JP3711775B2 - Bar code reader and program recording medium thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a barcode reader and a program recording medium for reading barcode information by irradiating light on a barcode and receiving reflected light.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, in a laser scanning bar code reader, a laser scanning mirror (vibration mirror or polygon mirror) is driven to reflect a laser beam so that a bar code to be scanned is optically scanned. In this case, the scanning range in which the laser scanning mirror performs one scanning is the laser irradiation range. Here, as a technique for controlling the laser irradiation range (scanning width), various methods are known. That is, a method of controlling the exit width of the laser scanner using a physical or optical shutter device, a method of physically deforming (curving) the mirror while the flexible mirror is moving, and a laser refraction A method of changing the rate with a liquid crystal device is known.
[0003]
[Problems to be solved by the invention]
As described above, although the irradiation range can be controlled conventionally, it is extremely difficult to appropriately control the irradiation range each time according to the distance between the barcode to be scanned and the scanner and the barcode size. If there is dust near the barcode to be scanned or other barcodes are adjacent, they are read at the same time. For this reason, there has been a risk of causing a reduction in work efficiency such as occurrence of a reading error or reading of another barcode which is not a scan target.
An object of the present invention is to reliably irradiate only a portion where a barcode to be read actually exists by controlling a light irradiation range according to a region where the barcode exists.
[0004]
[Means for Solving the Problems]
Means of the present invention are as follows.
When the reading operation is performed with the light irradiation range being maximized, it is analyzed whether or not there is a predetermined change in the received reflected light, and a region where a barcode exists is recognized based on the analysis result. Recognition means, a first adjustment means for roughly adjusting the light irradiation range in accordance with the area recognized by the first recognition means, and a rough light irradiation range adjusted by the first adjustment means. A second recognizing unit that decodes the reading result when the reading operation is performed, and recognizes an area where the bar code exists based on whether or not the decoding result is a normal bar code; And a second adjustment unit that finely adjusts the light irradiation range according to the area recognized by the second recognition unit.
Therefore, by irradiating the area where the barcode to be read exists, it is possible to realize prevention of erroneous reading, improvement of processing speed, power reduction, and the like.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the overall configuration of a laser scanning bar code reader. This bar code reader is a handy type, controls the operation of the laser scanning bar code scanner unit (laser unit) 1 and the laser unit 1 and takes in the bar code image transferred from the laser unit 1. It comprises a main body system 2 for analysis and storage.
FIG. 2 is an overall configuration diagram of the laser unit 1. When power is turned on on the main system 2 side, the power ON / OFF signal POWER signal from the main system 2 is applied to the power supply 1-1 on the laser unit 1. Drive voltage is supplied to each of the laser irradiation control device 1-2, the scanning mirror control device 1-3, the scanning timing detection device 1-4, the light reception analysis device 1-5, and the laser light reception device 1-6 constituting the laser unit 1. And make them work. Here, when the laser irradiation ON / OFF signal LASER signal is given to the laser irradiation control device 1-2 from the main system 2 side, the laser irradiation control device 1-2 drives the laser irradiation device 1-7 to perform laser irradiation. At this time, the laser scanning mirror 1-8 (vibration mirror or polygon mirror) is driven by the scanning mirror control device 1-3, and reflects the laser beam from the laser irradiation device 1-7 to scan the laser beam. Scan the bar code. When the laser scanning is started in this way, the laser light receiving device 1-6 receives the laser reflected light and performs photoelectric conversion, and the light receiving analysis device 1-5 binarizes the black and white image of the barcode according to the scanning speed. Is transferred to the main system 2 as a barcode image signal IMAGE signal. At this time, the scanning timing detection device 1-4 detects a specific position of the scanning mirror 1-8, outputs a digital signal by a pulse or signal inversion as a scanning timing signal TIMING signal for each scanning, and gives it to the main system 2.
[0006]
The main system 2 has the CPU 2-1 as the core, and the CPU 2-1 is a central processing unit that controls the overall operation of the main system 2 according to various programs. The storage device 2-2 includes a storage medium 2-3 in which an operating system, various application programs, a database, character font data, and the like are stored in advance, and a drive system thereof. This storage medium 2-3 is fixedly mounted or detachably mountable, and is composed of a magnetic or optical storage medium such as a floppy disk, hard disk, optical disk, RAM card, or semiconductor memory. Yes. Further, programs and data in the storage medium 2-3 are loaded into the RAM 2-4 as required by the control of the CPU 2-1. Further, the CPU 2-1 receives a program and data transmitted from another device side via a communication line or the like and stores them in the storage medium 2-3 or a storage medium provided on the other device side. It is also possible to use programs and data stored in the communication line or the like. The CPU 2-1 is connected to the laser unit 1, the input device 2-5, and the display device 2-6, which are input / output peripheral devices, via a bus line. To control the operation. When the scanning timing signal TIMING that is inverted every time one scanning is completed is given from the laser unit 1, the CPU 2-1 determines the completion of one scanning based on the change of the rising and falling edges, and also performs one scanning from the laser unit 1. It is decoded based on the barcode image signal IMAGE given every time. In addition, when the CPU 2-1 executes the barcode reading operation with the laser irradiation range being maximized, the CPU 2-1 recognizes the area where the barcode exists based on the reading result, and performs laser irradiation according to the recognized area. Adjust the range. Here, the laser irradiation range is controlled by inputting a laser irradiation ON / OFF signal LASER to the laser unit 1. That is, the laser irradiation range is controlled by turning on the laser beam by setting the laser irradiation ON / OFF signal LASER to a high level and turning it off by setting it to a low level within one scanning period.
[0007]
FIG. 3 shows the configuration of the RAM 2-4. The normal reading counter RC counts the number of times the bar code has been normally decoded. The CPU 2-1 determines the predetermined number of times set in advance and the normal reading counter RC. By comparing with the value, it is monitored whether or not the data has been normally decoded a predetermined number of times. Here, when the data has been decoded normally for the specified number of times, the decoding result is stored in the barcode memory BM as barcode reading information. The scanning counter SC counts the time from the rising to the falling based on the laser scanning timing signal TIMING from the laser unit 1, and the value is updated following the laser scanning within one scanning period. go. The start position register SR stores the start position at which the laser beam is turned on, and the value of the scan counter SC corresponding to the start point position where the bar code exists is set. The end position register ER stores an end position at which the laser beam is extinguished, and the value of the scan counter SC corresponding to the end point position where the bar code exists is set. The barcode memory BM is a memory for temporarily storing normally-recognized barcode reading information, and the work memory WM is a memory for temporarily storing intermediate results during the barcode processing.
[0008]
Next, the operation of this bar code reader will be described with reference to the flowcharts shown in FIGS. Here, the programs described in these flowcharts are stored in the storage device 2-2 in the form of readable program codes, and the CPU 2-1 sequentially executes operations according to the programs.
FIG. 4 is a flowchart executed in response to an instruction to start reading. First, a laser irradiation ON / OFF signal LASER is given to the laser unit 1 to turn on the laser irradiation apparatus 1-7 (step A1), and the scan counter SC is cleared to start in accordance with the laser scanning timing signal TIMING from the laser unit 1. (Step A2). Then, the value of the scan counter SC is monitored, and while the value of the scan counter SC is updated, the light reception state of the reflected light and the corresponding value of the scan counter SC are acquired until it reaches a predetermined maximum value. The work memory WM is set (steps A3 to A5). Here, the maximum value is the maximum value of laser irradiation in one scanning period, that is, a value that defines the maximum laser scanning width. When the value of the scanning counter SC reaches the maximum value, laser irradiation ON / OFF The laser irradiation device 1-7 is turned off based on the signal LASER (step A6).
[0009]
In this way, the barcode reading operation is performed with the laser irradiation range being maximized, and the change state of the received reflected light and the value of the scan counter SC corresponding thereto are set in the work memory WM. The barcode block is recognized by analyzing the contents of. That is, FIG. 6A is a diagram for explaining a barcode block recognition method in this case. Here, in the figure, the horizontal axis shows the time and the vertical axis receives the reflected light, and when the laser irradiation is performed with the irradiation range maximized, is the change in the received reflected light regularly repeated intensities? If there is a regular change, the range is recognized as a barcode block in which a barcode exists. As a result of performing the barcode block recognition process in this way, if it is determined in step A8 that the barcode block is unrecognizable, the process returns to step A1, but if the barcode block can be recognized, The start position and end position of the recognized barcode block are acquired from the work memory WM and set in the corresponding start position register SR and end position register ER (step A9). That is, since the value of the scan counter SC corresponding to the change state of the received reflected light is set in the work memory WM, the value of the scan counter SC corresponding to the first change point of the reflected light is acquired as the start position. Then, the value is set in the start position register SR, and the value of the scan counter SC corresponding to the last change point of the reflected light is acquired as the end position and set in the end position register ER. Based on the recognized barcode block, the laser irradiation range is controlled to perform a reading operation (step A10).
[0010]
FIG. 5 is a subroutine showing the irradiation range control process. When the barcode block is recognized as described above (step B1), the values of the start position register SR and the end position register ER are read and started. The end position is determined from the position as the laser irradiation range, and the irradiation range is narrowed down (step B2). In this case, the laser irradiation range is narrowed down to the range defined by the values of the start position register SR and the end position register ER from the maximum irradiation range described above. A predetermined amount is subtracted from the value of the position register SR, and a predetermined amount is added to the value of the end start register ER, thereby narrowing the laser irradiation range to an eye slightly wider than the range defined by the start position and end position. FIG. 7 shows the state in this case, and the hatched portion in the drawing shows the laser irradiation range narrowed down based on the recognized barcode block. The laser irradiation range is slightly wider than the start position and end position of the bar code block, but the extent to which the laser irradiation range is increased differs depending on the response and accuracy of the scanner.
[0011]
In this state, the scan counter SC is cleared and started in accordance with the laser scanning timing signal TIMING (step B4), and the value of the scan counter SC is compared with the value of the start position register SR (step B5). (Step B6), and the value of the scan counter SC is updated until they match (step B7). Here, when the value of the scan counter SC matches the value of the start position register SR, the laser irradiation device 1-7 is turned on by the laser irradiation ON / OFF signal LASER given to the laser unit 1 (step B8). As a result, the laser beam is turned on. In this state, the scan counter SC is further updated (step B9), and the value of the scan counter SC is compared with the value of the end position register ER (step B10). It is checked whether they match (step B11), and the value of the scan counter SC is updated until they match (step B9). When the value of the scanning counter SC matches the value of the end position register ER, the laser irradiation range 1-7 is turned off by the laser irradiation ON / OFF signal LASER, and the laser beam is turned off (step B12).
[0012]
When the irradiation range is narrowed down and the barcode is read, the process proceeds to step A11 in FIG. 4 and the normal reading counter RC is initialized. Then, the barcode image data read according to the current irradiation range is decoded (step A12), and it is checked whether the barcode image data is normally decoded (step A13). In this case, if garbage is read together with the barcode or part of another barcode is read at the same time, the decoding becomes impossible and the process returns to step A1, but it can be decoded normally. In this case, it is checked whether it is the first decoding (step A14). Since this is the case where the first decoding is performed, the reading operation is performed again by controlling the irradiation range (step A15). Even in this case, the subroutine of FIG. 5 is called. However, since it is not the case where the barcode block is recognized but the case where the decoding process is performed, the process proceeds to step B3 and the values of the start position register SR and the end position register ER are determined. Is finely adjusted based on the decoding result to narrow down the irradiation range. In other words, the values of the start position register SR and the end position register ER are set to match the start / end positions of the normally decoded area based on the recognition of the barcode block. Fine-tune the to further narrow the irradiation range. FIG. 6B shows this state, and the laser irradiation range is finely adjusted to a slightly wider size than the normally decoded region. Thereafter, the process proceeds to execution of Steps B4 to B12. While the value of the scanning counter SC is updated, when the value reaches the value of the start position register SR, the laser beam is turned on, and when the value of the end position register SR is reached, the laser is turned on. Turn off the beam.
Then, the process proceeds to step A16 in FIG. 4, the normal reading counter RC is updated, and the value is compared with the specified number of times to check whether it has been read normally for the specified number of times (step A17). The process returns to step A12 until the above-described operation is repeated.
[0013]
As described above, in this barcode reading apparatus, when the reading operation is performed with the laser irradiation range being maximized, the area where the barcode exists is recognized based on the reading result, and the laser is matched to the area. Since the irradiation range is adjusted, it is possible to irradiate only the portion where the barcode to be read exists. FIG. 8 shows a case where two barcodes are adjacent to each other within the maximum irradiation range. When laser scanning is performed in the maximum irradiation range, two barcodes A and B are read in one scan. In this embodiment, When the first barcode A is read, the irradiation range is set to an area where the barcode A exists, so the barcode B is not read. This makes it clear which barcode has been read, and does not read extra garbage or barcodes, thus preventing misreading and making it unnecessary to decode portions outside the area where barcodes exist. Therefore, the processing speed can be improved and the irradiation range is narrowed, resulting in a reduction in power consumption.
In addition, as a method for recognizing a region where a barcode exists, a method for analyzing whether or not there is a predetermined change in received reflected light, and a method for recognizing a region where a barcode exists based on the analysis result, There is a method of recognizing the area where the barcode exists based on whether or not the decoded result is a legitimate barcode when the read result is decoded. Can be adjusted. In other words, after roughly adjusting the laser irradiation range according to the barcode area recognized based on the change in reflected light, fine adjustment of the laser irradiation range according to the barcode area recognized based on the decoding result can do. Further, since the adjustment of the laser irradiation range is performed by controlling the laser irradiation ON / OFF signal LASER, the control can be performed easily and easily.
[0014]
In the above-described embodiment, the method for recognizing the barcode area based on the change in the reflected light and the method for recognizing the barcode area based on the decoding result are used in combination. May be. Further, although the laser beam is irradiated, a light emitting diode may be used as a light source. Further, the scanning direction is not limited to a single direction, and bi-directional scanning that performs left-right scanning may be used.
【The invention's effect】
According to the present invention, by controlling the light irradiation range according to the area where the barcode exists, it is possible to reliably irradiate only the part where the barcode to be read is actually present. It is possible to realize prevention, improvement of processing speed, power reduction, and the like.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of a barcode reader.
FIG. 2 is a block diagram showing a configuration of a laser unit 1;
FIG. 3 is a diagram showing a configuration of a RAM 2-4;
FIG. 4 is a flowchart showing a barcode reading operation.
FIG. 5 is a flowchart detailing steps A10 and A15 (control of irradiation range) in FIG. 4;
FIG. 6A is a diagram for explaining a method for recognizing a barcode presence area according to a light reception state of reflected light, and FIG. 6B is a diagram for explaining a method for recognizing a barcode existence area based on a decoding result. Figure to do.
FIG. 7 is a diagram showing how a laser irradiation range is adjusted in accordance with a barcode presence area when the barcode presence area is recognized according to a reflected light reception state;
8A is a diagram showing a case where scanning is performed with the laser irradiation range being maximized, and FIG. 8B is a diagram showing a case where scanning is performed with the laser irradiation range being narrowed down.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laser unit 1-2 Laser irradiation control apparatus 1-4 Scanning timing detection apparatus 1-7 Laser irradiation apparatus 1-8 Laser scanning mirror 2 Main body system 2-1 CPU
2-2 Storage device 2-3 Storage medium 2-4 RAM
RC Normal reading counter SC Scan counter BM Barcode memory SR Start position register ER End position register WM Work memory LASER Laser irradiation ON / OFF signal TIMING Laser irradiation timing signal

Claims (2)

In the barcode reader that reads the barcode information by irradiating the barcode and receiving the reflected light,
When the reading operation is performed with the light irradiation range being maximized, it is analyzed whether or not there is a predetermined change in the received reflected light, and a region where a barcode exists is recognized based on the analysis result. Means of recognizing
First adjusting means for roughly adjusting the light irradiation range according to the area recognized by the first recognizing means;
When the reading operation is performed in the rough light irradiation range adjusted by the first adjusting means, the reading result is decoded, and the barcode is determined based on whether or not the decoding result is a normal barcode. A second recognition means for recognizing a region where
Second adjusting means for finely adjusting the light irradiation range according to the area recognized by the second recognizing means;
A bar code reading apparatus comprising: A recording medium having a program code read by a computer,
A function that analyzes whether or not there is a predetermined change in the received reflected light when performing a reading operation with the light irradiation range maximized, and recognizes the area where the barcode exists based on the analysis result ,
A function to roughly adjust the light irradiation range according to the recognized area;
When the reading operation is performed in this adjusted rough light irradiation range, the reading result is decoded and the area where the barcode exists is recognized based on whether or not the decoding result is a normal barcode. Function to
A recording medium having a program code for realizing a function of finely adjusting a light irradiation range according to the recognized area.

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