutout circuit, 26 ... Normalization circuit, 27 ... Character recognition circuit, 28 ... Character dictionary, A ... Character pattern, 51 ...
Sample pattern processing unit, 52 ... Matching processing unit, 5
3 ... area / pattern designation unit, 54 ... matching processing unit,
61 ... First memory (first dictionary means), 62 ... Second memory, 63 ... First memory (first dictionary means).

Claims (4)

[Claims] 1. A reading unit for optically reading a character on an object to be read, and a recognition unit for recognizing the read character by collating a part of a character pattern read by the reading unit with a reference reference pattern. A character recognition device comprising: 2. A reading means for optically reading a character on an object to be read, a character pattern read by the reading means, and a first for reference.
First recognition means for recognizing a read character by collation with a reference pattern; and designating means for designating a specific area for the character pattern read by the reading means when the recognition results of the first recognition means are plural. A character recognition device comprising: a second recognition means for recognizing a read character by collating a pattern of a specific area designated by the designation means with a second reference pattern for reference. 3. A reading means for optically reading a character on an object to be read, a character pattern read by the reading means, and a first for reference.
First recognition means for recognizing a read character by collating with a reference pattern, and when there are a plurality of recognition results by the first recognition means, a character read by the reading means in a specific area corresponding to a mutual combination of these recognition results. It is characterized by further comprising: designating means for designating the pattern, and second recognizing means for recognizing the read character by collating the pattern of the specific region designated by the designating means with the second reference pattern for reference. Character recognition device. 4. A first dictionary means in which a first reference pattern corresponding to the whole image of the reference character is registered, and a second dictionary means in which a second reference pattern corresponding to a partial image of the reference character is registered. Reading means for optically reading a character on the object to be read, and first recognizing means for recognizing the read character by collating the character pattern read by the reading means with the first reference pattern in the first dictionary means. When there are a plurality of recognition results of the first recognition means, a specific area corresponding to the mutual combination of the recognition results is designated for the character pattern read by the reading means, and the registered content of the second dictionary means is specified. Of the above-mentioned designation means for designating a predetermined second reference pattern in accordance with the mutual combination of the recognition results, and the second reference pattern designated with the pattern of the specific region designated by this designation means. Yo Character recognition apparatus characterized by comprising a second recognition means for recognizing a read characters, the.