JPH04205075A - Character reader - Google Patents

Abstract

PURPOSE:To detect an accurate character position and to improve character reading accuracy by providing a character reader with the function that if the width of a detected character is not width of one character, the width of the relevant detected character is separated or connected based on information of the immediately preceding and following characters to detect the accurate position of character. CONSTITUTION:For example, if dust is adhered between character '3' and character '7' of a character string printed as '29375', profile data 15a in the X direction of the character string is obtained, and the Y-direction position detecting processing is applied to the profile data 15a to obtain a Y-directional position 16a. Profile processing is applied to the character string to obtain Y-directional profile data 15b, 15c, 15d, and 15e in an area for Y-directional 16a. In the character width detecting processing, each character width 16b, 16c, 16d, or 16e is detected. Further, in the character width error discriminating processing, each character width is compared with a preset character width 16a, and if a character width 16d is judged abnormal, it is corrected. Thus, an accurate character position is detected, thereby being able to improve the character reading accuracy.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an industrial optical character reading device.

(Prior Art) Conventionally, industrial character reading devices have been used to read model numbers stamped or engraved on products flowing on a production line at manufacturing sites or the like. Many of the targets for reading industrial characters are strings of characters arranged horizontally in a single line, and the shapes of the characters are stable. However, the surface condition may be poor, such as engraved letters on the surface of castings, there may be no contrast between the letters and the background, or the position of the letters may fluctuate in model numbers produced by high-mix, low-volume production. Therefore, even if a single line is to be read, a method is adopted in which the entire screen is stored in a frame memory using an area sensor such as a television camera, and then the character area is detected and character recognition is performed.

FIG. 4 is a flowchart showing the reading procedure of a conventional character reading device. Reference numeral 1 denotes an input storage, which receives reflected light from a character string using an area sensor, converts the intensity of the light into a multi-gradation image signal, and stores the signal. 2 is a binarization process, in which multiple 111'lll image signals are compared with a certain threshold value and binarized to obtain a binarized image signal. 3 is character position detection, and the Y-direction range of the character string is determined from the X-direction profile data obtained by summing the values of the binarized image signal row by row in the X-direction. Similarly, the character width is detected from the X direction profile data. 4 is literary magazine 1! ! The glyph shapes corresponding to each detected character width are compared with a group of standard character images prepared in advance, and characters with high similarity are selected! ! ! I regret it.

FIG.

In character position detection 3, the range in the Y direction in which the character string is located is detected from the X direction profile data 5a of the value of the binary image signal. Y-direction profile data 5b in this Y-direction range.

The position of each character in the X direction is detected by finding the width of each character from 5c, 5d, 5e, and 5f.

(I! Problem to be solved by the invention) In general, stamped characters etc. on metal surfaces are in poor surface condition and may become faded or dirty. Even though such characters are recognizable to humans, conventional industrial character reading devices cannot obtain accurate profile data due to blurred, smudged, scratched, etc. characters. Therefore, there was a problem that the correct position of each character could not be detected from the profile data.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a character reading device that can detect the position of each character without being affected by blur, dirt, scratches, etc. of the characters to be read.

[Structure of the invention]

In order to achieve the above-mentioned objects, the present invention provides an image input means for receiving reflected light from a character string and outputting two-dimensional grayscale image data, and a binary-valued two-dimensional grayscale image data output from the image input means. Processing and converting binarized image data 2
a digitization processing means; a character string position detection means for detecting the Y direction range of a character string from the X direction profile data of the binarized image data output from the binarization processing means; Character width detection means detects the width of each character from the X direction profile data in the direction range, and each character is read by determining the degree of similarity between the character shape corresponding to the detected character width output by the character width detection means and the set character shape. In a character reading device having a character recognition means, the character width detected by the character width detection means is compared with the set character width, and if it is determined that the detected character width is larger, the detected character width is separated and the set character width is set. The present invention is characterized in that it includes a detected character width optimization means which, when determining that the detected character width is smaller than the detected character width, synthesizes the detected character width with the adjacent character width and outputs the result to the character recognition means.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

However, parts that overlap with Figure 4 are omitted.

FIG. 1 is a diagram showing the flow of character position detection 3 in a character reading device according to the present invention. 6 is X-direction profile processing, in which the values of the binarized image signals are summed row by row in the X-direction to obtain X-direction profile data. 7 is a character string position detection process in the Y direction, in which the Y direction position of the character string is detected from the X direction profile data. 8 is Y-direction profile processing, in which the values of the binarized image signals in the Y-direction range of the detected character string are summed row by row in the Y-direction to obtain X-direction profile data. 9 is character width detection processing;
The width of each character is detected by mechanically using the 0 part of the obtained X-direction profile data as a character break. 10 is character width abnormality determination, in which each detected character width is compared with a preset character width to determine whether there is any abnormality in the detected character width. Reference numeral 11 is character width size determination, in which when there is an abnormality in the detected character width, the detected character width is compared and determined with a preset character width. 12 is character width separation processing,
When the detected character width is larger than a preset character width, the detected character width is separated from the preceding and succeeding detected character widths and character pitch information, and each is made into the width of one character. 13 is a character width connection process, and if each successive detected character width is smaller than a preset character width, the successive detected character widths are connected based on the previous and succeeding normal detected character widths and character pitch information. to make the width one character. The character position detection 14 is thus completed by detecting the Y-direction position of the character string and the width of each character from the profile data.

The operation of the embodiment configured as above will be explained below.

As shown in FIG. 2, a case where dust is attached between "3" and "7" of the character string printed as "r 29375J" will be described. In character position detection 3, X-direction profile processing 6 obtains X-direction profile data 15a of the character string r29375J to be read. This X
In the character string Y direction position detection process 7, the character string Y direction position 16a is determined from the direction profile data] 5a.
In the Y-direction profile processing 8, the Y-direction position of this detected character string [Y-direction profile data 15b, 15c in the area 16a.

Find 15d and 1.5e.

Y direction profile data 15b, 15c, 15d,
From 15e, in the character width detection process 9, each character width 16b is determined.

16c, 16d, and 16e are detected. Then, in the character width abnormality determination 10, by comparing each of these detected character widths with a preset character width (equal to the character width 16b), it is determined that there is an abnormality in the detected character width 16d.

Next, in the character width size judgment 11, it is determined that the abnormal detected character width 16d is larger than a preset character width. Therefore, in character width separation processing 11, this detected character width 1
Based on the detected character widths 16c and 16e before and after 6d and the character pitch information, the detected character width 16d is determined as character width 16d, ]6d
Separate into 2.

Detecting the position of one character in the above steps 9 Next, as shown in the third step, the character string "r 29375J" is printed.
7" is faint. In character position detection 3, character string r 29 in X direction profile processing 6
375'' is obtained, and in character string Y direction position detection processing 7, the Y direction position of the character string ], 8a is obtained from this X direction profile data. Further, in the Y-direction profile processing 8, Y-direction profile data 17b, 17c in the region of the Y-direction position 18a of this detected character string.

Find 17d, 17e, 17f, and 17g. In character width detection processing 9, Y direction profile data 17b,
17c, 17d.

From 17e, 17f, 17g, each character width is 18b, 1
8c, 18d, 18e.

Detects 18f and 18g. Character width abnormality judgment 10 detects that the detected character widths 18e and 18f are abnormal, and character width size judgment 11 detects that the detected character widths 17e and 17f are abnormal.
is smaller than a preset character width.

Therefore, in the character width connecting process [3], the detected character widths 18d and 18g before and after this detected character width group 18e and 18f are
Based on the character pitch information, the detected character widths 18e and 18f are connected to obtain a character width of 18ef. In this way, character positions are detected.

According to this embodiment, even if the character string to be read is blurred, scratched, etc., it is possible to detect the correct character position.

〔Effect of the invention〕

As described above, according to the present invention, it is evaluated whether the detected character width is the width of one character, and if it is not the width of one character, the detected character width is separated from the preceding and succeeding character information or the character width is increased by connecting the detected character width. Optimize and detect. Therefore, even if the character string has scratches, dirt, or blur, the character width will not be detected incorrectly or cannot be detected, and the character position can be detected accurately. This makes it possible to accurately determine the character shape corresponding to one character position, and provides a character reading device with high character reading accuracy.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the character position detection process in an embodiment of the present invention, and FIG. 2 shows an image of a character string with dirt on the reading target and its X-direction and Y-direction profile data in the embodiment. 3 is a diagram showing an image of a blurred character string to be read and its X-direction and Y-direction profile data in an embodiment, FIG. 4 is a flowchart showing the steps of a conventional character reading device, FIG. 5 is a diagram showing an image of a character string to be read and its X-direction and Y-direction profile data. 1... Input storage, 2... Binarization processing, 3
...Character position detection, 4...Character recognition, 5a...
・X direction profile data, 5b, 5c, 5d, 5e, 5f-Y direction profile data, 6...X direction profile processing, 7...Y direction position detection processing of character string, 8...Y direction profile process. 9...Character width detection processing, 10...Character width abnormality determination,
11...Character width size judgment, 12...Character width separation processing, 13...Character width connection processing, 14...Character position detection end, ]58...X direction profile data, 15b, 15
c, 15d, 15e=Y direction profile data, 1
6a...Y direction position of character string, 16b, 16c, 16d, 16e, 16d, .
16d, -character width, 17a...X direction profile data, 17b, 17C, 17d, 17e, 17f
, 17g...Y direction profile data, 18a...Y direction position of character string. 18b, 18c, 18d, 18e, 18f,
18g, 18ef・=character width. Agent Patent Attorney Noriyuki ChikaFigure 1Figure 2Figure 3

Claims (1)

[Claims] Image input means for receiving reflected light from a character string and outputting two-dimensional grayscale image data; and two-dimensional grayscale image data output from the image input means.
Binarization processing means that performs digitization processing and outputs binarized image data, and detects the Y-direction range of the character string from the X-direction profile data of the binarized image data output from the binarization processing means. character string position detection means for detecting the width of each character from Y-direction profile data in the Y-direction range of the binarized image data; In a character reading device that has a character recognition means that reads each character by determining the degree of similarity between set character shapes, the character width detected by the character width detection means is compared with the set character width, and the detected character width is determined to be larger. If the detected character width is determined to be larger, the detected character width is separated, and if the detected character width is determined to be smaller, the detected character width is combined with the adjacent character width and outputted to the character recognition means. A character reading device characterized by: