JPS62120585A - Bar code recognizing device by image scanner - Google Patents

Abstract

PURPOSE:To attain the highly accurate reading with a simple constitution by detecting width according to a decided result when black and white decided results in plural sampling areas are the same. CONSTITUTION:A bar code to be read is raster-scanned by an image scanner 1, converted into a binary black and white picture signal and stored in a picture memory 2. A shadowed part extraction part 3 extracts some part of the bar code picture stored in the memory 2 in the length direction and picture data in the sampling area. A black and white decision and width detection part 4 decides whether an extracted shadowed value is a black or white line, judges whether the shadowed width is a thin or thick line and finally recognized the bar code. A bar code decoding part 5 decodes width information from the detection part 4, and transmits it to a host system side.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a barcode recognition device that uses an image scanner to read barcodes, which are often used for managing products, and more particularly.

The present invention relates to a barcode recognition device that enables highly accurate recognition even in barcode images with degraded image quality by reducing the influence of noise.

[Secondary] U-branch - In general, many types of reading devices such as Ben type and optical type are used to read bar codes.

When using such a reading device, when a reading error occurs, by immediately rereading, accurate input processing becomes possible. However, with this type of reading device, there is a limit to the improvement in processing efficiency.

Therefore, when processing a large number of barcodes recorded on, for example, forms, conventionally, barcode recognition apparatuses that read barcodes using an image scanner have been used.

However, when processing a large number of barcodes using an image scanner, higher reading accuracy is required.

In a barcode recognition device using a conventional image scanner, a method of recognizing a barcode image by pattern matching or the like can be considered, but if such a recognition method is adopted, the device becomes expensive.

This causes an inconvenience.

Therefore, the barcode recognition device using an image scanner of the present invention solves the above-mentioned inconveniences in conventional barcode recognition devices, and focuses on the characteristics of barcodes as objects to be recognized.

It is an object of the present invention to provide a recognition device that can perform highly accurate reading by effectively utilizing the characteristics and using means with a relatively simple configuration.

(2) - One Precept To this end, the barcode recognition device using an image scanner of the present invention detects a sampling area from barcode image data read by an image scanner with respect to a sampling area set in advance in the longitudinal direction of the barcode. A diagonal shadow extraction means extracts the image data of and detects the number of black pixels in the length direction of this image data, and the number of black pixels from this diagonal shadow extraction means is input, and this number of black pixels is set at a predetermined threshold value. Consisting of a black and white determining means for determining black and white, a width detecting means for detecting the line width of an area determined as black by the black and white determining means, and a decoding means for decoding the line width detected by the width detecting means. I try to do that.

Further, the oblique shadow extraction means is configured to detect the number of black pixels in the length direction from a plurality of different sampling areas, and the black and white determination means is further provided with a comparison means for comparing the black and white determination results. When the black and white determination results for the plurality of sampling areas by the comparing means match, the determination result is sent to the width detecting means so that more accurate reading can be performed.

Next, a barcode recognition device using an image scanner according to the present invention will be explained with reference to the drawings.

One embodiment thereof will be described in detail.

FIG. 1 is a functional block diagram showing an embodiment of the main structure of a barcode recognition device using an image scanner according to the present invention. In the drawing, 1 is an image scanner (image reading device).

Reference numeral 2 indicates an image memory, 3 indicates a diagonal shadow extraction section, 4 indicates a monochrome determination and width detection section, and 5 indicates a barcode decoding section.

The barcode to be read is raster scanned by an image scanner 1 and converted into a black and white binary image signal.

The black and white binary image signal output from the image scanner 1 is temporarily stored in the image memory 2.

The oblique shadow extraction unit 3 extracts image data of a portion in the length direction of the barcode image stored in the image memory 2, that is, a sampling area (as described later, the length may be about several tens of dots).

In order to reduce the influence of noise, the black-and-white determination and width detection section 4 first determines whether the diagonal value extracted by the diagonal extraction section 3 is a white line or a black line using a predetermined threshold.

Next, the barcode is recognized by determining whether the width of the diagonal shadow is a thin line or a thick line.

Note that since three types of barcode widths are actually used, it is determined which one of them is used.

The barcode decoding section 5 decodes the width information given from the black and white determination and width detection section 4.

Convert it to character code etc. and send it to the host system side.

FIG. 2 is a diagram showing the relationship between an example of a barcode and the position at which the bar is read by the barcode recognition device using the image scanner of the present invention.

In the barcode recognition device using an image scanner of the present invention, as shown in FIG. 2, a sampling area of a predetermined width is set for the bar in advance. This sampling width may be about 5, for example, 20 to 30 dots.

FIG. 2 shows a case where three sampling areas are set. The reason why a plurality of sampling areas are set in this way is to more reliably eliminate the influence of noise that occurs in the read barcode image due to dirt on the bar or the like.

If a simple recognition method is sufficient, it is sufficient to set only one such sampling area. but,
In order to perform high-precision reading, it is necessary to
For example, if you set three sampling areas and
The reading result of the second sampling area is compared with the reading result of the second sampling area, and when the two match, black and white is determined based on the reading result.

If the two do not match, further compare the reading result of the third sampling area with the reading result of the first or second sampling area, and determine whether it is black or white based on the reading result when both match. I do.

In this way, by performing black and white determination processing for a plurality of sampling areas, barcode reading accuracy is significantly improved.

The following FIG. 3 shows the barcode recognition apparatus using the image scanner of the present invention shown in FIG.

FIG. 3 is a diagram for explaining the principle of a barcode identification method. In the drawings, w1 to w5 indicate line widths given to the black and white determination section, and W indicates a basic line width.

As already explained, the image data of the barcode read by the image scanner is stored in the image memory 2 shown in FIG.

In the barcode recognition device using an image scanner of the present invention, from the barcode image data stored in the image memory 2, 1, for example, 20
Data in a preset sampling area of about 30 dots is extracted.

Next, as shown in the lower part of FIG. 3, the number of black pixels of the bar is counted for this sampling width.

This is taken as a shading value (such processing is performed by the shading extraction unit 3 in FIG. 1).

Then, black and white is determined using a predetermined "threshold value" for this shading value. As the "threshold", for example, a value of about 172, which is the maximum value of the shading value, is used.

In the case of barcodes, black and white lines exist alternately, and the line width of the black and white lines is an integral multiple of the width of the most mended line.

Therefore, focusing on such characteristics, black and white may be determined first using a "threshold value" that is approximately half the maximum value of the shading value.

As a result of such processing, a part of the bar in the upper part of FIG. 3 shows. Noise caused by dirt such as circles is removed.

Next, the line width W 1 ''-W 5 is calculated for each black and white portion as shown in the lower part of FIG.

Then, the actual line width is recognized based on the calculated line widths W, ~w5.

The basic line width W is used to recognize the actual line width, and the determination is made based on the following conditions. Note that this basic line width W is a predetermined value and is an ideal value for a repair line. Specifically, this "threshold value" is (ideal value of thick line + ideal value of thin line) Xi/2.

For example, the actual line width is: ■ W when w<1.5W ■ 2W when 1,5W≦w<2.5W■ 2.5W:
When aw<3.5W, it is recognized based on the relationship of 3W (these processes are performed by the black and white determination and width detection unit 4 in FIG. 1).

Through such processing, the actual line widths of white and black are recognized, as shown in the bottom row of FIG. In the case of FIG. 3, the recognition is as follows: "black W, white W, black 2W, white W, black W".

Such recognition results are sent to the next barcode decoding section 5.
and converted to the corresponding character code.

By the way, as already explained, in order to perform high-precision processing of barcode image data, it is necessary to perform processing to determine whether the line is a white line or a black line at multiple locations, detect whether the determination results match, and then determine whether the line is a white line or a black line. If there is a difference, the next line width calculation process is performed based on the determination result, and if there is a mismatch, the same process of determining whether it is a white line or a black line is repeated until a match is made, further improving reading accuracy. be able to.

FIG. 4 is a diagram for explaining the principle of comparing image data of two sampling areas in the barcode recognition device using an image scanner of the present invention.

If the barcode has a lot of dirt, as shown in Figure 4,
When the image data of the first and second sampling areas are different, when the number of black pixels is detected as shown in the lower diagram of FIG. 3, there will be a discrepancy between the two detection results.

In this way, when a discrepancy occurs in the detection results, the image data of the third sampling area is further compared with the image data of the first or second sampling area,
Processing is performed to recognize the actual line width for the matched image data.

Since the number of lines of a read barcode is constant, a mismatch between the two means that a reading error has occurred in the image data of one of the sampling areas.

Therefore, through such processing, it is possible to prevent errors in recognizing the actual line width, and it is possible to perform highly accurate reading.

As explained in detail above, in the barcode recognition device using an image scanner of the present invention, the sampling area is determined from the barcode image data read by the image scanner with respect to the sampling area preset in the longitudinal direction of the barcode. A diagonal shadow extraction means extracts the image data of and detects the number of black pixels in the length direction of this image data, and the number of black pixels from this diagonal shadow extraction means is input, and this number of black pixels is set at a predetermined threshold value. Consisting of a black and white determining means for determining black and white, a width detecting means for detecting the line width of an area determined as black by the black and white determining means, and a decoding means for decoding the line width detected by the width detecting means. I try to do that.

Further, the oblique shadow extracting means is configured to detect the number of black pixels in the length direction from a plurality of different sampling areas, and the black and white determining means further includes:

By adding a comparison means for comparing black and white determination results, and when the comparison means matches the black and white determination results for multiple sampling areas, the determination results are sent to the width detection means, thereby achieving higher accuracy. It is configured so that it can be read.

Summer - Further Therefore, according to the barcode recognition device using an image scanner of the present invention, the influence of noise can be reduced and high-precision reading can be performed simply by using means with a relatively simple configuration.

In particular, if image data read in multiple sampling areas is processed, the reading accuracy can be sufficiently increased even in cases where isolated noise is likely to occur, such as with scanners that read documents by placing them on contact glass. I can do it. This excellent effect can be achieved.

[Brief explanation of drawings]

Hair ± 凰 is a functional block diagram showing an example of the essential configuration of a barcode recognition device using an image scanner of this invention, and IJL is a functional block diagram showing an example of a barcode and a barcode recognition device using an image scanner of this invention. 1 is a diagram for explaining the principle of the barcode identification method in the barcode recognition device using the image scanner of the present invention shown in FIG. FIG. 3 is a diagram for explaining the principle of comparing image data of two sampling areas in the barcode recognition device using an image scanner according to the present invention. In the drawings, 1 is an image scanner, 2 is an image memory, 3 is a diagonal shadow extraction section, 4 is a monochrome determination and width detection section, and 5 is a barcode decoding section. Patent Applicant: Ricoh Co., Ltd. - Patent Attorney: Toshitaka Kankawa 1. Figure 2. Figure 3. Figure 4. Threshold

Claims (1)

[Claims] 1. With respect to a sampling area set in advance in the length direction of the barcode, image data of the area is extracted from barcode image data read by an image scanner, and the length of the image data is a diagonal shadow extraction means for detecting the number of black pixels in the horizontal direction, and the number of black pixels from the diagonal shadow extraction means is input;
black and white determining means for determining the number of black pixels using a predetermined threshold; width detecting means for detecting the line width of an area determined as black by the black and white determining means; A barcode recognition device comprising: decoding means for decoding line width. 2. In the barcode recognition device using an image scanner as set forth in claim 1, the oblique shadow extraction means is configured to detect the number of black pixels in the length direction from a plurality of different sampling areas, and performs black and white determination. The means includes a comparison means for comparing the black and white judgment results, and when the black and white judgment results for the plurality of sampling areas by the comparison means match, the judgment result is sent to the width detection means. A barcode recognition device featuring: