JP2975720B2 - Optical character reader - Google Patents

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 optically reading characters written in a character entry frame on a form.

[0002]

2. Description of the Related Art Conventionally, in an optical character reading apparatus, as shown in FIG. 4, a character entry frame 11 is printed on a form in black, and characters entered in the character entry frame 11 are read. Many methods have been adopted.

[0003] In this case, in order to know the existence range of each character, a partition line 1 that separates each character in the character entry frame 11 is used.
It is necessary to accurately detect the position of 1a. Therefore, conventionally, a histogram of black bits in a partition line direction (vertical direction) is obtained from the entire image data including the character entry frame 11, and a position where the histogram is equal to or more than a predetermined value is determined as a position where the partition line 11a exists. Was.

However, in such a system, FIG.
As shown in the figure, when the partition line 11a is printed or blurred by a dotted line, or when the partition line and the character overlap, the histogram value is less than a certain value, and the peak position of the histogram value is unclear. In some cases, the position of the partition line cannot be accurately detected. As a result, there is a problem in that a character is erroneously cut out from the entire image, and a reading error occurs.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. Even if the line of the character entry frame on the form is not printed as a clear solid line, the character entry frame line can be obtained. It is an object of the present invention to provide an optical character reader capable of accurately reading a character even when the character overlaps the character.

[0006]

In order to achieve the above-mentioned object, an optical character reading apparatus according to the present invention is provided with an image of a character on a form on which a character entry frame for entering a character is printed together with the character entry frame. Image reading means for reading as data, image data storage means for temporarily storing image data read by the image reading means, and image data stored in the image data storage means continuing in the first axis direction . A black bit string having a predetermined number of bits or less is detected, and a second axis direction orthogonal to the first axis direction is detected for the detected black bit string.
A histogram calculating means for obtaining a histogram of the orientation , and a histogram among the frame lines constituting the character entry frame, based on the histogram calculated by the histogram calculating means .
And borders position detecting means for detecting a position of the first axis direction of the two axial to the printed border of the detected black bit string, a frame detected by the frame line position detecting means
Erasing means for erasing black bits existing at the position of the line from the image data stored in the image data storing means; and an image stored in the image data storing means after the erasing means erases the black bits. A character extracting means for extracting image data one character at a time from the data, and a character recognizing means for recognizing characters from the image data extracted by the character extracting means.

[0007]

In the optical character reading apparatus according to the present invention, the histogram calculating means detects a black bit string having a predetermined number of consecutive bits or less in the first axial direction from the image data stored in the image data storing means. For black bit strings
A histogram in a second axis direction orthogonal to the first axis direction is obtained. Based on the histogram calculated by the histogram calculating means, the frame line detecting means detects the first of the frame lines printed in the second axis direction among the frame lines constituting the character entry frame .
The axial position of is detected. Erasing means, from the image data stored in the image data storage means, to erase the image data of the detected border by border detection means. The character extracting means sequentially extracts one character of image data from the image data after erasing the character entry frame. Character recognition is performed on the character image data.

Therefore, in this optical character reading apparatus, even when the character entry frame is partially printed or dashed by dotted lines, or when the character entry frame and the character are overlapped, the character can be accurately read. Characters entered in the entry box can be read.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an optical character reading device according to an embodiment of the present invention. In the figure, P is a form in which a character entry frame is printed in black on the front surface. Reference numeral 1 denotes an image scanner for optically reading the characters entered in the character entry frame on the form P as image data together with the character entry frame. 2 denotes a provisional image data read by the image scanner 1 on a line basis. This is a row image memory for storing. Further, 3 detects, from the image data stored in the row image memory 2, a group of black bit strings continuous in the X / Y-axis direction (horizontal / vertical) and having a predetermined number of bits or less, and targets these black bit string groups. It is a histogram calculation unit for obtaining histograms in the X / Y axis directions. Reference numeral 4 denotes a frame line detection unit that detects the position of each frame line forming the character entry frame in the X / Y-axis direction based on each histogram obtained by the histogram calculation unit 3. Reference numeral 5 denotes a frame erasing unit that erases (converts to white bits) the image data of each frame detected by the frame detecting unit 4 from the image data stored in the row image memory 2. 6 is 1 in order from the image data remaining after erasing the character entry frame.
This is a character cutout recognition unit that detects and cuts out image data for characters and performs character recognition on the cutout character image data.

Next, the operation of the optical character reading apparatus of this embodiment will be described. Here, a form P in which the line of the character entry frame and the character overlap is taken as an example.

When an image for one line including the character entry frame on the form P is read by the image scanner 1, the image data is stored in the line image memory 2. FIG.
(A) shows image data for one line of a form stored in the line image memory 2, and 21 in the figure shows an image of a character entry frame. Thereafter, the histogram calculation unit 3 scans the row image memory 2 in the X / Y-axis direction and obtains the X / Y values for only the line segments constituting the character entry frame in the image data.
A histogram of each black bit in the Y-axis direction is obtained.

Hereinafter, for simplicity of description, only processing performed on a frame in the Y-axis (vertical) direction of a character entry frame will be described with reference to the drawings. FIG. 3A is an enlarged view showing a part of the image data stored in the row image memory 2. The histogram calculation unit 3 scans this image data in the X-axis (horizontal) direction, and black bit strings 31, 32 in which the number of continuous black bits is equal to or less than a fixed value (here, 3 bits).
(A part surrounded by a square in the figure) is detected. Next, the histogram calculator 3 counts the number of black bits in the Y-axis (vertical) direction for each of the groups of the black bit strings 31 and 32 to obtain a histogram value shown in FIG. FIG. 2B is a histogram of the frame in the Y-axis (vertical) direction obtained from the entire image data of FIG. 2A in this manner.

Next, as shown in FIG. 3 (c), the frame line detecting section 4 sets the range of the histogram value in FIG. It is determined as a range in which a frame line in the (vertical) direction exists, and the information is sent to the frame line erasing unit 5. As a result, the frame line erasing unit 5 generates a black bit string 32 (enclosed by a square in the drawing) in which the number of black bits continuous in the X-axis (horizontal) direction within the line width range is equal to or less than a fixed value (here, 3 bits). Then, all of these black bits are converted to white bits to erase the character entry frame. Note that the same processing is performed for the frame line in the X-axis (horizontal) direction of the character entry frame, and is deleted. FIG. 2C shows image data obtained as a result of the above processing.

Thereafter, the image data from which the character entry frame has been erased is output to the character cutout recognition unit 6. The character cutout recognition unit 6 converts the image data that has only this character string into
Regardless of the character entry frame, the existence range of character image data is detected one character at a time by the free pitch method, cut out, and character recognition is performed to output character code data.

Thus, according to the optical character reading apparatus of this embodiment, by utilizing the fact that the line of the character entry frame is thinner than the line of the character, the character entry frame is selected from the entire form image including the character entry frame. Is detected and erased, and characters are cut out from the remaining image data by the free pitch method, so if the character entry frame is printed or dotted with dotted lines Also, even when the character entry frame and the character overlap, it is possible to accurately determine the position of the character entry frame and delete it,
Character reading errors can be further reduced.

[0016]

As described above, according to the optical character reading apparatus of the present invention, when the character entry frame is partially printed with a dotted line or is blurred, or when the character entry frame overlaps the character. In such a case, it is possible to accurately read the characters entered in the character entry box.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining an operation from storage of image data in a row image memory in FIG. 1 to erasing of a character entry frame from the image data.

FIG. 3 is a diagram for explaining an operation in the case of detecting a position of a line in a Y-axis direction of a character entry frame in the operation of FIG.

FIG. 4 is a diagram for explaining a conventional character entry frame detection method.

FIG. 5 is a diagram for explaining a problem of a conventional character entry frame detection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Image scanner 2 ... Row image memory 3 ... Histogram calculation part 4 ... Border line detection part 5 ... Border line deletion part 6 ... Character cutout recognition part

Claims (1)

(57) [Claims] 1. An image reading means for reading a character on a form on which a character entry frame for entering a character is printed as image data together with the character entry frame, and temporarily storing the image data read by the image reading means. an image data storing means for, detecting a black bit string equal to or less than a predetermined number of bits consecutive from the image data storage means is stored in the image data in a first axial direction, the first and the detected black bit string to the subject a histogram calculation means for calculating a histogram of the second axis direction orthogonal to the first axis direction, based on the histogram calculated by the histogram calculation unit, wherein the frame border constituting the character entry box
And borders position detecting means for detecting a position of the first axis direction of the second axial the printed border of the detected black bit string, a frame detected by the frame line position detecting means Erasing means for erasing black bits existing at the position of the line from the image data stored in the image data storing means; and an image stored in the image data storing means after the erasing means erases the black bits. An optical character reading device comprising: character extracting means for extracting image data one character at a time from data; and character recognizing means for recognizing characters from the image data extracted by the character extracting means.