KR940006118B1 - Middle bar detection and correct character decision method and apparatus of bar code system - Google Patents

Abstract

The device consists of a buffer part (20) for buffering character width data (cTa, cTb, cTc, cTd), an add part (30) for adding character width data (cTa),(cTc) of falling edge and character width data (cTb),(cTd) of rising edge, a comparative part (40) for comparing outputs (cTa+cTc or cTb+cTd) of the add part (30) with four, six, and eight module, and a signal generating part (50) for outputting a middle bar signal using output data of the comparator (40) and correct character signals.

Description

Method and device for middle bar detection and party character detection of bar code system

1 is a decoder peripheral circuit diagram of a barcode read system according to the present invention.

2 is a block diagram of the intermediate bar detection and party character discrimination device in FIG.

3 is a characteristic diagram showing a code (UPC) system of bar codes applied to the present invention.

4 (a) is a configuration diagram of a character applied to the present invention, Figure 4 (b) is a table showing a delta distance system of adjacent bars and a space module sum applied to the present invention.

5 (a) and 5 (b) is a signal detection characteristic diagram by the delta distance method applied to the present invention.

6 is a characteristic diagram of a middle bar detection waveform according to the present invention;

7 (a) to 7 (l) are operating waveform diagrams according to FIG.

* Explanation of symbols for main parts of the drawings

20: buffer 21-24: buffer

30: Adder 31-34: Adder

40: comparator 41-44: comparator

50: signal generator 51: mono multi vibrator

52, 53: flip-flop AD1-AD5: end gate

The present invention relates to a method and apparatus for detecting a bar bar and a party character of a bar code system. In particular, after detecting a center guard bar of a bar code, the character on the right side of the bar code is inverted to enable bidirectional scanning and character width. The present invention relates to a method and apparatus for detecting a middle bar of a bar code system and a party character discrimination method to allow only party characters to be compared.

In general, in a barcode system, a barcode signal is input from a peripheral circuit of a barcode decoder to detect a character's characteristic to discriminate only a party character to read a barcode.

However, in the past, it was difficult to detect the middle bar, and thus, it was difficult to recognize whether the character was a legitimate character when scanning each character.

In view of such a conventional problem, the present invention detects a middle bar when the sum data of character widths between adjacent edges of a barcode is 4 modules after the start bar is detected, and when the adjacent character width data is the same, and the middle bar is detected, the right character. If the sum data of the character widths between adjacent edges is less than 8 modules than 6 modules after inverting, the method and device for detecting the middle bar and party character of bar code system that recognizes 7 modules and discriminates them as party characters are praised. This will be described in detail with reference to the accompanying drawings.

1 is a decoder peripheral circuit diagram of a barcode reader system according to the present invention, as shown therein, a barcode detection unit 2 for detecting a barcode signal input from a scanner, and a barcode signal of the barcode detection unit 2 as a pulse signal. By the punch generating part 3 to convert, the counter part 4 which counts the output of this pulse generating part 3, and the count value of the barcode pulse and the counter part 4 of the said pulse generating part 3, A start bar detector 5 for detecting a start guard bar (SGB), a base module generator 6 for generating a base module, and a character width comparison unit 7 for comparing the character width CCW; , A middle bar detection unit 8 for detecting a center bar (CGB), an end bar detection unit 9 for detecting an end bar (EGB), and a similar character determination unit 10 for determining similar characters ), The total character discriminating unit 11 for determining the total character (TOT), and the parity check The control unit 1 which receives the checker unit 12, the start bar SGB, the character width CCW, the middle bar CGB, the end bar EGB, and the entire character TOT to control barcode reading. An error check unit 4 for checking and compensating for errors under the control of the control unit 1, an input / output memory unit 13 for storing each result of processing data under the control of the control unit 1; A bar code reading unit 15 which receives the bar code data from the input / output memory unit 13 and determines the bar code, and controls the system to scan the bar code and host the bar code data recognized by the bar code reading unit 15. A microprocessor 16 for controlling transmission to the side, a transmission / reception 17 for transmitting the barcode data recognized by the control of the microprocessor 16 and receiving data on the host side, the transmission / reception unit 17, and a host computer. Interface unit for interfacing communication with (19) 18).

Here, in the present invention, the character width comparison unit 7 and the intermediate bar detection unit 8 are constituted by a new hardware. The intermediate bar detection and party character discrimination apparatus of the barcode system according to the present invention is shown in FIG. As described above, the buffer unit 20 which receives character width data cTa, cTb, cTc, and cTd latched at each count value between the falling edge and the falling edge of the character and the rising edge and the rising edge, and the buffer unit ( Adder 30 for summing character width data (cTa), (cTc) between falling edge and falling edge input through 20) and character width data (cTb), (cTd) between rising and rising edges, respectively. The output data (cTa + cTc or cTb + cTd) of the adder 30 is compared with four modules, and the character width data (cTa, cTc) (cTb, cTd) are compared and the output data (cTa +). a comparison unit 40 for comparing the cTc) with the 6 and 8 modules, respectively and determining whether or not it is a 7 module, and each comparison unit of the comparison unit 40 By combining the output data, the signal generator 50 is configured to generate a signal according to a corresponding condition, and output a middle bar detection signal, a character width comparison signal, and a control signal to the controller 1.

The buffer unit 20 receives first and second buffers 21 and 22 and third buffers for character width data cTa and cTb and cTc and cTd respectively, which are counted immediately before the edge. Character buffer data (cTa, cTb) counted immediately before and by combining the four buffers (23, 24), the start bar signal (SGB), the rising edge and the rising edge detection signals (FTc), (FTa), respectively, AND gates (AD1) and (AD2) for applying the enable signals (G) of the first and second buffers 21 and 22 and the third and fourth buffers 23 and 24 to receive (cTc and cTd), respectively. Consists of

The adder 30 adds the character width data cTa between the falling edges, cTc, and the character width data cTb and ccb between the rising edges inputted through the buffer unit 20, respectively (cTa). + cTc), (cTb + cTd) The first, second, adders 31 and 32 and the falling edge width data that are currently input without passing through the buffer unit 20 (cTa + cTb) And four adders (33) and (34).

The comparator 40 includes a first comparator 41 for comparing the sum data (cTa + cTc or cTb-cTd) between the adjacent edges of the adder 30 and the four module data of the basic module generator 6. Second and third comparators 42 for comparing the sum data cTa + cTc between the same edges of the adder 30 and the 6 module data and 8 module data of the basic module generator 6, respectively; 43 and a fourth comparator 44 for comparing the data between adjacent edges of the adder 30 (cTa = cTc) and (cTb = cTd).

The signal generator 50 compares the output signal of the mono multivibrator 51 with the moner multivibrator (MM) 51 which generates a constant period high potential signal by the module comparison output of the comparator 40. An AND gate AD3 for AND-combining the output of the fourth comparator 44 for detecting the middle bar of the unit 40, and a middle bar signal in synchronization with the output signal of the AND gate AD3. An AND gate outputting a character character signal according to the detection of 7 modules by AND-combining the flip-flop 52 outputted to the 6 module comparison output and the 8 module comparison output of the comparison unit 40 to the control unit 1. (AD4), the AND gate AD5 for and combining the middle bar signal of the flip-flop 52 with the output of the monovibrator 51, and the control unit in synchronization with the output signal of the AND gate AD5. Flip-flop 53 for outputting a control signal for inverting the right character to (1) It consists of a.

Referring to the operation and effects of the present invention configured as described above are as follows.

The general bar code system is composed of a universal product code (UPC) system as shown in FIG. 3, which consists of a left margin, a start bar, a left character, a middle bar, a right character, an end bar, and a right margin. The center is composed of left and right isomorphs.

Here, the space is detected as "0" and the bar is detected as "1".

As shown in FIG. 4 (a), the character has a value in which left and right characters are inverted. That is, when the left character value of "1101" is "0", the right character value "0" has a value inverted mutually to "1110010".

In addition, the table structure of the module sum of the adjacent bars and the space by the delta distance method for each character is configured as shown in FIG. 4 (b). For example, the character on the left is Ta = 5, Tb = If 3, Tc = 2 and the right character is Ta = 2, Tb = 3, Tc = 5, it represents a decimal “0”, the left character is Ta = 4, Tb = 2, Tc = 3 and the right character is Ta = When 3, Tb = 2 and Tc = 4, the decimal number “9” is represented. That is, the left and right characters have symmetrical values.

Here, the delta distance method means that a bar code signal is a continuous combination of a space ("0") and a bar ("1"). When a character constitutes a character, the rising edge, the rising edge, and the falling edge of adjacent spaces and bars are formed. It is a method of forming a character by detecting edges and falling edges.

Referring to the output waveform of the pulse generator 3 by the delta distance method, as shown in FIG. 5 (a), the falling edge to the next falling edge are Ta when scanning in the right direction, and the rising edge to the next edge is shown. The rising edge is Tb, and the falling edge from the end of Ta to the next falling edge is Tc. On the other hand, as shown in FIG. 5 (b), the falling edge to the next falling edge is Ta when the scan in the left direction is Ta, and the rising edge to the next rising edge is Tb, and the end of Ta in the left scan is Tc is from the falling edge to the next falling edge.

A module is a basic unit constituting a character, and the character is composed of seven modules by a combination of spaces and bars. Therefore, one character is one character from the start falling edge of Ta to the end falling edge of Tc.

Therefore, in the barcode reading control method according to the present invention, which is controlled through the microprocessor 6, the microprocessor 16 checks the speed of the motor and turns on the laser when it is normal when the system is turned on.

Accordingly, the laser beam is scanned on the barcode through the barcode scanner, and the light reflected by the barcode is received from the barcode received by the laser beam, and received by the optical sensor.The decoder decodes the value received by the optical sensor as a barcode signal to surround the decoder. To the circuit.

In the decoder peripheral circuit, as shown in FIG. 1, a process for barcode recognition is performed through each unit.

The delta distance for detecting the values Ta, Tb, and Tc for character determination as shown in FIG. 5 by detecting the rising edge, the next rising edge, the falling edge, and the next falling edge of the adjacent bar and the space of one character. A pulse is generated for a character by the method, and the character pulse is counted through the counter unit 4 to count each count value (cTa, cTb, cTc), the total count value of one character (cTa + cTc), and barcode recognition. A series of data such as a parity bit value, a similar character discrimination value, barcode type information, etc., of which a direction is known, is input to the barcode reader 15.

Since the microprocessor 16 is a barcode type, barcode recognition direction, each type (UPC-A, UPC-E, EAN-8, EAN-13) recognized from the barcode reader 15 that is a code (UPC, EAN) reading chip After receiving a sequence of processes for data transmission by receiving information about a character of the character and transmitting a barcode data to a host, the transceiver unit 17 and the interface unit 18 are enabled. The bar code data processed by the handshaking method is transmitted to the host computer 19 in accordance with the standard serial communication standard (RS-232C).

Here, a description will be given of the party character discrimination operation according to the middle bar detection and character comparison which are the gist of the present invention.

As shown in FIG. 6, the UPC code system includes a start bar ("101"), a left character group, a middle bar ("1010"), a right character group, and an end bar ("101"). The number of characters is the same, and the left character is composed of space, bar, space, and bar order, and the right character is composed of bar, space, bar, and space order.

For bidirectional scanning, make the left character group and the right character group the same system, not inversion, and compare the 4th, 6th, 8th, and 10th modules of the basic module generator 6 in the parity determination unit 12 to the left or right side. Determine if it is a scan.

In this way, the middle bar is detected for bidirectional scanning, and the right character is inverted by the middle bar detection, thereby making the system the same (not inverted) as the left character.

That is, the role of the middle bar recognizes the middle bar and informs the control unit 1 so that the control unit 1 outputs a control signal to the pulse generator 3 to invert the right character signal after detecting the middle bar. To do that.

In the present invention, the method of determining whether the character width data between the edges is the same (cTa = cTc or cTb = cTd) in order to recognize the middle bar, and the sum data (cTa + cTc or cTc + cTd) of the character widths between the edges are four modules. Take a way to determine authorization.

That is, when a barcode signal as shown in FIG. 7 (a) is inputted, the pulse generator 3 generates pulse signals Ta corresponding to each edge and edge as shown in FIGS. 7 (c) to 7 (f). , Tb, Tc, and Td, and counts the values between the respective edges in the counter unit 4, and then detects the start bar through the buffer unit 20 (j) and 7 (l). In synchronization with the signals of the same FTc and FTa, the first and second buffers 21 and 22 buffer the edge width data cTa and cTb, and the third and fourth buffers 23 and 24 buffer the edge width data ( cTc and cTd) are respectively buffered.

At this time, the adder 30 receiving the signal through the buffer unit 20 performs a summation operation. The first, second adders 31, and 32 add character width data between edges, respectively (cTa +). cTc, cTb + cTd) and output to the first comparator 41 of the comparator 40, and the third, fourth adders 33, 34, which have received a character signal not through the buffer part 20, Character width data between falling edges are summed (cTa + cTc) and output to the second comparator 42 and the third comparator 43 of the comparator 40, respectively.

Accordingly, the first comparator 41 compares the output data (cTa + cTb or cTb + cTd) of the first and second adders 31 and 32 with the four module data of the basic module generator 6. If it is equal (P = Q), the trigger signal is output to the mono multivibrator 51 of the signal generator 50, and the mono multi vibrator 51 outputs a high signal of a constant time constant to detect an intermediate bar in the high signal section. Let's do it.

Here, the middle bar detection is performed when the fourth comparator 44 compares the character width (cTa = cTc) of the falling edge and the character fit (cTb = cTd) of the rising edge to be equal (P = Q) to output the middle bar signal. A control signal is output, and the AND gate AD3 of the signal generator 50 logically combines the control signal of the fourth comparator 44 with the output signal of the nomomulti vibrator 51 to clock the flip-flop 52. By applying the pulse signal, the flip-flop 52 outputs the middle bar signal as shown in FIG. 7 (h) to the control unit 1.

When the middle bar signal is detected, the signal generator 50 logically combines the middle bar signal of the flip-flop 52 with the output of the multi-multiplier 51 by the AND gate AD5. The flip-flop 53 synchronized with the output outputs the waveform inversion signal to the control unit 1 to invert the pulse to invert the character on the right side of the pulse generator 3 under the control of the control unit 1. .

Then, the six comparators 42 and 42 receive the sum data (cTa + cTc) of the character widths between the adders 33 and 34 from the falling edges from the adders 33 and 34, and the six modules that are the outputs of the basic module generator 6 and In the case of 7 modules compared to 8 modules, the AND gate AD4 of the signal generator 50 logically combines the outputs of the second and third comparators 42 and 43 to the control unit 1 to 7 modules. Outputs a party character signal indicating that the character width is.

As described above, according to the present invention, the character width between the edges is calculated according to the logical combination after the detection of the start bar, the middle bar is detected, and the right character signal after the detection of the middle bar is inverted to enable bidirectional scanning. By performing the hardware determination, there is an effect that can be easily applied to the detection of the middle bar of the UPC (or EAN) load and the party character discrimination.

Claims (6)

After detecting the bar of the bar code, comparing the sum data of the character widths (cTb-cTd) between the adjacent rising edges and the sum data of the character widths (cTa + cTc) between the falling edges is equal to 4 modules, Compare the character width data (cTb, cTd) and the character width data (cTa, cTc) of the falling edge of (cTb = cTd) (cTa = cTc). After performing the bidirectional scan by inverting the character, the sum data (cTa + cTc) of the character width data between falling edges is compared to 6 modules and 8 modules. Intermediate bar detection and party character identification method of a bar code system, characterized in that the recognition. A buffer unit 20 for buffering the character width data cTa, cTb, cTc, and cTd, and character width data cTa, cTc, and rising edge of the falling edge inputted through the buffer unit 20; The adder 30 that adds the character width data cTb and cTd, and the sum data cTa + cTc or cTb + cTd, which are outputs of the adder 30, are compared with the four modules, and the character width is compared. A comparator 40 for determining whether or not it is the same (cTa = cTc, cTb = cTd) and comparing the sum data (cTa + cTc) with 6 and 8 modules to determine whether or not it is a 7 module, and each of the comparator 40 Apparatus for detecting the middle bar and party character of the bar code system, characterized in that consisting of a signal generating unit 50 for outputting the middle bar signal by combining the comparison output data and outputs the party character signal. The first and second buffers 21 of claim 2, wherein the buffer unit 20 receives character width data (cTa + cTb) and (cTc, cTd), which are width data between edges counted immediately before, respectively. , 22) and the third and fourth buffers 23 and 24, and the start bar signal SGB, the rising edge and the rising edge detection signals FTc and FTa, respectively, are combined in combination, and the character width data immediately counted. an AND gate for applying the enable signals G of the first and second buffers 21 and 22 and the third and fourth buffers 23 and 24 to receive (cTa, cTb) and (cTc, cTd), respectively. AD1), middle bar detection and character identification device of the bar code system, characterized in that consisting of (AD2). 3. The adder 30 further comprises character width data cTa (cTc) between the falling edges and character width data cTb (cTd) between the rising edges, which are input through the buffer unit 20, respectively. (CTa + cTc), (cTb + cTd) to sum up (cTa +) to add the first, second adders 31 and 32, and the falling edge width data currently input without passing through the buffer unit 20, respectively. cTc) Intermediate bar detection and party character discrimination apparatus of a bar code system, characterized in that the third, fourth adder (33), (34). 3. The comparator 40 according to claim 2, wherein the comparator 40 compares the sum data (cTa + cTc or cTb + cTd) and the four module data between adjacent edges of the adder 30, and the addition. Adjacent second and third comparators 42 and 43 for comparing the sum data cTa + cTc, 6 module data and 8 module data between the same edges of the unit 30, respectively. An intermediate bar detection and party character discrimination apparatus of a barcode system, characterized by comprising a fourth comparator (44) for comparing whether data between edges is equal (cTa = cTc) and (cTb = cTd). The signal generator 50 includes a monomultivibrator (MM1) 51 for generating a signal held at a predetermined interval by the four-module comparison output of the comparator 40, and the monomultivibrator 51. Control the middle bar signal in synchronism with the output signal of the AND gate AD3 and the AND gate AD3 for AND-combining the output signal of < RTI ID = 0.0 >) < / RTI > An AND that combines the flip-flop 52 outputted to the unit 1 with the 6 and 8 module comparison signals of the comparator 40 and outputs the just character signal according to the detection of the 7 modules to the control unit 1. In synchronism with the output signal of the AND gate AD4, the AND gate AD5 for and combining the middle bar signal of the flip-flop 52 and the output of the monomultivibrator 51, and the output signal of the AND gate AD5. Flip-flop 53 for outputting the right character inversion control signal to the control unit 1 Intermediate bar detection and party character identification device of a bar code system, characterized in that consisting of.