JPH06274671A - Bar code information reader - Google Patents

Abstract

PURPOSE:To store bar codes in a memory with less storage capacity and to prevent decode time from being prolonged more than needed. CONSTITUTION:The reflected light intensity of the bar code composed of bars and spaces is in time series detected by a linear sensor 12, sample/hold circuit 20 and binarizing circuit 22. Time series data expressing bars and spaces are counted and converted to width information by a white/black change point detection part 24 and a bar/space width counter 26. In this case, the bar/space width counter 26 starts counting corresponding to a count amount component previously set by an idle read amount setting part 30 and a count enable signal (a): outputted after counting by an idle read counter part 28. Thus, in the case of storing the width information in a memory 32 (such as a FIFO), the width information after the data just for the previously set width is stored in the memory 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code information reader for reading bar code information, and more particularly to a bar code information reader for storing a bar code in a memory with a small storage capacity.

[0002]

2. Description of the Related Art Conventionally, various bar codes have been widely used for managing products, packages, and the like.

In a bar code information reading apparatus for reading and decoding such a bar code, a conventional reading method is laser scanning,
A technique such as imaging with a linear sensor or an area sensor is used. Specifically, in the laser method, a laser beam spot is scanned on a bar code and the intensity of reflected light from within this spot is detected in time series.
In a linear sensor or an area sensor, a bar code image is formed on these sensors using an optical system, and light amount information detected by each element of the sensor is serially read out.

Here, it is standardly determined that a normal bar code is provided with a blank portion called a quiet zone 102 around the bar code 100, as shown in FIG. Therefore, when the black-and-white image information of the barcode 100 is read by these methods, the blank portion without the barcode 100 is read at the beginning of scanning.

However, if the margin is wide, a large amount of information that is not necessary for decoding the bar code is taken in, the memory capacity is wasted and the decoding time is longer than necessary. Therefore, various methods for starting reading barcode information have been proposed so that many blank areas are not read.

For example, in Japanese Patent Laid-Open No. 4-268982, as shown in FIG. 5B, when a plurality of barcodes 100A and 100B are included within the reading range of the line sensor, only one of them is used. Disclosed is a reading device that fetches barcode information into a decoding unit and performs decoding. In the reading device disclosed in this publication, only the count value for the bar code having the start position within the reading permitted range is written in the count value memory and decoded. That is, in the reading device of this publication, it is judged that a bar code exists by detecting the quiet zone 102 on the start side, and the reading of bar code information is started.

[0007]

However, in the prior art as disclosed in the above publication, since the quiet zone is used for detecting the start position of the bar code, the margin width around the bar code is less than the specified value. Sometimes
There is a problem that the start position of the barcode cannot be found and the reading cannot be started.

Alternatively, even if the margin portion has a prescribed value or more, due to stains such as voids, only the margin portion having a prescribed value or less can be found, and there is a problem that reading cannot be started.

On the contrary, when the margin is very wide, the conventional technique disclosed in the above publication starts reading after reading the quiet zone.
The data in the blank area before the barcode starts is stored. As a result, a large amount of useless information irrelevant to the bar code information is taken into the memory, which causes a problem that the memory capacity is wasted and the decoding time is longer than necessary.

The present invention has been made in view of the above points, and it is possible to prevent unnecessary information that is not necessary for decoding a bar code from being captured, so that the bar code can be stored in a memory with a small storage capacity. However, it is an object of the present invention to provide a bar code information reading device that does not unnecessarily lengthen the decoding time.

[0011]

In order to achieve the above object, a bar code information reading apparatus according to the present invention comprises a detecting means for detecting the reflected light intensity of a bar code consisting of a bar and a space in time series, and the above detection. A conversion unit that counts data representing time-series bars and spaces obtained by the unit and converts the data into width information, a memory for storing the width information, and width information output from the conversion unit in advance. It is characterized by comprising storage control means for storing the data for the set width and thereafter in the memory.

[0012]

That is, according to the bar code information reading apparatus of the present invention, the detecting means detects the reflected light intensity of the bar code consisting of the bar and the space in time series, and the converting means detects the time obtained by this detection. Counts data that represents a series of bars and spaces and converts it into width information. Then, when storing the width information in the memory, the storage control means causes the memory to store the data after the preset width of the width information output from the converting means. That is, the width information is stored in the memory after skipping a preset skip amount. Therefore, it is possible not to capture unnecessary information that is not necessary for decoding the barcode information.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the embodiments of the present invention, the principle of the present invention will be explained first in order to help understanding of the present invention. The bar code information reader of the present invention detects the presence of a bar code without using a quiet zone as in conventional readers.

One of the specific methods is a method of setting and fixing the skip reading amount from the beginning as shown in FIG. 1 (B). This method is effective in the case where the bar code is directly drawn or the bar code label on which the bar code is drawn is attached, and the bar code always exists at almost the same position on the medium. For example, if you want to read the barcode information by moving the card with the barcode label with the barcode drawn along the guide,
The length of the margin from the edge of the card to the edge of the label where the bar code label begins is almost fixed. Here, if the setting of the read skip amount is appropriate, it means that the unnecessary data is hardly included in the data acquired after skipping the read skip amount set from the beginning.

Therefore, according to this method, regardless of the presence or absence of the bar code, the data after the point where the end of the bar code is considered to be valid data is stored in the memory to store the bar code information. You can avoid getting unnecessary information that is not needed for decoding.

As another method, among the data read out in time series, as shown in FIG. 3 (B), the data after the point at which the white that first appears changes to black is stored in the memory. It is a thing. Barcodes consist of a bar and a space in any type of bar code, but the first and the last is always a bar. Therefore, the first white-to-black transition point means the edge portion of the first or last bar of the barcode.

According to this method, the data after the edge portion of the bar forming the bar code is stored as valid data, so that unnecessary information that is not necessary for decoding the bar code information is not captured. be able to.

Further, by using these two methods at the same time, it is possible to skip the blank area up to the quiet zone and detect the change point from white to black after that point, which is more effective. Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1A,
Barcode information reader 1 according to the first embodiment of the present invention
It is a block block diagram of 0.

That is, the bar code information reading device 10
Is a linear sensor 12, a drive pulse generator 14,
Drive circuit 16, amplifier circuit 18, sample-and-hold (S / H) circuit 20, binarization circuit 22, white / black change point detection unit 24, bar / space width counter 26, idle reading counter unit 28, idle reading amount It is configured by a setting unit 30, a memory 32, a decoder unit 34, and a decoding result output unit 36.

The linear sensor 12 is for picking up an image of a bar code, and the drive pulse generator 14 produces various signals for driving the linear sensor 12. The drive circuit 16 adjusts the voltage and current of the signal generated by the drive pulse generator 14 and supplies the signal to the linear sensor 12.

The amplifier circuit 18 is the linear sensor 12 described above.
Of the output signal of the linear sensor 12 is amplified by the S / H circuit 20, and the S / H circuit 20 samples the output signal of the linear sensor 12 and holds the signal level. The binarization circuit 22 binarizes the signal level held by the S / H circuit 20, and the white / black change point detection unit 24 up-edges the data signal output from the binarization circuit 22. , The down edge is detected, and a count start / stop command is given to the bar / space width counter 26. The bar / space width counter 26 counts the width of the bar and the width of the space according to the start / stop command.

The idle reading counter section 28 outputs a count enable signal for permitting the bar / space width counter 26 to start the counting operation after counting by a preset count amount. It is set by the reading amount setting unit 30.

The memory 32 stores the width data counted by the bar / space width counter 26. Then, the decoder unit 34 decodes the width data stored in the memory 32, and the decoding result output unit 36.
Outputs the decoding result of the decoder unit 34 to a host computer (not shown) or the like.

That is, in the bar code information reading apparatus having such a structure, an image of the bar code is formed on the linear sensor 12 by using an optical system (not shown). Of course, the linear sensor 12 needs to be arranged in the arrangement direction of the bar and the space so that the width of the bar and the width of the space can be read. Here, an area sensor may be used instead of the linear sensor 12. For example, in the case of a two-dimensional bar code (such as PDF417), the bar code information is written in two directions, vertical and horizontal, so it is better to use the area sensor at a time for the bar code image. It is advantageous that the whole can be imaged. When reading a two-dimensional barcode using a linear sensor, it is necessary to move the area imaged by the linear sensor to read the entire barcode. In this embodiment, the linear sensor 1 is used for simplification.
A case of reading a one-dimensional bar code (JAN code or the like corresponds) using 2 will be described.

Various signals for driving the linear sensor 12 are generated by the driving pulse generator 14.
The voltage and current are adjusted by the drive circuit 16 and then input to the linear sensor 12.

Due to the difference in the black / white color of the bar / space of the bar code, there is a difference in the amount of light received by the linear sensor 12, and this difference is output from the linear sensor 12 as a time-series voltage difference signal. It Since this output signal is usually weak, the amplifier circuit 18 amplifies the signal. Then, the S / H circuit 20 causes the linear sensor 1 to
Of the 2 pixel output signals, the signal is sampled at an output portion near the stable pixel center, the signal level is held, and binarized by the binarization circuit 22.

An example of the output of the binarization circuit 22 is shown in FIG. In this example, since the reflected light intensity from the bar portion is smaller than that in the space portion, the bar portion is represented by a low level output signal and the space portion is represented by a high level output signal.

The output signal of such a binarization circuit 22 is
The white / black change point detection unit 24 is entered. Here, the up edge and the down edge of the binarized data signal are detected. This edge is a signal point that represents the boundary between the bar and the space. When the white / black change point detector 24 detects the up edge and the down edge, it gives a count start / stop command to the bar / space width counter 26. This allows the bar / space width counter 26 to
Bar width and space width can be counted. The clock used for counting may be a clock synchronized with the clock used for the S / H. However, the bar / space width counter 26 starts to operate after the idle read counter section 28 outputs the count enable signal. This count enable signal is output after being counted by the count set by the blank read amount setting unit 30.

The width data counted by the bar / space width counter 26 is sent to the memory 32 and stored therein. The memory 32 can be realized by using, for example, a first-in first-out (FIFO) memory.

Here, in FIG. 1A, the count enable signal from the idle reading counter section 28 is input to the bar / space width counter 26, but it may be input to the memory 32 instead. At this time, the bar / space width counter 26 performs a count operation regardless of the count enable signal, and the data after the count enable signal is output is stored in the memory 32.

FIG. 2B shows an example of the memory contents.
S1 represents the width of the left margin of the leftmost bar, B2 represents the width of the first bar, S2 represents the width of the next space, and the widths of the bars and spaces in that order.

That is, this first embodiment is shown in FIG.
As shown in FIG. 5, this is an example in which the first method in which the skip reading amount is set and fixed by the blank reading amount setting unit 30 from the beginning is embodied.

Therefore, according to the first embodiment, regardless of the presence or absence of the bar code, the data after the point where the end of the bar code is considered to be valid data is stored in the memory 32. This makes it possible to prevent unnecessary information that is not necessary for decoding the barcode information from being captured. Next, a second embodiment of the present invention will be described.

FIG. 3A shows a block diagram of a bar code information reading apparatus 10 'according to the second embodiment of the present invention. In the figure, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

That is, the difference between the second embodiment and the first embodiment is that the output signal of the bar / space width counter 26 is replaced by the white → black detecting section 38. . The white-to-black detecting unit 38 receives the output of the white / black change point detecting unit 24, skips the preset empty reading amount by the empty reading counter unit 28, and then changes from the first appearing white to black. The edge of the signal to be detected.

With such a configuration, the relationship between the output of the binarization circuit 22 and the data stored in the memory 32 is as shown in FIG. Is as shown in FIG.

In the second embodiment, the idle reading counter section 28 is used. However, when there is no other bar code than the bar code within the reading range of the line sensor 12,
Instead of skipping the reading by the blank reading counter unit 28, the white → black detection unit 38 may detect the bar at the end of the barcode and start the reading from the beginning of the reading range.

That is, this second embodiment is shown in FIG.
As shown in FIG. 2, the second data is stored in the memory 32 after the point at which the white that first appears changes to black.
This is an example in which the above method is embodied.

Therefore, according to the second embodiment, since the data after the edge portion of the bar forming the bar code is stored as valid data, unnecessary information which is not necessary for decoding the bar code information is stored. Can be excluded.

As the data stored in the memory 32, as shown in FIG. 4C, the width from the edge changing from the space to the bar to the edge of the same condition next,
A value obtained by adding the widths of adjacent spaces and the width of a bar may be stored, such as the width from an edge that changes from a bar to a space to an edge of the same condition that comes next. 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. Further, the reflected light intensity of the scanning laser beam spot may be used instead of the CCD image signal. In addition, the present invention can be variously changed and modified, and is widely applicable to a reading start method of a character scanner.

[0041]

As described in detail above, according to the present invention,
It is possible to prevent unnecessary information that is not necessary for decoding the barcode from being captured, so that the barcode can be stored in the memory with a small storage capacity and the barcode information can be read without unnecessarily increasing the decoding time. A device can be provided.

That is, according to the present invention, since the bar information of the bar code and the space width necessary for decoding the bar code are stored in the memory without waste, the hardware such as the memory can be minimized. Also, the time required for decoding can be reduced.

[Brief description of drawings]

FIG. 1A is a block configuration diagram of a barcode information reading device according to a first embodiment of the present invention, and FIG. 1B is a diagram for explaining the principle of a first method of the present invention. is there.

FIG. 2A is a diagram showing a relationship between an output of the binarization circuit in FIG. 1A and data stored in a memory,
FIG. 7B is a diagram showing data stored in the memory.

FIG. 3A is a block configuration diagram of a barcode information reading apparatus according to a second embodiment of the present invention, and FIG. 3B is a diagram for explaining the principle of the second method of the present invention. is there.

FIG. 4A is a diagram showing the relationship between the output of the binarization circuit in FIG. 3A and the data stored in the memory;
(B) is a figure which shows the data stored in a memory, (C) is a figure which shows the other example of the data stored in a memory.

FIG. 5A is a diagram showing a quiet zone in a normal barcode, and FIG. 5B is a diagram showing a method of loading a barcode into a memory in a conventional reader.

[Explanation of symbols]

10, 10 '... Bar code information reader, 12 ... Linear sensor, 14 ... Drive pulse generator, 16 ... Drive circuit, 18 ... Amplification circuit, 20 ... Sample and hold (S / H) circuit, 22 ... Binarization circuit , 24 ... White / black change point detection unit, 26 ... Bar / space width counter, 28 ...
Blank reading counter unit, 30 ... Blank reading amount setting unit, 32 ... Memory, 34 ... Decoder unit, 36 ... Decode result output unit, 3
8 ... White → black detector.

Claims (1)

[Claims] 1. A detection means for detecting the reflected light intensity of a bar code composed of a bar and a space in time series, and counting the data representing the time-series bar and space obtained by the detection means and converting them into width information. Conversion means for storing the width information, a memory for storing the width information, and a storage control means for storing, in the memory, data after a preset width of the width information output from the conversion means. A bar code information reading device characterized by the above.