JPS6155148B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for selecting and detecting a specific code from a large number of codes.

For example, in a label reader that reads information by scanning a barcode, a start mark and a stop mark are present without one code in order to clearly restrict the range of information reading of the barcode.
Therefore, a special bar structure is used to clearly distinguish the start mark and stop mark from the barcode information that exists between them, and the start mark and stop mark are distinguished from barcodes displaying other information. This is required.

For this reason, conventionally, when scanning a bar code having a special bar width of a start/stop mark, a means for detecting the start/stop mark using a comparator has been considered. However, the numerical data obtained based on scanning the bar width has some errors due to the difficulty of completely uniformizing the bar code width over the entire length and the fact that the scanning condition cannot be kept constant at all times. must be allowed.
That is, when scanning a start/stop mark, it is recognized as a start/stop mark based on numerical data within a certain range. However, the conventional circuit configuration for detecting start/stop marks taking such errors into account has had the disadvantage of being complicated.

The object of the present invention is to read-only memory (hereinafter referred to as
The object of the present invention is to provide a method for detecting a specific code such as a start/stop mark for a label reader while distinguishing it from other codes by skillfully using a ROM (abbreviated as ROM).

Hereinafter, the method according to the present invention will be explained in detail based on one specific example with reference to the drawings. FIG. 1 is a block diagram showing the basic configuration for carrying out the present invention, and in the figure, 1 is a label reader. This label reader 1 scans barcode labels attached to articles to be sorted, etc.
A number of numerical pulse trains proportional to the bar width are output for each bar scan. 2 is a shift register, for example, as shown in the figure, three memory circuits 2a, 2b, 2
After inputting the number of pulses of the digitization pulse train for each scanning bar output from the label reader 1 to the storage circuit 2c, and storing the number of pulses of the digitization pulse train accompanying the first bar scan, , when the numeric pulse train associated with the scanning of the next bar is input to the storage circuit 2c of the shift register 2, the count value previously stored in the storage circuit 2c is transferred to the storage circuit 2b, and the count value is transferred to the storage circuit 2c. counts the number of pulses in the numeric pulse train accompanying the second bar scan. In this way, when three inputs corresponding to three sets of numerical pulse trains accompanying the scanning of three bars are received in the memory circuit 2c, each scan is applied to the memory circuits 2a, 2b, and 2c according to the order of the inputs. The number of pulses in the pulse train is counted for . 3 and 4 are ROMs, and the ROM 3 receives storage contents from storage circuits 2a and 2b of the shift register 2 to address designation terminals 3b and 3a, respectively. now,
The count values addressed to the addressing terminals 3a and 3b are X and Y, respectively, and the output terminal 3c reads "1" only when the ratio of Y/X is 4 and within the range of about 20%. It is assumed that writing work is being performed. To describe this writing work specifically, Y = 4X as shown in the graph shown in Figure 2.
To detect a 20% error range based on the relationship of
The possible range of Y is determined for each value of .
For example, if X and Y are numbers within the range regulated by 8 bits, and when X = 20, if it is within the range of 76≦Y≦84, then X is 1 so that the output terminal 3c reads “1”.
Information is written to the ROM 3 so as to define the range of Y for each value from 64 to 64.
In this way, in the XY relationship shown in FIG. 2, it is possible to write so that the output "1" is read from the ROM 3 only within the range between the chain lines.

On the other hand, the ROM4 has its address designation terminals 4a,
Each count value of the storage circuits 2c and 2b of the shift register 2 is addressed to 4b. And this ROM4 has its address designation terminal 4a,
When the count values added to 4b are X' and Y', respectively, the output of output terminal 4c is set to "1" with an error tolerance of ±20% based on the relationship of Y'/X']1/4. It is assumed that the settings are as follows. This setting means is performed in a manner equivalent to the writing means performed in ROM3. 5 is an AND gate, and the output signals from the output terminals 3c and 4c of the ROMs 3 and 4 are respectively input to the input terminals 5a and 5b, and when both read out "1", the output terminal 5c becomes "1". Read out.

In the above configuration, a method for detecting a start mark as a special code by scanning a bar code on a label as shown in FIG. 3 is as follows. First, the label R as shown in Fig. 3 has bars b ₁ , b ₂ , b ₃ forming the start mark and the following barcode B displaying the label information (in the figure, one of the barcodes is part and stop mark are omitted). Now, it is assumed that the bars b ₁ , b ₂ , and b ₃ forming the start of this label R have a bar width ratio of 4:1:4 as shown in the figure. Therefore, in the first scan of bar b ₁ , a numerical pulse train proportional to the bar width is output from the label reader 1, and this pulse number is first sent to the shift register 2.
is stored in the storage circuit 2c. Next, when scanning the bar _b2 constituting the start mark, the label reader 1 outputs a pulse train whose number is proportional to the width of the bar _b2 , and the pulse train is outputted from the storage circuit 2 of the shift register 2.
At the same time, the stored contents (count values) of the digitized pulse train based on bar b ₁ scanning, which have been stored in the storage circuit 2c, are transferred to the storage circuit 2b. Next, for the scanning of bar _b3 , the number of pulses of the digitized pulse train corresponding to this is stored in the storage circuit 2c of the shift register 2, and
Based on the action of each memory circuit 2a, 2b,
2c, assuming that the bar widths of the three bars b ₁ , b ₂ , b ₃ that constitute the start mark of the label are in the ratio of 4:1:4, each storage circuit of the shift register 2 The count values of the digitized pulse trains 2a, 2b, and 2c should be in a ratio of 4:1:4. However, as described above, these ratios often do not appear accurately due to slight non-uniformity of the bar width or changes in scanning conditions. Therefore, the ratio between the count value of the memory circuit 2b and the count value of the memory circuit 2a of the shift register 2 is 4, and the count value of the memory circuit 2b of the shift register 2 is 4.
The ratio between the count value of b and the count value of memory circuit 2c is 1/
4, the tolerance is determined, and its action is based on the above principle.When the outputs of ROMs 3 and 4 both read "1", the output terminal 5c of the AND gate 5 becomes "1". As a result, the start mark as a special mark can be clearly detected within a certain tolerance. Next, the original information of the label reader, such as the barcode that regulates the sorting location of the article to which it is attached, is scanned, but by detecting the start mark, it is clear that the reading of the barcode for the following information will start. Needless to say, it will be transformed into At this time, the original barcode B that displays label sorting information, etc. may have at least one different ratio among multiple sets of two adjacent bars so that it does not include the same bar configuration as the start mark. Therefore, there is no risk of confusion with the barcode that constitutes the start mark. After the scanning of the barcode B indicating the sorting of the articles is completed, a stop mark (not shown) (for example, having the same structure as the start mark or a structure in which the order of the bars is changed) is detected to detect the end of reading.

In addition, in the above embodiment, in detecting a start mark having a bar ratio of 4:1:4, the ratio of adjacent bars b ₁ and b ₂ or b ₂ and b ₃ is set to 4 and 1/4, respectively. Sometimes ROM3, to detect the start mark within a 20% tolerance.
This shows an example in which the contents of 4 are set, but if you add a ROM written using the same principle with a ratio of 1:1 between bars b ₁ and b ₃ , you can set any 2 that constitutes the start mark. It is possible to check the ratio of all the bars of a book, thereby further improving accuracy, and the number of bars constituting the start mark is not limited to three. Furthermore, when the bar configurations of the start mark and stop mark are different, an independent ROM may be added or writing in ROMs 3, 4, etc. may also be used to detect both marks. Furthermore, the present invention is not limited to detecting start/stop marks of a label reader, but can be widely applied as means for selecting and detecting a special code from a large number of codes.

As described above, the special code detection method according to the present invention sequentially counts and stores the number of pulses of a plurality of digitized pulse trains obtained by scanning a special code, etc. in each storage circuit of a shift register, and Any two of the count values to the circuit are set as a set, and addresses are specified to each separate ROM, and each ROM is
The above ROMs 3 and 4 are written in such a way that the output is output only when the count values of the two memory circuits addressed by the bar code are within a certain tolerance based on a certain ratio determined by the bar code width. Do each ROM
A start mark as a special code is detected when outputs 3 and 4 are all "1". Based on this method, extremely complicated circuits have been required due to tolerances when detecting special codes such as start/stop marks in label readers, among many other codes. The start/start code in the label reader can be executed with extremely high accuracy by using only simple means such as ROM writing without the need for complicated circuit means.
Special codes such as stop marks can be detected.

FIG. 4 relates to an improvement of the circuit shown in FIG. 1. That is, in FIG. 4, which shows only the parts that are different from FIG. 1, 6 is a ROM, and the label reader 1
and a shift register 2 are interposed between the storage circuit 2c. This ROM 6 is responsible for zoning the addressing signal. That is, this ROM6 has an address designation signal of, for example, 8.
Zones input up to bit 255 in a geometric progression.
It is written to be output in 32 blocks. As a result, in the circuit shown in Fig. 1,
It is possible to make the capacity of ROMs 3 and 4 extremely small. That is, for example, in order to detect the ratio of inputs of 8 bits each, an extremely large capacity is required.
ROMs 3 and 4 are required, but if this is to detect a ratio of 5 bits each, the capacity of ROMs 3 and 4 can be significantly reduced, resulting in the advantage that the overall cost can be significantly reduced even when adding ROM 6. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram for implementing the present invention;
FIG. 2 is a graph for explaining the operation, FIG. 3 is a plan view showing an example of a label, and FIG. 4 is a block diagram showing another embodiment. 1... Label reader, 2... Shift register,
2a, 2b, 2c... memory circuit, 3, 4...
ROM, 5...and gate, 6...ROM.

Claims (1)

[Claims] 1. The number of pulses of a plurality of digitized pulse trains obtained by scanning a series of codes etc. is sequentially stored in each storage circuit of a shift register, and at least one pair of pulses obtained by scanning a special code etc. In order to detect the ratio relationship of the number of pulses in a digitized pulse train with a certain tolerance range of error, a read-only memory (ROM) is set up to detect the ratio of one or more two numbers, and the ratio of each two number is determined. A special code detection method characterized in that the address of the count value of a storage circuit whose ratio is to be detected is specified for the ROM to be detected, and the special code is detected when all ROM outputs are output. 2. The special code detection method according to claim 1, wherein the special code is a plurality of bars forming start/stop marks of a label for a label reader. 3. Through a zoning ROM that inputs the number of pulses of a plurality of numerical pulse trains obtained by scanning a series of codes, etc., and outputs the pulses guided to one of several zones according to the input count value. One or more pulses are sequentially stored in each memory circuit of the shift register, and are used to detect, within a certain error tolerance, the ratio of the number of pulses in at least one pair of digitized pulse trains obtained by scanning a special code, etc. Set the ROM to detect the ratio of two numbers, and then specify the address of the count value of the storage circuit that should detect the ratio to the ROM that detects the ratio of each two numbers, and detect the ratio of all the above two numbers. A special code detection method characterized in that a special code is detected when a ROM output is issued. 4. The special code detection method according to claim 3, wherein the special code is a plurality of bars forming start/stop marks of a label for a label reader.