JPS584485A - Symbol demodulator - Google Patents

Abstract

PURPOSE:To prevent misreading, by reading a bar code symbol in 1/4 unit so that the said bar code symbol can be read at any location and providing lateral lines at upper and lower end of the symbol code. CONSTITUTION:The time width of white/black for an input signal is measured at a counter 4 and the result is stored in a shift register 5. The normality of the data is discriminated at check sections 10, 11, 12 and 13. If a normal data, a control section 14 sets a gate 25 via an output control section 24 to store the data in the register 5 to buffers 29 and 30. When data for two characters' share is stored in the buffers 29 and 30, the section 24 opens a gate 33 to output the data in the buffers 29 and 30 via a demodulation section 35. No misreading can be caused by providing lateral lines having >= two times the reference width at the upper and lower end of the bar code symbol.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a symbol demodulation device for reading barcode symbols attached to products etc. for mechanization of retail trade.

Currently, the barcode symbol in which the product code number is attached to a stick in the longitudinal direction has a universal symbol Ij.
P C (Universal Product Code)
) /A, UP C/E, EAN (Euro
pean Article Number) 18 digits, 1
3 digits and J A N (Japan Article N
nmber) There are 18 digits, 13 digits, etc. There are various methods of reading the code, one of which is a method of scanning a laser beam and using its reflection to read a black and white bar code symbol. This method using laser light has a feature that the reading direction range is wider than other methods.

FIG. 1 is a diagram showing an 8-digit barcode symbol. Two-digit code A starting from the left.

There are B, C, and D, and the guard par 1゜11e on both ends is the center of code A, B%C, D, that is, code B and code C.
Center bar 2 is in the middle. When reading the barcode symbol shown in Fig. 1, conventionally, codes A and B sandwiched between guard bar 1 and center bar 2 and center bar 2 are read.
and the code C1D written by the guard par 1 were read by scanning the laser beam twice. In this method, the readable direction is about 67 degrees, which is less than 90 degrees, so there are directions in which reading cannot be done even if a laser beam is scanned in a grid pattern.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide a symbol demodulation device that is capable of reading barcode symbols in any direction by reading the barcode symbols in units of O. The goal is to provide the following.

Hereinafter, the present invention will be explained in detail using examples of the present invention.

The basic principle of the present invention is shown in FIG. Conventionally, line S1 and line S
2 was the limit that could be read.

In other words, this is because the two-digit codes A and B6 or C and D are read in the same scan, and the angle between Sl and 82,
That is, the readable direction (angle) α was 67°.

Since the present invention reads the two-digit codes A, B, and C%D in separate scans, for example, when reading the code D in FIG. 2, it is clear that S3 and 84 are the limits that can be read. As such, the readable direction (angle) β of the present invention is approximately 106°.As a result, it is possible to read a barcode symbol in any direction by scanning a laser beam in a grid pattern, for example. becomes.

FIG. 3(a) shows an embodiment of the present invention. Input terminal 3 is connected to shift register 5 via counter 4 . Shift register 5 check output 6.7.8.9Fi
Guard bar length, center bar length, check section 1 respectively
0, input to inputs 15, 16, 17, and 18 of the control unit 14 via the margin length check unit 11, character length check unit 12, and character number check unit 13. Control outputs 19, 20, 21, and 22 of the control section are connected to each of the f:r-) control sections 10.11 and 12.13Vc, respectively. Further, the output 23 of the control section is connected to the gate 25 via the output control section 24. The output 26 of the shift register 5 enters the gate 25. gate 2
Outputs 27 and 28 of 5 go into buffers 29 and 30, respectively, and outputs 31 and 32 of buffers 29 and 30 go to gate 33.
to go into. Output 34 of gate 33 is output to output 36 via demodulator 35 .

A counter 4 measures the time width of white and black of a barcode signal input from an input terminal 3, and the result is stored in a shift register 5. A guard par length and center bar length check section 10, a margin length check section 11, a character length check section 12, and a character number check section 13 determine whether the data stored in the shift register is a regular signal.

If the data is normal data, the control section opens the gate 25 via the output control section 24 and stores the data stored in the shift register 5 into the buffer 29 or 30. Buffers 29 and 30 [When data for two characters is stored, the output control unit 24
3 is opened, and the data for the two characters stored in the buffer is input to the demodulator 35. The demodulator 1 section 35 demodulates the data into a code and outputs it.

The above operation will be explained in detail with respect to the check section.

FIG. 3(b) shows an input signal input to the input terminal 3.

Pulses PO to P6 are sequentially input. The time from the falling edge of PO to the falling edge of PL is calculated from the rising edge of TOSPI to P2.
TI is the rising edge of Pi, and T2 is the falling edge of P2 from the falling edge of Pi.
, from the rise of P2 to the rise of P3 is T3, from the fall of P2 to the fall of P3 is T4, from the rise of P3 to the rise of P4 is T5, from the fall of P3 to the rise of P4 is T6, P4
From the rising edge of P5 to T7, from the falling edge of P4 to P
The falling edge of P5 is T8, the rising edge of P6 from the rising edge of P5 is T9, and the falling edge of P6 from the falling edge of P5 is TIO.

The guard bar length, center par length, and check section is a section that checks the guard bar-1 or the center bar, and checks the conditions of T2 in Tl and T+1 in Tn, and if the conditions match, it is notified to the control section.

The above n is 2116 if there is a center bar after four characters, and 29 if there is a center bar after four characters.

The margin check section determines whether the guard bar length, center bar length, and information checked by the check section are guard bars or center bars.

If the above condition is TI during TO, the center bar, T
If O>3TI, it is determined that there is a guard bar, and the control unit 14 is notified. Character length check section 12
Now check the character length. The current character length CN (N is an integer from 1 to 6) is compared with the previous character length CN-1, and if they do not match and the ratio exceeds a predetermined value, it is determined to be a misreading and the control is performed. The character number checking unit 13 checks the number of characters. The check uses Ktf2, 4.6 characters as the base number for 8 digits, and Ktf2, 4.6 characters for 12 digits. When a barcode symbol is read by a number, which is a feature of the present invention, the base number is 2 or 3 characters, and when a barcode symbol can be read by a number, in other words, the 8 of the barcode symbol is scanned. In this case, it is also possible to use a 4 or 6 character number as the base number.

The present invention performs processing in units of two digits.

This may result in inconvenient misreading.

FIG. 4 represents a barcode symbol.

It is assumed that the scanning line moves from the right side of each character C1 to C8. c6 1110010% c7 1100110,
Let c8 be 1010000.

FIG. 5 is an enlarged view of the barcode symbol of A19. Generally, the guard bar GB (represented by 1 in Fig. 4) is read first, but if the scanning moves on the line E under the above conditions, the character 80F area is read as the guard bar CB. It may be misread. In other words, the conditions for guard bar GB are 101 and oooo before that.
This is because ooo exists, and scanning along line E in FIG. 5 satisfies this condition.

In the present invention, in order to solve the above-mentioned misreading, the bar code symbol is provided with horizontal lines having a smaller reference bar width and twice the line width at the upper and lower ends of the bar code symbol. FIG. 6 shows the case where a horizontal line H is provided at the top end of the barcode symbol shown in FIG. 5 (the horizontal line provided at the bottom end of the barcode symbol is not shown). In other words, even if it is misread as guard bar GB, the rCooooooo before 101 does not depend on it, so it will not ultimately be determined as guard bar CB. It also occurs in

Next, FIG. 7 shows a case where CB (01010) is misread between characters. The only characters that can be the first 01 of a CB are stone 0, stone 3, E4, and E6, and the following 0
The only character that can be 10 is 06. Therefore, this sequence does not exist for the right character. Further, unless the character to the right of o6 is also 06, the phase shift will not be established.

FIG. 8 shows an example of misreading due to phase shift.

As shown in FIG. 8, the regular character i6 is misread as stone 6 due to phase shift, but there is no problem since the value does not change.

Next, FIG. 9 shows an example of misreading due to a newly provided bar. This is not a problem because Luca misreads the regular characters 04, El, and 3 as the false character o6, and the modulus 10 cannot be taken.

As mentioned above, processing barcode symbols in units of two digits is generally thought to result in many misreadings, but the reference width is By providing at least twice as many horizontal lines, there is almost no possibility of misreading, and it becomes possible to process in units of two digits.

Additionally, since it is now possible to process in units of two digits, reading and reading performance in all directions has been improved.

4. A simple explanation of the first page, Figure 1 shows the barcode symbol, Figure 2 shows the 2 digits,
A diagram showing the effective reading direction when reading a code in units of 4 digits, FIG. 3 is a diagram showing an embodiment of the present invention, FIG. 4 is a diagram showing a barcode symbol, and FIG. 5 is a diagram showing a barcode symbol. FIG. 6 is a diagram showing the prevention of misreading of barcode symbols, and FIG. 7 is a diagram of the barcode used in the present invention.
．． FIG. 8.9 is a diagram explaining that there is no problem even if misreading occurs in the apparatus according to the present invention.

l... Cart bar, 2... Center bar °-110.
・Guard par length center par length check section, 11...
- Margin length check section, 12...Character length check section, 13...Character number check section, 24...
・Output control section, H...Horizontal line provided at the top of the Nokuichi code symbol.

Patent applicant: Fujitsu Limited

Claims (1)

Claims: 1) A symbol demodulation device characterized in that the barcode symbol reading device includes means for reading barcode symbols in units of length. 2) A patent claim characterized in that a horizontal line having a line width at least twice the basic bar width is provided on a side part along the longitudinal direction of the barcode symbol, and means for reading a barcode symbol having the horizontal line is provided. The symbol demodulation device according to the range fa1 term.