JPS63163585A - Bar code reader - Google Patents

Abstract

PURPOSE:To prevent a mistake in reading due to the fluctuation of a scanning speed by correcting the level of a multivalued level signal stored in a storing part based on detected scanning speed information, and correcting the bar code width of a bar code symbol. CONSTITUTION:A scanning speed in the reading window 12 of a bar code reader is obtained from the rotating speed of rollers 20a, 20b. Then, based on this scanning speed, the output signal of a CCD (Charge-Coupled-Device) 17 is corrected in level and bar code widths of white and black are corrected. Accordingly, the influence due to the deflection of the hand of an operator or the adjustable speed in the scanning speed can be removed and a stable reading can be attained. Thereby, even when the bar code reader is scanned, a reading accuracy similar to a still state can be expected, the generality is improved and the operability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a barcode reading device for inputting product sales data into an electronic cash register serving as a product sales data registration device.

[Prior Art] Some of the largest restaurants such as supermarkets and convenience stores that sell a wide variety of foods and miscellaneous goods have adopted a POS system called JAN type PO8. In this system, a product code called JAN code is printed as a barcode on the product, and this JAN code is printed on the product.
The code is read by a barcode reader and registered for sale in the storage section of the electronic cash register. Three types of barcode readers are commercially available: stationary scanners, hand scanners, and pen scanners. Among these, hand scanners irradiate light from an LED with a reading window facing the entire barcode, capture the reflected light from the barcode through the reading window, and use it as a solid-state image sensor.
<church-Coup Id-Dv i c
e), the light is received, converted into an electrical signal, and subjected to signal processing such as amplification and decoupling, thereby determining the white and black widths of the barcode.

By the way, in the conventional JAN code system, the standard barcode symbol length is 32.29M, and the average length of the reading window of a hand scanner is 50 to 60#I. Therefore, barcodes could be read simply by pointing the reading window onto the barcode symbol. However, recently the barcode symbol length has become approximately twice as long as before74.
．． 58mn+ JAN code is sometimes used, and in this case, it is not possible to capture the barcode simply by pointing the reading window of the hand scanner. Therefore, in such cases, a double-touch method is adopted in which the barcode is read twice by sliding a hand scanner over the barcode symbol.

[Problems to be Solved by the Invention] However, when a barcode symbol is read twice by sliding the reading window of a hand scanner, the reading window shifts from above the barcode symbol due to the shaking of the operator's hand, causing the reading to fail. There was a risk that it would become impossible. In addition, since the white and black barcode width information is replaced with a time element and output, changes in the acceleration/deceleration of the scanning speed may cause the barcode width to be incorrectly captured, resulting in reading errors. That was a problem.

Therefore, the present invention provides a barcode reading system that enables stable barcode reading and scanning, prevents reading errors due to fluctuations in scanning speed, and improves barcode reading accuracy and operability. ! The purpose is to provide an i-location.

[Means for Solving the Problems] The present invention receives reflected light from a barcode symbol taken in through a reading window of a barcode reader housing by a solid-state image carrier through an optical system, and adjusts the amount of reflected light. It is converted into a corresponding electrical signal, further converted into a multi-level heir and stored in the storage unit, and the rotational speed of a roller attached near the reading window of the barcode housing is detected by a rotational speed detection means. The scanning speed of the reading window is detected by the scanning speed detection means based on the rotational speed information, and the level of the multi-level signal stored in the storage section is corrected by the barcode correction means based on the detected scanning speed information. hand,
The barcode width of the barcode symbol is corrected.

[1! ¥1 By taking such measures, the electrical signal corresponding to the amount of reflected light from the barcode symbol is increased to a multilevel level.
At the same time, the scanning speed of the reading window is detected from the rotational speed information of the roller attached to the reading window, and the multilevel signal stored in the storage unit is A level correction is performed to correct the barcode width of the barcode symbol.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the structure of a barcode reader (hand scanner) in the barcode reading device of this embodiment. In the figure, a reading window 12 is provided on the front end surface of an L-shaped barcode reader national body (hereinafter simply referred to as the housing), and when the reading window 12 is opposed to a barcode symbol 13, the housing L built in 11
Light is emitted from an illumination light source 14 such as an ED. and,
Reflected light from the barcode symbol 13 is taken into the housing 11 through the reading window 12, reflected by the mirror 15, and formed into an image on the light receiving surface of the CCD 17 via the lens 16. C.C.
The D17 sequentially outputs N air signals according to the amount of reflected light that has formed an image, and the outputted electrical signals are amplified by an amplifier circuit 18 and then sent via a cable 19 to an electronic system, which will be described later. Trust built into cash registers, etc.
Sent to the processing unit.

A roller 20a is provided on the reading side of the housing 11.

20b is attached to make sliding scanning of the housing 11 in the six directions indicated by arrows in the figure stable and easy. Further, at least one of the rollers 20a and 20b (for example, 20
In a), as shown in FIG. 2, a magnet 21 is attached to the negative side, and a Hall element 22 is provided at a position facing the magnet 21. The rotation time of the magnet 21 that rotates integrally with the roller 20a is detected by the Hall element 22, and a detection signal is sent to the signal processing section via the cable 19. In addition, in Figure 2, 23
．． 23 is a housing protrusion plate, and 1l12 of this protrusion plate 23
A roller @25 is inserted into the roller 4 to rotatably support the rollers 20a and 20b.

FIG. 3 is a circuit diagram of the signal processing section.

In the figure, the quantization circuit 30 converts the output signal from the CCD 17 applied to the terminal 31 into a multi-level signal (
For example, it is quantized into 10 steps) and stored. The counter 32 counts the number of pulses of the clock signal applied to the terminal 33 as a counter i! Counting is performed based on a reset signal given from the I control circuit 34 at appropriate times, and the counting data is sent to the scanning speed conversion table 35. The counter division circuit 34 is connected to the inverter G1. Resistor R, capacitor C.

AND gate G2 and flip-flop DI.

D2, and sends out a reset signal every time the detection signal from the Hall element 22 is applied to the terminal 36. Therefore, the counter 32 repeats the counting operation of clock pulses every time the roller 20a rotates once, and when the rotation of the roller 20a is fast, that is, when the scanning speed of the barcode reader is fast, the count data is small. When the rotation of the roller 20a is slow, that is, when the scanning speed of the barcode reader is slow, the count data becomes large.

Scanning speed data corresponding to the counting data from the counter 32 is preset in the scanning speed conversion table 35, and the bar code corresponding to the counting data from the counter 32 is set in advance in accordance with the synchronization signal given via the AND gate G3. The scanning speed of the reader is determined and the scanning speed data is corrected by the circuit 3.
Send on 7.

The correction circuit 37 corrects the level of the multilevel signal stored in the quantization circuit 30 based on the scanning speed data sent from the scanning speed conversion table 35, thereby adjusting the white and black colors of the barcode symbol 13. Each barcode width is corrected, and the corrected level signal is given to a decoder 38 to decode the barcode information.

Here, the correction circuit 37 will be specifically explained.

Now, if the reflected light from the barcode symbol 13 formed in the order shown in Fig. 4(a) is captured with the card reader stationary, the output signal from the CCD 17 will have the waveform as shown in Fig. 1). It becomes a square wave. Therefore, if we convert this waveform into 2@ with 1/2 of the peak level as the threshold, we can
” is white and “0” is black, and the width of a white or black barcode can be read with high precision depending on the number of consecutive pixels.

On the other hand, if the reflected light from the same barcode symbol 13 is captured by scanning the card reader in the six directions of the arrows in FIG. The output signal has a waveform M or N shown in FIG. 3(b). Here, the scanning speed of waveform M is faster than that of waveform N, the accumulation time for one pixel is shorter, and the accumulated voltage due to the reflected light from white reaches its peak level by scanning 10 pixels. Waveform M is 5
This is a case where the accumulated voltage due to the reflected light from white reaches its peak level by scanning for a pixel.

That is, if the scanning speed is fast, it takes a long time for the accumulated voltage due to the light reflected from white to reach the peak level, and if the scanning speed is slow, the voltage reaches the peak level in a short time. Therefore, in the correction circuit 37, the peak value of the multilevel signal stored in the quantization circuit 30 is detected, and based on the scan rate data from the scan speed conversion table 35, the correction circuit 37 detects the peak value of the multilevel signal stored in the quantization circuit 30, The level is corrected so that the predetermined number of pixels is set to "1" and the others are set to rOJ. In other words, Figure 4 (
In the case of waveform M in b), for high-speed scanning speed data, 10 pixels before the peak value are set to "1", and the others are set to "0". Further, in the case of waveform N, for low-speed scanning speed data, 5 pixels before the peak value are set as "1", and the values other than the peak value on the back are set as rOJ. By doing so, the change in the storage time of the CCD 17 due to scanning by the barcode reader is corrected.

As described above, in this embodiment, the scanning speed in the reading window 12 of the barcode reader is controlled by the rollers 20a and 20b.
CCI)1 based on this scanning speed.
The white and black barcode widths are corrected by level-correcting the output signal of 7, which eliminates fluctuations caused by operator hand shake and acceleration/deceleration of the scanning speed, making stable reading possible. Become. Therefore, even if the barcode reader is scanned, it can be expected to have the same reading accuracy as in a stationary state, increasing versatility. Also, there is a roller 2 in the reading window.
0a and 20b, and the influence of scanning fluctuations can be ignored, improving the operability of the barcode reader.

Note that the present invention is not limited to the above embodiments.

For example, in the embodiment described above, the rotation time of the roller 20a is detected by the action of the magnet 21 and the Hall element 22, but the invention is not limited to this. For example, the roller 20a may be formed with a mirror surface and a reflective type The rotation time may be measured by a sensor. It goes without saying that various other modifications can be made without departing from the spirit of the invention.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to stably read and scan barcodes, prevent reading errors due to fluctuations in scanning speed, and improve barcode reading accuracy. Moreover, it is possible to provide a barcode reading device that can improve operability.

[Brief explanation of the drawing]

1 to 4 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a structural diagram of a barcode reader, FIG. 2 is an enlarged view of the main part, and FIG. 3 is a signal processing section. The circuit configuration diagram, FIG. 4, is a diagram for explaining the correction circuit. DESCRIPTION OF SYMBOLS 11... Housing, 12... Reading window, 13... Barcode symbol, 14... Illumination light source, 15... Mirror, 16... Lens, 17... CCD, 18...
Amplifier circuit, 20a, 20b...roller, 21...
Magnet, 22... Hall element, 30... quantization circuit,
32...Counter, 35...Operation speed conversion tape/
Murmur 37...correction circuit, 38...decoder. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] A barcode reader housing has a reading window that captures reflected light from a barcode symbol, and within this housing, the reflected light captured from the reading window is received via an optical system and converted into an electrical signal corresponding to the amount of reflected light. A solid-state image sensor for conversion, a storage unit that quantizes and stores the electrical signal from the solid-state image sensor into multilevel levels, and a rotational speed detector that detects the rotational speed of a roller attached near the reading section of the barcode housing. scanning speed detection means for detecting the scanning speed of the reading window based on the rotational speed information of the roller detected by the rotational speed detection means; A barcode reading device comprising: barcode correction means for correcting the barcode width of the barcode symbol by correcting the level of a multilevel signal stored in the storage section.