JP2000163511A - Optical character reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read mixture of documents different in drop-out colors. SOLUTION: A recognition part is arranged which recognizes characters as symbols based on picture data obtained by reflected light from a document corresponding to plural color light sources, and when character symbols are recognized based on reflected light from the form corresponding to plural light sources are recognized, character recognition results corresponding to plural colors are compared with each other, and recognition characters are discriminated based on comparison results. This comparison utilizes the characteristic that noise springs out in pictures read out by light sources different in drop-out colors, and both pictures from blue/blur drop-out colors are discriminated by the degree of correct or erroneous read (step 62), the degree of similarity per character (step 63), and the difference in overall area of black picture element components in a read field (step 64), and the degree of similarity per character (step 65) is used as a factor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical character reader for reading characters and symbols from image data of a form on which a dropout color is described, and more particularly to an optical character reading apparatus for reading a form having different dropout colors. The present invention relates to an optical character reader that identifies a dropout color of a form and reads characters.

[0002]

2. Description of the Related Art In general, an optical character reader uses a color frame to surround a specific portion of a form with a color frame in order to indicate a specific reading range of the form to a writer or the like. The character is recognized based on the image data by the reflected light. The color of the frame not to be read is called a dropout color.

[0003] However, the dropout color differs depending on the type of form, and the conventional optical character reading apparatus has a drawback that forms with different dropout colors cannot be mixedly read.

In Japanese Patent Application Laid-Open No. Hei 5-28313, characters and figures are described with red and blue dropout colors to distinguish between characters and figures. There has been proposed an apparatus in which a light source is attached, a red dropout image and a blue dropout image are taken, and character recognition and graphic reading are performed. In this method, character recognition is performed on which image and figure reading is performed on which image.

[0005]

The optical character reading apparatus in which a single color dropout color is set according to the prior art described above, for example, includes a form in which red is a dropout color and a form in which blue is a dropout color. If the color of the light source is different from the color of the dropout written on the form when read in the state where it was read, the frame etc. by the dropout color will spring up in the obtained image, that is, the dropout color that should originally disappear Frame, etc., described above, erupts as noise, and there is a problem that accurate character recognition is difficult.

In an optical character reader having a plurality of light source colors, it is necessary to designate a dropout color for each form to be read in advance, and to perform character reading using the light source of the designated dropout color. There was a defect. That is, in the conventional apparatus, it is necessary to specify in advance which image is to be read, and it is not possible to identify the dropout color of the form from the image corresponding to the light source and perform character reading. was there.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the disadvantages of the above-mentioned conventional optical character reader, and to identify a drop-out color of a form from image information obtained by mixing forms having different drop-out colors. An object of the present invention is to provide an optical character reading device capable of reading characters.

[0008]

According to the present invention, there is provided an optical character reading apparatus for reading a character symbol from image data of a form on which a dropout color is described, comprising: a light source having a plurality of colors; A recognition unit for recognizing character symbols based on image data based on reflected light from a form corresponding to a color light source. The first feature is to compare character recognition images corresponding to and to determine image data to be recognized based on the comparison image.

Further, according to the present invention, in the optical character reading apparatus according to the first aspect, a character recognition image corresponding to the plurality of colors is determined based on a character recognition rate, and a dropout color image having a high recognition rate is selected. And the determination of the character recognition image corresponding to the plurality of colors is performed by determining whether the total area of the black pixel components in the reading range is small, in the optical character reading device according to the first and second characteristics. A third feature is that an out-color image is selected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical character reader according to an embodiment of the present invention will be described. First, the principle will be described. The present invention aims at performing reading in a mixed manner irrespective of the color of the dropout, whereas the form is conventionally sorted by the color of the dropout,
For this purpose, images are respectively taken from light sources having different dropout colors, read from each image data, and the recognition result of the image of the dropout color corresponding to the document is determined using the read results.

This determination is based on the characteristic that an image in which the dropout color has been correctly erased has a good reading rate, and an image in which the dropout is protruding has a characteristic that the protruding components become noise and the reading rate decreases. There is a way to do this. Specifically, the visibility of the dropout color reflects on the correct reading rate and similarity, and (1) images with good readability and (2) images with good similarity obtained during recognition are dropped out. If the image can be regarded as an image in which the color is not exposed, and if the dropout color is exposed, the total area of the components to be recognized in the reading field becomes large, and (3) the area of the component to be read in the reading field becomes large. Small ones take advantage of a property that can be considered a missing image of the dropout color.

Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining an optical character reading apparatus to which the present invention is applied. This optical character reading apparatus includes a display 1, a keyboard 2, a mouse 3, and an arithmetic unit 4.
And a stacker 6 connected to the main body of the optical character reading apparatus via a data transfer cable 9 for stacking a plurality of forms, and separating and conveying the stacked forms one by one. And a reading unit including a light source unit 7 for taking an optical image of the conveyed form and a discharging unit 8 for the read form. It is assumed that the light source section 7 has two types of light sources, a red light source and a blue light source.

As shown in FIG. 2, the form to be read in this embodiment is a form identification number 10a and a form identification number 1 surrounded by a red dropout color.
A form 12 having a reading unit 11a whose location is designated by 0a and which is similarly surrounded by a red dropout color
And a form 13 having a reading unit 11b which is also designated by the form identification number 10b and the form identification number 10b which are framed by a blue dropout color and which is similarly framed by a blue dropout color; It is assumed that there is a form identification number 10c surrounded by a dropout color and a form 14 having a reading part 11c similarly designated by the place and designated by the form identification number 10c and also surrounded by a red dropout color. . In addition, the form identification numbers 10a to 10c are arranged at the same vertical position from either the leading end or the rear end of the form, and the horizontal position from the left end or the right end, and the form identification number indicates the type of the form. Represents. If the form identification numbers are the same, the read information such as the dropout color, read position, and character type of the form is the same.

In the present embodiment, the two types (red / blue drop color) of the form shown in FIG. 2 are stacked on the stacker 6 of the reading unit of FIG. 1, and the form is formed by an instruction from the optical character reading apparatus main body. The sheet is separated and transported one by one, and the light image of the transported form is separately read by the light source unit 7 using two types of red light source and blue light source.

FIGS. 3 and 4 show the read image data and the like.
This will be described with reference to FIG. First, when the read field 14 of the red dropout color form 12 shown in FIG. 3 is read by a red light source, the image data does not show a red frame as indicated by an arrow 15 and the numeral “123” is displayed inside. A clear image is obtained. Similarly, when the image data is read by a blue light source, the image data has a red frame as shown by an arrow 16, and noises N of vertical and horizontal lines around a numeral "123" in the image data.
Is included.

Next, when the reading field 14 of the form 13 of blue dropout color shown in FIG. 4 is read by a blue light source, the image data does not show a blue frame as indicated by an arrow 19, and the character " 456 "becomes a clear image. Similarly, when the image is read with a red light source, an arrow 18
As shown in the figure, the image data has a blue frame and a vertical and horizontal line noise N is included around the number “456” in the image data.

FIG. 5 shows an outline of processing for two image data read by the red and blue light sources, respectively. In this process, the leading / rear / left / right sides of each image data are detected for the background black image (form reference side calculation step 21), and the target reading position of the reading field 14 is calculated (reading). Position calculation 22). This is to check whether there is a dropout color near the reference side of the form, the color is revealed in either image, and the detection of the reference side of the form is correct. Next, this processing calculates character recognition / similarity with a reference character pattern / total number of black pixels for the two read images,
Based on these values, it is determined which of the two image data read by the red and blue light sources is to be selected (recognition result determination step 23).

The method of this determination will be described with reference to FIG. First, in this determination, character recognition is performed using a red drop color (step 60) and character recognition is performed using a blue drop color (step 61), and it is determined whether each recognition result is correct or incorrect (step 62). For example, when a character is recognized by a well-known pattern matching method, when the pattern can recognize three characters out of three characters, a case where even one character cannot be recognized is determined as an erroneous reading.
For example, when the character "123" in the read field 14 of the form is recognized, the recognition result 25 (character "123") in the red dropout as shown in FIG. (When characters “1? 3” and “2” cannot be read) are erroneously read, as shown in FIG. 7B, the recognition result 28 (character “123”) in the red dropout and the recognition result 29 (blue) in the blue dropout. Characters "123") are both correct, FIG.
As shown in (c), the recognition result 31 (character “1? 3”) in the red dropout and the recognition result 32 (character “1? 3”) in the blue dropout are both determined to be misread.

In this step 62, one of them is a correct reading,
If the other is misread, it means that the dropout color of one image matches the predetermined one, and the noise shown in FIG. 4 gushes out due to the mismatch of the dropout color of the other image with the predetermined one. In order to do so, it is determined that the character read from the correctly read image data is correct, and this is output (step 66).

In step 62, if both images are read correctly (the noise is less pronounced) or erroneously read (both do not match the allowable range), the similarity per character is calculated, and the difference between the similarities is calculated. It is determined whether or not is larger (step 63). This similarity is determined by comparing, for example, a set of black pixels per reference character and a set of black pixels of the read image as shown in FIG. If the difference between the similarities is large in step 63, that is, if one of the similarities is larger than the other, it is determined that the character read from the image data having the large similarity is correct, and this is output (step 63). 67).

If the difference between the similarities is small in step 63, this process detects the total area of the black pixel components in the read field 14 and determines whether this difference is large (step 64). It is determined that the character read from the image data having the small total area of the pixel components is correct, and this is output (step 68). This determination makes use of the characteristic that an image in which the dropout colors do not match has a large amount of noise, and is likely to have a mismatch. That is, as shown in FIG. 9, the black pixel number (dot number) 38 of one character (number 1) 36 of the read field in the red dropout color of the red dropout form is a predetermined number because there is no noise. On the other hand, the number of black pixels per character in the reading field in the blue dropout color of the red dropout form increases due to noise due to the noise component of the frame, and images with mismatched dropout colors are likely to have noise. This is based on the characteristic that there is a large possibility that there is a mismatch.

Next, in the present process, if the difference in the total area of the black pixel components in step 64 is not large, the similarity per character is calculated, and it is determined that the character read from the image data having the large similarity is correct. Is output (step 65). This determination is made in steps 62, 63, and 64 described above.
In the case where the judgment in is not given, only the degree of similarity per character is judged as a factor. In addition, when correcting characters due to unknown character recognition in this device, specify whether or not there is a dropout color,
Output the image to the display and make corrections.

As described above, the optical character reading apparatus according to the present invention prepares a plurality of light sources having different dropout colors, and mixes the forms of the dropout colors having different color light sources.
Without specifying the dropout color, the image in which the dropout color of the form has disappeared can be identified from the image information and the character can be read. In addition, the image displayed on the display when making corrections may be good if the dropout color has disappeared, such as when the entry frame is written in dropout, and the item of date of birth may be dropped. If the character of the dropout color represents an item, such as when it is written in outcolor,
In some cases, it is easier to correct the remaining part, so it is preferable to specify whether or not there is a dropout color and display the image to be displayed on the screen using the dropout color determination.

Incidentally, the optical character reading apparatus according to the present invention can be represented as the following embodiment. <Embodiment 1> There is a light source for collecting the image information of a form by deleting information of a specific color written on the form, and has a plurality of light sources for deleting different colors. There is a mechanism to collect image data from each light source, and depending on the light source, there are multiple drop-out image data of a specific color, and the light source corresponding to the dropout color of the form from those image data An optical character reader having a recognition function of identifying an image of the image and performing character recognition. <Embodiment 2> Having the mechanism of Embodiment 1 described above, without specifying the color of the dropout form, reading different forms of the dropout color in a mixed manner without selecting colors. An optical character reader characterized by the above-mentioned. <Third Embodiment> The third embodiment has the mechanism of the first and second embodiments, and specifies whether image information to be displayed on a screen has dropout information or no dropout information when performing a correction, An optical character reader characterized by displaying a screen with dropout information in the case, and displaying a screen without dropout information in the absence of the dropout information.

[0025]

As described above, the optical character reading apparatus according to the present invention is provided with the recognition section for recognizing characters on the basis of the image data by the reflected light from the form corresponding to the light sources of a plurality of colors. When recognizing character symbols from reflected light from a form corresponding to the light source, character recognition results corresponding to multiple colors are compared, and recognition characters are determined based on the comparison result,
It is possible to identify a dropout color of a form from image information obtained by mixing forms having different dropout colors and read characters.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical character reading device according to an embodiment of the present invention.

FIG. 2 is a diagram showing forms having different dropout colors.

FIG. 3 is a diagram for explaining an image obtained by taking a red dropout form with a red dropout and a blue dropout.

FIG. 4 is a view for explaining an image obtained by taking a blue dropout form with a red dropout and a blue dropout.

FIG. 5 is an exemplary view for explaining an outline of a recognition method according to the embodiment;

FIG. 6 is an exemplary view for explaining a determination method from a recognized result according to the embodiment;

FIG. 7 is an exemplary view for explaining determination from correct reading / misread of a character recognition result according to the embodiment;

FIG. 8 is an exemplary view for explaining a determination method from character similarity according to the embodiment;

FIG. 9 is an exemplary view for explaining a determination method based on the total number of dots in a read field according to the embodiment;

[Explanation of symbols]

1: display, 2: keyboard, 3: mouse, 4:
Arithmetic unit, 5: optical character reading device, 6: stacker for placing a form, 7: light source unit for taking a form image, 8: form discharge unit, 9: data transfer cable, 10: form identification number, 11: form identification number Reading unit corresponding to the form identification number, 12: red dropout form, 13: blue dropout form, 1
4: read field, 15: image captured by red dropout form with red dropout, 16: image captured by red dropout form with blue dropout, 1
7: Image of red dropout line exposed, 18: Image of blue dropout form imported by red dropout, 19: Image of blue dropout form imported by blue dropout, 20: Blue dropout line Exposed, 21: form reference side calculation, 22: reading position calculation.

Claims (3)

[Claims] An optical character reading apparatus for reading a character symbol from image data of a form on which a dropout color is described, wherein a plurality of color light sources and image data by reflected light from a form corresponding to the plurality of color light sources are provided. A recognition unit for recognizing character symbols based on the reflected light from a form corresponding to a light source of a plurality of colors. An optical character reading device for determining image data to be recognized. 2. The method according to claim 1, wherein a character recognition image corresponding to the plurality of colors is determined based on a character recognition rate, and a dropout color image having a high recognition rate is selected.
The optical character reader according to the above. 3. The optical character reading apparatus according to claim 2, wherein the character recognition image corresponding to the plurality of colors is determined by selecting a dropout color image having a small total black pixel component area within the reading range. apparatus.