JPH0620094A - Character recognition device - Google Patents

Abstract

PURPOSE:To provide the character recognition device which optically reads a document printed in type and accurately recognizes symbols or the like even of low recognition precision. CONSTITUTION:In a general optical character recognition device 20, vertical positions in rows and forms of circumscribed rectangles for symbols which are not included in the recognition object but frequently appear in a specific document or for symbols which have character forms resembling those of another symbols and cannot be accurately recognized by collation of only character features at the time of recognition are stored in a dictionary memory 6 as a register dictionary together with their character features to recognize the type characters more accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character recognition apparatus for reading a document containing characters as an image and recognizing the read character image as a character.

[0002]

2. Description of the Related Art As a character recognition device for recognizing a character image of a document by computer processing, character information to be recognized, for example, a Japanese character is CCD (charge coupled device).
There is known an optical character recognition device (OCR) in which photoelectric conversion is performed using, for example, the photoelectrically converted electric signal is cut out for each character image unit, and the recognition unit recognizes each character image according to a predetermined recognition logic. ing.

As a recognition method, the contour is traced from the start point of the character, a direction code is given, this is compared with a similar standard pattern in the dictionary as a direction code string, candidates are listed in order of similarity, and the character There is a recognition method such as outputting the code.

[0004]

In the above-mentioned character recognition device, when reading a type document, the type symbol to be recognized is about 200 characters.
It is very small compared to the number of symbols that appear in printed documents for reading. In addition, a symbol that is not included in the recognition target in the character recognition device is often used in a specific document.

Therefore, when a standard pattern is simply created as a character to be recognized and stored in a character recognition dictionary, when reading and recognizing a general document, standard patterns having similar character characteristics increase. As a result, the recognition accuracy is reduced, and the number of standard patterns is increased, which causes a disadvantage such as a reduction in the recognition processing speed.

In order to solve such a problem, in a handwriting character recognition device, a character that is difficult to recognize in collation with a standard pattern, for example, a character feature that a user individually has in a character recognition dictionary. The method of registering with is considered.

However, even if such a method, that is, the method of registering only the character feature in the dictionary is applied as it is, the shape similarity such as a symbol in a printed document is high, and
For characters whose vertical position or arrangement in the line determines the recognition result, for example, especially for symbols, ","
Information such as when the code to be output differs depending on whether it is located above or below the character, such as "and", and "-" and "-", and whether the character is close to a square. The positional relationship between characters that should be judged at the same time, as well as ruby, superscript, subscript, etc., is important, and simply processing them will cause problems in character extraction and recognition processing, which is rather inconvenient. Is.

An object of the present invention is to solve the above problems and to provide a character recognition apparatus which has high accuracy in character recognition and can perform recognition processing at high speed.

[0009]

According to the present invention, a dictionary memory in which a standard character image of a predetermined character to be recognized is stored, and at least one line composed of a plurality of characters arranged in one direction is displayed. In a character recognition device including a reading unit that reads the read original as an image and a recognition unit that refers to the dictionary memory and recognizes the character image from the reading unit as a character, the character image from the reading unit is displayed. With respect to the display means, the character designating means for designating the display area of the character image of one character among the character images displayed on the display means, the position in the line and the designated character with respect to the character image designated by the character designating means. Detecting means for detecting the rectangular shape of the display area, and converting the character image into a standard character image for the character designated by the character designating means. A character recognition apparatus, characterized in that together with the detection result by the stage and a registration means for registering in the dictionary memory.

[0010]

According to the present invention, in the character recognition device, the reading means reads a document in which at least one line constituted by arranging a plurality of characters in one direction is displayed as an image and determines a predetermined recognition target character. The recognition unit refers to the dictionary memory storing the standard character image to recognize the character image from the reading unit as a character. At this time, the display means displays the character image from the reading means, the character designating means designates a display area of a character image of one character among the character images, and the detecting means displays a line for the designated character image. The position and the rectangular shape of the display area of the designated character are detected, the character image of the designated character is converted into a standard character image by the registration means, and the standard character image is registered in the dictionary memory together with the detection result by the detection means.

[0011]

1 is a block diagram of a character recognition device 2 according to an embodiment of the present invention.
It is a block diagram which shows the structure of 0 whole. Character recognition device 2
Reference numeral 0 includes a recognition unit 1, an input / output unit 2 and an input unit 7. The recognition unit 1 includes a ROM 3 that stores a program that controls the entire recognition unit 1, an image memory that stores a read image on coordinates, and a RAM 4 that serves as a work buffer for processing such as cutout and registration dictionary creation when recognizing characters. , CPU for controlling the entire character recognition process according to the program in the ROM 3
(Central processing unit) 5, a standard pattern used for collation at the time of character recognition processing, a dictionary memory 6 for storing a registered dictionary 16 which will be described later, and a character feature from an image for one character cut out from the image memory. The feature extraction unit 8 to extract, the character features extracted by the feature extraction unit 8 of the input character image, and the standard pattern in the dictionary memory 6 are collated,
It is composed of a character recognition dedicated processor 9 for outputting character codes in order of similarity, and an interface 10 for inputting / outputting data to / from an external device. The input unit 7 is an optical input device such as a scanner that reads a document image.

Further, in this embodiment, the recognition unit 1 and the input / output unit 2 are connected via an interface to exchange data. The input / output unit 2 displays the original image of the document image input in the input unit 7 and the input / output unit 2 by the user to instruct a processing mode such as registration and recognition processing, and will be described later. An external storage for storing and storing a keyboard 12 used for designating registered characters, a later-described registration dictionary, and files created by the input / output unit 2 in processes other than character recognition, such as a floppy disk. An external output 13 for writing and reading data to and from the CPU, a CPU 14 for controlling the entire input / output unit 2, and the like.

FIG. 2 is a perspective view showing the external appearance of the character recognition device of this embodiment. The input unit 7 is a scanner, which irradiates an original with light from a light source to scan the original and reflects the reflected light to a CCD.
It is a device that performs photoelectric conversion using a (charge-coupled device) or a photomultiplier tube and converts the image written on the paper into an electrical signal to read.

The input / output unit 2 is a computer having a general function as a computer, and performs not only the creation of the registration dictionary of this embodiment but also various other calculation processes when the character recognition process is not performed. The display unit 11 is a CRT (cathode ray tube) display and displays the original image of the document of the present embodiment, the recognition result, and the like. Further, in the registration mode, the character image to be registered in the original image displayed on the display screen is registered by dot display or by enclosing it in a rectangle using the cursor 19 displayed in an appropriate size and shape. specify. The registration designation of the character image may be performed using a light pen. Further, when the character recognition process is not performed, the display unit 11 displays an input screen of another calculation process performed by the input / output unit 2, a mode selection screen, or a processing result.

The keyboard 12 instructs the input / output unit 2 to select a mode or move the cursor 19 to specify a character image, and in other processing operations, the input / output unit 2 receives input data and instruction data. give. The external output 13 is a device such as a disk drive, and writes / reads a data file or the like to / from an external storage such as a floppy disk.

FIG. 3 is a diagram showing a procedure for creating a recognition dictionary. The feature extraction unit 8 and the CPU 5 create a registration dictionary in the registration dictionary buffer 15 in the RAM 4 and add the same registration dictionary 16 to the standard pattern 17 of the dictionary memory 6 to create a recognition dictionary. From the original image displayed on the display unit 11, the user inputs 1 to the input / output unit 2 using the keyboard 12.
The character image for the character is specified, and the character code of the character image is input.

This data is transferred from the input / output unit 2 to the CPU 14
Is given to the recognition unit 1 via this data, the feature extraction unit 8 extracts character features using this data, and the CPU 5 compares the designated character image with an adjacent character image,
The position information occupied in the line of the designated character image, that is, the position coordinates in the image memory and the shape information of the circumscribing rectangle are detected and stored in the registration dictionary buffer 15 of the RAM 4 together with the given character code. .

At this time, the CPU 5 determines whether or not this character data should be registered as a registration dictionary based on the following criteria, and displays the result on the display unit 11 of the input / output unit 2.

If the following conditions are met, registration will not be performed.

(1) The number of registered characters exceeds the limit.

(2) There is an abnormality in the image of the part to be registered.

(3) There is the same one registered before.

The registered contents of the registered character image are displayed on the display unit 11. This registration dictionary 16
It is added to the standard pattern 17 in the dictionary memory 6.

FIG. 4 is a diagram showing a specific configuration of the registration dictionary 16 created in the RAM 4 and the dictionary memory 6 shown in FIG. In the registration dictionary 16, the position from the center of the line,
And data relating to similar characters in the shape of a circumscribed rectangle are classified and arranged so as to be adjacent to each other.

For example, as shown in the line of FIG. 4, a group of characters whose vertical length is approximately equal to the width of the line and which is located at the center of the line, as shown in the line of FIG. Group whose vertical length is less than the width of the line and the character is below the center of the line, the vertical length of the character is less than the width of the line and the character is The data is classified into groups above the center of, and is stored in the dictionary memory 6 so that the dictionary data relating to them are adjacent to each other.

The registered dictionary 16 is secured in the RAM 4 as the registered dictionary buffer 15, and the data in the dictionary memory 6 is updated in accordance with the registered dictionary update from the input / output unit 2 and the instruction such as the registered dictionary use mode.

Since this dictionary has the same structure in the RAM 4, if the number of registrations exceeds the upper limit, if it is transferred to the input / output unit 2 and data is stored in the external storage device, a new registration dictionary is created. Can be created. If this is the same as the original of the previously created dictionary for registration, it is sufficient to call the dictionary from the input / output unit 2 to the recognition unit 1, and it is not necessary to repeat the same work.

In the present embodiment, the dictionary registered in the input / output unit 2 is stored in the external storage device, but the recognition unit 1
An external storage device may be attached to and the data may be stored therein.

FIG. 5 is a flowchart showing the operation when the character recognition device 20 of this embodiment creates the registration dictionary 16, and FIG. 6 shows the document 18 read by the input unit 7,
9 is a diagram showing an example of an original image displayed in the image processing screen of the display unit 11. FIG.

The registration process is started when the user operates the keyboard 12 of the input / output unit 2 to instruct the registration mode.

At step k1, the document 18 shown in FIG. 6A is optically read by the scanner in the input section 7, and the image on the document 18 is stored in the coordinates of the image memory in the RAM 4. At step k2, the original image input from the input unit 7 is enlarged and displayed on the display unit 11 of the input / output unit 2 as shown in FIG.

At the next step k3, it is judged whether the image processing is input or the key input for instructing the end of registration is made. If there is a key input for ending the registration processing, the process goes to step k10 to select the next processing mode, for example, , Recognition processing, etc. can be selected. If there is an image processing input at step k3, the process proceeds to the next step k4.

In step k4, as shown in FIG. 6 (2), for example, first, the start and end of one side of the rectangle surrounding the character image in the vertical or horizontal direction is set by the cursor 19 to display one side. After that, the end of the set side is set as the start end, and the end of the side orthogonal to this side is set as the cursor 1
By setting in 9, the rectangle is determined and the character image to be registered is designated. The method of enclosing the character image in a rectangle using the cursor 19 may be another method, or may be directly input to the display screen using a so-called light pen. When the designation of the registered character image is completed, the next step k
Go to 5.

At step k5, on the display screen 11,
It requests the user to input the character code and waits for the input. When the character code is input, the process proceeds to the next step k6.

At step k6, the feature extraction unit 8 extracts character features from the designated registered character image in the registered dictionary buffer 15 in the RAM 4 shown in FIG.
Calculates the position coordinates of the specified character image in the image memory from the position data of the character image specified by the rectangle provided by the CPU 14, and determines the position of the character image from the center of the line, the shape of the circumscribed rectangle, etc. To detect.

At the next step k7, the CPU 5 judges whether or not this character data should be registered in the registration dictionary 16,
If registration is not possible, the process moves to step k9 and the display unit 11
It is displayed that the character data designated by is not registered and the process returns to step k3.

If it is determined in step k7 that the CPU 5 can register the character data, the process proceeds to next step k8.

At step k8, the registration dictionary created in the registration dictionary buffer 15 of the RAM 4 is added to the dictionary memory 6 as the registration dictionary 16. Then, the process proceeds to the next step k9, the registration status of the registration data is displayed on the display unit 11, and the process returns to step k3.

When it is determined in step k3 that the key input for ending the registration is determined, the process proceeds to step k10. In step k10, for example, it is determined that the processing mode such as the recognition processing is selected next, and when the recognition processing mode is continuously selected for registration, the recognition dictionary updated in steps k3 to k9 is added. The recognition processing is performed based on this. Therefore, the registered character is treated as a new recognition target character.

At the next step k11, the CPU 5 cuts out a character image for one character from the image memory and sends it to the work buffer of the RAM 4. In step k12, the feature extraction unit 8 extracts the character feature from the cut out character image.

In step k13, the character recognition dedicated processor 9 performs the character recognition processing on the extracted character features based on the contents of the dictionary memory 6. At this time, the character recognition dedicated processor 9 performs the character recognition processing. Which registration dictionary to use is determined based on the position data from the center and the shape of the circumscribed rectangle.

At the next step k14, the character recognition dedicated processor 9 rearranges the recognition results obtained at step k13 in the order of similarity and displays them on the display unit 11 to finish the processing. If the end key is pressed in step k10, the process ends.

As described above, according to the present embodiment, the characters are not included in the recognition target character in the character recognition processing of the general type document, but depending on the document, the collation based on the symbol having the high appearance frequency or the character feature is sufficient. Even for symbols in a printed manuscript that causes a decrease in recognition accuracy, the upper and lower positions in a line are detected from the characters before and after, and registered in the dictionary along with the shape of the circumscribed rectangle. CP
More accurately by determining whether or not the U5 uses the registration dictionary 16 based on the position in the line of the input character image or the shape of the circumscribing rectangle, or in the case of using, which registration dictionary to use. Character recognition can be performed according to the situation.

[0044]

As described above, according to the present invention, the character recognition device has the character designated by the character designating means for designating the display area of the character image of one character among the character images displayed on the display means. Regarding the image, the detecting means detects the position in the line and the rectangular shape of the display area of the designated character, converts the character image into the standard character image for the character designated by the character designating means, and detects the result together with the detection result by the detecting means. Since the character image is registered in the dictionary memory, it is possible to perform accurate recognition processing even for a character image that is erroneously recognized by simply matching with the standard character image.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a specific device that constitutes the character recognition device 20 of the present embodiment.

FIG. 3 is a diagram showing a procedure for creating a recognition dictionary.

4 is a diagram showing a specific configuration of a registration dictionary 16 created in a RAM 4 and a dictionary memory 6 shown in FIG.

FIG. 5 is a flowchart showing an operation when the character recognition device 20 of the present embodiment creates a registration dictionary 16.

6 is a diagram showing an example of a document 18 read by an input unit 7 and an original image displayed in an image processing screen of a display unit 11. FIG.

[Explanation of symbols]

 1 Recognition Unit 5 CPU (Central Processing Unit) 6 Dictionary Memory 7 Input Unit 9 Character Recognition Processor 11 Display Unit 12 Keyboard 20 Character Recognition Device

Claims (1)

[Claims] 1. A reading in which a dictionary memory in which a standard character image of a predetermined recognition target character is stored, and a document in which at least one line constituted by arranging a plurality of characters in one direction is displayed as an image A character recognition device that recognizes a character image from the reading unit as a character by referring to the dictionary memory, a display unit that displays the character image from the reading unit, and a display unit that displays the character image on the display unit. A character designating unit that designates a display region of a character image of one character from the displayed character images; and a position in a line and a rectangular shape of the display region of the designated character with respect to the character image designated by the character designating unit. Detecting means for converting the character image into a standard character image for the character designated by the character designating means, and the detection result by the detecting means. A character recognizing device, characterized in that the character recognizing device includes a registration means for registering in the dictionary memory.