JPH01269187A - Code reader - Google Patents

Abstract

PURPOSE:To output only an error signal concerning the reading of a code such as a bar code, and to prevent a useless error signal from being issued by outputting the error signal of a decoding error after a character code adjacent to a start code or a stop code is decoded. CONSTITUTION:A counter circuit 260 is incremented by the signal of a signal line Na, and a counted value is inputted from a signal line Nu to a character number comparator 262. When the counted value from the signal line Nu arrives at a constant set at a constant memory 261 beforehand, the character number comparator 262 outputs the signal to a signal line No. For example, when 2 is set at the constant memory 261, after the two character code are read by a character code bit image comparator 258, the error signal is outputted from an OR circuit 264 by the signal outputted from the character code bit image comparator 258 to a signal line Ni, and an alarm is sounded through a buzzer by a buzzer control circuit 263. Thus, the code reading operation can be made efficient without being troubled by the useless alarm.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention scans and reads a code displayed on a medium (for example, a bar code display) with a photoelectric converter or the like, and converts the information shown by the code into a computer. The present invention relates to a code reading device that decodes and outputs a signal that can be processed by a computer, and particularly relates to a code reading device that suppresses the output of meaningless error signals and improves comfort during use.

[Conventional technology]

Code reading devices photoelectrically convert codes displayed in various code systems on media such as forms and the surface of goods using scanners such as optical reading devices, and decode and output signals that can be processed by computers such as microprocessors. It is something to do. The displayed codes include special display codes such as barcodes and Carla codes, as well as general characters, and in order to decipher these codes, certain standards must be set for the display method. This standard includes regulations regarding display intervals and display ranges. For example, barcodes include those listed on pages 3 to 9 of the Japanese Industrial Standard (J Is
Standard (ANSI:MHlo, 8M
-19833, page 8, etc.

FIG. 2 is an explanatory diagram of an example of a barcode code as an example of a display code and its read waveform, where (a) is a displayed barcode, and S is a start code (or stop code).
, C1 indicates the first character code, and C2 indicates the second character code.

Also, (b) is a read waveform obtained by scanning the barcode in (a) in the direction of the arrow. Here, the bars shown in black in (a) (there are narrow bars and wide bars) are at high level (“H”). , the read waveform is shown as a low level (“L”) for white spaces (there are narrow spaces and wide spaces).

When reading such a code, a photoelectric converter (scanner) is scanned in the direction of the first character C1 from just before the start code in FIG. 2(a) in the direction of the arrow.

At this time, it is determined based on the start code S whether or not the code reading operation has started normally. If the start is determined to be abnormal, the device will be reset; if the start is determined to be normal, the symbol bar and space (“H” and L) will be displayed.
Decoding is performed according to the count value of pulses such as a clock corresponding to the . Then, when the reading of the code is completed and the stop code is confirmed, the read data is output from the decoder.

Note that there is also a method in which each character is sequentially decoded and output.

FIG. 3 is a block diagram illustrating the circuit configuration of a conventional code reading device, in which 101 is a photoelectric conversion section, 104 is a counter section, 106 is a stop determination section, 107 is a decoder section,
109 is a start determination section.

In FIG. 2, the photoelectric conversion unit 101 scans and reads the barcode, converts it into two system codes of 'H' and 'L', and outputs it. and “L” time is counted and output using the clock signal CL, and this counting is (i)
Method of sequentially outputting the value being counted (count value), (ii
) A method of outputting the count value every time the counting of "H" and "L" is completed, (iii) A method of temporarily storing the count value of "H" and "L" and outputting it after the barcode counting is completed. , etc.

Further, the start determination section 109 performs a start determination based on the count value from the counter section 104, and resets the operation of the counter section 104 when it is determined that there is a start error. The stop determination unit 106 makes a stop determination based on the count value output from the counter unit 104, and when determining a stop, causes the decoder unit 107 to decode the count value output from the counter unit 104. The decoder section 107 decodes the count value from the counter section 104 and outputs the result as read data.

The photoelectric conversion unit 101 is provided with a photoelectric converter, a binarization circuit, a fast space detector, a first edge detector, a second edge detector, and a fast bar/space determination circuit (not shown). The electrical signal read by scanning the barcode is converted to “H” by the binarization circuit.
When the first space detector detects a space, the electrical signal changes from the first space to a bar (“L” → “H”) and is output.
”) or change from bar to space (“H′ = “L”)
is detected by a first edge detector, and a bar-to-space change (“H”-“H”) or a space-to-bar change ( (L"→"H") is detected by the second edge detector.

The counter unit 104 is reset by the first edge detector and the second edge detector, and the respective “H”
and "L" time, and if this counted value exceeds a preset overflow value (for example, if the scanner is stopped midway), a reset signal is issued to reset the device. In addition, “H” and “L” of electrical signals
When the count value of " does not exceed the overflow value, the count value of these bars or spaces is sent to the decoder section 107.

The start determination unit 109 also compares the count values of at least the first bar and space counted by the counter unit 104, and determines whether the count value of the space or bar is equal to or less than a certain constant times the count value of the immediately preceding space or bar. If there is, it is determined that it has started. In this case, the first bar/space determining unit counts the sum of bars and spaces after detecting the first bar, and when this number reaches a predetermined value, the start determining unit 109 performs a start determination.

If the start determination unit 109 determines that the count value of a space or bar exceeds a certain constant multiple of the count value of the immediately preceding space or bar, no start determination is performed and a reset signal is issued to reset the device. Ru.

Further, the stop determining unit 106 determines that the bar or space currently being read is a stop when the count value of the bar or space that is currently being read becomes a certain constant times or more the count value of the immediately preceding space or bar. The decoding operation of decoder section 107 is controlled.

The decoder unit 107 decodes the meaning of the code of the barcode based on the count value of the clock CL corresponding to the width of the bar or space of the read barcode, as shown in FIG. Bit image converter 2
3. Bit image memory 24, character converter 25
and an output circuit 26.

The bit image converter 23 operates on the detection output of the second edge detector from the signal line i, converts the count value input from the signal line t into a bit image, and stores the bit image in the bit image memory 24 via the signal line W. Make me remember. If an error occurs during this conversion, a reset signal is output. The bit image memory 24 (i) stores the bit image from the signal line W, and (ii) sends the stored bit image by signal input from the signal line V to the character converter 25 via the signal line X. (iii) When a reset signal is input, the stored bit image is cleared.

The character converter 25 starts operating in response to a signal input from the signal line 2, converts the bit image coming from the bit image memory 24 into a character, and supplies this to the output circuit 26 via the signal line y. Note that a reset signal is output when an error occurs during character conversion.

Then, the output circuit 26 sends out the character signal from the signal line y to the output line 2, and supplies it to a display means (not shown).

Upon completion of this transmission, a reset signal is output.

FIG. 4 is a circuit diagram showing the configuration of the character converter 25, in which 253 is a start code bit image memory, 254 is a start code bit image comparator, 25
5 is a stop code bit image memory, 256 is a stop code bit image comparator, 257 is a character code bit image memory, 258 is a character code bit image comparator, 259 is a character code memory, 263 is a buzzer control circuit, 252 is a switch ,2
50, 251, 265.42 are OR circuits, and 24 is a bit image memory.

As shown in the figure, the bit image converter 23 of FIG.
The bit image memory 24 connected to the signal line W is
The character converter 25 is connected to a switch 252 by a signal line
One input terminal of 8 is connected to signal line C and signal line T, respectively.

Further, the other input terminals of the start code bit image comparator 254, the stop code bit image comparator 256, and the character code bit image comparator 258 are connected to the start code bit image memory 25, respectively.
3. Stop code bit image memory 255 and character code bit image memory 257 are connected by signal line S, signal line Te, and signal line G. One output terminal of the start code bit image comparator 254 is connected to the switch 252 and the OR circuit 251 by a signal line.
One output terminal of the character code bit image comparator 258 is connected to the other input terminal of the OR circuit 251 by a signal line N.

The output terminal of this OR circuit 251 is
connected to one input terminal of the R circuit 42;
The other input terminal of the stop determination unit 106 in FIG.
The output terminals of are connected by a signal line V. OR circuit 42
The output terminal of is connected to the bit image memory 24.

Further, the other output terminal of the start code bit image comparator 254 is connected to one input terminal of the OR circuit 250 and one input terminal of the OR circuit 265 through signal line Q. Similarly, the other output terminal of character code bit image comparator 258 is connected to the other input terminal of OR circuit 250 and the other input terminal of OR circuit 265 via signal line 2.

Furthermore, the output terminal of the stop code bit image comparator 256 is connected to the output circuit 26 of FIG. The input terminal of the character code memory 259 is connected to the input terminal of the character code memory 259, and the output terminal of this character code memory 259 is connected to the second
It is connected to the output circuit 26 shown in the figure. The output terminal of the OR circuit 265 is connected to the buzzer control circuit 263 by a signal line.

In the conventional code reading device having such a configuration, when the stop determination section makes a stop determination and a stop determination signal is output, this stop determination signal is transmitted from the signal line V through the OR circuit 42 to the bit image memory. 24, and the decoding operation of the decoder section 107 is controlled.

First, the bit image for the first character is read out from the bit image memory 24, and the start code bit image comparator 2 is read out from the switch 252 via the signal line
54. Then, the bit image of the start code stored in advance in the start code bit image memory 253 and the bit image input from the signal line C are compared, and if the two do not match, a reset signal is sent to the signal line C. This reset signal is output
The device is reset by being output through the R circuit 250, and this reset signal is then output to the OR circuit 26.
5 as an error signal to the buzzer control circuit 263, and a buzzer generates an alarm.

When the comparison in the start code bit image comparator 254 results in a match, a match signal is output to the signal line 2, and the match signal switches the switch 252 to connect the signal line X and the signal line 2. At the same time, the match signal is output to the OR circuit 2.
51, bit image memory 24 via OR circuit 42
The bit image for the next character is read out from the bit image memory 24, and the bit image for the next character is input to the switch 25.
2 through the stop code bit image comparator 256
is input to the character code bit image comparator 258.

The character code bit image comparator 258 has, for example, a comparison circuit for the characters represented by the barcode, and compares the bit image (the barcode is The bit image input from the signal line 2 is successively compared with the bit image input from the signal line 2 to check whether or not they match. As a result of this comparison, the bit image stored in the character code bit image memory 257 has
If there is a bit image that matches the bit image input from the signal line 2, a signal is sent to the signal line 2, and the character code corresponding to the matched character code bit image is read out from the character code memory 259.
The signal is input to the output circuit 26 in FIG. 2 via the signal line y.

At this time, character code bit image comparator 2
A signal is also sent from signal line 58 to signal line N, and this signal is OR
It is input to the bit image memory 24 via the circuit 251 and the OR circuit 42, and the bit image for the next character is read out from the bit image memory 24.

Furthermore, when the character code bit image comparator 258 compares, if a bit image matching the bit image input from the signal line 2 is not found among the bit images stored in the character code bit image memory 257, An error signal is output to signal line 2. This error signal is manually input to the buzzer control circuit 263 via the OR circuit 265, and a buzzer alarm is issued.This error signal is also output as a reset signal via the OR circuit 250, so that the device can be reset. It will be done.

In this way, bit images for each character of the character code are successively compared with the bit images stored in the character code bit image memory 257. Then, when the bit image input from the signal line 2 to the stop code bit image comparator 256 matches the bit image of the stop code stored in advance in the stop code bit image memory 255, the end of code reading is confirmed. , an end signal is output from the stop code bit image comparator 256 to the signal line S. This end signal is input to the output circuit 26 shown in FIG. 2, and the code reading data is outputted from the output circuit 26 and supplied to a display means (not shown).

[Problem to be solved by the invention]

In the above-mentioned conventional technology, the comparison in the character code bit image comparator 258 shows that the bit image input from the signal line does not match any of the bit images previously stored in the character code bit image memory 257, and the bit image is decoded. If it is not possible, an error signal is immediately output, and the buzzer control circuit 263 issues an alarm using a buzzer.

However, with this type of code reader, erroneous input may occur if the circuit is unstable immediately after power is turned on, and characters may be printed near the code such as a bar code to be read, making it difficult to read. During operation, the 2 system code may be incorrectly input from this character.

Error signals issued in response to such erroneous inputs are essentially meaningless, and with this type of code reading device, the barcode or other code that you are attempting to read may be difficult to read due to dirt or changes in scanning speed. Only if this is not possible should an error signal be output and an alarm issued.

The present invention has been made based on the current state of code reading devices described above, and its purpose is to output only error signals related to reading of target codes such as barcodes, and to emit meaningless error signals. It is an object of the present invention to provide a code reading device that has comfortable operability without any friction.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a photoelectric conversion unit that reads a code displayed on a medium, and a system that responds to changes in the two system numbers output from this photoelectric conversion unit. a counter unit that counts the time spent using a clock signal; a start determination unit that determines the start of reading based on the count value output from the counter unit; and a start determination unit that determines the start of reading based on the count value output from the counter unit. The start determination section includes a stop determination section that makes a determination, and a decoder section that decodes the count value output from the counter section, and the start determination section has a reset means that resets the counter section when a start determination error occurs, The determining section has an actuating means for activating the decoder section when determining a stop, and the decoder section outputs an error signal indicating a decoding error after at least one character code adjacent to the start code or the stop code is decoded. The present invention is characterized in that it has a configuration including an output means for.

[Effect]

Based on the count value output from the counter section, the count values of at least the first bar and space are compared in the start judgment section, and if the count value of the space or bar is equal to or less than a certain constant multiple of the count value of the immediately preceding space or bar. If so, a start determination is made as to whether reading can be started.

Then, the meaning of the sign of the barcode is decoded in the decoder section based on the count value corresponding to the width of the bar or space of the barcode output from the counter section. In this case, once the bit image of the start code is confirmed, bit images corresponding to the character code are sequentially decoded for each character.

After at least one character code adjacent to the start code (or stop code in the case of reverse reading) is decoded by the output means provided in the decoder section, a decoding error error signal is output. An error signal is output and an alarm is issued only when a reading error occurs in the original reading of the barcode, such as a change in scanning speed when reading the barcode or dirt adhering to the space. An alarm will not be issued if there is an incorrect input due to circuit instability immediately after the power is turned on, or an incorrect input due to reading characters other than barcodes.

When the code reading is completed and the stop code is confirmed, the code read data is supplied from the decoder section to the display means.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a character converter according to an embodiment of the present invention, and the same reference numerals as in FIG. 4 correspond to the same parts.

In the figure, 253 is a start code bit image memory, 254 is a start code bit image comparator, 255 is a stop code bit image memory, 25
6 is a stop code bit image comparator, 257 is a character code bit image memory, 258 is a character code bit image comparator, 259 is a character code memory, 260 is a counter circuit, 261 is a constant memory, 262 is a character number comparator, 263 is the buzzer control circuit. Also, 42. 250.251°264
252 is an OR circuit, 252 is a switch, and 24 is a bit image memory.

In the embodiment shown in the figure, a counter circuit 260, a constant memory 261, a character number comparator 2
62 is added, the signal line S is connected to the input terminal of the counter circuit 260, and the output terminal of the counter circuit 260 is connected to one input terminal of the character number comparator 262 by the signal line N. The output terminal of the constant memory 261 is connected to the other input terminal of the character number comparator 262 by a signal line N.
The output terminal of 62 is connected to one of the input terminals of OR circuit 264 by a signal line.

Note that, in FIG. 1, unlike the character converter shown in FIG. 4, the signal line H is not connected to the input terminal of the OR circuit 265.

The configuration of other parts in the embodiment of the present invention is the same as that of the conventional code reading device already explained using FIGS. 3 and 4.

In such a configuration, the OR circuit 42 acts as an actuation means.
Further, the counter circuit 260, constant memory 261, character number comparator 262, and OR circuit 264 constitute output means.

The operation of the above configuration will be explained below.

The stop determination signal from the stop determination section is the signal vAv
When the bit image is applied to the OR circuit 42 through the bit image memory 24, the bit image for the first character is read out from the bit image memory 24. This first bit image is manually input to the start code bit image comparator 254, as in the case of the conventional code reading device described above, and is compared with the start code bit image stored in advance in the start code bit image memory 253. be compared.

When the start code is confirmed by this comparison, a match signal is output to the signal line 2, and this match signal causes the switch 252 to send a signal '!'! sx and signal line are connected, and
By the match signal applied to the bit image memory 24 via the OR circuit 251 and the OR circuit 42, the bit image for the next character is read out from the bit image memory 24, and the bit image is sent to the stop code bit image comparator 256 and the character code bit. Image comparator 258
is input. If the start code is not confirmed by the comparison by the start code bit image comparator 254, a reset signal is output from the signal line H via the OR circuit 250.

When the start code is confirmed by the start code bit image comparator 254, the character code stored in the character code bit image memory 257 is compared to the bit image input to the character code bit image comparator 258 as described above. A comparison is made with the corresponding bit image. If the bit images do not match in this comparison, a reset signal is issued from signal line 2 via OR circuit 250.

When the character code bit image comparator 258 confirms that the bit images match, a signal is output to the signal line, and this signal causes the character code memory 259 in which the character code represented by the bar code to be previously set. The corresponding character code is read out from the input signal and outputted to the signal 'Ay', which is then outputted to an output circuit (not shown).

At the same time, the counter circuit 260 is incremented by the signal on the signal line S, and the counted value is input to the character number comparator 262 from the signal line N. This character number comparator 262 outputs a signal to the signal line No. 0 when the count value from the signal line N reaches a constant (for example, 2) set in the constant memory 261 in advance.
is set, after two character codes are read by the character code bit image comparator 258, the character code bit image comparator 25
8 to the signal line 2, the OR circuit 26
4 outputs an error signal, and a buzzer control circuit 263 issues an alarm using a buzzer.

Therefore, for example, if there is an incorrect input that occurs when the circuit is in an unstable state immediately after the power is turned on, or if there is an incorrect input from a character other than the code that is being read, such as a bar code, the buzzer will not alert you. An alarm is issued only when the target code cannot be read, such as a change in scanning speed or a change in scanning speed. Therefore, the code reading operation can be performed comfortably and efficiently without being bothered by meaningless alarms.

Other operations, such as confirmation of the stop code by the stop code bit image comparator 256 and output of code read data from the output circuit to the display means based on this confirmation, are performed by the conventional code reading device described above. This is the same as in the case of .

In the above embodiment, when two character codes are read from the code in the character code bit image comparator, a four-color signal is output for subsequent processing. The present invention is not limited to the embodiments, and for example, when one character code is read, a subsequent error signal may be output.

Further, in the embodiment, a configuration in which the decoding operation is performed in the order of the start code, character code, and stop code has been described, but the present invention can also perform reverse scanning, and the decoding operation can also be performed in the order of the stop code, character code, and start code. It is also possible to have a configuration that allows this.

〔Effect of the invention〕

As explained in detail above, according to the present invention, an error signal is not output even if the circuit is in an unstable state immediately after the power is turned on or if an incorrect input is caused by reading a character other than a code, and an error signal is not output due to the accumulation of dirt or a change in scan speed. An error signal is output only in cases where the code cannot be read. Therefore, the code reading operation can be performed efficiently and comfortably without being bothered by the generation of meaningless alarms.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the main part of an embodiment of the present invention, FIG. 2 is a barcode display example as an example of a code and its read waveform, and FIG. 3 is a diagram showing the configuration of a conventional code reading device. FIG. 4 is a block diagram showing the configuration of the main part of FIG. 3. 24--Bit image memory, 42,250
゜251.264-----OR circuit, 252--
---All changers, 253.--1--Start code bit image memory, 254..-m--Start code bit image comparator, 255-----
-1 Stop code bit image memory, 256-
・-Stop code bit image comparator, 257-
...-Character code bit image memory, 25
L--Character code bit image comparator, 259--Character code memory, 2
60-----Counter circuit, 261--Fixed number memory, 262--Character number comparator. Figure 2

Claims (1)

[Claims] (1) A photoelectric conversion unit that reads the code displayed on the medium;
a counter unit that uses a clock signal to count the time corresponding to the change in the binary signal output from the photoelectric conversion unit; a start determination unit that determines the start of reading based on the count value output from the counter unit; The start determination unit includes a stop determination unit that determines whether to stop reading based on the count value output from the counter unit, and a decoder unit that decodes the count value output from the counter unit. The stop determining section has an actuating means for activating the decoder section at the time of stop determination, and the decoder section has a reset means for resetting the counter section when determining a stop code. 1. A code reading device comprising an output means for outputting an error signal indicating a decoding error after a character code is decoded.