JPH06274672A - Optical reader - Google Patents

Abstract

PURPOSE:To transfer data from a storage part to a data processing part by using a data length, which can be handled in the data processing part to a maximum extent. CONSTITUTION:A signal processing part 2 performs the adjustment or A/D conversion of an output signal level of a reading block 1 for reading a bar code symbol and counts the widths of bars and spaces. A serial/parallel conversion part 3 successively stores the information in parallelly arranged memories 41, 42, 43.... Then, the data are simultaneously read from these parallelly arranged memories 41, 42, 43... and the plural data are transferred to a decode block 5. Within the decode block 5, the decode processing of the bar code symbol is performed by using the information. The decoded result is displayed by a decoded result display block 6.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a bar code reader and an O
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reading device such as a CR, and more particularly to reading / writing data optically detected in a memory.

[0002]

As a reading means in a bar code reader for reading and decoding bar code symbols,
Conventionally, means such as laser scanning, imaging with a linear sensor or an area sensor, and the like have been used.
Specifically, in the laser system, the laser beam spot is scanned on the bar code symbol, and the intensity of reflected light from within this spot is detected in time series. Further, in a linear sensor or an area sensor, a bar code symbol image is formed on these sensors by using an optical system, and light quantity information detected by each element of the sensor is read out serially.

The detected (read) data is usually stored in a memory device. For example, JP-A-4
In Japanese Laid-Open Patent Publication No.-256085, the configuration shown in FIG. That is, a first-in first-out memory (hereinafter, FIFO) is used as the storage unit 100. In this configuration, the data read by the barcode detection unit 102 is stored in the storage unit 100, the barcode data group is detected by the barcode recognition unit 104, and the barcode data group is stored in the storage unit 100. The stored address is stored in the address storage unit 106. The bar code demodulator 108 uses this address to
Bar code data is read from the storage unit 106 and demodulation processing is performed.

[0004]

By the way, in such a configuration, the types of data stored in the memory are classified into the following two types.

That is, one is a value obtained by A / D converting the reflected light intensity from the detected bar code symbol. A normal bar code reader mainly performs A / D conversion by binarization, but when gradation is required, A / D conversion of several bits is also used. At this time, it is sufficient to use up to 8 bits of A / D conversion for the gradation to be used.

[0006] The other is information on the width of the bar and the space forming the bar code symbol. This width information is obtained by counting the widths of bars and spaces with a clock synchronized with the data serially read by the bar code detection unit 102. Such width information can be sufficiently expressed if it has an 8-bit data length. On the other hand, most of the MPUs that mainly work in the bar code demodulation unit 108 can handle a large amount of data of 16 bits or 32 bits.

However, in the conventional configuration, the data transfer from the storage unit 100 to the demodulation unit 108 depends on the data length of the storage unit 100, and the number of data to be transferred is 8-bit transfer. For this reason, it takes a long time to transfer, which causes an increase in decoding time. Further, in an apparatus for reading characters such as OCR, similarly, it takes a long time to transfer the characters from the storage unit to the character discriminating unit, which causes an increase in character discriminating time.

The present invention has been made in view of the above points, and transfers data from the storage unit to the data processing unit by maximizing the data length that can be handled by the data processing unit such as the demodulation unit and the character discrimination unit. It is an object of the present invention to provide an optical reader that can be used.

[0009]

In order to achieve the above object, an optical reader according to the present invention comprises a detecting means for detecting the reflected light intensity of information recorded on a recording medium in time series, and the above detecting means. Serial-parallel conversion means for converting the serial data output from the means into parallel data, storage control means for storing the parallel data converted by the serial-parallel conversion means in a memory arranged in parallel, and the memory And a data processing unit that performs a predetermined process using the data read simultaneously from the.

[0010]

That is, according to the optical reader of the present invention, the detecting means detects the information recorded on the recording medium, for example, the reflected light intensity of the bar code symbol or the character in time series. The serial-parallel conversion means converts the serial data output from the detection means into parallel data, and the storage control means stores the parallel data in memories arranged in parallel. And the data processing means
Using the data read simultaneously from the memory, predetermined processing such as decoding processing of bar code symbols and character discrimination is performed.

[0011]

EXAMPLE An example of the present invention will be described below. Figure 1
FIG. 1 is a block diagram showing an outline of a bar code symbol reading device as an embodiment of an optical reading device to which the present invention is applied.

In the figure, the reading means of the reading block 1 can be realized by a conventionally used means such as laser scanning or imaging by a linear sensor or an area sensor. Then, the signal processing unit 2 performs signal level adjustment, A / D conversion, and the like. When it is desired to store the width information of the bars and spaces in the memory, the width of the bars and spaces is counted in this signal processing unit 2. This information is converted by the serial / parallel converter 3 into memories 4 ₁ , 4 ₂ , 4 ₃ arranged in parallel.
Will be stored in sequence.

Then, data is simultaneously read from the memories 4 ₁ , 4 ₂ , 4 ₃ ... Arranged in parallel, and a plurality of data are transferred to the decoding block 5. This information is used in the decoding block 5 to decode the barcode symbol. The decoding result is displayed by the decoding result display block 6.

Here, the number of memories arranged in parallel is set to the number obtained by dividing the data length that can be handled by the decode block 5 by the data length at the output of the serial / parallel conversion unit 3. For example, the data length that can be handled by the decode block 5 is 3
When the output is 2 bits and the output of the serial / parallel conversion unit 3 is 8 bits, it is only necessary to arrange the FIFOs capable of handling the 8-bit data length in 4 systems in parallel.

With such a configuration, data transfer from the memories 4 ₁ , 4 ₂ , 4 ₃ ... To the decode block 5 is performed using the entire data length that can be handled by the decode block 5, so that the data transfer time is increased. It is shorter than before.

Hereinafter, this embodiment will be described with reference to FIGS.
Will be described in more detail with reference to. In the following description, the type of data stored in the memory will be described as bar and space width information. Of course, it is also possible to replace the reflected light intensity from the barcode with data for A / D conversion. 2 is shown in FIG.
FIG. 3 is a block diagram showing the configuration of in more detail.

First, in this embodiment, an image of a bar code symbol is formed on the CCD linear sensor 10 by using an optical system (not shown). Of course, the linear sensor 10
The arrangement direction of is arranged in the arrangement direction of the bar and the space so that the width of the bar and the space of the barcode symbol can be read.

An area sensor may be used instead of the linear sensor. For example, in the case of a two-dimensional bar code symbol (such as PDF417), bar code information is written in two directions, vertical and horizontal, so it is better to use the area sensor once for the bar code. This is advantageous because the entire symbol image can be captured. When reading a two-dimensional bar code symbol using a linear sensor, it is necessary to move the area that can be imaged by the linear sensor and read the entire bar code symbol. In this embodiment, for simplification, a case where a linear sensor is used to read a one-dimensional bar code (JAN code or the like corresponds) will be described.

Various signals for driving the linear sensor 10 are generated by the drive pulse generator 12, and after adjusting the voltage and current by the drive circuit 14,
Input to the linear sensor 10. The black / white color of the bar / space of the bar code symbol causes a difference in the amount of light received by the linear sensor 10, and the difference is output from the linear sensor 10 as a signal in which a voltage difference occurs in time series.

Since this output signal is usually weak, the amplifier circuit 16 amplifies the signal. After that, the sample-and-hold circuit (S / H) 18 samples the output signal of each pixel of the linear sensor 10 near the stable pixel center and holds the signal level. Then, it is binarized in the binarization circuit 20.

The output signal of the binarization circuit 20 is a bar /
The space width counter section 22 is entered. Here, first 2
After the binarization, the up edge and down edge of the data signal are detected. This edge is a signal point that represents the boundary between the bar and the space. That is, the bar / space width counter unit 22 measures the data transfer time from the up edge to the down edge and from the down edge to the up edge,
Width information of bars and spaces. The clock used for counting may be a clock synchronized with the clock used for sample and hold. The width data thus counted is input to the write control unit 26 after being latched by the latch 24. In the write control unit 26, serial data latched in order is converted into parallel data, which is sequentially sent to and stored in the memories 28A to 28D arranged in parallel. The relationship between the above count, latch, and write is shown in FIG.

The memories 28A to 28D are, for example, F
It can be realized by using IFO. This memory 28A-28D
As a specific method of writing to the memory, for example, the output signal lines of the latch 24 are arranged in parallel in the memories 28A to 2A.
Connect all 8D in the same way. However, if only write commands to the FIFO are sequentially switched, the parallel memory 28A
To 28D are sequentially written.

The written data is transferred to the bar code demodulation section 30. In this embodiment, the bar code demodulation unit 30 is mainly composed of a digital signal processor (DSP). Here, other MP instead of DSP
You may use U. Memory (FIFO) 28A to 28D
Data transfer from the bar code demodulator (DSP) 30 to the bar code demodulator (DSP) 30 is performed at the same time, and is input to the DSP 30 as 32-bit data.

In the configuration of FIG. 2, the data length latched by the latch 24 is 8 bits, and the FIFOs 28A to 28D are provided.
Each data length is also 8 bits, and DSP3
The data length that can be handled by 0 is considered to be 32 bits.

FIG. 4 shows how the data stored in the FIFOs 28A to 28D is transferred to the DSP 30 side. In this way, the data from the FIFOs 28A to 28D
The data on the SP 30 is assigned and transferred from the upper order to the lower order. Of course, it is not limited to the upper and lower positional relationships of FIG.

The DSP 30 is a program ROM
Working R according to the software stored in 32
The AM 34 is used as a work area to demodulate the bar code information from the width information. However, here, DSP
It is necessary for the software to recognize which of the higher order and the lower order of the data transferred to the 30 side is the first one in time series. The data decoded in this way is
It is output by the decoding result output unit 36.

By the way, in order to read new data written in the FIFO, the write pointer and the read pointer have the following regulations. That is, the write pointer precedes the read pointer and must not pass. Furthermore, depending on the type of FIFO, a relative address pointer width of a certain width or more is specified for the read and write pointers.

In the configuration of FIG. 2, such pointer management is performed by the up / down counter 38 and the pointer management block 40. A specific operation example of such pointer management is shown in FIG.

That is, the up / down counter 38 is
The write command to the FOs 28A to 28D counts up, and the read command from the FIFOs 28A to 28D counts down. Here, the write command uses only one system of the plurality of FIFOs 28A to 28D.
In FIG. 2, a write command to the FIFO "A" 28A is used. This allows all FIFOs 28A-28D
When one data is written in each, the "1" pointer is incremented. The counter 38 is cleared by a read start command. Therefore, the output of the up / down counter 38 is the FIFO 28.
It is the relative pointer difference between the read pointer and the write pointer of A to 28D.

This relative pointer difference is input to the relative pointer comparison unit formed in the pointer management block 40. Based on the comparison result, the enable / disable control of the read / write from the FIFOs 28A to 28D is performed. In the configuration of FIG. 5A, reading is not performed until the write pointer precedes by the minimum relative pointer width in the FIFO standard.

Then, the count output is further counted up, the count output exceeds the minimum relative pointer width in the FIFO standard, and the maximum relative pointer width in the FIFO standard −α.
Writing and reading are performed in the following cases. Where α
Means the maximum expected number of data captured in one scan of the linear sensor 10.

Further, when the count output exceeds the maximum relative pointer width −α in the FIFO standard and is less than the maximum relative pointer width in the FIFO standard, only reading is performed.

As a result, when the serial data from the linear sensor 10 is written in the FIFOs 28A to 28D, the relative address pointer exceeds the maximum relative pointer width in the FIFO standard (the write address pointer becomes the read address pointer). Catching up),
It is possible to prevent a problem that writing to the FIFOs 28A to 28D has to be stopped in the middle of data for one scan.

As the data to be stored in the memories 28A to 28D, as shown in FIG. 3B, the width from the edge changing from the space to the bar to the edge of the same condition that comes next, and the width from the bar to the space. A value obtained by adding the widths of adjacent spaces and bars, such as the width from a changing edge to the next edge under the same condition, may be stored. Such a width counter method can deal with the case where the printing accuracy is poor and the width of the bar becomes thicker or narrower than the specified value. In addition, the linear sensor 1
Instead of the CCD image signal of 0, the reflected light intensity of the scanning laser beam spot may be used.

Further, the data is transferred from the memories 28A to 28D to the DSP 30 in the above embodiment, but of course, this is not the only case. For example, the working RAM 34 in FIG. 2 has a data length of 32 bits. If so, the data may be transferred to the working RAM 34 instead of being transferred to the DSP 30.

As the memory, 28A-2 of FIG.
Although the description has been made by using the FIFO like 8D, the present invention is not limited to this and can be configured by using other memory elements such as dual port RAM, static RAM, and dynamic RAM.

The present invention is not limited to the above-described embodiment, but can be widely applied to data storage and reading methods in a character scanner (OCR) or the like.

[0038]

According to the present invention, it is possible to provide an optical reading apparatus capable of transferring data from a storage unit to a data processing unit by making maximum use of the data length that can be handled by the data processing unit.

Therefore, for example, in the case where the optical reading device is a bar code symbol reading device, the data from the memory is transferred to the MPU by effectively using the data length of the MPU used in the bar code information demodulation section. , The transfer time is short, and the time required for decoding can be shortened.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an outline of a barcode symbol reading device as an embodiment of an optical reading device to which the present invention is applied.

FIG. 2 is a block diagram showing the configuration of FIG. 1 in more detail.

FIG. 3A is a diagram showing a relationship between a count and latches and writes, and FIG. 3B is a diagram showing a relationship between them by another method.

FIG. 4 is a diagram showing how data stored in a FIFO is transferred to a DSP side.

5A is a diagram for explaining a specific operation example of pointer management, and FIG. 5B is a block configuration diagram of a conventional barcode symbol reading device.

[Explanation of symbols]

1 ... read block, 2 ... signal processing unit, 3 ... serial-parallel conversion unit, 4 _1, 4 _2, 4 ₃ ... memory, 5 ... decoding block, 6 ... decoding result display block 10 ... CC
D linear sensor, 12 ... Drive pulse generator, 14
... drive circuit, 16 ... amplification circuit, 18 ... sample and hold circuit (S / H), 20 ... binarization circuit, 22 ...
Bar / space width counter section, 24 ... Latch, 26 ... Write control section, 28A to 28D ... Memory (FIF
O), 30 ... Bar code demodulator (DSP), 32 ... Program ROM, 34 ... Working RAM, 36 ... Decode result output section, 38 ... Up / down counter, 40 ... Pointer management block.

Claims (1)

[Claims] 1. A detection means for detecting the reflected light intensity of information recorded on a recording medium in time series, and a serial-parallel conversion means for converting serial data output from the detection means into parallel data. Storage control means for storing parallel data converted by the serial-parallel conversion means in memories arranged in parallel; and data processing means for performing a predetermined process using the data read simultaneously from the memory. An optical reading device characterized by the above.