JPH09297807A - Device and method for reading bar code - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the bar code reading device which does not reflect the influence of changes in a state such as staining and blurring of a bar code on its reading process as much as possible. SOLUTION: When the bar code is irradiated with light from a light source 111 and the lightness of its reflected light is read by a CCD 112, an A/D conversion part 113 quantizes the read lightness with a gray scale consisting of a specific number of gradations and stores the quantized data in an image memory 12. Further a discrimination part 13 binarizes the stored lightness of the reflected light according to a specific rule and discriminates the array pattern of the bar code from the lightness of the binarized reflected light. Then a data conversion part 14 converts the array pattern of the bar code discriminated by the discrimination part 13 into code data. Consequently, a read permissible range can be expanded corresponding to changes in state such as the staining and blurring of the bar code.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a reading surface on which, for example, a bar code is printed, with light, and changes the light amount (brightness (shade)) of the reflected light by a CCD (Charge Co
The present invention relates to a bar code reading device and a bar code reading method for reading an array device such as an up-sized device) to identify the arrangement pattern of the bar code. The present invention relates to a bar code reading device capable of minimizing an obstacle caused by a change in the state of a bar code such as fading.

[0002]

2. Description of the Related Art There has been a remarkable spread of computer systems in recent years, and with this spread, the types of data to be handled have been diversified, and the amount thereof has become enormous and tends to increase. It is in.

In such an information-oriented society, the effort spent for data input cannot be ignored,
Thorough labor saving is being made every day. Then, as one that contributes to the labor saving of such data input work, there is a data input process using a barcode.

This bar code is, for example, POS (Po
Int Of Sales (point-of-sale information management) and other sales information management systems at retail stores, as well as inventory management systems, order management systems, and production management systems in the production and distribution industries. As shown in FIG. 7, various types of information are expressed by arranging mainly white and black stripe patterns at different intervals. A bar configured in either white or black is distinguished by its thickness. A thin bar is called a narrow bar (21a, 22a) and a thick bar is called a wide bar (21b, 22b). The narrow bars (21a, 22a) and the wide bars (21b, 22a)
The information represented by the arrangement of b) is read by a bar code reader, converted into a code indicating alphanumeric characters, and delivered to a main body device such as a personal computer.

Bar code readers include, for example, a light source and a CC.
A scanner having D and the like is provided, and this scanner irradiates a bar code with light, reads the brightness (shade) of the reflected light with a CCD, and quantizes the binary value to output. Then, the barcode array pattern is identified from the output data from the scanner, and the identified array pattern is converted into code data.

Here, the lightness means the amount of reflected light. When the amount of light is large, the part irradiated with the light is a whiter part, and when the amount of light is small, the part irradiated with the light is a blacker part. Therefore, if the amount of light is large, the part irradiated with the light is expressed as “light”, and if the amount of light is small, the part irradiated with the light is expressed as “dark”.

With this, the user can input various information such as the type and price of the product in the same format as the input from the keyboard only by causing the barcode reader to read the barcode.

FIG. 8 shows one principle of binarization of a bar code reader. When irradiating a bar code with light and reading the lightness (shade) of the reflected light with a CCD, if the bar code is in a normal state, the peaks of the appearance frequency are at relatively deep ends of (dark) and (light). It should appear prominently. Therefore, normally, in a barcode reader, a threshold value 23a for determining white and a threshold value 23b for determining black are set, and reading is performed based on these threshold values 23a and 23b. .

However, according to such a principle, there is a problem that the reading becomes impossible or the reading becomes erroneous in the following cases. (1) When the reading surface is soiled In this case, as shown in FIG. 9, for example, the frequency of appearance of the range to be determined as white decreases, and a new peak 24 due to soiling appears instead. And this new peak 24
When the lightness in which the symbol appears appears exceeds the threshold value 23a, which is supposed to be contained, a failure such as unreadable or erroneous reading occurs. (2) When the barcode itself is faint In this case, contrary to (1), as shown in FIG. 10, for example, the frequency of appearance of the range that should be judged as black decreases, and instead the new appearance due to fading occurs. Peak 25 appears. If the brightness of the new peak 25 exceeds the threshold value 23b that should be contained, a failure such as unreadable or erroneous reading occurs. In addition, it is highly conceivable that such a state may occur not only in faintness, but also when a barcode is printed by a printer having a low definition such as a dot printer.

As described above, when the bar code reader determines that the bar code cannot be read (rejected) depending on the state of the bar code itself, the user must re-input through the keyboard or the like. Further, when misreading occurs, there is a problem that it is not only a temporary effort to correct only that information, but also a large-scale correction work is inevitable in some cases.

[0011]

As described above, in the past, when the light was applied to the bar code and the lightness of the reflected light was taken in, the bar code was printed by being quantized by two values. It is very vulnerable to changes in the status itself, such as the read surface being smeared or the bar code itself being faint, and it is impossible to read or misread due to such a change in the status. This frequently occurs, resulting in a re-entry process and a user's task of correcting information.

The present invention has been made in view of the above circumstances, and provides a bar code reading apparatus and a bar code reading method that do not affect the reading process as much as possible by the influence of dirt or blurring of the bar code. The purpose is to

[0013]

According to the present invention, there is provided a bar code reading apparatus which identifies a bar code array pattern by irradiating a bar code to be read with light and reading the brightness of the reflected light. A capturing means for capturing the brightness of the reflected light in a gray scale consisting of a predetermined number of gradations; and a binarizing means for binarizing the brightness of the reflected light captured in the gray scale by the capturing means according to a predetermined rule. , Identifying means for identifying the barcode array pattern from the brightness of the reflected light binarized by the binarizing means, and data for converting the barcode array pattern identified by the identifying means into code data It is equipped with a conversion means, and it is possible to expand the allowable reading range for changes in the status such as dirt and blur of the barcode. And butterflies.

In the present invention, when the bar code is irradiated with light and the brightness of the reflected light is captured, it is not binarized such as white or black but captured.
For example, the brightness is captured as a gray scale having 16 gradations. Then, the brightness of the reflected light thus captured is binarized by the binarizing means according to a predetermined rule.

This binarization is performed, for example, by calculating a distribution of the brightness of the reflected light from the barcode to be read and analyzing the calculated distribution.
It is possible to correct stains and blurring in a considerable range, and it is possible to greatly expand the readable permissible range for the state.

Further, according to the present invention, in a bar code reading apparatus for illuminating a bar code to be read and reading the brightness of the reflected light to identify the array pattern of the bar code, an image memory and the bar code reader are provided. Capture means for binarizing the brightness of reflected light and storing it in the image memory, and rectangular area detecting means for detecting a rectangular area formed by either one of the binarized data stored in the image memory, Identification means for identifying the array pattern of the rectangular areas detected by the rectangular area detection means,
Data conversion means for converting the array pattern of the rectangular area identified by the identification means into code data, and it is possible to expand the allowable reading range with respect to changes in the state such as dirt and blur of the barcode. Characterize.

In the present invention, when the bar code is irradiated with light and the brightness of the reflected light is captured, the binarized data is stored in the image memory, and then one of the binarized data, for example, black is used. The rectangular area to be detected.

Then, the data conversion means performs code conversion on the detected array pattern of the rectangular area. As a result, local stains and blurring do not affect the entire reading process, and the reliability can be dramatically improved. Further, if the lightness of the reflected light at this time is captured in gray scale as described above, and then the rectangular area is detected after binarization, the reliability can be further improved.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) • Capture of Reflected Light by Gray Scale First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 shows a schematic configuration of a bar code reader according to this embodiment. As shown in FIG. 1, the barcode reader 1 of this embodiment includes a control unit 10, a scanner 11, an image memory 12, an identification unit 13, and a data conversion unit 14.

The control unit 10 controls the bar code reader 1 as a whole. The scanner 11 includes a light source 111 for irradiating a bar code to be read with light, a CCD 112 for capturing the brightness of reflected light for this irradiation, and a C
An analog / digital conversion unit (A / D conversion unit) 113 that quantizes the brightness captured by the CD 112 with a gray scale having a predetermined number of gradations (for example, 16 gradations), and reads a barcode from the control unit 10. Is instructed, the light source 111 irradiates the barcode with light, the CCD 112 captures the brightness of the reflected light, and the A / D conversion unit 113 quantizes the information in gray scale.

The image memory 12 is the scanner 11
Holds the quantized information captured by. The identification unit 13 binarizes the information stored in the image memory 12 (brightness of reflected light quantized in gray scale) based on, for example, its distribution, and based on this binarized information, an array pattern of barcodes. Identify. Then, the data conversion unit 14 converts the array pattern of the barcode identified by the identification unit 13 into code data such as alphanumeric characters and outputs it.

The operation procedure of this embodiment will be described with reference to FIG. When reading the barcode printed on the reading surface, the scanner 11 of the barcode reader 1 uses the light source 11
The bar code is irradiated with light by 1, and the brightness of the reflected light is captured by the CCD 112, and the information is captured by the A / D converter 11
3 is quantized with a gray scale having a predetermined number of gradations (step A1).

This quantized information is stored in the image memory 1
2 and the stored information is binarized by the identification unit 13 according to a predetermined rule (step A).
2). This binarization is performed, for example, by calculating a grayscale distribution, analyzing the calculated distribution, and setting a threshold value at an appropriate location. Then, the identification unit 13 further identifies the array pattern of the barcode from the binarized data (step A3).

Then, the data conversion unit 14 converts the array pattern of the bar code identified by the identification unit 13 into code data such as alphanumeric characters (step A4), and the converted data is the main body of a personal computer or the like. Output to the device (step A5).

As a result, even if the bar code itself is faint as shown in FIG. 3A (in this example, the fading amount is large in the order of 15a <15b <15c), it is captured. The reflected light is not immediately binarized, but is once captured in gray scale and is binarized in consideration of the tendency. Therefore, correction can be performed as shown in FIG. The information indicated by the code can be read more accurately.

(Second Embodiment) Identification of Bar Code Array Pattern by Detecting Rectangular Area Next, referring to FIGS. 1, 4 and 5, the second embodiment of the present invention will be described.
An embodiment will be described. The configuration is the same as that of the first embodiment, but the A / D conversion unit 113 of the scanner 11 and the identification unit 13 are
Perform operations different from those in the first embodiment.

The A / D converter 113 of the scanner 11 according to this embodiment is similar to the conventional scanner 11 in that the CCD 112 is used.
The brightness of the reflected light captured by is quantized by a binary value. on the other hand,
The identification unit 13 scans the image memory 12 to detect a rectangular area formed by one (for example, black) of the binarized data, and further identifies the array pattern of the detected rectangular area.

For example, it is assumed that the scanner 11 binarizes a bar code as shown in FIG. In this case, in the conventional case, when the lines of 16a and 16b are adopted as the sample, the information can be normally read, but when the line of 16c is adopted as the sample, an error is likely to occur. Is extremely high.

On the other hand, in the bar code reader 1 of the present embodiment, the identification unit 13 detects the rectangular area 17 from the captured binarized data, as shown in FIG. 4 (b).
Then, the identifying unit 13 identifies the detected array pattern of the rectangular areas 17 (1 in FIG. 4B).
8).

Therefore, it is possible to prevent the stain on a part of the bar code from adversely affecting the entire reading process, and it is possible to dramatically improve the reliability of the reading process.

Now, the operation procedure of this embodiment will be described with reference to FIG. When reading the barcode printed on the reading surface, the scanner 11 of the barcode reader 1
The barcode is irradiated with light from the light source 111, the brightness of the reflected light is captured by the CCD 112, and the information is quantized by the A / D converter 113 in binary (step B1).

This quantized information is stored in the image memory 1
2, the identification unit 13 scans the image memory 12 to detect a rectangular area formed by one of the binarized data (for example, black) (step B).
2). Then, the identification unit 13 further identifies the detected array pattern of the rectangular area (step B3).

Then, the data conversion unit 14 converts the array pattern of the rectangular area identified by the identification unit 13 into code data such as alphanumeric characters (step B4), and the converted data is the main body of a personal computer or the like. Output to the device (step B5).

(Third Embodiment) As a third embodiment, an embodiment in which the first and second embodiments are combined will be described with reference to FIGS. 1 and 6.

That is, in this embodiment, the A / D converter 113 quantizes the brightness of the reflected light captured by the CCD 112 with a gray scale. Then, the identification unit 13 binarizes the grayscale-quantized information according to a predetermined rule, detects a rectangular area formed by one (for example, black) of the binarized data, and further detects this. Identify the array pattern of the rectangular area.

Therefore, in the present embodiment, more appropriate binarization is performed, and there is no influence of local stains, so that the reliability can be dramatically improved.

Next, the operation procedure of this embodiment will be described with reference to FIG. When reading the barcode printed on the reading surface, in the barcode reader 1, the scanner 11 irradiates the barcode with light from the light source 111, captures the brightness of the reflected light with the CCD 112, and A / D converts the information. The unit 113 quantizes with a gray scale having a predetermined number of gradations (step C1).

This quantized information is stored in the image memory 1
2 and the stored information is binarized by the identification unit 13 according to a predetermined rule (step C
2). Next, the identification unit 13 detects a rectangular area formed by one of the binarized data (for example, black) (step C3). Then, the identification unit 13 further identifies the array pattern of the detected rectangular area (step C
4).

Then, the data conversion unit 14 converts the array pattern of the bar code identified by the identification unit 13 into code data such as alphanumeric characters (step C5), and the converted data is the main body of a personal computer or the like. Output to the device (step C6). As a result, it becomes possible to execute the reading process corresponding to the change of the state such as the stain or the blur of the barcode.

[0040]

As described above in detail, according to the present invention, when the bar code is irradiated with light and the brightness of the reflected light is captured, the barcode is not immediately captured as the binarized data but a predetermined number. Since it is captured as a gray scale consisting of gradations of, for example, binarization is performed according to its distribution,
The reading process according to the state of the bar code can be performed, and the occurrence of erroneous reading due to the change of the state of the bar code can be prevented as much as possible, and the reliability thereof can be improved.

Further, since the rectangular area is detected from the binarized data thus captured and the code conversion is performed from the array pattern of the detected rectangular area, for example, the influence of local stains on the bar code is read out. It is possible to prevent the effect on the whole.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a barcode reader according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation procedure of the first embodiment of the present invention.

FIG. 3 is a conceptual diagram for explaining binarization of the first embodiment.

FIG. 4 is a conceptual diagram for explaining binarization according to the second embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation procedure of the second embodiment.

FIG. 6 is a flowchart illustrating an operation procedure of the third embodiment of the present invention.

FIG. 7 is a diagram for explaining the configuration of a barcode.

FIG. 8 is a distribution diagram of the brightness of reflected light for explaining the principle of reading a barcode.

FIG. 9 is a distribution diagram of the brightness of reflected light for explaining a reading obstacle due to stains on a barcode.

FIG. 10 is a distribution diagram of the brightness of reflected light for explaining a reading failure due to a blur of a barcode.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bar code reader, 10 ... Control part, 11 ... Scanner, 12 ... Image memory, 13 ... Identification part, 14 ... Data conversion part, 111 ... Light source, 112 ... CCD, 113 ... A
/ D converter.

Claims (5)

[Claims] 1. A bar code reading apparatus for identifying the array pattern of the bar code by irradiating the bar code to be read with light and reading the brightness of the reflected light, wherein the brightness of the reflected light is a predetermined number. A capturing unit that captures a gray scale composed of gradations, a binarizing unit that binarizes the brightness of the reflected light captured by the capturing unit in the gray scale according to a predetermined rule, and a binarizing unit An identification means for identifying the array pattern of the barcode from the brightness of the reflected light that has been binarized; and a data conversion means for converting the array pattern of the barcode identified by the identification means into code data, Bar code reading characterized by being able to expand the allowable reading range for changes in the status such as dirt or scratches on the bar code Ri apparatus. 2. A bar code reading device for recognizing an array pattern of the bar code by irradiating a bar code to be read with light and reading the brightness of the reflected light, the image memory and the brightness of the reflected light. A binarizing unit for binarizing and storing the binarized region in the image memory; a rectangular region detecting unit for detecting a rectangular region formed by one of the binarized data stored in the image memory; An identification means for identifying the array pattern of the rectangular area detected by the means; and a data conversion means for converting the array pattern of the rectangular area identified by the identification means into code data. A bar code reading device characterized by being able to expand the allowable reading range for changes in conditions such as faintness Place. 3. A bar code reading apparatus for illuminating a bar code to be read and reading the brightness of the reflected light to identify the array pattern of the bar code, wherein an image memory and the brightness of the reflected light are provided. With a grayscale consisting of a predetermined number of gradations, and a binarization for binarizing the brightness of the reflected light captured with the grayscale by this capturing means according to a predetermined rule and storing it in the image memory. Means, a rectangular area detecting means for detecting a rectangular area formed by one of the binarized data stored in the image memory, and an array pattern of the rectangular areas detected by the rectangular area detecting means. Identification means and data conversion means for converting the array pattern of the rectangular areas identified by the identification means into code data A bar code reading apparatus comprising: a bar code reading apparatus capable of expanding a reading allowable range with respect to a change in a state such as dirt or blur of the bar code. 4. A bar code reading method for illuminating a bar code to be read and reading the brightness of the reflected light to identify the array pattern of the bar code, wherein the brightness of the reflected light is a predetermined number. Captured with a gray scale consisting of gradation, binarize the brightness of the reflected light captured with this gray scale according to a predetermined rule, and identify the array pattern of the barcode from the binarized brightness of the reflected light, A barcode reading method, characterized in that the identified array pattern of the barcodes is converted into code data. 5. A bar code reading method for illuminating a bar code to be read and reading the brightness of the reflected light to identify the array pattern of the bar code, wherein the brightness of the reflected light is binarized. Stored in the image memory, the rectangular area formed by one of the binarized data stored in the image memory is detected, the array pattern of the detected rectangular area is identified, and the identified rectangular area A barcode reading method, characterized in that the array pattern of the above is converted into code data.