CN1035287C - Barcode marking reading device - Google Patents

Abstract

A comparing section compares the coordinates of the four corners of a bar code symbol newly detected by a bar code symbol detecting section and stored in a primary buffer, with the coordinates of the four corners of a bar code symbol having been detected and stored in a secondary buffer. If the coordinates of the newly detected bar code symbol differ from those of the detected bar code symbol, a control section causes a decoding section to decode the bar code symbol on the basis of image data stored in a frame memory. On the other hand, if not so, it is determined that the newly detected bar code symbol is invalid, thereby inhibiting decoding of the same to prevent double-reading.

Description

Barcode marking reading device

The present invention relates to a bar code mark reading device for reading bar code marks, in particular to a device for preventing double reading. The term "dual read" in this manual means to read the content of the barcode mark (decoding)

Transmit the bar code mark of the data to the host computer, and then take another image and decode it and transmit it to the host computer.

In recent years, with the popularization of point-of-sale (POS) systems, barcode markings have become ubiquitous. There are dozens of coding systems in this barcode mark, representative ones are: JAN/UPC/EAN code, ITF (five-two) code, CODE39, NW-7 code, CODE128, etc. These barcode marking systems are called unary barcode markings, and the amount of information that can be accommodated is more than a dozen characters.

On the other hand, POS systems are widely used in department stores, supermarkets, and other places where products are sold, and barcode reading devices are used as terminals. There, the bar code mark reading device is required to be cheap, easy to use, and read the bar code mark correctly.

The basic content of the barcode mark reading method is as follows, that is, the light from the light source is illuminated on the barcode mark, and the barcode mark is scanned, and the light reflected on the bar code mark is collected on the light receiving element inside the reading device. The output signal of the light-receiving element is decoded in the electrical circuit composed of a microcomputer, etc., and the bar code mark is read accordingly.

The bar code mark reading device is divided into the type that scans the bar code mark at all times and the type that scans the bar code mark according to the operation of the reading switch, etc., especially, among the former type that always scans the bar code mark, the one that is read once A so-called "double-read prevention" function in which a barcode mark cannot be read again is important. Especially for pricing in supermarkets, etc., this function is naturally necessary. That is, if the bar code mark is read by the bar code reading device, if the item with the bar code mark is still there for a while, or the action of taking the item is slow, the same bar code mark is read several times, Or the item that does not intend to read its barcode mark is read several times while moving here or there, and the actual number of purchased items and the number that is finally read and transferred to the host may be inconsistent.

Here, in the conventional unitary barcode symbol reading device, it is proposed that when the content of the continuously read barcode symbols is the same, one barcode symbol is judged as repeated reading, and the barcode symbol read later is called invalid as a method to prevent double reading. As a method of preventing double reading, the method of taking and not reading the bar code mark after a certain period of time after the data is transferred to the host computer are proposed.

In recent years, there has been a controversy over the lack of information in the one-element barcode mark, and therefore, various encoding systems called binary barcode marks containing a large amount of information have been developed. One of these is called a data code. This data code can be binary black-and-white figure, is made of L-shaped outer frame and black-and-white boundary and its internal data area, and is a square figure as a whole. However, in a binary barcode symbol reading device for reading such a binary barcode symbol, there is no proposal for an effective method for preventing double reading.

If the anti-double reading method of the above-mentioned one-element barcode mark is applied to this two-element barcode mark reading device, because the amount of information of the two-element barcode mark is significantly more than that of the one-element barcode mark, the comparison processing time of the data must be too long . In addition, the decoding process of the binary barcode mark itself is very complicated and takes a long time. Therefore, the conventional method of comparing decoded contents has a problem that the processing time is long, and it is not suitable for a binary barcode symbol reading device as it is.

In addition, the so-called method of not reading subsequent barcode marks for a certain period of time after transferring data to the host computer is very difficult to set for a certain period of time, and it is not easy to read the subsequent barcode marks when the setting time is long. When the setting time is short, the problem of reading the same barcode symbol twice still remains. In addition, if the operator leaves the label on which the barcode mark is recorded there, it will eventually become "double read".

In view of the above problems, the present invention aims to provide a barcode symbol reading device capable of preventing double reading by simple and high-speed processing.

The bar code mark reading device that provides in the first mode of the present invention has: the bar code mark is photographed at regular time intervals, and the photographing and storage device of storing the image information obtained by the photographing is stored; The image information in the above-mentioned imaging and storage device detects the position detection device of the position information of the barcode mark; stores the first position storage device of the bar code mark position information detected by the above-mentioned position detection device; stores the position information obtained by the above-mentioned position detection A second position storage device for the barcode mark position information detected by the device; a comparison device for comparing the two position information stored in the first and second position storage devices; judging according to the comparison result of the comparison device When the two position information are different, a decoding device for decoding the content of the barcode mark obtained from the image information captured and stored in the storage device.

According to the second aspect of the present invention, the double reading prevention device provided has: a position detection device, which detects the position information of the bar code mark based on the image information obtained by photographing the bar code mark at regular time intervals; device, which stores the position information of the barcode mark detected by the above-mentioned position detection device; the second storage device stores the position information of the bar code mark detected by the previous position detection device; A comparison device for comparing two position information in the two storage devices; a control device, which generates a decoding permission signal when it is judged that the two position information are different according to the comparison result of the comparison device.

That is, in the bar code mark reading device of the first style and the device for preventing double reading of the second style according to the present invention, there are first and second storage means for storing the position information of the bar code mark and comparing two The comparison device of position information compares the position of the barcode mark that has been decoded with the position of the newly read barcode mark. If they are the same, the newly read barcode mark is invalid and will not be decoded. Prevents double reads.

Also, the bar code mark reading device provided according to the third aspect of the present invention has: an imaging device for imaging a bar code mark composed of bars and spaces; a bar code mark detection device, from the above imaging device The presence or absence of the bar code mark is detected by the output signal; the bar code mark decoding device is used to interpret the content of the bar code mark obtained from the image of the above bar code mark captured by the above-mentioned camera device; the control device is controlled by the above-mentioned After the barcode symbol decoding device decodes the barcode symbol, according to the above barcode symbol detecting device, when there is at least one state where the barcode symbol cannot be detected, the operation of the subsequent barcode symbol decoding device is permitted.

That is, after the barcode symbol is decoded by the barcode symbol decoding device in the barcode symbol reading device of the third style of the present invention, unless the barcode symbol detecting device fails to detect the barcode symbol at least once, the control device prohibits subsequent reading of the barcode symbol. The operation of the barcode symbol decoding device, so the barcode symbol is not read in until it is detected that the barcode symbol is detached from the barcode symbol reading device, thereby preventing "double reading".

Fig. 1 is the block diagram that the first embodiment of the present invention forms;

Fig. 2 is the flowchart of the action in order to explain the first embodiment;

3A to FIG. 3C are a series of flow charts for more detailed description of the barcode mark detection process in the flow chart of FIG. 2;

4 is a diagram showing scanning directions and detection coordinate points for obtaining four corners of a barcode mark;

Fig. 5 is a diagram showing an image of two substantially orthogonal straight lines and coordinate points at four corners obtained from the detected coordinate points;

Fig. 6 is a diagram showing the structure of a PDF417 mark as an example of a binary barcode mark;

Fig. 7 is a flow chart showing the detection processing of the barcode mark related to the second embodiment;

Fig. 8 is hypothetical, project the barcode mark image of the PDF417 that has 4 * 1 mark arrays to be configured as the model figure of the frame memory unit layout;

9A and 9B are a series of flowcharts of the scanning and detection subroutines in FIG. 7;

Fig. 10 represents the figure of the composition of the eighth embodiment;

Fig. 11 is a flowchart for explaining the actions of the eighth embodiment;

Fig. 12 is a pattern diagram for illustrating the parallel movement of barcode marks;

Fig. 13 is a block diagram of the composition of the ninth embodiment of the present invention;

Fig. 14 is a flowchart for explaining the operation of the ninth embodiment.

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

Fig. 1 is a block diagram showing the constitution of the first embodiment of the present invention. In this figure, a CCD image sensor 10 captures image information of a label on which a bar code mark is printed, a commodity, etc. attached to an article not shown in the figure. The frame memory 12 temporarily stores image information captured by the above-mentioned CCD image sensor 10 .

The barcode mark detection processing unit 14 finds out the barcode mark from the data stored in the frame memory 12, and outputs its position information. The primary buffer memory 16 sequentially stores the position information of the barcode mark detected by the barcode mark detection processing unit 14 and transfers the stored mark position information to the secondary buffer memory 18 or the comparison unit 20 . The secondary buffer memory 18 stores the marker position information sent from the primary buffer memory 16 and transfers the stored marker position information to the comparison unit 20 . The comparison unit 20 compares the two mark position information sent from those primary and secondary buffer memories 16 and 18 .

The decoding processing unit 22 reads data from the bar code marking stored in the frame memory 12 based on the position information of the bar code marking detected by the above-mentioned bar code marking detection processing unit 14, decodes the content of the bar code marking, and converts The result of the code is transferred to a host computer not shown in the figure.

The control unit 24 controls each unit such as the CCD image sensor 10, the barcode mark detection processing unit 14, the primary buffer memory 16, the secondary buffer memory 18, the comparison unit 20, and the decoding processing unit 22.

In addition, the above-mentioned barcode mark detection processing unit 14 , comparison 20 , decoding processing unit 22 , and control unit 24 constitute a CPU 26 .

Hereinafter, in the configuration as above, the processing procedure for reading the bar code mark will be described with reference to the processing flow chart of FIG. 2, taking the already published data code as an example.

According to the control of the control unit 24, first, the image signal of the barcode mark is captured by the CCD image sensor 10 and stored in the frame memory 12 (step S1). Next, the barcode mark is detected by the barcode mark detection processing part 14 (step S2). That is, in the case of a data code symbol, for a pattern with an L-shaped outer frame, the coordinates of the four corners can be found by detecting this pattern. Then, it is judged whether there is a barcode mark, and finally whether the coordinates of the four corners are obtained (step S3). If there is no barcode mark in the captured image, go back to the above step S1.

Here, the detection of the barcode mark and the determination of the presence or absence of the barcode mark in the above-mentioned steps S2 and S3 will be described in more detail with reference to the flowcharts of FIGS. 3A to 3C .

The barcode mark detection processing unit 14 scans the frame memory 12 in the horizontal direction (X) every several screen units, for example, as shown in FIG. 4 . That is, first, after initially setting the Y coordinate at the initial value Y ₀ (step S21), the X coordinate changes from the initial value X ₀ to the maximum value X _N every few screen units, and scans in the horizontal direction (step S22). Then, the coordinate points of the first detected black level and the last detected black level in this scan are stored (step S23). Next, the Y coordinate is updated at predetermined intervals A (step S24), and it is judged whether the result exceeds the maximum value Y _N (step S25). If not, return to the above step S22 and repeat the above processing.

Then, if all the scanning in the horizontal direction is completed, connect the coordinate points of the initially detected black level, and find a straight line A (L ₁ in Figure 5 ) connecting multiple coordinate points (such as more than 4), such as this If the straight line A exists (step S26), all coordinate points P _A on the straight line A are stored (step S27). Equally, connect the coordinate point of the black level that detects at last, look for the straight line B that a plurality of coordinate points (for example more than 4) link together, if this straight line B exists (step S28), will all on this straight line B The coordinate point P _B is stored (step S29). Afterwards, it is judged whether the straight lines A and B are substantially orthogonal (step S30), if they are orthogonal, the intersection point b (see Fig. 5 ) of the two straight lines A and B is calculated from the stored coordinate points P _A and P _B coordinates (step S31).

On the other hand, in the above-mentioned step S30, if it is judged that the two straight lines A and B are not substantially orthogonal (including the occasion that the two straight lines A and B cannot be found), then scan in the vertical direction (Y) to perform Same deal. That is, after first setting the X coordinate initially with the initial value X ₀ (step S32), the Y coordinate is changed from the initial value Y ₀ to the maximum value Y _N every several screen units, and scanning is performed in the vertical direction ( Step S33). Then, the coordinate points of the first detected black level and the last detected black level in this scan are stored (step S34). Next, the X coordinate is updated at predetermined intervals B (step S35) and it is judged whether the result exceeds the maximum value X _N (step S36). If not, go back to the above step S33 and repeat the above processing. Subsequently, after the scanning of all vertical directions is completed, the coordinate points of the initially detected black level are connected, and a straight line C connecting a plurality of coordinate points (for example, more than 4) is found. If this straight line C exists ( Step S37), store all the coordinate points PC on the straight line _C , (step S38). Similarly, connect the coordinate points of the last detected black level, and look for a straight line D (for example, L ₂ in Fig. 5 ) connecting a plurality of coordinate points (for example, more than 4), if such a straight line D exists (step 39), storing all the coordinate points _PD on the straight line D (step S40). Then it is judged whether there are two straight lines substantially orthogonal among the straight lines A to D (step S41). If there is no orthogonality, it is assumed that there is no barcode mark (step S42), the process ends, and the process returns to the above-mentioned step S1.

Also, if two substantially orthogonal straight lines exist, the coordinates of the intersection point b (see FIG. 5 ) of the two straight lines are calculated from the stored coordinate points on the two orthogonal straight lines (step S43).

Then, the coordinates a, b, c, and d of the four corners of the barcode mark are determined from the calculated intersection b of the two straight lines and the detected coordinate points. That is, scan and read data along two orthogonal straight lines in the direction of the upper intersection point b (step S44), and store the last coordinate points of the black level as points a and c (step S45). Then calculate the coordinates of point d from the coordinates of the three stored points a, b, and c, store the result, and use the coordinates of the obtained four corners of points a, b, c, and d as the position The information is output to the primary buffer memory 16 (step S46). Finally, in the case of a data code, since the shape of the barcode mark is a square, if the lengths of the intersection and one side are known, the four corners can be determined simply. In addition, it does not matter even if the coordinates of these four corners and the position of the mark do not coincide correctly.

In this way, the coordinates of the found four corners are temporarily stored in the primary buffer memory 16 , and the primary buffer memory 16 transfers the position information to the comparison unit 20 and the secondary buffer memory 18 . While the secondary buffer memory 18 transfers the stored position information to the comparison unit 20, after storing the position information of the mark sent from the primary buffer memory 16, in the comparison unit 20, the data from the primary buffer memory 16 and the secondary buffer memory 16 are compared. Compare at least one coordinate point among the two groups of four-point coordinates sent by buffer storage 18, and judge whether they are identical (step S4). In this judgment, if the error of each coordinate point is the degree of several picture units, it is regarded Are the same. Here, when the judging position is the same, the same barcode mark is judged to be read twice, and this mark is regarded as invalid, and a warning signal indicating the action of the double-reading mechanism is issued to urge to change the barcode mark, that is, to change the product ( Step S5). Thereafter, return to the above-mentioned step S1 to perform the following read-in.

In addition, in the above-mentioned step S4, when it is determined that the positions are different, a process of specifying the position of the bar code mark (rest confirmation process of the bar code mark) is performed. That is, it reads again directly (step S6), and performs mark position detection in the barcode mark detection processing part 14 similarly to the above-mentioned step S2 (step S7). Then, the new position information is stored in the primary buffer memory 16, and is compared with the position information of the most recent mark stored in the secondary buffer memory 18 in the comparison unit 20 (step S8). This time, if the positions are the same, it is considered that the barcode marks are determined.

Then, if the position of the barcode mark is determined, that is, if it is confirmed to be stationary, then the control unit 24 gives a decoding permission signal to the decoding processing unit 22, and accordingly, the decoding processing unit 22 performs decoding of the bar code mark (step S9). That is, in the decoding processing unit 22, using the mark position information from the bar code mark detection processing unit 14, the frame memory in which only the bar code mark exists is sequentially scanned along the bar code mark as shown in FIG. 5, and the bar code mark information is decoded. Subsequently, the result of decoding is transferred to the host computer not shown in the figure (step S10), and after the warning signal for the purpose of notifying that a bar code mark has been read is sent (step S11), the process ends and gets back to the above-mentioned steps S1 shifts to the reading of the following barcode marks.

On the other hand, if it is judged that the positions are different in the above-mentioned step 8, the control unit 24 judges that the bar code mark has moved, and it is considered that the bar code mark, that is, the replacement operation of the commodity, does not perform decoding by the decoding processing unit 22. Code, return to the above step S1 and transfer to the next read-in.

In short, in the present first embodiment, after the bar code mark is changed, just use the CCD image sensor 10 to take an image, immediately use the CCD image sensor 10 to take an image again, if there is no mark movement, just start decoding. And until the mark to be decoded is replaced, the cycle of steps S1-S5 will be repeated, and then decoded, which prevents double reading.

If for taking away the barcode mark of this deciphered code and causing in mark movement to take pictures, just become the result that can pass through step S4 to step S6, in this case, get back to step S1 according to the static confirmation with step S8 to eliminate, Decoding again prevents double reading.

In the insertion of subsequent bar code marks, it is eliminated by the static confirmation of step S8, and decoding does not start until this bar code mark stops.

However, in this case, if the barcode mark does not move during the time between when the barcode mark is read in step S6 and when the bar code mark is read in step S1, it will be judged to be in position after all in step S4. Similarly, the processing after step S6 cannot be performed, and there is a possibility that decoding will not be performed at any time. However, in this case, according to the warning signal in step S5, the above-mentioned situation that cannot be read is reported to the operator, and the position of the barcode mark is moved a little to take countermeasures.

Thus, in the first embodiment, since only the positional information of the barcode marks is compared, the comparison process is performed simply and quickly. Also, since the decoding is determined from the position of the bar code mark, double reading in the bar code mark replacement operation can also be prevented. second embodiment

In the above first embodiment, the barcode mark uses a data code, and the present invention is not limited thereto, no matter it is PDF417, CODE49, or other binary barcode marks.

Therefore, a case where PDF417 is additionally used will be described as a second embodiment. Here, the structure of the PDF417 mark is as shown in FIG. 6 . That is, this barcode mark has: the mark part 28 that should be the area of a plurality of information components that the bar code symbol group that is formed by the bar and the space that is combined by bar and space; Start code 30 and end code 32. Thus, a code, except the end code 32, consists of 4 bars and spaces, while the end code 32A consists of 5 bars and 4 spaces. Furthermore, the start and end codes 30, 32 begin with thick bars 30A, 32A called "bold bars". As long as the thick bars 30A, 32A having this feature are detected, the coordinates of the four corners of the mark can be found.

The flag unit 28 is a flag array 28C composed of a code called a row indicator 28A that exists adjacent to the start code 30 and the end code 32, and a plurality of data columns 28B that describe actual data between them. constituted. In the row indicator 28A, the size of the flag in the row direction and the column direction, reliability level, and the like are described. Among them, the reliability level is a level with the ability to correct errors for PDF417, and there are nine levels in total. Therefore, by reading the information of the row indicator 28A, the information size of the barcode mark and the like can be determined.

This Figure 6 shows a barcode indicium with a 4x2 array of markers.

This second embodiment is different from the above-mentioned first embodiment only in the barcode mark detection process (step S2 in FIG. 2 ), so only this part will be described with reference to the processing flow chart in FIG. 7 . In this specification, flowcharts are written in the description format of the programming language C.

FIG. 8 is a schematic diagram showing a hypothetical image of a barcode symbol of PDF417 having a 4×1 mark array projected into a frame memory 12. The projected image 34 of the barcode mark is detected. That is, in the barcode mark detection processing part 14, at first the frame memory 12 is scanned with every several picture frame units in the horizontal (X) direction, and the start code 30 and the end code 32 are detected (step S51), Locate the four corners of the barcode marking 34. If the barcode mark 34 cannot be found in the horizontal scan (step S52), the frame memory 12 is scanned in the vertical (Y) direction, and the four corners of the barcode mark 34 are similarly found (step S53). If all can not find under the situation of mark 34 like this (step S54), exit this processing as not having barcode mark (mark to detect). That is, return if you get unmarked information. Furthermore, in this specification, because the notation method of C language becomes the notation method in this figure, but if it is notation method according to FORTRAN, etc., it becomes the so-called identification mark with no mark. Returns the writing method. Also, regarding the above-mentioned step S52 or S54, when the four corners of the barcode mark are found, this process is exited as there is a barcode mark (detected mark).

Here, regarding steps S51-S53, the subroutine for detecting the barcode mark 34 will be described in detail with reference to FIGS. 9A and 9B.

First, in order to read every several picture units, as the value of the read position count n, initially set the value corresponding to the predetermined picture unit increment scan-inc of the above-mentioned several picture units ( Step S61), judging whether it is horizontal scanning or vertical scanning (step S62), if it is horizontal scanning, read the data of the nth line from the frame memory 12 (step S63). In the case of vertical scanning, the data of the nth column is read (step S64).

Next, it is judged whether or not the start code 30 exists in the extracted data series (step S65). If it exists, it is judged whether it belongs to the initial detection in the current image data (step S66). Then, when it is the first time, the detected coordinates are registered as the coordinate variable e (step S67). If it is not the first time, the detected coordinates are registered as the coordinate variable g (step S68).

Next, similarly, it is judged whether or not the end code 32 exists (step S69). If it exists, it is judged whether it is the result of initial detection (step S70). In the case of the first time, the detected coordinates are registered as the coordinate variable f (step S71). If it is not the first time, the detected coordinates are registered as the coordinate variable h (step S72).

Then, the next scanning position is set by adding the above-mentioned picture unit increment scan-inc to the value of the read position count n (step S73), and it is judged whether this position is outside the picture (step S74). If it is within the drawing, return to the above-mentioned step S62 to read the next data series.

On the other hand, if it is outside the drawing, it is judged whether two points are found in the start code/end code detection coordinates (steps S75, S76). That is, it is judged whether the plural coordinate numbers e, g, f, and h are all defined, and if not defined, it is judged that the barcode mark has not been detected, and the reading of the barcode mark is moved to the following.

When all the coordinate variables are defined, the coordinates of the four corners of the barcode mark are calculated and stored (step S77). Specifically, a straight line passing through the coordinates e and g is obtained, and then, starting from the position (i, j) where the coordinates e and g enter several picture units inside the thick bar, it moves toward the upper/lower edge direction of the mark Observe the data, the initially found boundary coordinates are stored as coordinate complex numbers m and n respectively. Make a vertical line from the coordinates m and n to the straight line passing through the coordinates e and g, and the intersection points are a and b, which are the coordinates of the two angles on the starting code side of the barcode mark. The end code side is also processed in the same way, and c and d of the two corners can be obtained.

In this case, the two corners c and d do not correspond to the coordinates of the corners of the actual barcode mark, and since there is no problem even if these coordinate points are used, these coordinate points c and d are used for calculation simplification. Needless to say, to determine the code shape of the end code 32, data is read from the points c and d in the direction of the above-mentioned perpendicular line, thereby also obtaining the coordinates of the actual corners of the bar code mark.

The coordinates of the coordinate points a, b, c, and d of these four corners obtained are output to the primary buffer memory 16 as the mark position information, and are compared with the position information stored in the secondary buffer memory 18 to prevent barcode marks from being distorted. Double read. third embodiment

For the above-mentioned first and second embodiments, the barcode mark of the above step S6 is read into and implemented immediately, for example, if it is carried out after 1 or 2 seconds, because it can be confirmed that the barcode mark is indeed positioned, it can be carried out more correctly. read. fourth embodiment

In addition, for the above third embodiment, if considering that the reading of the bar code mark of the above-mentioned step S6 carried out after 1 or 2 seconds must be to read in other bar code marks, then the position comparison process of the bar code marks of step S8 can be omitted , in this way, it can be processed relatively quickly. fifth embodiment

For above-mentioned first and second embodiment, get back to step S1 and carry out the bar code mark read-in processing immediately after above-mentioned step S11 sends warning signal, but have sufficient time interval owing to waiting for people to change bar code mark, for example 2, 3 seconds, if the reading of the barcode mark in step S1 is performed again in this way, it is possible to omit the above-mentioned steps S6-S8, and it becomes possible to perform the processing more quickly. The above-mentioned third and fourth embodiments are also the same, when returning to step S1 from step S11, it is better to wait for a time interval for people to fully change the barcode marks.

Then, when returning to step S1 from above-mentioned step S5, it is also better to wait for a time interval in which people have enough to change the barcode marks. sixth embodiment

The position information of the barcode mark may be one, two or three of the four coordinates of the four corners of the mark. seventh embodiment

In addition, in the above-mentioned first to sixth embodiments, the combination of the CCD image sensor 10 and the frame memory 12 is used as the imaging element, if a CMD (charge modulation device) that can be randomly accessed is used Since it has the function of frame memory, it becomes unnecessary to provide additional frame memory. eighth embodiment

As an eighth embodiment, a system for reading binary barcode marks attached to commodities flowing on a belt conveyor will be described.

Fig. 10 is a structural diagram of the system of this embodiment. A binary barcode mark 38 is pasted on various items 36 , such as the whereabouts of the item, the name of the item, the quantity, etc. are digitized on the binary barcode 38 . Each article 36 moves in a certain direction at its own speed along with the belt conveyor 40, and takes an image of the barcode mark 38 when the camera 42 installed at a predetermined position passes under it. Video camera 42 is often to take pictures repeatedly, owing to use the cause of flashing high-speed shutter, because object 36 is moving, imaging is not blurred. The barcode mark captured by the camera 42 is decoded by the decoder 44 , and the flow of the articles 36 is controlled by the conveyor controller 46 according to the decoded content.

The configuration of the decoder 44 is the same as that of the frame memory 12 and subsequent configurations of the first embodiment, and only the processing content of the comparison unit 20 is different.

Referring to FIG. 11, the decoding process of this embodiment when PDF417 is used as a binary barcode symbol will be described in detail.

First, the camera 42 repeatedly captures images, and the captured image data is stored in the frame memory 12 (step S80). In the barcode mark detection processing unit 14, the data is read from the frame memory 12, and the coordinates of the four corners of the barcode mark are detected according to the aforementioned mark detection method (step S81). Then, determine whether to find the coordinates of the four corners, finally determine whether there is a mark (step S82) in the drawing, if not, just get back to the above-mentioned step S80, and transfer to the following image to read.

Again, if it is judged that the barcode mark exists, the coordinates of the detected four corners are stored in the primary buffer memory 16 as position information, and the position information of the previous mark stored in the secondary buffer memory 18 is compared in the comparison part 20. compared to. In the comparison unit 20, the coordinates of the four corners are first compared to determine whether the previous mark position is the same as this time (step S83). If the position is the same, it is judged that the same bar code is read continuously again, and the mark read in this time becomes invalid and does not decode, and returns to above-mentioned step S80, and shifts to the image reading next time.

On the other hand, when the positions are different, in the eighth embodiment, because the barcode mark 38 moves on the belt conveyor, attention should be paid to the fact that the barcode mark moves in a certain direction at a constant speed. Figure 12 shows an image 48 of the barcode indicia projected on the frame memory. In this figure, 50 represents the image S1 of the mark obtained by the previous imaging, and 52 represents the image S2 of the mark obtained by this imaging, points a, b, c, d and points a', b', c', d ' represent the coordinate positions of the detected four corners respectively. The barcode mark 38 is moving on the belt conveyor 40, and after the mark S1 is read, the mark S2 moved in parallel with the movement of the belt conveyor 40 is read. The absolute positions of the marks S1 and S2 are different, but relative to each other, if there is such a relationship that the belt conveyor 40 moves in parallel within the imaging interval, it should be judged that the same barcode marks 38 are continuously read in again. The imaging interval of the camera 42 is short, and the same mark is often read in different positions.

Therefore, in the eighth embodiment, it is necessary to judge whether the bases corresponding to the four corners of the two marks S1 and S2 move in parallel (step S84). If they move in parallel, it is judged as the same barcode mark For the second continuous read-in, return to the above step S80 and transfer to the next image read-in. Furthermore, if it is a completely different position, it is read in as a new barcode mark, decoded by the decoding processing unit 22 (step S85), and the decoding result is forwarded to the conveyor controller 46 (step S86). And, at this time, the position information of the decoded symbol from the primary buffer memory 16 is output to the secondary buffer memory 18 . Thereafter, return to the above-mentioned step S80, and transfer to the next image capture.

In this way, not only the coordinate positions of the four corners of the marks are compared, but also comparison processing for judging whether there is parallel movement is provided, thereby preventing double reading of barcode marks moving in a certain direction. ninth embodiment

Next, a ninth embodiment of the present invention will be described.

FIG. 13 is a diagram showing its configuration. A label or the like including a bar code mark 54 is illuminated by an illuminating device not shown in the figure, and the reflected light thereof enters a camera 56 . In the camera 56, the optical signal is converted into an electrical signal, and a synchronization signal and the like are added to form a video signal, which is sent to a video circuit 58. In the video circuit 58, the synchronizing signal is separated from the input video signal, followed by A/D conversion and digitization. This digitized signal is stored in frame memory 60 .

The image on the label containing the barcode mark 54 stored in the frame memory 60 is scanned by the high-speed arithmetic circuit (image information is detected from the memory 60), and the presence or absence of the barcode mark 54 and the decoding of the barcode mark 54 are implemented. The decoded content is temporarily stored in the decoding result storage memory 64 . After the decoding is completed, the high-speed calculation circuit 62 clears the decoding permission flag (decoding is prohibited).

CPU 68 controls each component, for example, outputs to video circuit 58 the sending start signal that instructs to send image into frame memory 60, and outputs the detection start signal of bar code mark 54 and the decoding of bar code mark 54 to high-speed calculation circuit 62. The code start signal also controls the operation of each part that receives the detection status signal of the barcode mark 54 from the high-speed calculation circuit 62 and the decoding and inspection end signal of the barcode mark 54 . In addition, when the barcode mark 54 can be detected, the decoding permission flag 66 (decoding permission) indicating whether it is possible to decode the barcode 54 is set, and the information of the barcode mark 54 recorded is taken out from the decoding result storage memory 64, and the control The host interface circuit 70 transfers this information to a host computer not shown in the figure.

Hereinafter, the operation of the "double reading" preventing mechanism of the barcode symbol reading device configured in this way will be described with reference to the flowchart of FIG. 14 .

First, the CPU 68 outputs a start signal to the video circuit 58, and sends an image to the frame memory 60 (step 91). After this step image is sent in, CPU68 outputs the detection start signal of barcode mark 54 to high-speed computing circuit 62, carries out the detection of barcode mark 54 by high-speed computing circuit 62 (step S92). The detection of this bar code mark, also known various methods besides what has been described above, for example, as disclosed in Japanese Patent Publication No. Hei 2-23483, it is known that there are a plurality of Judgment of situation of parallel bar has method of barcode mark. Also, for binary barcodes such as PDF417, DATA, CODE, etc., a method for detecting the existence of barcodes can be obtained by confirming the existence of the so-called initial thick barcode and the characteristic part of the L-shaped frame. Subsequently, the high-speed calculation circuit 62 outputs the detection result of the barcode mark 54 to the CPU 68 as a detection status signal.

CPU 68 judges whether there is barcode mark 54 in the image sent into frame memory 60 according to the detection status signal coming from this high-speed calculation circuit 62 (step S93). Then, when the barcode mark 54 does not exist, return to the above-mentioned step S91, and instruct to send the image again. And when the bar code mark 54 exists, output the decoding start signal of the bar code mark 54 to the high-speed calculation circuit 62, and carry out the decoding of the bar code mark 54 in the high-speed derivation circuit 62 (step S94). The high-speed calculation circuit 62, corresponding to this decoding start signal, after confirming the fact of the set decoding permission flag 66 (decoding permission), marks the bar code from the image of the bar code mark 54 sent into the frame memory 60. information is decoded. In addition, the high-speed arithmetic circuit 62 checks the decoding result (step S95). The inspection of the decoding content is included in cases where only the decoding result is confirmed (JAN/UPC/E AN code, ITF (five-interval two-line) code, CODE39, NW-7 code, CODE128, etc.), with error correction Occasionally (binary barcode symbols such as PDF417, DATA, CODE, etc.) are also available. Afterwards, the high-speed calculation circuit 62 provides the decoding and inspection completion signal of the barcode mark 54 containing the information of the inspection result to the CPU 68.

Here, CPU 68 judges (step S96) from the above-mentioned decoding of high-speed computing circuit 62 and the completion signal of inspection, and when it cannot be decoded correctly, returns to above-mentioned step S91, and starts repeating from image sending in again. Also, when the decoding can be performed correctly, the CPU 68 outputs a decoding result hold signal to the high-speed arithmetic circuit 62 . The high-speed calculation circuit 62 temporarily stores the decoded content in the decoding result storage memory 64 in response to the decoding result holding signal, and clears the decoding permission flag 66 (decoding prohibited) (step S97).

Next, the CPU 68 fetches the information of the recorded barcode mark 54 from the decoding result storage memory 64, controls the host interface circuit 70, and transfers the information to a host computer not shown in the figure (step S98).

The later processing is part of the "double read" prevention function.

That is, again, a signal to start image input to the frame memory 60 is output from the CPU 68 to the video circuit 58 to input an image (step S99). After the sending of this image is completed, the presence or absence of the barcode mark 54 is detected by the high-speed arithmetic circuit 62 (step S100). Here, when the barcode mark 54 exists in the image sent into the frame memory 60, the fact that the decoding permission flag 66 is cleared is confirmed (step S101), and the sending of the image from the above-mentioned step S99 is repeated. As a result, after the transfer to the host is completed, if there is still a bar code mark 54, if the bar code mark 54 that has been transferred to the host is judged to have not been taken away from the reading device, subsequent processing will not be performed. .

On the other hand, when the barcode mark 54 does not exist (step S101), once again, the video circuit 58 sends a start signal to the image input of the frame memory 60 from the CPU 68 to input the image (step S102). After the sending of this image is completed, the presence or absence of the barcode mark 54 is detected by the high-speed arithmetic circuit 62 (step S103). Here, when the barcode mark 54 exists in the image sent into the frame memory 60, the fact that the decoding permission flag 66 is cleared is confirmed (step S104), and the sending of the image from the above-mentioned step S99 is repeated. That is, as steps S102 to S104, the same processing as that of the above-mentioned steps S99 to S101 is repeated.

When it is judged in step S104 that there is no barcode mark 54, the CPU 68 sets the decoding permission flag 66 (step S105). That is, when the barcode mark 54 does not exist in the image continuously sent to the frame memory 60 for the second time, the decoding permission flag 66 is set. Thereafter, return to the above-mentioned step S91, and repeat the above-mentioned processing.

As explained above, in the present ninth embodiment, the function of preventing "double reading" can be realized only based on the detection of the presence or absence of the mark, so the processing speed is very fast. . As a result, since the decoding process prior to the barcode mark 54 must always require the mark detection process, in contrast to the problem that can be solved as long as it takes the time until the mark detection process is completed in this example, in the past, it was necessary at this time. The time required until the decoding process is completed needs to be added. Also, if the label on which the barcode mark 54 is recorded is left there, there is no "double reading", and since no additional parts such as switches are used, it can be said that the number of parts and operability are very good. .

As previously mentioned, when the barcode mark 54 does not exist in the images that are continuously sent into the frame memory 60 for the second time, the decoding permission flag 66 is set only when the barcode mark 54 is removed, then when the barcode mark 54 is removed When the reading device and the barcode mark 54 vibrate for some reason, an image is sent to the frame memory 60 by this timing method, and if the barcode mark 54 is not removed, it is finally judged that the barcode mark 54 does not exist, and in addition When moving the barcode mark on the way of taking it away, the image is also judged as the barcode mark 54 does not exist, but once the barcode mark 54 stops during this process, no matter the barcode mark 54 that has been decoded is also removed. Decoding, and finally the so-called double reading thing becomes gone.

Here, in this ninth embodiment, when the barcode mark 54 does not exist in the images that are continuously sent into the frame memory 60 for the second time, the decoding permission flag 66 will not be set until the barcode mark 54 is removed, but, for example, once If it does not exist, the bar code mark 54 will be taken away to set the decoding permission flag 66 so that it is also possible to prevent the "double reading" function from being completed. As in this embodiment, the decoding permission flag 66 will be set when it is judged as non-existent twice in a row, and in the case where the reading device and the bar code mark vibrate for some reason, with this timing method The frame memory 60 has sent the image, and when the barcode mark 54 is not removed, it is judged that the barcode mark 54 does not exist. There is concern, and when the barcode mark 54 is moved as a result during the removal action, the image is judged to be invalid. There is a barcode mark 54, but if once the barcode mark 54 stops during this process, no matter whether it is the barcode mark 54 that has been decoded, it will be decoded again, and as a result, double reading will also occur when there is concern, you can In terms of preventing double reading, this embodiment improves reliability. In addition, it is not limited to two consecutive times, and the same effect can be obtained by using more than three times.

In addition, in order to avoid the above-mentioned concerns, actually, there is a close relationship between the reading period from when the image of the barcode mark 54 is sent to the frame memory 60 to when the presence or absence of the barcode mark 54 is determined. That is, this read-in cycle is too long, although the barcode symbol 54 is changed into but not yet decoded barcode symbol 54 becomes not decoded in this period of time from the sending in of step S99 to the sending in of step S102. Therefore, in this embodiment, this read-in cycle is about 0.3 seconds. Tenth embodiment

In the above-mentioned ninth embodiment, detect the barcode mark 54 in the image sent in sequence to replace, for example, the frame memory 60 has the capacity of two graphs to send the image into the graph frame with a limited time interval, on the two frames When the barcode mark 54 is detected, the decoding permission flag 66 is set, and the same effect can be obtained. eleventh embodiment

In addition, in the above-mentioned first to tenth embodiments, the type of the barcode mark to be read is not particularly limited, and the detection method of the barcode mark 54 uses JAN/UPC/EAN code, ITF (five lines every two lines) code , CODE39, NW-7, CODE128, etc., can be used for various barcode mark detection methods, and various barcode mark detection methods related to binary barcode marks (CODE16K, CODE49, PDF417, DATA, CODE, etc.) It's okay to get up.

In this way, each embodiment does not limit the type of barcode marks, and is particularly effective for binary barcode marks that take a long time to read.

Claims (3)

1, apparatus for reading of bar-code marks, it comprises at interval bar-code marks is made a video recording every official hour, stores shooting and memory storage by the image information of this shooting gained, it is characterized in that this apparatus for reading of bar-code marks also comprises:

By the position-detecting apparatus that detects the positional information of bar-code marks in the image information that is stored in above-mentioned shooting and the memory storage;

The primary importance memory storage that rheme is put the bar-code marks positional information that detection device detects is used in storage;

Storage according to above-mentioned position-detecting apparatus at the second place memory storage that than the positional information in the primary importance memory storage is the positional information of the bar-code marks that detects on the previous time point;

To being stored in two comparison means that positional information compares in above-mentioned first and second location storage devices; With

According to the comparative result of above-mentioned comparison means, judging that two positional informations are different occasions, the code translator that the content of the bar-code marks that the image information that stores is got is deciphered from above-mentioned shooting and memory storage.

2, apparatus for reading of bar-code marks is used prevents from the dual device that reads to it is characterized in that this device comprises:

According at interval the image information of bar-code marks shooting gained is detected the position-detecting apparatus of the positional information of bar-code marks every official hour;

First memory storage that rheme is put the positional information of the bar-code marks that detection device detects is used in storage;

Storage according to above-mentioned position-detecting apparatus at second memory storage that than the positional information in first memory storage is the positional information of the bar-code marks that detects on the previous time point;

To being stored in two comparison means that positional information compares in above-mentioned first and second memory storage; With

According to above-mentioned comparison means result relatively, judge that two positional informations are different time marquis, send the control device of decoding enabling signal.

3, apparatus for reading of bar-code marks is provided with being the camera head of purpose by bar and empty the shooting every the bar-code marks of forming, and it is characterized in that this apparatus for reading of bar-code marks also comprises:

Detect the bar-code marks detection device that has or not of bar-code marks by the output signal of above-mentioned camera head;

Explain the bar-code marks code translator of content of this bar-code marks of image of above-mentioned bar-code marks of free above-mentioned camera head shooting; With

After bar-code marks being deciphered by above-mentioned bar-code marks code translator, according to above-mentioned bar code detection device, when existence at least once can not detect the state of bar-code marks, give the control device of the action of later above-mentioned bar-code marks code translator with permission.

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