JP2900714B2 - Barcode detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for detecting a bar code from a signal input from an image input device in a mail automation device or the like.

[0002]

2. Description of the Related Art A bar code used in a postal automation system indicates information depending on whether or not bars having a uniform width are arranged at regular intervals (pitch) or not.

In this type of bar code detection system, an input signal of a fixed number of bits (hereinafter referred to as a new input signal) input by scanning the bar code from an image input device.
Is processed by the previously input signal (old input signal), and at the same time, the presence or absence of a bar code is determined.

A conventional technique will be described with reference to FIG. The new input signal input from the image input device is first divided into nine types of jump destinations according to the contents of the upper 4 bits of the old input signal, and the new input signal is processed by each jump destination.
As a processing method, when it is determined that there is a barcode because the barcode interval is constant, the position of the new input signal is masked to correct the signal deviation due to sampling deviation and ink scattering.

FIG. 6 shows an example of a processing method. In the example,
The 0th and 7th bits are forcibly set to "0" according to the old input signal
(No data) and the new input signal is registered as it is for the other bits. In the nine types of jump destinations divided by the upper 4 bits of the old input signal, each of the jump destinations is divided into the following four destinations (five types per one type) by the data of the lower 4 bits, and the new input signal is processed again. , The processed signal is registered as the old input signal, and at the same time, the presence / absence of the barcode is determined.

[0006]

In the conventional bar code detection system, the program configuration is complicated and a large number of branches occur in the program according to the input data. If the barcode becomes longer or shorter due to problems on the transport path or being printed on other models, it is very difficult and complicated to read those barcodes because a significant change in the program is required. .

[0007]

According to the bar code detection method of the present invention, a bar code printed by scanning a sheet is detected.
In the bar code reading method, scan on the paper
Input the binarized image obtained from the image input device, and check it first.
Predetermined bit based on the position of the issued bar
The data is based on the mask data that is the binarized image data of the range.
Search the on / off table and add the mask data
Repeat the detection of the presence / absence of the bar
A means for detecting the code. Even if the bar code pitch slightly changes, the bar existence position is periodic, so input data for detecting the next bar based on the bar detected first and input this data in advance. The information is converted into information on the next reference position and the presence / absence of a bar according to the set table, and the bar is similarly detected while shifting the reference position.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. First, the first embodiment will be described with reference to FIGS. 2 to 4 in accordance with the flow of FIG.

First, a bar code is read by a bar code reader and input as binary data (101). As shown in FIG. 4, the barcodes targeted by the present invention are such that bars having a single pitch are arranged in parallel, and information is indicated by the intervals between the bars. The bar code is scanned in a direction perpendicular to the bar, and is input as binary data indicating "0" where the bar is not "1" where the bar is. Particularly, in this embodiment, the timing is set so that three "1" s are input when one bar is scanned. By scanning the barcode, input data as shown in FIG. 4 is obtained. The input data includes an error at the time of input, has a slight variation in the bar interval, and includes noise indicated by N due to bar code contamination or the like.

Next, a start bit is detected, and mask data is created based on the start bit (10).
2). The start bit is checked from the beginning of the input data, and when two “1” s continue, the second “1” bit is set as the start bit. This start bit indicates the detection of the first bar of the bar code. In FIG. 4, the bit indicated by (1) is the start bit. Mask data is created using the start bit as a reference position. The mask data covers 8-bit input data from the fourth bit input data to the eleventh bit input data counted from the start bit.
In FIG. 4, input data in the range indicated by (2) is obtained as mask data. The number is represented in octal and indicates the number of bits from the reference position. Next, a data search is performed by referring to the table using the master data (10).
3). A specific example of this table is shown in FIG. This table has two numerical values for each value of the mask data. These two values are a value indicating the presence or absence of a bar (lower row) and a value indicating the position (upper row). The value indicating this position serves as a reference position for inputting the next mask data. The value of this position is shown in hexadecimal number in FIG.
It is indicated by a value in which only one bit becomes “1”. This "1" bit indicates the position in the mask data.
FIG. 3 shows this correspondence. In FIG. 4, the mask data of (2) is “00011100”.
Referring to the table of FIG. 2 with this value, the position is “08H”.
The presence or absence of a bar is "1", indicating that a bar is present.
That is, the presence of the bar is detected at the position where the number is “0”.

Then, the result is registered (104). At this stage, two bars are detected, including the start bit.

Then, it is checked whether or not all of the input data checks have been completed. If all of the checks have been completed, the process is terminated. If not, the process proceeds to the next mask data creation (106).

The creation of the next mask data is similarly performed based on the reference position obtained in the previous processing (106).
In the previous processing, since the bar is detected at the number “0”, the mask data is obtained from the input data of 8 bits from the fourth position after the position. This mask data is in the range of (3) in FIG. This mask data is “00111000”, and the position value “10H” and the bar existence “1” are obtained from the table. This position corresponds to the position of number 7. Hereinafter, the same processing is repeated. The mask data obtained next is the input data obtained in the range of (4) in the range of the fourth to eighth bits after the number 7 in (3). This mask data is all 0s. According to the table of FIG. 2, the position of this all 0 is 08
H indicates a bar. In the mask data in the next range (5), “1000011” with noise N at the beginning
0 "is obtained. This data has a position of 0 in the table.
2H indicates the presence of a bar. The noise N has been removed from the values in this table. By the above operation, the presence or absence of the bar is registered as 1, 1, 1, 0, 1, and it can be recognized that three bars are continuous and one bar is provided at one interval.

[0014]

As described above, the present invention can easily cope with long or short bar code pitches by using a table registration method based on the pitch between bar codes. The effect is that the program can be easily changed.

[Brief description of the drawings]

FIG. 1 is a flowchart of an embodiment of the present invention.

FIG. 2 is a table according to an embodiment of the present invention.

FIG. 3 is a view showing mask data according to the embodiment of the present invention.

FIG. 4 is a schematic diagram for explaining the operation in the flowchart of FIG. 1;

FIG. 5 is a flowchart of a conventional technique.

FIG. 6 is a schematic diagram of data processing according to the related art.

Claims (1)

(57) [Claims] In a bar code reading method for scanning a paper sheet and detecting a printed bar code, a binarized image obtained from an image input device that scans a paper surface is input, and the binarized image is detected first. Based on the bar position
Mask that is binary image data in a predetermined bit range
Data retrieving data on / off table based on the
Detection of presence / absence of bar and its position in mask data
A bar code detection method, comprising means for repeatedly detecting a bar code.