JPH01133185A - Bar code reader - Google Patents

Abstract

PURPOSE:To attain sure reading without being affected by the variance of printing quality and to improve the reliability of the title device by providing black and white threshold setting circuits and individually setting black and white data deciding thresholds levels. CONSTITUTION:Pulse width read out by a bar code reading circuit 1A is counted by a width counting circuit 1B and respective width values are stored in a width register 1B. At the time of slow scanning, respective threshold setting circuits 9L, 9M calculate and set up the threshold levels of the succeeding black 7P and white 7Q on the basis of the width values of current black 7A and white 7B. When an input signal is a trailing edge signal 20 or a leading edge signal 21, a black/white data detecting circuit 1E decides the immediately preceding data as white or black. A data (0/1) deciding/registering circuit 9N compares the input data with the thresholds set in the circuits 9L, 9M and stores '1' and '0' respectively at the time of larger input data (wide value) and smaller input data (narrow value). Threshold updating/setting circuits 9P, 9Q update/set the thresholds successively to decide the 0/1 of the succeeding black and white data on the basis of the black and white data (width values) inputted immediately before their setters.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a barcode reading device.

BACKGROUND OF THE INVENTION In recent years, barcode reading devices have been used in home appliances, such as video tape recorders (hereinafter referred to as VTRs), in combination with wireless remote control transmitters (hereinafter referred to as remote control transmitters).
It is used to simplify various switch operations when reserving television programs. Barcode tables used for reservation operations are supplied by VTR manufacturers and magazines that carry TV program information, but barcode printing formats, printing accuracy, printing requirements, etc. vary, and barcode reading operations are difficult. In this case, if the scanning start position, scanning speed, etc. at the time of input are not within predetermined conditions, reading errors or malfunctions may occur.

For this reason, the conventional remote control transmitter has a barcode input section 1, for example, as shown in FIG. Barcode decoding section 2. It has a remote control signal output section 3, a remote control transmission switch input section 4, and a buzzer output section 5, and scans the display surface while irradiating the barcode display surface 6 with visible light, etc. from the barcode input section 1, and uses the reflected light. Read the barcode array as shown in Figure 5. The barcode display surface 6 has a black bar 7A having two widths, narrow width and wide width.
White (spaces) 7B having different widths are arranged alternately according to the barcode display contents, and barcode groups 7 representing predetermined meanings are arranged. 7 out of 7 barcode groups
C is a start code section representing a start, and 7D is a data code section, where the first data 7H is represented using five black (bars), and the next data 7I is represented using five white (space). In FIG. 5, there are two types of data, 7H and 71, but they can be arranged to represent 2Xn types of data if necessary.

Further, 7E is a stop code section indicating the end of the barcode. This barcode display method is called an interleaved 2-5 barcode. In this method, in the data code section 7D, black bars) and white (spaces)
are repeated alternately, and black bars) have only black (bars), and Father's Day (spaces) have only white (spaces), making them codes with meanings.

Furthermore, in this barcode, starting from black (bar),
It always ends in black (bar). In addition, before the first black (bar) begins, there is always a scan start point 8 indicating the scan start position for barcode input and a start margin 7F, and at the same time, after the last black (bar) there is always a stop margin 7G. There is. Usually, this barcode is displayed on paper, a synthetic resin sheet, or other displayable surface by printing, transferring, painting, or other displayable means.

In FIG. 4, the barcode decoder 2 inputs black (bars) and white spaces alternately at the barcode input section l, and uses the stored data to perform a pass/fail check on the start code section and the data code section. The data in the data code section is separated into black (bar) and white space (white space), separated, decoded, and stored. The remote control signal output section 3 outputs a signal when the transmission switch is inputted at the remote control transmission switch input section 4.
The barcode decoder 82 extracts the decoded and stored data, converts it into a remote control transmission format, and sequentially outputs it as an infrared remote control signal.

The buzzer output section 5 outputs a predetermined buzzer sound when determining whether the data decoded by the barcode decoding section 2 is acceptable or when the remote control transmission switch is input.

Further, to explain the barcode input unit 1 in detail, the barcode reading circuit IA irradiates the barcode display surface 6 with visible light, converts the reflected light into an electrical signal, checks whether there is a change in the input, and reads the barcode. The code is read by an electrical signal, the pulse width of the electrical signal that has started reading is counted by a counting circuit IB,
A margin detection circuit IC detects a margin portion. Width counting circuit I
If the width value of the white (space) counted in B is more than the predetermined value [8 times the width of the black (bar) input just before], that is, when the start margin 7F (Figure 5) is recognized, Start barcode reading and further capture the next input signal. The threshold setting circuit ID has a value for determining that the first black (bar) data input after the detection of the start margin 7F is set to "O" and the next data (white) is set to "°1", that is, adjacent black Or set the threshold for white data.The black/white data detection circuit IE uses the data immediately before the input signal as white data when it is a falling signal, and uses the data immediately before the input signal as black data when it is a rising signal. The data (0/1) judgment/registration circuit IF compares the input data with the already set threshold, and when the input data is larger than the threshold, it is judged as data "l-" and when the input data is smaller than the threshold. The threshold update setting circuit IG determines the next input barcode signal based on the data determined by the data (0/1) determination/registration circuit IF. After the threshold is updated, the barcode signal that continues to be input passes through the barcode reading circuit IA and the width counting circuit IB, and then is checked by the margin detection circuit IC to determine whether the stop margin is 7G or not. is checked, and the data is registered through the black/white data detection circuit IE and the data (0/1) judgment/registration circuit IF until the stop margin 7G is detected, and then the barcode is registered again through the threshold update setting circuit IG. Returning to the reading circuit IA, the above-described operation is continued.Note that the first input data that passes through the threshold setting circuit ID is
This is only when the start margin 7F is detected by the margin detection circuit IC. The threshold setting circuit ID and the threshold update setting circuit IG set the threshold for O/1 judgment of the next data based on the input data. The black data is used to set the threshold for determining the next white data, and the white data is further used to set the threshold for determining the next black data. Or, as a threshold for determining white data, it is calculated and set based on the immediately preceding white or black data.Now, while repeating data detection and determination, a stop margin of 7G is detected by the margin detection circuit IC. When the barcode input is completed, the barcode decoder 2
The operation begins.

Both the start margin 7F and the stop margin 7G are
A white space that is eight times or more wider than the previously input black (bar) width) will be detected as a margin the next time it is input.

Problems to be Solved by the Invention Barcodes are usually provided on paper or synthetic resin sheets by printing or transfer, but if you look at the display surface as an enlarged model, as shown in Figure 6. , a black bar formed with ink, paint, etc.) has an actual width of 7L, which tends to swell slightly compared to the standard width of 7J. On the other hand, the white space sandwiched between black (bars) on both sides has an actual width of 7M, which is narrower than the regular width of 7K due to the influence of the black (bars) on both sides.

If adjacent black and white data are the same, their widths should originally be equal. However, on a practical level, as mentioned above, printing.

There is a tendency for the transfer section to become wide (there is a tendency for it to become wide), so setting the threshold for O/1 judgment of the next data based on the immediately preceding adjacent data may prevent data from being read correctly and malfunctions due to variations in print quality. There was an invitation.

In addition, normally, the margin detection circuit IC determines that there is a margin when the white (space) that comes after the black (bar) is equal to or larger than 8 times black, but when posting a TV program, In the case of a barcode display example as shown in FIG. 7, which is often seen in magazines, etc., if the scanning speed at the time of inputting the barcode is high, the barcode may not be read correctly. In FIG. 7, 8 is a scanning start mark of a scanner (not shown) when inputting a bar code. However,
If you are not familiar with the input operation, you may end up scanning from point 8N, which is slightly to the left of the scan start mark 8, instead of scanning from within the scan start mark 8. (Normally, when scanning starts from scan start mark 8, the input part of the reflected light is placed on scan start mark 8, so the next start margin 7F
is more than 8 times black, and this scanning start mark 8 and start margin 7F will not be judged as part of the data of barcode 7, but if you increase the scanning speed from point 8N of Group X, which is off from this point, you will see the start margin. Since the width count value of 7F is less than 8 times the width count value of scan start mark 8, even scan start mark 8 and start margin 7F may be determined to be part of barcode group 7 as the object. , it becomes impossible to read the correct data.・As mentioned above, when inputting a barcode, conventional barcode reading devices often cause reading errors or malfunctions due to variations in the display quality of the barcode display section and the handling of the scanner, resulting in remote control transmission. As a result, the operation of the machine on the receiving side was often contrary to the user's expectations, so there was a need for a highly reliable barcode reading device that could read barcodes reliably and quickly. Ta.

The present invention has been made in consideration of the above-mentioned conventional problems, and an object of the present invention is to provide a highly reliable barcode reading device that eliminates barcode reading errors and malfunctions.

Means for Solving the Problems The present invention includes a threshold setting circuit for black bars) and a threshold setting circuit for white (space). This is a barcode reading device that can determine whether each piece of data is O or 1 by comparing it with a threshold and store the data.

Effects According to the above configuration, each threshold for black data determination and white data determination is set individually, so barcodes can be reliably read and repeated over and over again without being affected by variations in print quality of barcode display. It is possible to provide a highly reliable barcode reading device that does not require repeated reading operations.

Example An embodiment of the present invention will be described based on the accompanying drawings.

FIG. 1 is a block diagram of the circuit configuration of the device according to the embodiment. In the figure, the main part of the embodiment is located in the barcode input section 9, and the other blocks that are the same as those in the conventional example are given the same numbers. Grant and explain (.

The barcode input section 9 irradiates the barcode pattern (FIG. 2(A)) on the barcode display surface 6 with visible light, etc., converts the reflected light into an electrical signal, and further converts the reflected light into an electrical signal as shown in FIG. 2(B). The part that shapes the waveform into a rectangular wave signal and reads the barcode has the following configuration.

First, the width counting circuit IB counts the pulse width of the electric signal that is started to be read by the barcode reading circuit LA, and when the input signal receives a rising signal 21 or a falling signal 20 as shown in FIG. 2(B). , the count value up to that point is stored in a width register (not shown) as a black or white width value, and after storage, the count is sequentially cleared and counting starts anew from zero. The start margin detection circuit 9J for detecting the start margin 7F detects when the width count value of the first input white (space) data is 8 times or more the width count value of the black (bar) input immediately after that. If there is, it is determined that the start margin is 7F.

Next, the threshold setting circuit 9L for black (bar) is as follows.
This is a circuit unit that uses the current value of black (bar) 7A to determine the O/1 of black (bar) 7P that comes after the next white (space) 7B. (bar)
The barcode scanning speed detection circuit 9H performs a speed check based on the width, and when the width count value is less than a predetermined value (i.e., high-speed scanning), the pre-registered high-speed scanning is performed according to the value. The threshold is immediately set from the threshold memory 9R without calculation. Also,
When the width count value is greater than or equal to a predetermined value (ie, low speed scanning), a threshold is calculated and set based on the width count value. The threshold setting circuit 9M for white (space) uses the value of the next input white (space) 7B to set the next black bar) 7P (white space)? This is to judge O/1 of Q, and the scanning speed detection circuit 9H performs a speed check based on the value of the width register, currently the white (space) width count value, and when the width count value reaches a predetermined value. When it is less than the value (that is, high-speed scanning), no calculation is performed from the pre-registered threshold memory 9R for high-speed scanning according to the value (the extraction threshold is immediately set. greater than or equal to a predetermined value (
In other words, during low-speed scanning), a threshold is calculated and set based on the width count value.

If the width of the white (space) that continues to enter after inputting the last black bar (72) of the barcode is 8 times or more the width of black 7Z, the barcode end margin detection circuit 9 considers it as a stop margin 7G and detects the barcode. Finish inputting, same as conventional example (
The operation in the barcode decoding section 2 is performed.

In the black/white data detection circuit IE, the input signal is
As shown in Figure (B), when the falling signal 20 is present, the data immediately before the falling signal 20 is detected as white (space) data, and when the rising signal is 21, the immediately preceding data is detected as black (bar) data.

In the data (0/1) judgment/registration circuit, the input black or white data (width count value) has already been set by the black (bar) threshold setting circuit 9L or the white (space) threshold setting circuit 9M. When the input data is larger than the threshold (that is, when it is a wide value), it is determined that the data is "1" and the input data is stored as 1. When the input data is smaller than the threshold (that is, when the width is a narrow value), it is determined that the data is "0", and the input data is stored as "O".

The black (bar) threshold update setting circuit 9P sequentially updates and sets every other black data for 0/1 judgment based on the previously input black data, and repeats this process. At the time of updating, like the threshold setting circuit 9L for the black bar), the scanning speed detection 9H performs a speed check based on the value of the width register, and when the width count value is less than a predetermined value (that is, high-speed scanning), , the threshold memory 9R for high-speed scanning registered in advance according to the value.
It is immediately extracted without any calculations and the threshold is set. When the width count value is greater than a predetermined value (ie, low speed scanning), a threshold is calculated and set by calculation based on the width count value.

The threshold update setting circuit 9Q for white (space) is
This is the same as replacing the operation of the black threshold update setting circuit 9P with a white space.

FIG. 3 shows the above configuration as shown in the microcomputer 10.
FIG. 2 is a circuit diagram of an example formed using 0. When a power switch 104 connected to a DC power source 111 is turned on, current is passed to the light emitting element 101 via the microcomputer 100, and it emits visible light or the like. This light emitting element 101
When the light emitted by the barcode display surface 6 is scanned,
When the light receiving element 102 receives the reflected light from the barcode display surface 6, converts the light into an electrical signal, and inputs it to the microcomputer 100 via the A/D converter, the microcomputer 100 reads and decodes the barcode. , drives the transistor 113 and outputs an output to the buzzer 105 to indicate whether the data is good or bad, and if it is "good", the data is stored. When the transfer key 106 for remote control transmission is pressed, the microcomputer 100 retrieves the data and
Convert the data to remote control transmission format and send transistor 1
15 to drive the light emitting element 10 such as an infrared light emitting diode.
The remote control signals are sequentially transmitted from 7 onwards. In addition, the third
Codes 108, 109, 110, 112, and 1 in the figure
14 is a resistor, and 116 is a coil.

When the power switch 104 is turned on and the barcode display surface 6 is scanned with the light emitted from the barcode reading circuit IA, the reflected light from the barcode display surface 6 is converted into an electrical signal and the barcode is read. Start.

For example, in FIG. 2(A), inside the scanning start mark 8
Start scanning from mark 8A to the right side, and at the same time start counting the width.
When entering the black (bar) area, a falling signal 22 shown in FIG. 2 (B) is generated, and the width count value of the white space (white space) that had been counted by the width counter circuit IB until then is stored in the width register. The width is newly counted from zero. Furthermore, continue scanning as it is, and when it exits the black bar) part, the rising signal 2
3 is generated, this black (bar) width count value is stored in the width register, and counting of the width of the starting margin 7F is newly started from zero. Also, the falling signal 2, which is the start of black data,
The space register value, which is the data immediately before step 2, and the width register value storing the kiln width value are compared in the barcode start margin detection circuit 9J, and here, the space register value is 8 times the kiln width value. , it is not considered the beginning of a barcode and this data is ignored. As the scanning continues, when it passes through the start margin 7F and enters the first black bar of the barcode, a falling signal 2 is generated.
0 is generated, and the width count value of the start margin 7F is stored in the edge register, then further transferred to the white (space) width register, and counting of the width of the black 7A is newly started. When the scanning continues and the black area is exited, a rising signal 21 is generated and the blank count value is stored in the width register. Additionally, counting of the width of the white space 7B on the right starts from zero. The white (space) width register value storing the width value of the start margin 7F and the kiln width register value storing the black 7A width value are compared by the barcode start margin detection circuit 9J, and the start margin 7F is compared with the kiln width register value storing the width value of the black 7A width. is more than 8 times the width of black 7A, so the beginning of the barcode is recognized.

Furthermore, based on the width value of black 7A stored in the width register, the black (bar) threshold setting circuit 9J sets black 7A as data "O" and sets it to the white space on the right (7B).
Next to (black bar) the threshold for determining 0/1 of 7P is calculated and set. When scanning continues and exits white 7B and enters black 7P, a falling signal is generated,
The white 7B width count value is stored in the width register. Also, the width counting circuit IB newly starts counting the width of black 7P from zero. Next, based on the width value of white 7B stored in the width register, the threshold setting circuit 9M for white space) sets white 7B as data ``0'' and the white 7 that follows the black 7P on the right.
A threshold for determining O/1 of Q is calculated and set. However, when setting each of the thresholds, the scanning speed detection circuit 9H performs a speed check, and if the speed is high (for example, 50 c+l/sec or more), the threshold memory 9R for high-speed scanning is used based on the width register value. A plurality of pre-stored data are retrieved according to the width register value and are used as black or white thresholds. In other words, during high-speed scanning, the calculation is performed immediately without complicated calculation processing.
Since the data is retrieved from the ROM and set, the processing time is extremely short and high-speed reading is possible.

Next, check the barcode end margin detection circuit 9 to confirm that the stop margin 7G has not been reached, and continue scanning.
When it exits and enters white 7Q, a rising signal is generated and black 7P
The width count value is stored in the width register. Also, the width counting circuit IB starts counting the width of white 7Q from zero. Since the signal that entered first was a rising signal in the black/white data detection circuit IE, the data immediately before entering white 7Q is detected as black data.

Furthermore, the data (0/1) judgment/registration circuit compares the previously detected black data 7P with the threshold already set in the black (bar) threshold setting circuit 9L, and determines the O/1 value.
Make 1 judgment. Now, as shown in FIG. 2(A), this black data 7P has a narrow width, so it is determined and registered as "0".

Next, based on the black data 7P, a new threshold is set in the threshold update setting circuit 9P for black bars, and the process returns to barcode reading, and the above operation is repeated until the stop margin 7G is detected. However, the threshold values for O/1 determination are those that are sequentially updated and set, and those set by the threshold setting circuits 9L and 9M are not used.

In addition, the threshold setting circuit 9L for inputting next to black 7P (the data is white 7Q, so the data O/1 judgment is white data 7Q and white space) is compared, and white is used to update the new threshold. (space) threshold update setting circuit 9Q is used. In this way, the thresholds for black and Yamakawa are individually set and used for O/1 determination, so that the quality of read data is not influenced by variations in finish (printing, etc.) on the barcode display surface.

Also, a black/white threshold update setting circuit 9P.

The threshold setting operation of both circuits 9Q and 9Q during high-speed scanning is similar to that of the threshold setting circuits 9L and 9M described above.

As the barcode reading progresses and the stop margin 7G is detected, the barcode reading ends and the captured data is transferred to the barcode decoding section 2. From then on, the operations of each section are the same as in the conventional example and will be omitted. .

According to the configuration of this embodiment, since the margin detection circuit is divided into two parts, one for start and one for stop, and the detection method is changed, the barcode pattern shown in the conventional example in FIG. Even if the scan starts, the white width value from the X mark 8N, which is the data immediately before the scan start mark 8, is not more than 8 times the black 8, so the scan start mark 8 and the start margin 7F are judged as one of the barcode data. There is nothing to do, and the start margin 7F is black (bar)? Since the number is more than 8 times that of A, the start of the barcode can be correctly recognized and reading errors or malfunctions will not occur. The margin to the left of the scan start mark 8 (the margin with the cross mark 8N) displays many barcode patterns in magazines that publish TV programs, so there is actually little margin in this area. Moreover, since the barcode pattern including the scanning start mark is enclosed in a single frame to distinguish it from other patterns, there are no scanning errors.

As described above, according to this embodiment, threshold setting circuits are provided exclusively for black and Yamakawa, and are set individually, and the individually set thresholds for black or self-respect are used in data O/1 judgment. This makes it possible to eliminate reading errors and malfunctions caused by variations in barcode printing specifications.

In addition, the margin detection circuit is divided into one for the start margin and one for the stop margin (one circuit in the conventional example), and when detecting the start margin, the white data immediately before the input black data is compared with the black data. Therefore, even if the scanning start position deviates from the scanning start mark, the barcode pattern can be read correctly and there is no fear of malfunction.

In addition, even if the barcode is input by scanning the barcode display surface at high speed, a scanning speed detection circuit is installed to detect the speed. Since the threshold corresponding to the speed is immediately extracted and set from the threshold of

As described above, this embodiment makes it possible to provide a highly practical and highly reliable barcode reading device.

Effects of the Invention As is clear from the description of the embodiment above, separate threshold setting circuits are provided for black (bar) and white (space), so when determining O/1 of data, black data This makes it possible to provide a highly reliable barcode reader that can read barcodes correctly and reliably even if there are variations in the printing condition of the barcode display, and its practical effects are It is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration block diagram of an embodiment of the present invention;
Figure 2 (A) is a typical barcode pattern diagram, Figure 2 (B) is a signal waveform diagram when reading the barcode, Figure 3 is a circuit diagram of the same example, and Figure 4 is a conventional FIG. 5 is a block diagram of the circuit configuration of the example device, FIG. 5 is a bar code pattern diagram, FIG. 6 is an enlarged model diagram of the same bar code, and FIG. 7 is a display example diagram of the bar code pattern. IA...Barcode reading circuit, IB...
・Width counting circuit, IE...Black/white data detection circuit, 6...Barcode display surface, 9L...
Threshold setting circuit for (black bar), 9M...
・Threshold setting circuit for white (space), 9P...
...Threshold update setting circuit for black (bar), 9
Q: Threshold update setting circuit for white (space), 9N: Data (0/1) judgment/registration circuit. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 Figure 7B Figure 3 Figure 4 Figure 5 GH Figure 6 Figure 7/8~

Claims (1)

[Claims] A barcode reading means that converts the barcode display into an electrical signal, a counting means that counts the pulse width based on the output from the barcode reading means, and a black (bar) that is set based on the output from the counting means. a threshold setting means for white (space); and a threshold setting means for white (space);
Threshold update setting means, black/white data detection means for detecting whether the read barcode signal is black (bar) or white (space), and black/white data detection means for detecting whether the read barcode signal is black (bar) or white (space);
Alternatively, a barcode reading device comprising data determining means for individually comparing white (space) data and the threshold setting value for black or white, and determining and registering data 0/1.