JPS6262390B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that automatically reads characters in documents such as arbitrary forms and books.

Conventional devices of this type have limited formats, such as readable documents with reference marks printed in advance, or designated frames with characters written correctly within them. However, the disadvantage was that it was completely impossible to read characters from arbitrary documents such as forms and books.

In order to eliminate the above-mentioned conventional drawbacks, the present invention captures documents such as forms and books as blurred images through a filter made of a light-diffusing material, further converts the blurred images into binarized and patterned images, and then scans the documents. The system recognizes the position, length, etc. of a character string, and reads each character based on the recognition results.The purpose is to accurately and quickly read characters from any document. The object of the present invention is to provide an automatic reading device. The invention will now be explained in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of an automatic character reading device of the present invention, in which 1 is a document, 2 is an imaging section, 3 is a blurred image recognition section, 4 is a character string recognition section,
Reference numeral 9 denotes a character reading means composed of a reading head driving section 5, a reading head 6, a character cutting section 7, and a character recognition section 8. takes a blurred image of the document 1 through a filter made of a light-diffusing material, and the blurred image is sent to the blurred image creation section 3 to
The character string is converted into a value and pattern, and the character string recognition section 4 recognizes the position, length, etc. of the character string. Based on the recognition result, the reading head drive section 5 operates to cause the reading head 6 to recognize the character string of the document 1. The character information is extracted for each row by scanning along the line, and the character information is sent to the character cutting section 7.
The characters are cut out one by one, recognized by a character recognition section 8, and encoded.

FIG. 2 is a diagram showing the configuration of the imaging section 2. In the figure, 21
is a TV camera whose shooting range includes the entire document 1, 21
a is a lens portion of the TV camera 21, 22 is a plurality of filters made of a light-diffusing material arranged in front of the TV camera 21, 23 is a motor, 23a is a shaft of the motor 23, and 24 is attached to the shaft 23a. Electromagnetic clutch 25 connects filter 22 to clutch 2
4, and the filter 22 is a support rod connected to the shaft 2.
3a as a center, each rotates independently via a clutch 24, so that the lens portion 21a can be moved forward and backward onto the optical axis. 26 is blur amount instruction information, 27
is the lens unit 21 based on the blur amount instruction information 26.
A drive circuit determines the number of filters 22 to be inserted in front of a and controls the operation of the clutch 24 and the motor 23; 28 is a rotation instruction signal for the motor 23; and 29 is an ON signal for the clutch 24. The filter 22 is made of a material such as opalescent glass, alabaster glass, or frosted glass, and its function is as shown in FIG. 3, in which a single incident light beam L is scattered inside or on its surface and becomes a large number of transmitted lights L. When a plurality of filters 22 are combined, the degree of scattering, that is, blurring, increases as the number of filters increases. Further, the blur amount instruction information 26 is given manually or from a control circuit (not shown) based on the document size of the document 1, the character size, feedback information of the recognition result of the character string recognition section 4, and the like. Next, the operation will be explained. Here, it is assumed that the focus position of the TV camera 21 is on the document 1 without the filter 22. When the blurring amount instruction information 26 is input, the drive circuit 27 determines the number of filters 22 to be inserted in front of the lens portion 21a according to the information, and at this time, the number of filters 22 already inserted in the front of the lens portion 21a is If so, select the filter 22 to be moved by taking this into consideration, and move the clutch 24 accordingly.
The on signal 29 is sent to the terminal. Further, when a rotation instruction signal 28 is applied to the motor 23, the motor 23 rotates by a predetermined angle, and accordingly, the clutch 24 rotates the filter 22 in the ON state, and the necessary number of filters 22 is set in front of the lens 21a. . Thereafter, when the blurred image creation section 3 issues an image capture command to the TV camera 21, the TV camera 21 takes a blurred image of the document 1 through the filter 22 and sends it to the blurred image creation section 3.

FIG. 4 is a block diagram of the binarization circuit of the blurred image creation section 3. In a blurred image of characters, the density of characters with high density such as kanji and characters with low density such as kana and numbers are significantly different, and if the entire image is binarized with the same threshold, the characters This is inappropriate because a blur pattern that accurately indicates the rows cannot be obtained. Therefore, as shown in FIG. 5a, the image memory 31 storing the blurred image is divided into a large number of small areas 31a, and a density histogram as shown in FIG. 5b is taken for the small areas 31a, and its inflection point A is An appropriate blur pattern can be obtained by binarizing as a threshold value and performing this for each small area. In FIG. 4, reference numeral 31 denotes an image memory with intermediate density, which stores the blurred image sent out from the imaging section 2. 32 is a small area 31a of the image memory 31
33 is a histogram creation circuit that creates a density histogram of the small area 31a based on the information in the buffer memory 32; 34;
35 is an inflection point detection circuit that detects an inflection point from the histogram; 36 is a threshold; and 37 is a comparator. To explain the operation, first, the small area 31a is taken out from the image memory 31 and stored in the buffer memory 32.
Based on this, a density histogram is created by the histogram creation circuit 33 and stored in the memory 34.
The threshold value 36 is determined by the inflection point detection circuit 35 from the density histogram in the memory 34, and the threshold value 36 is determined by the buffer memory 32.
The comparator 37 compares the information with the information of the small area 31a in the image memory 31, converts it into a binary value, and stores it in the original location in the image memory 31. Thereafter, similar processing is performed on all other small areas of the image memory 31 to convert the blurred image into a binary blurred pattern and send it to the character string recognition section 4.

Figures 6a and b show an example of the original character pattern, its blur pattern, and the respective density distributions along the scanning line S. In the binarized blur pattern, high frequencies included in the original pattern are shown. It can be seen that the components have been removed.

FIG. 7 is a block diagram of the character string recognition unit 4.
4 is an image memory that stores the blurred image sent from the blurred image creation unit 3; 42 is a character area extraction circuit that extracts only the character area excluding "appendices, drawings", etc. from the blurred image; 43 is an image memory 4
1, a tilt correction circuit that detects the tilt of the image in 1 and corrects it by rotating the TV camera 21, etc.; 44, a m and σ calculation circuit that calculates the average value m of the width of the blur pattern of the character string and its standard deviation σ; 45 is a character string line extraction circuit that extracts a character string line that is the average of the midpoints of the blur pattern of a character string, and 46 is a character string end detection circuit that detects the upper, lower, left, and right ends of the blur pattern of a character string. The character area cutting circuit 42 and the skew correction circuit 43 are not necessary when the object to be read is a document consisting only of characters, and when there is no skew of the document due to a document guide or the like.

FIG. 8 shows an example of a binarized blur image stored in the image memory 41, in which 101 is a character string blur pattern, 102 is the width of the blur pattern 101, 103 is the midpoint of the width 102, 104
105 is the break in the blur pattern 101, 105 is the line feed part of the blur pattern 101, 106 is the constriction of the blur pattern 101, and 107 is the blur pattern 1
01 is unevenness on the edge, 108 is noise patterned by dirt on the paper surface, 109, 110, 111, 1
12 is a character string line obtained by averaging the coordinates of the center point 103 of the blur pattern 101, 113 and 114 are arrows representing the x coordinate parallel to the character string and the y coordinate perpendicular to the character string, and 115 is a scanning line in the y coordinate direction. be.

Next, the operation of character string recognition will be described. first,
The m,σ calculation circuit 44 scans the entire screen in the direction of the scanning line 115, and calculates the width 102 of the blur pattern 101.
The average value m and its standard deviation σ are calculated and sent to the character string line extraction circuit 45. Next, the character string line extraction circuit 45 performs scanning with the y direction as the main scan for each blur pattern, determines the coordinates of the midpoint of the blur pattern according to the flowchart shown in FIG. Determine the coordinates of the column lines. now,
If the coordinate l(K-1) of the character string line 109 has already been determined and you want to newly determine the coordinate l(K) of the character string line 110, the y coordinate of the character string line 109 is determined by the command to start scanning. Scanning is performed in the y direction with C as the starting point, and the center point C of the blur pattern that first intersects is
(n) (n represents the scan number in the x direction) and the width d are calculated. In judgment 1, a judgment is made to remove the unevenness 107 and noise 108 at the edge based on the width d and m, the average value m and standard deviation σ obtained by the σ calculation circuit 44, and if Yes, the C(n) and d are After erasing, scanning in the y direction is continued, and if No, proceed to judgment 2. In judgment 2, it is judged whether or not the cut 104 has been passed using the coordinates C(n-1) of the midpoint obtained during the previous scan, and if Yes, the coordinates C(n-1) of the midpoint are used.
(n) and d are deleted to start the next scan, and if No, proceed to decision 3. In judgment 3, it is judged whether or not the line feed part 105 or the constriction 106 has been passed, and if no, the character string line 11 required by C(n) is
It is determined that it belongs to the blur pattern of 0, this is stored, and the next scan is started, and if Yes, proceed to determination 4. Judgment 4 uses the y-coordinate l(K-1) of the previous character string line 109 to determine whether it is the line break 105 or the constriction 106 that has passed, and if Yes, it is determined that it is the constriction 106. Then that C
(n), erase d and continue scanning in the y direction,
If No, it is determined that the line feed section 105 has been passed and C
It is determined that (n) is the first midpoint belonging to the desired character string line 110, the coordinates of the previous midpoint are deleted, and the next scan is performed. When scanning in the y direction is completed to the right end of the screen, the midpoint coordinate C(n) is determined to belong to the blur pattern of the character string line 110.
are averaged to calculate the y-coordinate l(k) of the character string line 110. Similarly, the coordinates below the character string line 111 can be determined.

As shown in FIG. 10, the character string end detection circuit 46 scans vertically 116 and 117 from the left end of the character string line 110 to the right end of the character string line 110, for example, using the coordinate l(K) of 110 as a reference. Detect the maximum value in the vertical direction of the blur pattern and select the upper end 11
8. Detect the coordinates of the bottom edge 119 and select the character string line 110
Scanning 120,1 in the horizontal direction with a predetermined width centered on
21 is performed to detect the maximum value in the horizontal direction of the blur pattern, and the coordinates of the left end 122 and right end 123 are detected.

The recognition results of the position, length, and width of the character string obtained as described above are sent to the reading head drive unit 5, and the reading head 6 is driven as described above. will be done. In addition,
A reading head drive section 5, a reading head 6, a character cutting section 7, and a character recognition section 8 constitute the character reading means 9.
Since the one used in conventional character reading devices can be used as is, no special mention will be made regarding this. Furthermore, instead of the reading head driving section 5 and the reading head 6, the TV camera 21 of the imaging section 2 may be configured to be capable of scanning and zooming, and this may be controlled to read each character of a character string.

As explained above, according to the present invention, there is provided an imaging unit that captures a blurred image of a document such as a form or a book through a filter made of a light-diffusing material, and a binarized and patterned image of the blurred image. a blur image creation unit for converting; a character string recognition unit that scans the patterned image and recognizes the position, length, etc. of the character string; and a character string recognition unit that scans the patterned image and recognizes the position, length, etc. of the character string; Since it consists of a character reading means that reads each character in a column, it is possible to create a blurred image simply by importing the document through a filter with light scattering properties, and by converting the blurred image into a binarized image. Since character strings can be converted into patterns with high frequency components removed from the original pattern, character strings in documents of all formats and formats can be correctly recognized and characters can be read accurately. Further, since a conventional character reading device can be used as is as a means for reading individual characters, the cost of the device can be reduced. Furthermore, since a blurred image is created using a filter, there is no change in the field of view compared to the case where a blurred image is created by shifting the focal position of the camera, and there is no need for correction, which simplifies the apparatus. In addition, conventionally, the contents of documents with arbitrary formats and formats were manually input into various processing devices using keyboards, etc., but with this device, it is possible to read them as is, so the input processing time is reduced. It has the advantage that it can be used as an automatic input device when creating a database from a large amount of existing documents and as an end input/output device in data communication.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a schematic diagram of the automatic character reading device of the present invention, FIG. 2 is a diagram of the configuration of the imaging section, and FIG. 3 is an explanation of light scattering in the filter 22. Figure 4 is a block diagram of the binarization circuit, Figure 5a is an explanatory diagram of division of a blurred image,
Figure b is the density histogram of a small area of the blurred image.
Figure 6a is an explanatory diagram of the original character pattern and its density distribution, Figure 6b is an explanatory diagram of the blurred character pattern and its density distribution, Figure 7 is a block diagram of the character string recognition section, and Figure 8 is an illustration of the character string recognition section. An explanatory diagram showing an example of a blurred image,
FIG. 9 is a flowchart of the character string line extraction circuit, and FIG. 10 is an explanatory diagram of detection of the upper, lower, left, and right ends of a blur pattern. DESCRIPTION OF SYMBOLS 1...Document, 2...Imaging unit, 3...Blurred image creation unit, 4...Character string recognition unit, 5...Reading head drive unit, 6...Reading head, 7...Character cutting unit,
8...Character recognition unit, 9...Character reading means, 22
...A filter made of a light-diffusing material.

Claims (1)

[Claims] 1. An imaging unit that captures a blurred image of a document such as a form or a book through a filter made of a light-diffusing material, a blurred image creation unit that binarizes the blurred image and converts it into a patterned image, and the patterned image. a character string recognition unit that scans the converted image and recognizes the position, length, etc. of the character string; and a character reading unit that reads each character in the character string according to the recognition results such as the position, length, etc. of the character string. An automatic character reading device comprising: means.