JPH0632067B2 - Bar code reader - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a bar code reader, and particularly when a bar code is read, the number of collations of read data is automatically set according to the intensity of reflected light. The present invention relates to a bar code reader.

Recently, due to the mechanization of the retail industry, the item code numbers, prices, etc. are represented by bar-shaped barcodes, which are printed on food and sundries. And in industries such as supermarkets that want to process a large number of shoppers in a short time, a bar code reader is installed to read this bar code, and the information recorded in the bar code is used for point-of-sale information management. .

Usually, in reading a barcode, a method of scanning the barcode printing surface with light such as a laser and demodulating coded data from reflected light modulated by the barcode is used. The intensity of this reflected light varies depending on the condition of the printed surface of the barcode, the distance from the light source, and the like.

Therefore, the read data is collated so that the reliability of the demodulated data does not change due to the intensity of the reflected light. Although this collation is considered so that the number of times can be changed, it is desirable that this number of times be changed automatically.

[Conventional technology]

FIG. 2 is a block diagram of a circuit showing an example of the bar code reader.

Reference numeral 1 is a display portion of an article on which a barcode is printed, and 2 is a barcode reading device. A light beam is projected from the optical unit 3 of the barcode reading device 2 to scan the display unit 1. This reflected light is the photoelectric conversion unit 4 of the bar code reader 2.
Is converted into an analog signal and enters the demodulator 5.

The bar code on the display unit 1 has GB (guard bars) on both ends.
A delimiter symbol called CB (center bar) is provided at the center of the area, and data is recorded between them. Then, one block is formed between the left GB and CB, and one block is formed between CB and the right GB, and data is recorded in each block.

The display unit 1 may be scanned by the light beam projected from the optical unit 3 in the directions of arrows A and D, but it is scanned in an inclined direction as shown in the directions of arrows E and F or the directions of arrows G and H. This is because there are many cases where there is a margin in this angle of inclination.

The analog signal that has entered the demodulator 5 is demodulated and converted into data. This data is collated the number of times instructed by the selection unit 6, and if the collation result is good, it is sent to the upper device via the terminal J.

Here, the selection unit 6 uses, for example, the setting pin (a) for setting the number of matchings,
The number of times of matching is instructed to the demodulation unit 5 by (b) and (c). That is, when the setting pin (a) is connected, it is instructed to match once, when the setting pin (b) is connected, it is instructed to match 1.5 times, and when the connection pin (c) is connected, it is instructed to match twice.

The one-time coincidence is a mode in which the data of the left block and the data of the right block of the bar code may be read once and collated. Whether the block is the left block or the right block can be determined by the configuration of the code. The 1.5 times match mode is a mode in which the left and right blocks of the barcode are read once and the left or right block is read once more, and collated. The double matching is a mode in which the left and right blocks of the barcode are read twice and collated.

[Problems to be solved by the invention]

Conventionally, the setting pins are switched manually. For example, when the price of an item is recorded on a barcode, in order to avoid troubles with customers, the number of times of collation is particularly increased to prevent reading errors.

Therefore, if the setting pin (c) is connected in order to make the coincidence twice, the positional relationship between the display unit 1 and the bar code reading device 2 is good, the intensity of the reflected light is appropriate, and the reading error does not occur. Even in the state, the next item cannot be processed unless the left and right blocks of the barcode are read twice and collated.

Therefore, there is a problem in that fixedly instructing the number of times of collation reduces the processing efficiency of the bar code reading device.

[Means for solving problems]

The above-mentioned problem is that the higher the level of the analog signal is, the higher the level of the analog signal is in the bar code reading device that scans the bar code with the light beam and collates and confirms the data obtained by demodulating the analog signal obtained from the reflected light. A plurality of comparison means, each of which is provided with one reference value out of a plurality of reference values that are designated to reduce the number of times of matching, and which compares the level of the analog signal with the given reference value, respectively; An instruction means for instructing the number of times of collation based on the comparison result of the plurality of comparing means is provided, and the level of the analog signal which fluctuates according to the intensity of the reflected light exceeds a reference value for designating the maximum number of times of collation. As a result, the bar code reader according to the present invention is adapted to indicate the number of times of matching designated by the reference value that the level of the analog signal exceeds.

[Action]

That is, when the reflected light is strong enough to clearly identify the barcode due to the intensity of the light reflected from the barcode, the matching is performed once, and as the reflected light becomes weaker, the matching is performed 1.5 times.
It is made to be strict with the agreement of times.

〔Example〕

FIG. 1 is a block diagram of a circuit showing an embodiment of the present invention.

In FIG. 1, operational amplifiers 7, 8 and 9 are used in place of the setting pins (a), (b) and (c) in FIG. The number of collations under the optimum condition can be designated.

The analog signal that has entered the demodulation unit 5 is branched and sent to the operational amplifiers 7, 8, and 9. The comparison voltage V is applied to the operational amplifier 7.
₁ is applied to the operational amplifier 8 and the comparison voltage V ₂ is applied to the operational amplifier 9
A comparison voltage V ₃ is supplied to each of them.

Here, the comparison voltage V ₁ indicates the level when the level of the analog signal is high, the intensity of the reflected light is appropriate and the reading of the bar code is stable, that is, the level when one coincidence is sufficient. V ₂ is the level when 1.5 matches are sufficient, and V ₃ is 2
Indicate the level when times matching is required.

Therefore, the operational amplifiers 7 to 9 send their respective outputs to the selection unit 6 according to the analog signal level from the demodulation unit 5.

When only the output of the operational amplifier 9 is input, the selection unit 6 instructs the demodulation unit 5 to match twice. Then, when the outputs of the operational amplifiers 9 and 8 are input, the coincidence is instructed 1.5 times. Furthermore, the operational amplifier 7,
When outputs of 8 and 9 are input, it is instructed to match once.

[Effects of the Invention] As described above, according to the present invention, the number of collations can be automatically changed in accordance with the analog signal level that varies depending on the intensity of reflected light. It is possible to improve the processing efficiency of the barcode reading device by performing the processing in the state.

[Brief description of drawings]

FIG. 1 is a block diagram of a circuit showing an embodiment of the present invention, and FIG. 2 is a block diagram of a circuit showing an example of a bar code reader. In the figure, 1 is a display unit, 2 is a bar code reader, 3 is an optical unit, 4 is a photoelectric conversion unit, 5 is a demodulation unit, 6 is a selection unit, and 7, 8 and 9 are operational amplifiers.

Claims (1)

[Claims] 1. A bar code reading device for scanning a bar code with a light beam and collating and confirming the data obtained by demodulating an analog signal obtained from the reflected light thereof, wherein the higher the level of the analog signal is, the higher the level of the analog signal is. A plurality of comparison means, each of which is provided with one reference value out of a plurality of reference values that are designated to reduce the number of times of matching, and which compares the level of the analog signal with the given reference value, respectively; Based on the comparison result of the plurality of comparison means, an instruction means for instructing the number of times of collation is provided, and the level of the analog signal fluctuating according to the intensity of the reflected light is set to a reference value for designating the maximum number of times of collation. A bar code reader characterized in that the number of collations designated by a reference value with which the level of the analog signal exceeds is instructed as the level becomes higher.