JPH0962770A - Information reading method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately read the code information on such a matrix code that has a larger size than a reading window. SOLUTION: A matrix code includes the data areas at both sides of a center pattern and is read by a bar code reader. This reader has a two-dimensional image sensor 4 including a reading visual field area corresponding to a reading window 6 and a main circuit 5 which decodes the electric signals received from the sensor 4. The sensor 4 and the circuit 5 are contained in the main body 13 of the bar code reader that includes the window 6 prepared against the center pattern and a single area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of an information reading method and apparatus for optically decoding information by a two-dimensional image sensor.

[0002]

2. Description of the Related Art Compared to conventional one-dimensional bar codes that represent symbols such as numbers by arranging black and white rod-shaped rectangles,
A matrix code, in which cells with black and white squares as the minimum unit are arranged vertically and horizontally in a matrix, a so-called two-dimensional bar code, has a high information density. It was effective when printing the information code on.

Therefore, recently, there has been used an apparatus which uses this matrix code and which optically reads the matrix code so that an operator can easily operate it with one hand.

This kind of optical information reading device reads a matrix code by using a two-dimensional image sensor in which light receiving elements are arranged in a matrix, and if the matrix code is located in the reading field, it is related to the angle. Can be read without.

[0005]

The device for optically reading the matrix code using the conventional two-dimensional image sensor has the following problems.

A two-dimensional image sensor used for a matrix code reading device is, for example, a charge-coupled device (CCD) area sensor having the largest number of light receiving elements.
The number of light receiving elements is about 800 elements × 500 elements,
On the other hand, in order to read the matrix code, the number of light receiving elements is 5 elements × 5 elements for one cell of the minimum unit, so information reading having a light receiving element of 800 elements × 500 elements is required. In the case of equipment, maximum 10
It becomes possible to read the matrix code of 0 cell × 100 cell.

However, some matrix codes have more than 100 cells × 100 cells, and even if the number of cells is 100 cells × 100 cells or less, one cell has a large size. is there.

In the case of such a matrix code, since the area occupied by the code becomes large, there is a problem in that the entire code cannot be captured and read at once by the two-dimensional image sensor.

The present invention accurately reads information even in the case of a matrix code having a large number of cells and occupying a large area, and also in the case of a small area matrix code having large cells accumulating information at a high density. An object of the present invention is to provide an information reading method and device capable of reading.

[0010]

In order to solve the above problems, in the information reading method of the present invention, the data in one area of the matrix code divided into at least two areas is read and stored, and then the other area. After reading and storing the data in, the read and stored data are combined and decoded.

Further, the matrix code used has a center pattern and a data area, which are preferably formed by white square cells and black square cells, and the matrix code has a center pattern. It is effective that the data areas are located on both sides of, respectively.

Further, in order to solve the above-mentioned problems, in the information reading apparatus of the present invention, in the main body provided with a reading window having a size facing one area of the matrix code divided into at least two areas, It includes a two-dimensional image sensor and a circuit for decoding and processing an electric signal from the two-dimensional image sensor.

The reading window preferably has a size corresponding to the reading field area of the two-dimensional image sensor.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION When the information reading method of the present invention as described above is used for a hand-held two-dimensional bar code reader, for example, data areas are located on both sides of the center pattern and these areas are white. Using the matrix code formed by square cells and black square cells, the reading field area corresponds to the size of the reading window inside the main body with the reading window facing the center pattern and one area. A two-dimensional image sensor and a bar code reader having a built-in circuit for decoding and processing an electric signal from the two-dimensional image sensor are used, and the reading window is placed with the center pattern and one of the data areas facing each other. Is temporarily stored, and then the reading window is moved relative to the coding direction, The data read by facing the reading window to the target pattern and the other data area is also temporarily stored, and then the matrix code is decoded by combining the two data read and stored. Even if the size is larger than the reading window, the information can be accurately and easily decoded.

[0015]

EXAMPLE A case of the handheld two-dimensional bar code reader will be described in detail below as an example.

In FIG. 1, which shows a schematic diagram of the structure of a two-dimensional bar code reader, 1 is a matrix code 2 (see FIG.
An illumination light source for irradiating a label printed with (3) is a lens for forming an image at a predetermined position of reflected light obtained by reflecting the irradiation light from the illumination light source 1 by the label, and 4 is a matrix code 2 imaged by the lens 3. In the two-dimensional image sensor for converting the image of 1 to an electric signal, the number of image elements of the used two-dimensional image sensor is 764 elements × 568 elements. Reference numeral 5 is a main circuit that decodes information by the electric signal input from the two-dimensional image sensor 4 and controls the illumination light source 1.
Reference numeral 6 denotes a reading window having a size corresponding to the reading field of view of the two-dimensional image sensor 4, which is formed in the main body 13, and the main body 13 includes the illumination light source 1, the two-dimensional image sensor 4, and the main circuit 5. ing.

When reading information, the information is read in the reading window 6 of the two-dimensional bar code reader in proximity to the label on which the information to be read is printed and recorded as a matrix code.

The illumination light source 1 comprises a plurality of red diodes (L
The irradiation light formed by the ED) and emitted from the illumination light source 1 is reflected on the surface of the label on which the recording medium of the matrix code 2 located near the reading window 6 is present. The reflected light reflected on the surface of the label is read by the reading window 6
After passing through the lens, the light is condensed by the lens 3 and is incident on the two-dimensional image sensor 4 to form an image of the matrix code 2, and the light is converted into an electric signal corresponding to the code.

An example of the matrix code 2 will be described with reference to the schematic diagram shown in FIG. This matrix code 2
Is larger than the reading visual field area of the two-dimensional image sensor 4, and the code is formed by arranging white square cells 7 or black square cells 8 in a matrix in the vertical and horizontal directions. The matrix code 2 is divided into a center pattern portion 9 and data area portions 10 located on both sides of the center pattern portion 9. The center pattern portion 9 is provided for facilitating cutting out of the matrix code. The data area portion 10 is formed by the parallel bar portion and the rectangular portion formed by 8 and the upper portion 10a formed by the cells 7 and 8 and located above the center pattern portion 9.
And a lower region portion 10b located at the bottom, the white cell 7 represents 0 and the black cell 8 represents 1.

When reading the matrix code 2, the center pattern portion 9 and the upper area portion 1 of the data area portion 10 are read.
Area 11 of 0a and area 12 of center pattern portion 9 and lower area portion 10b of data area portion 10 are read separately.

Next, the operation of reading the matrix code 2 will be described with reference to the flow chart shown in FIG.

Reading window 6 of two-dimensional bar code reader
However, the two-dimensional bar code reader is pressed against the label so as to cover the area 11 of the matrix code 2 to perform the image capturing process (step 1), and the captured image is stored in the image memory. Next, the cutout process (step 2) is started. In this cutout process, the stored image is processed, and first, the center pattern portion 9 is detected.
The position of the data area portion 10 is obtained based on the position of the center pattern portion 9 and its direction (step 3). When it is determined from these detections that the area 11 exists within the reading field, the cell value of the upper area 10a of the data area 10 is obtained and the value is stored in the memory (step 4). These reading operations are completed immediately when the handheld two-dimensional barcode reader is applied to the area 11.

Next, the reading window 6 of the two-dimensional bar code reader is moved relatively from the area 11 in the encoding direction, and the two-dimensional bar code reader is pressed on the label so as to cover the area 12 of the matrix code 2. An image capturing process (step 5) is applied, and the image captured and read is stored in the image memory. The image capturing process while moving the two-dimensional barcode reader from the area 11 to the area 12 is repeated several times until the area 12 is detected. That is, the cutout process (step 6) is performed to process the stored image, the center pattern portion 9 is first detected, and the position of the data area portion 10 is obtained based on the position and direction of the center pattern portion 9. (Step 7).
If it is determined from these detections that the area 12 exists within the reading field of view, the lower area portion 10b of the data area portion 10 is
Cell value is determined and stored in memory (step 8).

Next, the data of the two cell values stored in steps 4 and 8 are combined (step 9), and an error is corrected in the combined cell value data (step 10). Converting the converted cell value data into a corresponding code string (step 1
Decoding is completed by 1).

[0025]

According to the present invention, by means of the means described above, information of a matrix code having a large size, or a matrix code having a small size but storing information at a high density and having a large cell size. The information can be read accurately.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating the configuration of a handheld two-dimensional bar code reader according to an embodiment of the present invention.

FIG. 2 is an explanatory schematic diagram of a matrix code used in the handheld two-dimensional barcode reader.

FIG. 3 is an operation flowchart of the handheld two-dimensional barcode reader.

[Explanation of symbols]

 2 matrix code 4 two-dimensional image sensor 5 main circuit 6 reading window 7, 8 cells 9 center pattern part 10 data area part 11, 12 area 13 main body

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[Procedure amendment]

[Submission date] December 20, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

The present invention has a large number of cells ,
For large matrix codes, and a small number of cells
And have a bur large cells have an object to provide a information reading method and apparatus which can accurately read information, even if the large matrix codes of external dimensions.

[Procedure amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction contents]

[0025]

According to the present invention, by the means as described above, information of a matrix code having a large number of cells and a large outer dimension , or a cell having a small number of cells but a large number can be obtained.
It is possible to accurately read even information of a matrix code having a large external dimension .

Claims (5)

[Claims] 1. Information for reading and storing data in one area of a matrix code divided into at least two areas, then reading and storing data in the other area, and synthesizing and decoding the read and stored data. How to read. 2. The information reading method according to claim 1, wherein the matrix code has a center pattern and a data area, and these are formed by white square cells and black square cells. 3. The matrix code has data areas located on both sides of the center pattern.
How to read the described information. 4. A two-dimensional image sensor and a decoding process of an electric signal from the two-dimensional image sensor in a main body provided with a reading window having a size facing one area of a matrix code divided into at least two areas. An information reading device with a built-in circuit. 5. The information reading device according to claim 4, wherein the reading window has a size corresponding to a reading field area of the two-dimensional image sensor.