JPH04256084A - Bar code reader - Google Patents

Abstract

PURPOSE:To execute a firmware demodulation processing by extracting only bar code data among data which is read in a bar code detection part and executing a demodulation processing. CONSTITUTION:A storage control part 103 selects any of plural storage parts 102 and stores data which is read in the bar code detection part 101, and stores an address where the bar code data is stored in an address storage part 104 when bar code data is recognized. A bar code demodulation part 105 reads bar code data from the storage part 102 based on the address which is read from the address storage part 104 and executes the demodulation processing with firmware.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a POS (Point
of Sale) It relates to barcode reading devices used in terminals and the like.

0002

[Prior Art] A stationary barcode reader emits a laser beam from a reading window, an operator scans a barcode printed or affixed to a product that is moved over the reading window, and the reflected light is used to generate electrical signals. to read the barcode. Generally, in a barcode reading device for a POS terminal, an operator manually moves the product. For this reason, since the time for passing over the reading window is limited and the speed of the scanning beam is fast, the demodulation process to restore the contents of the read barcode is performed by hardware, and this hardware It is configured to correspond to the type of barcode, and is configured to read only one type of barcode.

[0003] In recent years, there has been a demand for stationary barcode reading devices to be able to read many types of barcodes. This is in addition to superstores, which require conventional reading speeds, as well as department stores, etc., which use barcodes different from those used for food items, which require fast reading speeds and hands-free operation. This is because stationary barcode reading devices have come into use.

0004

[Problem to be solved by the invention] Therefore, in order to read many types of barcodes and demodulate their contents, it is sufficient to configure hardware for each type of barcode, but this reduces the circuit size. The larger the size, the higher the cost. The present invention has been made in view of the above-mentioned problems, and provides a barcode reading device that uses hardware to extract only a group of barcode data from the data read by a barcode detection unit and demodulates it using firmware. With the goal.

[0005]

[Means for Solving the Problems] FIG. 1 is a diagram showing the principle of the present invention. In the figure, 101 is a barcode detection unit that reads barcodes, and 102 is a plurality of storage units that store data read by the barcode detection unit 101. 10
3 refers to which storage unit 102 the data read by the storage control unit is stored.
At the same time, barcode data is detected from the read data and stored in the storage unit 102.
Detect the address of this barcode data stored in . 104 is an address storage unit that stores the address detected by the storage control unit 103. 105 is a barcode demodulation unit that reads an address from the address storage unit 104, reads barcode data from the storage unit 102 using this address, and performs demodulation processing.

[0006] Furthermore, the storage unit 102 is configured with a ring buffer, and overwriting is performed until the barcode part is detected.

[0007] Furthermore, a combination of a barcode recognition circuit of the storage control section 103 and an address storage section 104 that stores an address for storing the barcode detected by this barcode recognition circuit in the storage section 102 is used as a barcode recognition circuit. Provided for each type.

[0008] Furthermore, a circuit is provided for operating only a desired set of the bar code recognition circuit and address storage section 104.

[0009]

[Operation] With the above configuration, data read by the barcode detection unit 101 is stored in the storage unit 102 selected by the storage control unit 103, and barcode data is detected from the read data and stored in the storage unit 102. The address of the stored barcode data is stored in the address storage unit 10.
4 is stored. The barcode demodulation unit 105 reads an address from the address storage unit 104, reads barcode data from the storage unit 102 based on this address, and performs demodulation processing. When the storage control unit 103 selects a storage unit 102 , it stores read data in one storage unit 102 until barcode data is stored, and once this barcode data is stored, subsequent data is stored in the next storage unit 102 . Once the barcode data is stored in the barcode section 102, the subsequent data is stored in the next storage section 102, and in the same manner, it is stored one after another in another storage section 102.

By making the storage unit 102 a ring buffer, barcode data is stored in the first ring buffer, and then read data is stored in the second ring buffer. During this time, the barcode demodulator 1
05 is reading the barcode data, the read data can be stored in the first ring buffer at the time when the second ring buffer stores the barcode data. In other words, barcode data can be stored alternately in the two ring buffers. Further, when barcode data is stored in the second ring buffer, if the barcode demodulator 105 has not read out the barcode data from the first ring buffer, it is stored in the third ring buffer. In this way, the storage capacity of the storage unit 102 can be reduced by cyclically storing read data in two ring buffers, or three ring buffers if two ring buffers are insufficient.

Furthermore, by providing a set of barcode recognition circuit and address storage unit 104 for each type of barcode desired to be read, the barcode demodulation unit 105 can perform the demodulation process of these barcodes using firmware. Since the barcode demodulation unit 105 can be used in common, the circuit scale of the demodulation device does not increase.

By providing a circuit that effectively operates only the set of barcode types to be read out of the set of the barcode recognition circuit and address storage unit 104, the set of barcode types that are not to be read is activated. It is possible to prevent misreading in which data scanned diagonally with respect to a barcode is mistakenly recognized as a barcode that is not to be read.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a configuration diagram of the stationary scanner of this embodiment. This device consists of an optical system and a control system. The optical system includes a laser section 1 that generates a laser beam, a laser control circuit 2 that controls this laser section 1, and a polygon mirror that reflects the laser beam of the laser section 1 into a bar. An optical unit 3 that scans the code, a motor 4 that rotates the polygon mirror, a photodetector 5 that receives laser light reflected on the barcode, and an amplifier circuit 6 that amplifies the output of the photodetector 5. , an analog/digital converter (A/D circuit) 7 that converts the output of the amplifier circuit 6 into a digital value, and an L that indicates the reading result.
It is comprised of an ED lamp 8 and a speaker 9 that generates a sound to inform the operator that a barcode has passed over the optical unit 3 and that the barcode has been read.

The control system includes a scanner control circuit 10 that controls the optical system, a demodulation circuit 11 that demodulates digital data from the A/D circuit 7, and an I/F control section 12 that interfaces with the POS terminal. be done.

FIG. 3 is a block diagram showing the configuration of the control system. The CPU 13, ROM 14, and RAM 15 perform bar code demodulation, optical system interface control, POS interface control, and the like. The interface section 16 interfaces with the POS terminal 18 via the driver/receiver 17. The optical system control unit 19 also interfaces with the optical system 21 via the driver/receiver 20. The bar width counter 22 counts the bar width from the bar code signal received from the optical system 21 to obtain the bar width. The buffer control unit 23 stores the bar width count data counted by the bar width counter 22 in the bar width count data buffer 2.
41 or 242, and when the start/stop detection circuit detects the start part and stop part of the barcode, the barcode data is switched between the buffers 241 and 242, and the barcode data is stored in the buffer 24.
1 or 242 is stored in the pointer instruction buffer 25.

Buffer 241 for bar width count data;
242 is a buffer that stores bar width count data, and the bar width count data written to this buffer 24 includes not only the bar code part but also data that includes black and white information such as characters printed around the bar code. (
(hereinafter referred to as garbage data) is also included. Therefore, if a lot of characters such as product descriptions are written around the barcode, there will be a lot of garbage data, and the buffer 24 will quickly become full. Therefore, in this embodiment, a ring buffer is used as shown in FIG. If a ring buffer is used, the garbage data portion can be overwritten, and the barcode data portion can also be overwritten after being read by the CPU 13 during demodulation processing, so that the storage capacity can be reduced. As a minimum storage capacity, it is sufficient to have a storage capacity equal to the maximum number of bars of the barcode. The pointer instruction buffer 25 stores the address of the barcode data stored in the bar width count data buffer 24.

Next, the operation of this embodiment will be explained with reference to FIGS. 5 to 7. FIG. 5 is an operational flow diagram of this embodiment. First, the barcode is scanned with a laser beam. Figure 6 shows a situation in which laser beams A and B scan a product with a barcode printed on it. Through this scanning, the barcode and garbage data such as printed characters around it are converted into white/black signals and detected. (Step 50), convert this digitally (
Step 51) The bar width of each of the white bar and the black bar is counted by the bar width counter 22 (Step 5
2). The above processing is performed by hardware.

FIG. 7 shows the bar width count data buffer 2.
41, 242 and the storage area of the pointer instruction buffer 25. The operation of these buffers is as follows. ■Data from the beginning of buffer 241 (
barcode data and garbage data). (2) If there is no barcode data by the end of the buffer 241, or if neither the start part nor the stop part is detected, the process returns to the beginning of the buffer 241 (step 53). - When the start/stop part of the barcode is detected, the start address and stop address are stored in the buffer 251 (step 54). ■Next, buffer the data in the buffer 242. ■Buffer 242 also operates in the same way as buffer 241 (
Steps 55, 56).

Here, the barcode data stored in the buffer 241 must be demodulated by firmware in the buffer 242 before the next barcode data is detected. If it does not seem to be completed, it is necessary to add another buffer 243. In addition, the rotation speed of the rotation motor 4 of the polygon mirror is set to 6000 r.
pm, that is, one rotation is 10 ms, the number of times that the laser beam scans the bar code during this period is about 1 to 3 times, and it is necessary to demodulate the bar code within 3 ms for three times. In fact, demodulation is possible in about 2 ms.

The bar code data read from the bar width count data buffer 24 is filtered to remove junk data (step 57). In this embodiment, in order to reduce the hardware circuit scale, the hardware only checks the start part, stop part, and the number of elements (number of white and black bars) between them, so garbage data is included, so the firmware Performs various checks specified in the code, performs final filtering, and deletes all garbage data. As a result, in FIG. 6, the B beam data and garbage data are discarded, and only the A beam data portion is extracted. One of these checks is a barcode adjacent character length check by firmware.

The barcode data thus extracted is demodulated by the firmware (step 58). Since the barcode data is entered many times, it is necessary to repeat steps 50-58 several times. If the demodulated data differs from the previously input data, all the different data is buffered (step 59). Since the data demodulated in this way may also include misread data, various checks specified in the code (for example, a check using a modulus 10 check code) are performed, and only barcode data that passes all checks is barcoded. It is determined that the code reading has been completed (step 60).

Although this embodiment has been described as reading one type of barcode, the start/stop detection circuit of the buffer control section 23 and the pointer instruction buffer 2
By providing the same number of pairs of barcodes as there are barcode types, these types of barcodes can also be read. Furthermore, by providing a circuit that effectively operates only the set of barcode types desired to be read among these sets, it is possible to prevent misreading from occurring. This is because if a set of barcode types that are not to be read is also activated, when the barcode is scanned diagonally, the same state as the barcode that is not to be read may occur, resulting in misreading.

[0023]

Effects of the Invention As is clear from the above explanation, the present invention extracts only barcode data from detected data and performs demodulation processing using firmware. does not require. Therefore, the circuit scale is reduced, and since the demodulation section is configured with firmware, the demodulation logic can be easily changed. Further, by using a ring buffer as a buffer for storing read data, the capacity can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a diagram showing the configuration of a stationary scanner according to an embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of this embodiment.

FIG. 4 is a diagram showing the configuration of a ring buffer.

FIG. 5 is an operation flow diagram of this embodiment.

FIG. 6 is a diagram illustrating scanning of a barcode with a laser beam.

FIG. 7 is a diagram illustrating a storage area of a buffer that stores detected data.

[Explanation of symbols]

13 CPU 14 ROM 15 RAM 19 Optical system control unit 20 Driver/receiver 21 Optical system 22 Bar width counter 23 Buffer control unit 24 Bar width count data buffer 25 Pointer instruction buffer

Claims (4)

[Claims] Claim 1: A barcode detection unit (101) that reads a barcode, and this barcode detection unit (101).
A plurality of storage units (102
) and the storage unit (102) that stores the data read by the barcode detection unit (101), and recognizes a group of barcode data from the read data, and stores the barcode data in the storage unit (102). )
A storage control unit (103
), an address storage section (104) that stores the address detected by this storage control section (103), and an address storage section (104) that stores the address detected by this storage control section (103);
A barcode reading device comprising: a barcode demodulation section (105) that reads barcode data from (102) and performs demodulation processing. 2. The barcode reading device according to claim 1, wherein the storage section (102) is constituted by a ring buffer. 3. A barcode recognition circuit of the storage control section (103) and an address storage section (104) for storing the address of the barcode detected by the barcode recognition circuit to be stored in the storage section (102). 2. The barcode reading device according to claim 1, wherein a set is provided for each type of barcode. 4. The barcode reading device according to claim 3, further comprising a circuit that operates only a desired set of the barcode recognition circuit and the address storage unit (104).