JPS62128380A - Character-bar code reader - Google Patents

Abstract

PURPOSE:To attain sufficiently required character/bar code reading by using an image sensor comprising a bar code image forming section having a high picture element density and a character image forming section with a low picture element density. CONSTITUTION:The image sensor 4 consists of a bar code image forming section 41 having a high picture element density and a character image forming section 42 having a low picture element density, and a binary signal obtained from the bar code image forming section 41 through a binarization circuit 52 is sent to a bar code identification circuit 7, and a binary signal obtained from the character image forming section 42 through a binarization circuit 51 is sent to a character recognition circuit 6 respectively. Since either a bar code or a character is formed actually on the image sensor, the result of the recognition of each recognition circuit is fed to a selection circuit 8 and which is better is selected. Since the height of the entire image sensor is smaller than the image- formed bar code, the bar code is formed on the bar code identification section. Thus, the required and sufficient character and bar code reading are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention relates to a hand-held optical reading device that optically reads characters and bar codes.

(2) Prior art and its problems Conventionally, there are hand scan type OCRs and barcode readers. Conventional hand-held OCR is, for example, published in Japanese Patent Application Laid-Open No. 1986-
It is described in Publication No. 16138. FIG. 4 shows an example of a conventional hand-held OCR.

Characters are read by holding a hand scanner 21 in a hand 22 and moving it over a paper 23.

A light source 24 illuminates the paper 23 and forms an image of the reflected light onto an image sensor 26 via a lens system 25 .

The output signal of the image sensor 26 is amplified by the amplifier circuit 27, and the binarization circuit 28 converts it into "white" (2) paper) and "black" (character).
After dividing into binary values, the identification circuit 29 identifies the characters. Further, a device for reading both characters and bar codes is described in, for example, Japanese Patent Laid-Open No. 59-81766, and its configuration is shown in FIG.

21 to 29 are the same as those in FIG. 4, so their explanation will be omitted.

The identification circuit 29 identifies characters and the binarization circuit 28
There is an identification circuit 30 for identifying a barcode from the output signal of the identification circuit 29.3o, and a selection circuit 31 outputs the correct one as a reading result based on the identification result sent from the identification circuit 29.3o.

For character identification, any resolution that can detect the line width is sufficient, so the dimension corresponding to the line width may be one pixel. However, in the case of barcode identification, bar widths cannot be distinguished by one pixel corresponding to a narrow bar width. This relationship and corresponding means will be explained using FIG. 4. The bar 32 has a width a
s bar 33 C width Now b=2 a.

One pixel of the image sensor 34 shown in FIG.
wA is the same as a of bar 32, and the threshold for binarization is 50.
%. When scanning at the position shown in FIG. 6, the two pixel columns of cells 35 and 36 in the bar 82 are "black", and the two pixel columns of the cell 37 and 88 in the bar 38 are "black".
Although the bar widths of bar 82 and bar 33 are actually twice as different, the number of "black" pixels is the same after scanning, and the bar widths of bar 82 and bar 33 are treated as the same. For this reason - the barcode cannot be identified.

On the other hand, the pixel size of the image sensor is a thin bar (line width 1
If a resolution 2 to 4 times that of /4B) is obtained, but if the resolution is made even smaller, an excessive amount of information will be obtained during character identification.

Character identification involves preparing various basic patterns in advance and identifying the characters by repeatedly comparing the obtained patterns with the basic patterns.
Detects line width (approximately 1/2 am to 1/2 am for OCR characters),
It would be nice if it were possible, but if an excessive amount of information is obtained, the following problems will occur in processing.

(I) Since the amount of basic patterns must be increased according to the amount of input information, a huge storage capacity is required.

(n) Since the number of patterns of input information increases in accordance with the amount of information, the determination algorithm becomes complex and requires an enormous amount of time to develop.

(I) For the same reason, the processing time required to reach character recognition also becomes enormous.

(3) OBJECTS OF THE INVENTION An object of the present invention is to improve upon the drawbacks of the prior art and to provide a hand-held optical reading device for reading characters and barcodes that is capable of accurate and efficient recognition.

(4) Means and operation for solving the problems The structure of the present invention is shown in FIG.

The image sensor 4 consists of a barcode imaging section with high pixel density and a character imaging section with low pixel density.

The binary code obtained from the barcode imaging section through the binarization circuit 51 is sent to the barcode identification circuit.The binary code obtained from the character imaging section through the binarization circuit 52 is used for character identification. sent to each circuit. In reality, either the barcode or the characters are imaged on the image sensor, so the identification results of each identification circuit are sent to the selection circuit to select the correct one.

FIG. 2 shows the operation of the character barcode reading device of the present invention.

FIG. 2 (1) shows the case where characters are imaged on the image sensor. The character imaging section 42 has a size sufficient to image characters. FIG. 2 (11) shows the case where a barcode is similarly imaged. Since the height of the entire image sensor is smaller than the imaged barcode, the barcode is necessarily imaged also on the barcode identification section.

In the case of a barcode, since the information is the width of the bars or the white areas between the bars, it is sufficient for the barcode identification section to have one line in the horizontal direction, or even if more accurate, two or three lines at most. In addition, it is necessary to make the pixel density of the barcode identification part finer than that of the character imaging part, as shown in Figure 2 (11). This is clear from the fact that they cannot be distinguished and the lines are of the same width.

(5) Examples An embodiment of the present invention will be described based on FIG.

An embodiment of the image sensor used in the present invention Fig. 3 (1
). The upper two lines are for barcode imaging, and the lower 50 lines are for character imaging. Pixel density Q, 05 for barcode
Since ax is , o is for letters, and i is , the total height is 10
．． It becomes 2IulL.

In addition, there are 800 columns for barcodes and 400 columns for characters in the horizontal direction, and the density is the same both vertically and horizontally, so the total width is 400 columns.
It becomes IuL.

As shown in Figure 3 (G) using this image sensor, if an optical system is constructed to image barcodes and characters on paper at a magnification of 1/2, the pixel density (resolution) on paper will be Q, l tttx for barcode, 0.2r for text
It becomes ItX, and the field of view is l O, 211ILX 8
Qmx becomes.

The height of the barcode is approximately 18rIuIL or more, so
The field of view height in 10.2 is always included in this range, and the barcode can be reliably imaged on the barcode imaging unit. Also - the total width of the barcode row is 0.66u (maximum module width) x 113 (number of modules) = 7458
Since the total width of the character string is less than 4%54auc (standard character pitch) x 23 (maximum number of characters) = 58.4111L, it all fits within the visual field.

By using this image sensor and optical system, a necessary and sufficient character-barcode reading device can be realized.

(6) Effects of the Invention According to the present invention, there is provided a barcode convergence area with a high pixel density that has sufficient resolution for the width of the narrowest bar of a barcode for barcode identification, and a Since an image sensor composed of a character imaging section with sufficient resolution and a somewhat low pixel density is used, a necessary and sufficient character-barcode reading device is possible.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of the character-barcode reading device of the present invention, FIG. 2 (1) (n) is a diagram showing its operation, and FIG. 4 is a diagram illustrating an image sensor used as an embodiment of the invention; FIG. 4 is a diagram illustrating a conventional hand-held OCR; FIG. 5 is a diagram illustrating a conventional hand-held OCR; FIG. 6 is a diagram showing a conventionally used image sensor. In the figure, 41 is a barcode imaging section, and 42 is a character imaging section. No. 10 (1) Bunmuyoshi 4 elephants (11) Ha'°-Code! @Izo No. 20 Figure 3 Figure 6 Procedure Amendment ”! June 2, 1985 [I Director General of the Patent Office, Uga Michibu 1, 'J1 Display 1985 Patent Item No. 270156 Z Characters of the name of the invention - Barcode reader 3, person making the amendment, 1 [Relationship with the case Patent applicant's office
5-15 Kitahama, Higashi-ku, Osaka Name (2X3)
President of Sumitomo Electric Industries, Ltd. Satoshi Kawakami Department 4, Agent address: Inside Sumitomo Electric Industry Co., Ltd., 1-1-3 Shimaya, Konohana-ku, Osaka (-H story Osaka 4 G I I O, 'l l )6
, NY (7, Supplementary Contents (1) Specification 8, page 6, line 6 1" and 7?" between the eyes, Insert sentence. UFurthermore, image sensor design]-m can be considered.In other words, device characteristics 1-, reading and writing for one screen of the image sensor must be done within a certain amount of time or real-time performance will be lost. However, if you unnecessarily create pixels in an image sensor and increase the number of pixels, the reading time per pixel must be increased accordingly.This is due to the image sensor manufacturing process 1: This poses a major constraint and makes implementation difficult.For this reason, it is safe to use the dense part for barcodes and the sparse part for characters.1

Claims (7)

[Claims] (1) A hand-held optical reader that optically reads characters and barcodes using an image sensor consisting of multiple photoelectric conversion elements has sufficient resolution for the width of the narrowest bar of a barcode for barcode identification. A character image sensor comprising a barcode imaging section with a high pixel density and a character imaging section with a slightly low pixel density and having a necessary and sufficient resolution for character identification.
Barcode reader. (2) The barcode imaging section of the image sensor used is 1
One of the line sensors whose lines consist of hundreds of pixels or more
The character-barcode reading device according to claim 1, characterized in that the character-barcode reading device consists of one or several lines. (3) The character imaging section of the image sensor used has a size sufficient to fit at least one line of character strings on a price tag or the like into the field of view, as set forth in claim 1. character-barcode reader. (4) The character-barcode reading device according to claim 1, wherein the character imaging section of the image sensor used has a field of view in the height direction that is smaller than the minimum barcode height. (5) The character-barcode reading device according to claim 1, characterized in that the total height of the image sensor used is smaller than the entire height of the barcode within the field of view. (6) The binary signal obtained from the barcode imaging section is sent to the barcode identification circuit, the binary signal obtained from the character imaging section is sent to the character identification circuit, and the identification results of both identification circuits are sent to the selection circuit. , the character-barcode reading device according to claim 1, wherein the correct one is selected. (7) The binary signal obtained from the barcode imaging section is sent to the barcode identification circuit, and the binary signal obtained from the character imaging section is sent to the character identification circuit. The character-barcode identification device according to claim 1, further comprising a selection circuit that adopts any of the identification results.