JPS583073A - Bar-code read system - Google Patents

Abstract

PURPOSE:To increase a processing speed, by detecting the number of transferred signals at each block, comparing it with a reference value, discriminating whether its decision is required or not, and making it unnecessary to decide a noise, etc. in case when a bar-code pen has been loaded. CONSTITUTION:Measured values t'1, t'2- by a read end detecting circuit 5 and a time whith measuring circuit 6 are stored in order in a memory 8. Subsequently, after a period t'7, a ''0'' period is continued. When it has exceeded an end timing TE, the detecting circuit 5 outputs its signal to a storage number counter 11, and sends out the number of signals of the memory 8 to a comparing circuit 12. To the comparing circuit 12, a reference value is transferred in advance, and in case when the number of signals of the memory 8 is smaller than the reference value, the comparing circuit 12 outputs NG, makes the memory 8 ineffective, and clears the counter 11. In case when said number of signals is not smaller than the reference value, the comparing circuit 12 outputs OK, and sends out measured values t1, t2 of the memory 8 to a deciding circuit through a register 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a barcode reading method, and more particularly to a barcode reading method having a noise removing means for removing noise generated when reading a barcode.

A barcode is attached to the sold product, and each time the product is sold, the barcode is read by a terminal device and the sales amount is printed out from a register, or the sales data is sent to a processor at the center to manage the product. Things like this are being done in the strict retail industry.

In this case, a barcode hand scanner such as a barcode pen is used to read the barcode marked on the product. , when placing the barcode fist pen 2 to read the barcode 3f, the time T in Fig. 1 (b)
As shown in o, this changes the reflectance and generates pulses, resulting in noise. Therefore, this noise and the barcode 3 at time T in FIG.
It is necessary to distinguish between the barcode signal and the barcode signal generated as a result of reading the barcode. Therefore, conventionally, barcodes are provided with barcodes, such as the start mark shown in Figure 2, to indicate the beginning and end of the barcode. By identifying these, they were able to recognize the essential barcode signal. Therefore, in order to identify the start mark and stop mark indicating the beginning and end of the barcode from the input signal of the barcode pen 2, complicated bars and codes are required, and it takes a long time to read the barcode. There was a problem.

Therefore, it is an object of the present invention to solve these problems and provide a barcode reading system having an identification means for easily identifying whether a signal input from the barcode reading means is noise or not. purpose. To this end, the barcode reading method of the present invention includes a reading means for reading the barcode, a waveform shaping means for shaping the output of the reading means, and a barcode determining means for determining the barcode based on the output of the waveform shaping means. In the barcode reading method, the barcode reading method includes a signal number counting means for counting the number of signals transmitted from the reading means, a barcode storage means for storing the barcode, and a reading end detection means for detecting the end of reading of the barcode signal. The present invention is characterized in that the number of signals read out when , and is detected is compared with a reference value, and based on the comparison result, the validity of the signals read out so far is tested.

Before describing one embodiment of the present invention in detail, the principle of the present invention will be briefly explained based on a 2° diagram. As shown in period T, a noise signal is generated. This number of noise signals is usually a signal with about 4 to 5 "1" parts, which is quite small compared to the number of signals of about 21 at the bottom in a normal bar code signal. Therefore, when a barcode is read, the number of signals transmitted until the end of the barcode occurs by scanning a certain amount of white area at the end is counted, and this number is 21. If it is less than 21, it is considered to be noise, and if it is 21 or more, it is assumed that there is a barcode signal in it, and if this is sent to the six-code judgment circuit, it will be able to judge the barcode even if it is clearly noise. There's no need to do it.

An embodiment of the present invention will be described below based on FIG. 3 and with reference to FIG. 2.

In the figure, the same reference numerals as the others indicate the same parts, 4 is a waveform shaping circuit, 5 is a reading completion detection circuit, 6 is a Fi time width measurement circuit, and 7 is a waveform shaping circuit.
is storage circuit, 8#-t, memory, 9F! register, 10
is a readout circuit, 11 is a storage number counter, 12 is a comparison circuit,
13C is a reference value generation circuit.

The waveform shaping circuit 4 shapes the analog signal output from the barcode pen 2 into a rectangular wave as shown in FIG.

The reading end detection circuit 5 detects the end point of reading the barcode signal, and measures the time of the "0" portion of the signal transmitted from the waveform shaping circuit 4, and determines whether this is the barcode end timing TE. When the limit is exceeded, an output is generated and the end of reading is detected.

The time width measuring circuit 6 measures the time of the "1" part and the time of the "0" part of the barcode signal, and
In the figure, ttI... is measured.

The storage circuit 7 performs control to store the t [~multi ÷...] output from the time width measurement circuit 6 in the memory 8.
Data is stored in the memory 8.

The memory 8 is a memory in which the measured value t[~t÷... of the time of "1" and "0" of the barcode signal measured by the time width measuring circuit 6 is stored.

Register 9 is an output register in which data read from memory 8 is temporarily set.

The read circuit 10 is a data read circuit that performs various controls for reading data stored in the memory 8.

The storage number counter 11 is a counter that counts the number of data stored in the memory 8, that is, the number of ti to ttI . . . .

A comparison circuit 12&i is a comparison circuit that compares the number of data stored in the memory 8 counted by the storage number counter 11 and a reference value indicating the number of barcode signals output from the reference value generation circuit 13. If the count value of the counter 11 is small, the data stored in the memo 138 is related to noise, and the data stored in the memory 8 is read out without assuming that the barcode signal is completely stored. There are 17 things.

However, if the count value of the stored number counter 11 is equal to or larger than the reference value, it is assumed that the memory 8 contains a bar code signal and its readout is controlled.

The reference value generation circuit 13 generates comparison reference values for the comparison circuit 12, and the number of reference values it outputs is at least the same as the number of signals constituting the barcode signal. Therefore, if the number of barcode signals set in the memory 8 is smaller than this reference value, it means that the barcode signal does not exist in a complete form in the memory 8 and contains noise. Indicates that it is meaningless to make a judgment using the judgment circuit.

Next, the operation shown in FIG. 3 will be explained.

When the barcode pen 2 is scanned onto a processed barcode on the barcode sheet, an output is generated from the barcode pen 2 in response to this, and this output is sent to the waveform shaping circuit 4. The waveform is shaped into a rectangular wave, and this rectangular wave is transmitted to the reading end detection circuit 5 and the time width measurement circuit 6. Then, in the reading end detection circuit 5, the rOJ
The time length of the period is measured, and the time width measurement circuit 6 measures the time length of the "1" period and the time length of the "0" period. In this way, the period t5, which is the first "1" in FIG. 8 are sequentially stored. Then, the period tl, which is defined by the last "1", is transmitted, resulting in a continuous "0" period. When this "0" period exceeds Tm, the reading end detection circuit 5 transfers the detection signal to the storage number counter 11.
The number of signals stored in the memory 8 up to that time is sent to the comparison circuit 12. At this time, the reference value outputted from the reference value generation circuit 13 is transmitted to the comparison circuit 12. As a result of this comparison, if the number of signals stored in the memory 8 is smaller than the reference value, the comparison circuit 12 outputs a mismatch signal NG, the storage circuit 7 invalidates the stored contents of the memory 8, and the storage number counter Clear 11. In other words, when this mismatch signal is output,
Since the barcode signal is not completely stored in the memory 8, it is regarded as noise and its contents are not extracted from the memory 8.

However, as shown in period T2 in FIG. 2 (b), when the barcode signal is completely read, the number of signals stored in the memory 8 either matches the reference value or if it contains noise. is larger than the reference value. therefore,
Based on the output from the reading end detection circuit 5, the comparison circuit 12
As a result of comparing the counted value of the stored number counter 11 with the reference value, if the counted value matches or is larger, the comparison circuit 12 outputs a match signal OK, controls the readout circuit 10, and reads the memory. Measured values 11, 1 .・
... are sequentially output to the register 9, and from the register 9, the measured values 1. ．． 12
... is sent and the barcode is determined. Further, the coincidence signal OK is transmitted to the storage number counter 11 and cleared.

As explained above, according to the present invention, by detecting the number of transmitted signals for each block and comparing it with a reference value,
It is immediately determined whether barcode determination is necessary or not. Therefore, the noise generated when the barcode pen is placed on the barcode sheet is not transmitted to the barcode judgment circuit for judgment.
Data processing speed can be improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a bar code reading method and problems in the prior art, FIG. 2 is an explanation of bars and codes and a detailed explanatory diagram of the present invention, and FIG. 3 is a diagram showing the configuration of an embodiment of the present invention. In the figure, 1 is a barcode sheet, 2 is a barcode pen, 3 is a barcode, 4 is a waveform shaping circuit, 5 is a reading end detection circuit, 6 time width measurement circuit, 7 is a storage circuit, and 8 is a memory , 9 is a register, 10 is a readout circuit, 11 is a storage number counter, 12 is a comparison circuit, and 13 is a reference value generation circuit. Patent applicant Fujitsu Ltd. Representative Patent Attorney Akira Yamatani

Claims (1)

[Claims] (1) In this barcode reading method, which has a reading means for reading a barcode and a barcode determination means for determining the barcode based on the reading output of the reading means, a signal for counting the number of signals transmitted from the reading means Counting thousands of steps,
A barcode storage means for storing a barcode, a reading end detection means for detecting the end of reading of the barcode signal, and a comparison means are provided, and the number of signals read when the end of reading of the barcode signal is detected is set as a reference value. A barcode reading method whose mission is to compare the signals and check the validity of the previously read signals based on the comparison results.