JP3005729B2 - 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.

[0002]

2. Description of the Related Art In the reading of type characters in a conventional optical character reading apparatus, the character form of the character to be read is a character which is only sharp and has a sharp outline. It consisted only of the center axis detection mechanism.

[0003]

In the conventional character recognition mechanism, a character having a low print density (faint) is recognized because of the premise that the target characters are sharp and the outline is clear. Thus, there has been a problem that the standard character and the central axis are shifted, erroneous reading and unreading occur, and the recognition rate is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical character reading device which corrects the deviation of the center value of the character height of each character and controls unread and erroneous reading of low-quality print characters with low print density. .

[0005]

An optical character reading apparatus according to the present invention comprises a line center value detecting means for detecting a line center value of a recognition target area comprising a plurality of character groups to be read, and a recognition target area. The character center axis detecting means for detecting the upper limit value and the lower limit value of each character and calculating the central axis in the horizontal direction for reading a printed character. The line center value obtained is compared with the central axis of each character detected by the central axis detecting unit for each character, and when a shift occurs, the difference between the upper limit value and the lower limit value of the preceding and following characters is obtained. And a character position comparing and correcting means for comparing the center value of the character having the larger absolute value in the direction of the line center value by a half value of the absolute value. Recognize dignified print characters The features.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing an example of character-one detection. The optical character reading device of FIG. 1 includes a line center value detection mechanism 3 and a center axis detection mechanism 5 for a character to be read, and a character position before and after (upper limit,
(Lower limit) A comparison correction mechanism 6 is provided.

[0008] The figure on the form to be read is photoelectrically converted by the photoelectric conversion mechanism 1, and the figure information is developed in the page buffer 2. As shown in FIG. 2, the line center value detection mechanism 3 calculates the line center value, and transfers only the graphic information of the recognition target area 20 from the page buffer 2 to the line buffer 24. For each character image in the line buffer 4, the horizontal character position is obtained as shown in FIG. 3 by the central axis detection mechanism for each character.
1, 12, 13 and the lower limit positions are 14, 15, and 16.

Subsequently, when the difference between the center values 11 to 13 of the respective characters and the center value 17 of the line buffer are compared with each other by the front and rear character position comparing and correcting mechanism 6 and different from each other, as shown in FIG. The difference between the upper limit (8 and 9 or 10 and 9) or lower limit (14 and 15 or 16 and 15) of characters (4 and 5 or 6 and 5) is compared.
The center values 11 to 13 for each character are corrected to the side where the difference is expressed (upper limit for 4 and 5 and lower limit for 6 and 5) by half of the difference 18 or 19.

The center axis of the partially blurred character in the above operation is equal to the center value when the character outline is clear, and the determination mechanism 7 for performing character matching minimizes the deviation from the standard character form of the character matching dictionary. Can be suppressed.

[0011]

As described above, the present invention is provided with a front and rear character position comparison and correction mechanism for correcting a shift of the center of each character due to a faint character in addition to a line position detection mechanism and a center axis detection mechanism for each character. Thus, the center of the low-quality print type having a low print density is corrected, and the effect of minimizing unread and erroneous reading is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating a recognition target area of a page buffer according to the present embodiment.

FIG. 3 is a diagram illustrating central axis detection for each character according to the embodiment;

FIG. 4 is a diagram illustrating a character position comparison correction before and after the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoelectric conversion mechanism 2 Page buffer 3 Line position detection mechanism 4 Line buffer 5 Center axis detection mechanism for each character 6 Front and back character position comparison and correction mechanism 7 Judgment mechanism 8 Upper limit of first character 9 Upper limit of second character 10 Third character Upper limit value of 11 11 Center value of 1st character 12 Center value of 2nd character 13 Center value of 3rd character 14 Lower limit value of 1st character 15 Lower limit value of 2nd character 16 Lower limit value of 3rd character 17 Line center value 18 Upper limit difference 19 Lower limit difference 20 Recognition target area

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G06K 9/20 G06K 9/32 G06K 9/34

Claims (1)

(57) [Claims] A line center value detecting means for detecting a line center value of a recognition target area comprising a plurality of character groups to be read, and an upper limit value and a lower limit value of each character in the recognition target area. And a character-based central axis detecting means for detecting a center axis in the horizontal direction and detecting a printed character, wherein the line center value detected by the line center value detecting means and the character-based center are detected. Compare the center axis of each character detected by the axis detection means, and when there is a shift , the upper limit of the character before and after
The difference between the values and the lower limit is calculated, and the absolute value of the difference is calculated.
Are compared with each other, and the central axis of the character having the larger absolute value is
An optical character reading apparatus, comprising: a front-back character position comparison / correction unit that corrects a half value of the absolute value in the line center value direction, and recognizes low-quality printed characters with a light print density.