JPH07319992A - Bar code reader - Google Patents

Abstract

PURPOSE:To read out a bar code even when relative moving speed between a scanning line and the bar code changes. CONSTITUTION:When relative speed between a bar code and a scanner head is constant, data (b) corresponding to the data (a) of previous data exists on the reference position of current data found out by adding a moving distance to the coordinates of the previous data obtained one scanning before. Since the moving distance at the time of acceleration is longer than that of at a fixed speed and a moving distance at the time of deceleration is shorter than that of at a fixed speed, the corresponding data (b) are located before and after the reference position found out from the moving distance of the fixed speed. Thereby, a prescribed range around the reference position found out by adding a moving distance obtained by preceding measurement to the coordinates of previous data is set up as a retrieving range, the address of data of a bar existing in the retrieving range is retrieved and the positioning of data extracted as the same part is executed to synthesize extracting data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reading device, and more particularly, it scans a bar code at a predetermined cycle by relatively moving a bar code and a sensor, and considers the degree of coincidence of scan data of each scanning line. The present invention relates to a bar code reader which combines bar code information by sequentially combining scan data and reads the bar code information.

[0002]

2. Description of the Related Art A bar code reader (one line scan type reader) which reads a bar code with one scanning line uses a single sensor and therefore has a simple optical system. It has the advantage of being small and inexpensive. However, in this 1-line scanning type reader, when the inclination between the scanning line and the bar code is large, only one fragmentary data of the bar code can be obtained in one scanning, so the scanning is performed plural times.
It is necessary to combine the scan data to obtain the entire code. Therefore, the bar code and the sensor are moved relative to each other to scan the bar code in a predetermined cycle, and the bar code is read by combining the scan data in consideration of the degree of coincidence. Are known.

In the conventional 1-line scanning type reader disclosed in Japanese Patent Laid-Open No. 1-86284, when scanning a bar code, the relative moving speed between the scanner and the bar code is kept constant, so that the scan data are exchanged with each other. I am trying to respond. Therefore, there is a problem that the bar code cannot be read when the relative movement speed between the scanner and the bar code changes.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 3-204790, in order to ensure the reliability of data, scan data is decoded and then combined. For this reason,
Only a decodable part has valid data, and a bar code having a large inclination with respect to a scanning line has a small amount of valid data, which makes it difficult to read.

The present invention has been made to solve the above problems, and in a 1-line scan type bar code reader for synthesizing bar codes, the relative movement speed between the sensor of the scanner and the bar code. The bar code can be read even when the bar code changes, and even if the inclination of the bar code to the scanning line is large, the bar code can be read and highly reliable data can be read from the scan data. The purpose is to provide a device.

[0006]

In order to achieve the above object, according to the present invention, a bar code and a sensor are relatively moved to scan the bar code at a predetermined cycle, and the degree of coincidence of the scan data of each scan line is considered. In a bar code reader that combines bar code information by sequentially combining scan data and reads the same, the scan data of preceding and following scan lines are compared to extract the same portion of the data from each scan data, and the same data is extracted. Data extraction means for calculating a movement amount according to the relative movement speed based on the difference in the coordinates of the corresponding bar or space of the part, and adding the movement amount to the coordinates of the previous scanning line in the subsequent scanning line. To search a region within a predetermined range including the determined reference position and extract a bar or space of a subsequent scan line corresponding to a bar or space of a previous scan line. Ri performs positioning of the same parts, and a code combining means for the combined data newly by combining the same parts in the synthetic data, characterized in that the provided.

[0007]

According to the present invention, the bar code and the sensor are moved relative to each other to scan the bar code at a predetermined cycle, and the bar code information is sequentially combined in consideration of the degree of coincidence of the scan data of each scan line. Combine and scan the barcode. The data extraction means compares the scan data of the preceding and following scan lines to extract the same portion of the data from each scan data, and determines the relative movement speed based on the difference in the coordinates of the corresponding bar or space of the extracted same portion. The corresponding movement amount is calculated. The code extracting means corresponds to the bar or space of the previous scanning line by searching for an area within a predetermined range including the reference position obtained by adding the movement amount to the coordinates of the previous scanning line in the subsequent scanning line. After that, the bar or space of the scanning line is extracted, and the same portion is aligned. As described above, in the present invention, since the scan data of the previous scan line and the scan data of the subsequent scan line are aligned, even when the relative movement speed between the barcode and the sensor changes, the barcode Can be read. Further, the code combining means combines the same extracted portion with the combined data to obtain new combined data.

The code combining means extracts the same part of the extracted data extracted as the same part and the combined data, and combines the same part as the extracted data of the combined data with the non-identical part of the combined data of the extracted data. It can be set to various synthetic data.

It should be noted that even in the extraction of the same portion of the extracted data and the synthetic data, it is possible to perform the alignment using the above-mentioned movement amount.

The front and rear scanning lines may be two continuous scanning lines or two scanning lines separated by a predetermined number.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows the overall configuration of the bar code reader of this embodiment. The barcode reader is the scanner 1
0, a decoder 12 including a microcomputer and an interface 14.

The scanner 10 as an optical sensor is
A laser beam scanning device including a semiconductor laser and a scanning device such as a polygon mirror or a galvano mirror that scans the laser beam, and a photoelectric conversion element that detects a reflected laser beam from a portion scanned by the laser beam The scanner head 10A is provided. The scanner head 10A includes a light source that illuminates the barcode surface, a lens system that collects the reflected light generated by the light source, and a photoelectric conversion element that detects the reflected light that is collected by the lens system. You may use what was comprised including the line sensor comprised by arranging a plurality in rows.
In this case, the line sensor can detect data for one scanning line at a time. A slit light source using a cylindrical lens or the like may be used as the light source, or the slit light source may be pulsed and used.

The scanner head 10A, via the amplifier 10B, converts an analog signal amplified by the amplifier 10B into a digital signal which is a binary signal, and an A / D converter 10C.
It is connected to the. The A / D converter 10C corresponds to a count value representing the width of a black bar or a white space by counting the rising edge to the falling edge of the digital signal and the falling edge to the rising edge of the digital signal, that is, a run length. It is connected to a counter 10D that outputs a count value as scan data.

The decoder 12 receives the scan data from the counter 10D via an input / output device (not shown) and outputs a scanner control signal to the scanner 10 via the input / output device. The CPU 12A will be described below. ROM 12 storing a program for a bar code reading routine
B, a previous data memory area (hereinafter, PDM) that stores scan data before one scan, a current data memory area (hereinafter, C) that temporarily stores current scan data
RAM 12 including a DM), a combined data memory area (hereinafter, SDM) for storing combined data, and an extracted data memory area (hereinafter, EDM) for storing extracted data.
C, and a bus such as a data bus for connecting these to each other.

According to this bar code reading device, when the display object on which the bar code symbol is displayed is scanned by the laser beam, the photoelectric conversion element of the scanner head 10A obtains an analog signal corresponding to the reflectance of the display object. . This analog signal is sequentially converted into a digital signal by the A / D converter 10C and output as scan data of a scan line, converted by the counter 10D into a count value representing the width of a bar or space, and decoded by the decoder 12. When the code is obtained, the decoded data is output to the interface 14.

Next, the processing contents of the decoder 12 will be described in detail with reference to FIG. In step 100, the flag F is reset, and in step 102, the scan data of the first scan line is stored in the PDM that stores the scan data of the previous scan, and in step 104, the scan data of the first scan line is currently stored. The scan data of is stored in the CDM which is temporarily stored.

In this embodiment, since it is possible to follow the change in the relative moving speed between the bar code and the scanner, it is determined that the scan data are similar, that is, the scanning intervals are close, in the processing described later. If this step 10
Discard the scan data in 4 and wait until the next scan,
It is also possible to store in the CDM only when the necessary scan data is input. Thereby, when the moving speed is low, only the minimum necessary scan data for combining can be used in the data combining described later, and the efficiency of the processing can be improved.

The scan data output from the counter 10D has a count value corresponding to the run length of the bar, a count value corresponding to the run length of the space, a count value corresponding to the run length of the bar, and so on. ,
Count values corresponding to these run lengths are stored in correspondence with one address.

In the next step 106, it is determined whether or not the flag F is set. If the flag F is reset, the synthesis start determination process described later is performed in step 108, and if the synthesis start determination process is successful, the step is performed. 11
If the flag F is set to 0 and the combination start determination process fails, the flag F is reset in step 112, and then the scan data stored in the CDM is stored in the PDM in step 114. And step 104
At, the scan data of the next scan line is stored in the CDM.

On the other hand, when it is determined in step 106 that the flag F is set, that is, when the synthesis start determination process is successful, the data extraction process described later is executed in step 116 and the data extraction process is successful. If so, the code combining process described below is executed in step 118,
If the code combining process is successful, a code determining process to be described later is executed at step 120. If the data extraction process and the code combination process have failed, the flag F is reset in step 122, and the scan data stored in the CDM is stored in the PDM in step 124. Also,
If the code determination process fails, that is, if the decoding cannot be completed up to the end of one bar code, the scan data stored in the CDM is converted to P in step 124.
Store in DM. It should be noted that if one bar code is entirely decoded, this routine is regarded as successful and this routine is ended. Further, the processes of steps 104 to 120 described above are executed in synchronization with the scanning by the laser beam.

As a result of the above, the CDM stores the current scan data which is the scan data in the subsequent scan line,
The scan data in the previous scan line is stored in the PDM as 1
Scan data before scanning will be stored.

Next, the synthesis start determination processing in step 108 will be described in detail with reference to FIG. This synthesis start determination processing is executed when the flag F is reset, that is, when scanning is started or when barcode data is not detected. This synthesis start determination process determines whether or not the scan data to be determined includes barcode data, and scans the barcode data from the scan data in order to improve the efficiency of the barcode synthesis process. This is to select the included part.

When the bar code symbol begins to pass through the first scan line, the scan line always starts from the upper right corner, the upper left corner, the lower right corner, or the lower left corner of the bar code symbol. It will cross the right or left edge of the symbol. Hereinafter, a case where scanning is performed from left to right, and the case where scanning is started from the lower left corner of the barcode symbol will be described.

In step 130 of FIG. 3, the data portion of the bar code is selected by searching the scan data stored in the PDM for a pattern existing at the right end or the left end of the bar code symbol as a start pattern.
In step 132, an offset indicating the position coordinate of the start pattern selected is calculated. Also, step 134
At step 136, the start pattern is retrieved from the scan data stored in the CDM, and the offset of the retrieved start pattern is calculated at step 136.

This start pattern is a pattern indicating the end of a bar code such as a guard bar, a character, a start character, and a stop character. By searching for this start pattern, it corresponds to the start of passing the scanning line of the bar code symbol. Can detect the part to
The data after this start pattern will include the barcode data. For example, when the code type is JAN code, the first three elements are bar, space, and bar, and the width ratio of bar and space is 1: 1: 1.
The four elements following the three elements represent, for example, 4 so that the width ratio of the bar and the space becomes 1: 1: 3: 2. Therefore, the start pattern can be detected by determining whether or not the 1: 1: 1 part is followed by the 1: 1: 3: 2 part. Further, since the guard bar is represented by 3 modules and one character is represented by 7 modules, the start pattern may be detected by determining whether or not a 3: 7 portion is present. And
All of the start patterns detected in this way are candidates. Therefore, the detected start pattern includes not only the actual start pattern but also a pattern in which a character or the like is erroneously detected as the start pattern.

The offset Fp _i of the start pattern at the address Pi is given by the following equation (1).

[0027]

[Equation 1] However, Mp _K is the data stored at the address k of the PDM.

FIG. 4 shows an example detected as the start pattern. In the PDM, the data having the start address P0, Pi, etc. is detected as the start pattern, and in the CDM, the data having the start address C0, Cj, etc. is detected as the start pattern.

In the next step 138, the start pattern detected from the scan data of the PDM and the start pattern detected from the scan data of the CDM are compared, and the code type and the character are the same and the offset relationship is correct. To search. Whether or not this offset relationship is correct can be determined by whether or not the following two conditions are satisfied.

[0030] However, Cj is the start address of the CDM start pattern,
N is the number of data of the start pattern of Cj of CDM, Mc _K is the data stored at address k of CDM, Fc _j is the offset of the start pattern of the start address Cj of CDM, and Fp _i is the start of the start address Pi of PDM. The offset of the pattern.

It is PD that satisfies the above expressions (2) and (3).
This is a case where the offset of the start pattern of M, that is, the coordinates of the head element exists between the coordinates of the head element and the coordinates of the end element of the CDM start pattern. When the above two expressions are not satisfied, when the portion other than the barcode symbol is erroneously detected as the start pattern, the scanning direction has an inappropriate relationship with the orientation of the barcode (that is, each symbol of the barcode is different from the scanning direction). 1) or a case where the inclination of the barcode symbol with respect to the scanning line is so large that it becomes unreadable.

In FIG. 4, the start pattern of the address Pi of the PDM and the start pattern of the address Cj of the CDM are detected as a corresponding set having the same code type and character and a correct offset relationship.

If it is determined in step 140 that the corresponding set of start patterns has been detected, step 142.
In step S1, the start pattern stored in the CDM is transferred to and stored in the SDM storing the synthetic data as the first part of the synthetic data. FIG. 5 shows a state in which the CDM data is transferred to the SDM.

Further, in steps 144 to 150, the minimum bar width is stored as a unit module, the used CDM address Cj is stored as the comparison start address Sp, and the CDM start pattern offset Fc _j.
Is stored as the initial value of the combined movement amount Ts, the difference between the offset Fc _j of the start pattern of the CDM and the offset Fp _i of the start pattern of the PDM is stored as the initial value of the movement amount SH, and the data number of the start pattern (for example, , 6) is stored as the initial value of the final address Dp of the coded portion, and the number of data of this start pattern is stored as the length Ld of the portion detected as the same portion. Then, in step 152, the synthesis start determination process is successful and the process proceeds to the next step. On the other hand, if it is determined in step 140 that the corresponding set does not exist, it is determined in step 154 that the synthesis start determination process has failed, and the process proceeds to the next step.

Next, the data extraction processing in step 116 will be described with reference to FIG. This data extraction process is
Paying attention to the fact that substantially the same pattern can be obtained in the bar code symbol portion by continuous scanning,
By comparing the scan data of DM and the same portion, that is, the portion having the same run length of the bar and the run length of the space, the data of the barcode portion is extracted without decoding. The comparison of scan data is limited to within a necessary range to shorten the processing time.

At step 160, the offset and the movement amount S
Calculate the initial address Cs of the CDM using H and.
It should be noted that this movement amount SH is based on the difference between the offsets which are the coordinates of the bars corresponding to the same portion, and will be described later in step 18
6 is calculated. Further, the initial value of the movement amount SH is calculated from the difference between the offsets of the start patterns that are the same portion as described above. As shown in FIG. 7, when the relative speed between the barcode and the scanner head is constant, the offset of the prior data and the movement amount according to the relative speed are added to the reference position of the current data, There is data b corresponding to the data a of the prior data. On the other hand, the amount of movement during acceleration is greater than the amount of movement during constant speed, and the amount of movement during deceleration is less than the amount of movement during constant speed. It will be located before and after the reference position obtained from the quantity.

For this reason, in the present embodiment, assuming that the bar code symbol and the scanner head do not move at a relatively constant speed, the moving amount obtained last time is added to the offset of the prior data to obtain it. A predetermined range including the reference position, for example, a predetermined range centered on the reference position is set as the search range, and the address of the bar data existing in this search range is set as the initial address Cs of the CDM. In this case, when there are a plurality of bar data within the search range, the smallest address is set as the initial address Cs. This search range is preferably ± M / 2 with the reference position as the center, where M is the number of modules that represent one character of the barcode. For example, in the case of the JAN code, one character is represented by seven modules. Therefore, it is preferable that the width is ± 3.5 module width around the reference position. In this case, the change range of the moving speed that can be handled depends on the relationship between the relative moving speed of the scanner and the bar code at that time and the inclination angle of the bar code symbol with respect to the scanning line. That is, even if the relative moving speed is the same, when the tilt angle is small, the range of change in the moving speed that can be handled becomes wider. The reference position does not necessarily have to be located at the center of the search range, but may be located at the right end of the search range during acceleration and the left end of the search range during deceleration.

In step 162, the initial value L0 of the comparison range L for comparison is calculated by adding the increment k represented by an arbitrary positive number to the length Ld of the portion detected as the same portion last time. The comparison range L is represented by the number of addresses, and the minimum value is set to 3 (corresponding to bar, space, and bar). In step 164, the initial value L0 is set as the comparison range L.

Since the previous data, which is the data one scan before, is the previous current data stored in the PDM, the start address Sp used in the previous synthesis is used as the PDM address in this data extraction process. In step 166, the start address Sp (the initial value is the address Cj of the start pattern) is set as the address P of the prior data (see FIG. 8).

In the next step 168, it is determined whether the sum P + L of the address P and the comparison range L is less than or equal to the final address Pn of the scan data stored in the PDM, and the end of the comparison range L is the previous data. It is determined whether or not it is located at the end, and in the following cases, the following conditions are determined in step 170.

[0041]

## EQU00002 ## P.ltoreq.Dp.ltoreq.P + L-1 (4) This condition includes a range including the final address Dp that can be coded, that is, a region that cannot be coded due to noise such as dust. This is a condition for searching an area, and is necessary to update the data of the noise portion with new data that does not include noise when noise other than the barcode is detected as scanning data in the past scanning. That is,
Noise is present in a portion of the bar code, and it is rare that a bar or space is lost in part, and a bar or space in its entirety is rare. The noise can be removed by using the scan data that does not include the noise.

In step 172, the offset Fp of the address P of the prior data is calculated, and step 174
To set the initial value Cs to the address C of the current data,
In step 176, the offset Fc of the address C of the current data is calculated. These offsets Fp and Fc are given by the following equations (5) and (6), respectively.

[0043]

[Equation 3] However, Mp _i is the PDM data of the address i.

[0044]

[Equation 4] However, Mp _K is the CDM data of the address j.

At the next step 178, the condition given by the following equation (7) is judged.

[0046]

## EQU5 ## | Fp-Fc + SH | ≤N (7) Note that N represents a predetermined range. The value of N can be determined based on the number of modules representing one character of the bar code, as in the case of obtaining the initial address Cs of the CDM, and is given by a width of ± 3.5 modules in the JAN code, for example. . This condition is a condition for determining whether or not the positional relationship of the same portion is correct (note that Fp-Fc + SH = 0 when the relative movement speed is constant), and the determination in step 178 is negative. In this case, it is determined that the positional relationship of the compared portions is inappropriate, and the process proceeds to step 188 without performing the comparison in step 180 to shift the compared portions so that the positional relationship is correct.

In step 180, the PDM address P ...
The data of P + L and the data of addresses C to C + L of CDM are compared. If it is determined in step 182 that these data are the same, that is, if the count values (run length) of the corresponding bars and spaces are equal, the address C of the CDM is determined in step 184.
The C to L data is extracted as the same portion, transferred to the EDM and stored (see FIG. 9). In step 186, the difference Fc-Fp between the offsets of the CDM and PDM is set as the next movement amount SH, and the address C is set as the next comparison start address Sp.
And the comparison range L is stored as the length Ld of the same portion,
In step 190, the data extraction is successful and the process proceeds to the next step.

On the other hand, steps 178 and 182
If the determination is negative, the comparison portion of the current data is shifted by a unit amount, and in order to compare the shifted current data and the prior data, the CD is added in step 188.
The address C of M is incremented by two. here,
The address C is incremented by 2 in units of a set of a bar and a space, that is, when the number of data 2 is 1.
This is because the data at the beginning of the comparison range of the current data is always bar data by shifting as a unit.

In step 190, if the same portion is not detected even after repeatedly comparing the address C of the CDM to the final address Cn and comparing, the address P of the PDM is incremented by 2 in step 192 to compare the preliminary data. The portions are shifted by a unit amount and the shifted previa data and the current data are compared as described above. In this case, the address C of the current data is returned to the initial value Cs in step 174.

If the same portion is not detected even after repeatedly comparing the address P of the PDM to the final address Pn and comparing, the comparison range L is decremented by 2 in step 196 and the comparison portion is narrowed by a unit amount. Search for the same part. In this case, the address P of the preliminary data and the address C of the current data are reset to the initial values in steps 166 and 174, respectively. If the same portion cannot be retrieved even if the comparison range L reaches the minimum range 3, the data extraction fails (step 199).
This routine ends. Then, the next scan is performed.

When the determination in step 168 is negative,
That is, when the trailing end of the comparison portion of the previa data reaches the final address, the comparison range L is narrowed in step 196 and the above processing is repeated. Further, when the determination in step 170 is negative, that is, when the address Dp is not included in the comparison portion of the preliminary data, the address P is changed in step 192 to include the address Dp in the comparison portion. To shift the comparison part.

Next, details of the code combining process in step 118 will be described. This combining process is performed by comparing and combining the extracted data obtained by the data extracting process and the already combined composition pattern, and combining the same part with the non-identical part to form a new composition pattern. The pattern is updated.

In step 200 of FIG. 10, a new combined movement amount Ts is obtained by adding the movement amount SH obtained by the code combining process to the combined movement amount Ts of the combined pattern. This combined movement amount Ts represents the offset of the data at address 0 of the SDM, and it is possible to compare the position with the extracted data by obtaining the offset of the combined data from this combined movement amount Ts. The initial value of the comparison range L is E
Let Le be the number of extracted data stored in DM,
The initial value of the EDM address E is set to 0, and the SDM address S is set to the start address Bp (the initial value is the start address of the start pattern) of the same portion searched previously (steps 202, 204, 208) (see FIG. 11). ).

In steps 206 and 210, the offset Fe of the address E of the extracted data and the offset Fs of the address S of the combined data are calculated according to the following equations (8) and (9).

[0055]

[Equation 6] However, Me _i is the EDM data of the address i.

[0056]

[Equation 7] However, Ms _j is the SDM data of the address j.

When it is determined in step 212 that the offset Fs and the offset Fe are equal to each other, that is, when the positional relationship between the extracted data and the combined data is correct, in step 214, the data of the EDM addresses E to E + L and the SDM are compared. When the data of the addresses S to S + L are compared and it is determined in step 216 that these data are the same, that is, when the positional relationship between the extracted data and the composite data is correct and the contents within the comparison range L are the same. Are the same part, and the start addresses of the comparison ranges L are E and S, so that in step 218, the data after the SDM address S + L is transferred to the EDM address E + L to
Update with En data. That is, new synthetic data is obtained by combining the same portion as the extracted data of the synthetic data with the non-identical portion of the synthetic data of the extracted data (see FIG. 12). Also, in step 220, the SDM start address S
Is stored as the head address Bp of the same portion.

In steps 224 to 234, similarly to steps 188 to 198 described above, the comparison part between the extracted data and the composite data, the comparison range is shifted by a unit amount until the same part is detected. The above process is repeated. If the same part is not detected even if the address S and the address E become the final addresses and the comparison range becomes the minimum range, the code combining process is failed as in the case of the code data extracting process.

FIG. 11 shows the search range for code combination, and FIG. 12 shows the updated state of the combined data.

Next, the code determination process of step 120 will be described. This code judgment processing is to decode the combined data stored in the updated and combined data memory and judge whether all the data are prepared. When all the data are collected, the code is output via the interface 14 and the code synthesizing process ends.

On the other hand, if all the data are not available,
The address Dp of the current memory data which is the source of the decrypted data is obtained from the last address of the decrypted data of the SDM, and this address Dp is stored. This address Dp is given by the following equation (10) as understood from FIG.

[0062]

[Equation 8] Dp = m−S + E + C (10) Here, m: address of the last SDM that can be decoded S: start address of SDM of the same part during code combining processing E: code combining processing EDM start address of the same portion at the time C: CDM start address of the same portion at the time of data extraction processing).

When the decodable address Dp is obtained, the code synthesizing process is continued.

In the above-described embodiment, the example in which the movement amount is determined based on the offset of the bar data, that is, the coordinate has been described, but the movement amount is determined based on the space offset, that is, the coordinate, and the position adjustment is performed. Good.

In the above embodiment, the case of scanning in a fixed direction has been described, but the case of scanning in the opposite direction or storing the run length of scan data in the data memory area in reverse order is also possible. It can be processed by the flow shown in 2.

Further, in the above embodiment, the run length comparison and combination are described with the example of the run length starting from the bar and ending at the bar. However, even if the comparison / combination is performed at the run length starting at the space, or the run ending at the space is performed. You may compare and combine by length.

[0067]

As described above, according to the present invention,
The bar or space corresponding to the bar or space of the previous scan line is extracted by searching the area within the predetermined range including the reference position obtained by adding the movement amount to the coordinates of the subsequent scan line, and the same portion is extracted. Since the combined pattern is obtained by aligning the non-identical part with the same part, the bar code can be read even if the relative movement speed of the sensor and the bar code changes, and the scanning line can be read. It is possible to read the barcode even when the inclination of the barcode is large with respect to, and it is possible to obtain highly reliable data from the scan data.

[Brief description of drawings]

FIG. 1 is a block diagram showing the outline of the present embodiment.

FIG. 2 is a flowchart showing a barcode reading routine.

FIG. 3 is a flowchart showing a combination start determination processing routine.

FIG. 4 is an explanatory diagram showing a search state of a start pattern.

FIG. 5 is an explanatory diagram showing a transfer state to the SDM when a start pattern is detected.

FIG. 6 is a flowchart showing a data extraction processing routine.

FIG. 7 is a diagram showing a positional relationship between a change in moving speed and a corresponding bar.

FIG. 8 is a diagram showing a search range of a data extraction process.

FIG. 9 is a diagram for explaining an extraction state of the same portion.

FIG. 10 is a flowchart showing a code combination processing routine.

FIG. 11 is a diagram showing a search range for code combination.

FIG. 12 is a diagram showing an updated state of combined data.

FIG. 13 is a diagram showing a relationship between each data and an address Dp.

[Explanation of symbols]

 10 Scanner 12 Decoder 14 Interface

Claims (1)

[Claims] 1. The bar code and the sensor are moved relative to each other to scan the bar code at a predetermined cycle, and the bar code information is combined by sequentially combining the scan data in consideration of the degree of coincidence of the scan data of each scan line. In the bar code reading device that reads the same, the scan data of the preceding and following scan lines are compared to extract the same portion of the data from each scan data, and based on the difference in the coordinates of the corresponding bar or space of the same portion, Data extraction means for calculating a movement amount according to the relative movement speed, and an area within a predetermined range including a reference position obtained by adding the movement amount to the coordinates of the previous scanning line in the subsequent scanning line are searched. The same portion is aligned by extracting the bar or space of the subsequent scan line corresponding to the bar or space of the previous scan line, and at the same time the composite data is aligned. Bar code reading device for a code combining means for a new combined data by combining the same parts in motor, characterized in that provided.