JP3580901B2 - Symbol information reader - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a symbol information reading device that reads symbol information such as a barcode.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a symbol called a barcode symbol which is printed on an article or the like, or printed on a tag or the like attached thereto, and indicates information on the article. This bar code symbol is used in the popular point-of-sale (POS) system and has become widely known.
[0003]
The bar code symbol is formed by combining bars and spaces having different widths in parallel to form a bar code character composed of one pattern. If necessary, there is a symbol in which necessary character groups including a check digit are arranged in parallel, and a characteristic predetermined pattern such as a start / stop character is arranged before and after.
[0004]
Barcodes used for general consumer goods are standardized as JAN (Japan Article Number). Another application of the barcode is a physical distribution symbol. This distribution symbol is obtained by adding a one-digit or two-digit distribution identification code before the JAN code.
[0005]
Each of the above-mentioned barcode symbols is called a one-dimensional barcode, and the amount of information that these code systems can have is about several tens of bytes, which is insufficient for actual use. Met.
[0006]
A symbol system called a two-dimensional barcode having a different structure has been proposed in accordance with such a demand for the information amount of the barcode.
According to these symbol systems, each of them has a feature that can encode much more information than a one-dimensional barcode. These systems are called stacked barcodes, and are a method of increasing the amount of information by stacking one-dimensional barcodes in the bar direction. As a representative of the stacked bar code, there is a code system called PDF-417.
[0007]
Conventionally, as a symbol information reader for reading the stacked barcode, for example, a laser scanning reader as disclosed in Japanese Patent Application Laid-Open No. 2-268382 is known. In this reader, a predetermined bar code is read by projecting a laser beam two-dimensionally and scanning, and symbol information is decoded.
[0008]
Also, Japanese Patent Application Laid-Open No. 2-268383 discloses an apparatus for capturing a barcode with a two-dimensional imaging device, loading the barcode image into a memory, and decoding barcode symbol information based on this data. I have.
[0009]
Further, there is an increasing demand for using such a barcode as a data carrier in FA (Factory Automation). This is for recognizing a product name, a destination, and the like of a distributed product while the distributed product is moving on a belt conveyor or the like.
[0010]
Conventionally, an RF tag or the like is generally used as a data carrier, but the tag is relatively expensive. If this tag can be substituted with a barcode, a low-cost data carrier is realized.
[0011]
As a conventional information reading apparatus for a moving article, Japanese Patent Application Laid-Open No. 56-118177 describes an optical inspection apparatus that performs a predetermined inspection based on a video signal obtained by scanning an image of a moving object. A circuit is disclosed for detecting, from a video signal, that an object has passed through the inspection field of view.
[0012]
[Problems to be solved by the invention]
However, as a problem of the above-mentioned Japanese Patent Application Laid-Open No. 56-118177, since the presence of the object is recognized from the width data of the video signal, the one-dimensional barcode such as JAN can be recognized. In a two-dimensional stacked barcode such as PDF417, even when the barcode label is not completely within the inspection field of view, the incomplete barcode label may be recognized and read processing may be performed. In such a case, barcode information cannot be read, resulting in a decrease in reading reliability and reading speed.
[0013]
Further, in order to read the information of the two-dimensional stacked bar code attached to the moving article, when the image is captured using a frame image using an interlaced image sensor, the image moves from the first read position to the next read position. As a result, there is a problem that the field components are shifted when two field images are combined.
Accordingly, it is an object of the present invention to provide a symbol information reading device that reads barcode symbol information of a moving two-dimensional barcode at high speed and with certainty.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an image pickup means for picking up a barcode consisting of a bar and a space and representing arbitrary information as a pattern as a two-dimensional image, and temporarily storing the two-dimensional images sequentially obtained by the image pickup means. Storage means for temporarily storing, a transfer means for transferring a two-dimensional image from the imaging means to the storage means, and sequentially reading out the two-dimensional images stored in the storage means, for the presence or absence of a barcode symbol within the imaging range. Recognition means for recognizing a bar code, a position detection means for detecting an existing position and a tilt of the bar code recognized by the recognition means within the imaging range, and detecting a scanning direction of the bar code; and a detection means for detecting the bar code scanning direction. Reading means for sequentially reading the barcode information from the two-dimensional barcode image in accordance with the scanning direction obtained, and reading the barcode information from the reading means. It is composed of a decoding means for decoding the informationThe transfer means compresses the two-dimensional image picked up by the image pickup means, transfers one scan line of a field component of the two-dimensional image picked up by the image pickup means, and then empties one line of the storage means Further including transferring a scan line, repeating the process until one field of image information is transferred, and copying the image information of one line above or below that line to a vacant line after completion, ForwardProvided is a symbol information reading device.
[0015]
The transfer unit compresses the two-dimensional image captured by the imaging unit., Storing only one field component of the captured two-dimensional image in the storage meansProvided is a symbol information reading device for transferring.OrThe transfer means,The two field components of the captured two-dimensional image are separately transferred to the storage unit. Alternatively, the transfer unit compresses the two-dimensional image picked up by the image pickup unit, transfers one scan line of the field component of the two-dimensional image picked up by the image pickup unit, and then transfers one line of the storage unit. Includes a processing operation to transfer the scan line after leaving it and repeat it until the image information for one field is transferred, and to copy the image information of one line above or below that line to the vacant line after completion. ,Forward.
[0016]
[Action]
The symbol information reading device configured as described above captures a moving two-dimensional barcode as a two-dimensional image, performs appropriate processing such as predetermined compression on the obtained two-dimensional image, and temporarily stores it. Then, the captured image is transferred to the storage unit, and after automatically recognizing the presence or absence of the barcode symbol, recognizing the position of the barcode symbol, sequentially reading the barcode information, and decoding the barcode information into the original information. I do.
[0017]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a schematic configuration of a symbol information reading apparatus according to a first embodiment, which will be described. This symbol information reading device is a configuration example for reading symbol information of a barcode symbol attached to a moving article or the like. Here, in the present embodiment, the symbol information is information on an article as an example, and is assumed to be, for example, an article name, a destination, and the like. Of course, the symbol information differs depending on what is used.
[0018]
This symbol information reading apparatus includes a stacked barcode label (hereinafter, referred to as a barcode label) 2 in, for example, a PDF-417 format, which is affixed to an article 1 or the like moved by a transport system 3 such as a belt conveyor. An imaging optical system 4 for optically forming the label 2, a two-dimensional imaging unit 5 for reading the formed barcode label 2 on a photoelectric conversion surface, and temporarily storing the read label image data (video signal). And a data processing device 7 for decoding the label image data into the original symbol information. A host device 16 such as a microcomputer for processing symbol information is provided outside. Further, an image transfer unit 17 that performs image processing such as image compression on the label image data (frame image) read by the two-dimensional imaging unit 5 and stores the processed image data in the frame memory 6 may be provided.
[0019]
The data processing device 7 includes a label detection unit 8 that detects whether the label image data stored in the frame memory 6 is readable in the imaging range of the imaging optical system 4 and a bar code label 2. 2 (label image data) for reading as label information, a decoding determining unit 10 for determining whether the read label information can be decoded, and a label information determined to be decodable as original symbol information. , A memory (including various registers for storing various constants and variables) 12, and a control unit 13 for controlling these components.
[0020]
The imaging optical system 4 and the two-dimensional imaging unit 5 are composed of, for example, a CCD camera.
The label detecting unit 8 determines whether the label image data stored in the frame memory 6 falls within the photographing range of the photographing optical system 4, that is, the position where the barcode label 2 photographed in the photographing range has no missing portion. The barcode label 2 is composed of a position detection unit 14 for detecting the barcode label 2 and a tilt detection unit 15 for detecting the degree of tilt of the barcode label 2.
[0021]
The data processing unit 7 can be replaced with, for example, a personal computer including a CPU and a memory.
Next, the above-described stacked barcode will be described.
[0022]
FIG. 2 shows a label structure of PDF-417 as an example of a stacked barcode. The bar code label 2 includes a label portion 21 which is a region of an information component to be decoded, which is composed of a bar code character group formed by a combination of a bar and a space, and a start / stop character which is arranged before and after the label portion 21. It has a code 22 and a stop code 23. One code is made up of four bars and spaces except for the stop code 23. The start and stop codes 22, 23 start from large bars 22A, 23A called "big bars".
[0023]
The label portion 21 is composed of a code called a row indicator 21A adjacent to the start code 22 and the stop code 23, and a label matrix including a plurality of data columns 21B in which actual data sandwiched between the codes is described. 21C. The row indicator 21A describes the size, security level, and the like of the label in the row and column directions. Therefore, by decoding the information of the row indicator, the information size of the label, the number of recoverable codes, and the like can be determined.
[0024]
FIG. 2 shows a barcode label having a 4 × 2 label matrix.
With reference to the flowchart shown in FIG. 4, label detection, label information reading, and decoding in the data processing device 7 will be described. FIG. 3 is a schematic diagram in which a label image of PDF-417 as described above is virtually projected on the pixel array of the frame memory 6.
[0025]
First, various parameters such as a frame memory, a threshold value, and various global variables are initialized (step S1). Next, a label image data (video signal) is fetched into the frame memory 6 by calling an image fetching routine described later (step S2). Next, a label detection routine, which will be described later, is called, and it is checked whether or not a barcode label exists using the fetched label image data. Further, if a barcode label exists, label image data is detected ( Step S3).
[0026]
Then, the result of the label detection processing in step S3 is determined (step S4). If there is no label (NO), the process returns to step S1, and the image capturing processing is performed again.
[0027]
Next, if a label exists (YES), a threshold determination routine described later is called, and processing is performed in an embedding check in step S11 and an optimal scan routine in step S12 and an intelligent scan routine in step S15 described later. A threshold (variable THRESHOLD) used for a process for extracting width information between edges from target line data is obtained (step S5).
[0028]
Next, an indicator information determination routine is called, the row indicator 21A of the label 2 is read, and the label size and the like are determined (step S6).
Then, it is determined whether or not the label size or the like has been determined in the determination routine of step S6 (step S7). If the label size has not been determined (NO), the process returns to step S1, and the image capturing again. Perform processing. On the other hand, if the label size or the like is determined (YES), a tilt redefinition routine described later is called to obtain a more accurate label tilt (step S8).
[0029]
Next, a scan equation determination routine to be described later is called, and various variables for scanning the entire surface of the label 2 are defined (step S9). Next, an embedding check routine to be described later is called to estimate the position of each codeword, and further, it is checked whether or not the position of each codeword is within the screen (step S10).
[0030]
Then, in step S10, it is determined whether the number of codes estimated to be unreadable exceeds a recoverable number (step S11). If it exceeds, it is determined that decoding is impossible (NO), and the step is repeated. The process proceeds to S1, and the image capturing process is performed again. On the other hand, if it is lower, the decoding is enabled (YES), the optimum scan routine described later is called, and the label is scanned over the entire surface at the optimum interval using the various variables defined in step S9, and the label information is read. Is read (step S12). Here, the optimal scan means a scan at an optimal interval so that the amount of calculation is the least and all label information can be determined.
[0031]
Then, it is determined whether or not the information read by the optimal scan in step S12 can be decoded (step S13). If the information can be decoded (YES), the process proceeds to step S16 to perform a decoding process. However, if decoding is not possible (NO), an intelligent scan routine to be described later is called to scan the code position that could not be read in step S12 using the various variables defined in step S10, and label information is read. Is read (step S14).
[0032]
Next, it is determined whether or not the information read in step S14 is decodable (step S15). If the information is decodable (YES) and if the information read in step S12 is decodable, a decoding process is performed ( Step S16). After the completion of the decoding process, the process returns to step S1 to read a new barcode label.
[0033]
However, if the decoding is impossible in step S16 (NO), the process returns to step S1 to capture the image.
In the decoding process in step S16, the read information is decoded by the optimum scan routine and the intelligent scan routine, and the decoded symbol information is output to the host device 14.
[0034]
Next, various processing routines in the flowchart of FIG. 4 will be described in detail below.
First, the image capturing routine called in step S2 shown in FIG. 4 will be described with reference to the diagram that captures only the field screen shown in FIG. 5 and the flowchart shown in FIG.
[0035]
The image capturing routine includes a process of transferring label image data (video signal) captured by the two-dimensional imaging unit 5 and temporarily storing the label image data in the frame memory 6.
[0036]
When an interlaced two-dimensional imaging unit 5 is used to read a barcode label attached to a moving article, barcode information cannot usually be read from the frame screen. That is, as described in the related art, the interlaced two-dimensional imaging device 5 combines two field screens (an odd component and an even component) for scanning an image while skipping one line at a time, thereby forming one frame screen. However, since the barcode label to be imaged is constantly moving, there is a positional shift between the first scan of the field image and the second scan of the field image. This is because if two field images are combined, the barcode label image will be misaligned.
[0037]
Therefore, in this embodiment, when the moving barcode label is read by using the interlaced two-dimensional imaging device 5, image information of only the field screen is transferred and taken in.
[0038]
In the image capturing routine, one (even number component or odd number component) field screen is transferred and captured (step S21). In this case, the field image is taken into the frame memory 6 without leaving a line, and the contents of the frame memory 6 at that time are as shown in FIG. In FIG. 5, the field image may be either an odd component or an even component. After this processing ends, the process returns to the main flowchart (FIG. 4).
[0039]
However, in this case, as shown in FIG. 5, one field image is compressed in the vertical direction, so that the height per line of the barcode label is reduced, and the reading conditions are stricter than the frame image. Become. Therefore, this method can be used when the ratio of the barcode label image to the target image is large and the height of one line of the barcode label is sufficient.
[0040]
Further, when the ratio of the barcode label image to the target image is small and the height of one line of the barcode label is not sufficient, various methods can be considered.
As one of them, first, two field screens (even component and odd component) are both separately transferred and captured. In this case, only the odd-numbered components are fetched into the frame memory 6 without leaving any rows, and then only the even-numbered components are fetched without leaving any rows. The contents of the frame memory 6 at that time are as shown in FIG. However, in FIG. 7, it does not matter which of the odd component and the even component is on the top.
[0041]
Here, the reason for transferring both the odd component and the even component is that two field images that originally imaged the same object are considered as different images, and if the upper image in FIG. 7 cannot be read, the lower image must be read. This is because reading can increase the reliability of reading.
[0042]
In this case, in the flowchart of FIG. 4, if the first determination in step S15 is (NO), the optimum scan in step S12 is tried again on the lower screen in FIG. Here, if the speed of the moving barcode label is known, the moving speed of the barcode label is added to the position information A, B, C, and D of the barcode label on the upper screen in FIG. By considering the scanning speed, the bar code label positions A ', B', C ', and D' on the lower screen of FIG. 7 can be calculated, so that it is not necessary to call the bar code label detection routine again. .
[0043]
If the moving speed of the barcode label is sufficiently negligible with respect to the scanning speed, the position information of the barcode label on the upper screen in FIG. 7 can be used as it is.
[0044]
There is also a method in which one field image is taken into the frame memory 6 at intervals of one line, and the contents of the frame memory of a line above the one line are copied to an empty line to improve the reliability of reading. . In this method, the copying can be easily realized by hardware, so that the bar code label reading speed is not lost at all.
[0045]
When the height of one line of the barcode label is sufficient, as shown in FIG. 8, an arbitrary number of pixels are added to all pieces of pixel information to make one pixel and stored in the frame memory 6. There is a way. This can also be easily realized by hardware, and has the effect of suppressing noise. FIG. 8 shows an example in which a total of four pixels in two rows and two columns are added to form one pixel.
[0046]
When the non-interlaced two-dimensional imaging device 5 is used, step S21 is to capture a frame image.
Next, the barcode label detection routine called in step S3 will be described with reference to the flowchart shown in FIG. 9 and the barcode label projection image shown in FIG. The bar code label detection routine detects the presence or absence of a bar code label, and detects the position information of the bar code label, that is, the extraction range (for extracting image data from the frame memory 6 in parallel with the bar code label). It includes two types of barcode label detection processing, namely, the variables STARTTOP and STOPBOTTOM) and obtaining the inclination of the barcode label (variable SLOPE). Here, the value of the variable STARTTOP indicates the top coordinate of the barcode label, and the content of the variable STOPBOTTOM indicates the bottom coordinate of the barcode label. The content of the variable SLOPE indicates the inclination of the barcode label.
[0047]
In the barcode label detection routine, first, a barcode label in-screen detection routine described later is called to detect a barcode label from the screen (label image data) stored in the frame memory 6 (step S31). It is determined whether or not the detected barcode label is completely on the screen (step S32). If it is not on the screen (NO), the process returns with information indicating that there is no barcode label. However, if it is within the screen (YES), a scan and detection routine to be described later is called to detect whether or not a start code exists in the label image data of the frame memory 6 (step S33). That is, the coordinates e and g shown in FIG. 10 are detected. When the start code is detected and determined by this routine, coordinate variables e and g on the frame memory 6 shown in FIG. 11 are defined. Here, the coordinate variable e is the coordinate of the smallest Y coordinate among several coordinates where the start code 22 is detected, and the coordinate variable e is the coordinate of the largest Y coordinate among some coordinates where the start code 22 is detected. Are respectively shown.
[0048]
Next, it is determined whether or not both coordinate variables e and g are defined (step S34). If not defined (NO), it is determined that there is no barcode label, and the process returns to the main flowchart. That is, the process returns with information indicating that there is no barcode label. As described above, the presence or absence of the barcode label is detected.
[0049]
Next, detection of position information of the barcode label, that is, calculation of an extraction range (variables STARTTOP and STARTBOTTOM) and an inclination of the barcode label (variable SLOPE) for extracting image data from the frame memory 6 in parallel with the barcode label. Is performed.
[0050]
That is, when it is determined in step S34 that both the coordinate variables e and g are defined (YES), the detection of the position information of the barcode label, that is, the image data is parallel to the barcode label is detected. Calculation of an extraction range (variables STARTTOP and STARTBOTTOM) for extraction from the frame memory 6 (step S35) and calculation of a barcode label inclination (variable SLOPE) (step S36) are performed. Then, the process returns with the information having the barcode label.
[0051]
Next, FIG. 12 shows the bar code label in-screen detection routine called in step S31 of the above-described bar code label detection routine and the determination of whether or not the bar code label in the screen is completely included in step S32. The flowchart shown and the detection in the barcode label screen shown in FIG. 13 will be described.
[0052]
This bar code label in-screen detection routine is for confirming whether or not the moving bar code label is completely contained in the frame memory 6, as described above. Even if the bar code label does not completely enter the frame memory 6, it is not possible to estimate the position and read the bar code symbol information depending on the number of codes outside the screen by using the intelligent scan described later. Although it is possible, the reading speed is reduced correspondingly, so such a routine is provided to correspond to the moving barcode label. Here, it is assumed that the barcode label is moving in the vertical direction with respect to the image.
[0053]
First, the start code 22 or the stop code 23 is detected in the upper line of the image (step S41). The details of this detection method will be described later. Next, it is determined whether or not detection has been performed (step S42). Here, when it is determined that either of them is detected (YES), it means that the upper part of the barcode label is not included in the image as shown in FIG. Therefore, in such a case, the process returns with the information that the barcode label is not on the screen. If not detected (NO), the start code 22 or the stop code 23 is detected in the lower line of the image (step S43).
[0054]
Next, it is determined whether or not detection has been performed (step S44). As described above, if it is determined that either of them is detected (YES), this means that the lower part of the bar code label is not included in the image, and information indicating that the bar code label is not on the screen. And return.
[0055]
If not detected (NO), the start code 22 or the stop code 23 is detected in the center line of the image (step S45). Next, it is determined whether or not a bar code label is detected (step S46). If no bar code label is detected (NO), the process returns with information indicating that the bar code label is not in the screen. However, if it is detected (YES), the process returns with the information that the barcode label is on the screen.
[0056]
Next, the scan and detection routine called in step S33 in the above-described barcode label detection routine will be described with reference to a flowchart shown in FIG. 14 and a diagram illustrating a scan method shown in FIG.
[0057]
This scanning and detection routine detects both the coordinate variables e and g as described above.
That is, first, a variable i used for counting the number of loops and a variable start for storing the number of detected start codes. num is initialized (step S51). Next, a row number n to be scanned and a scan interval nn are determined (step S52). Here row num is the number of rows of the target image. As shown in FIG. 15, the line numbers scanned in this subroutine employ a method of gradually narrowing the search width. This is similar to the NEWTON method that iteratively solves an equation.
[0058]
By using such a method, the start code 22 can be detected at high speed regardless of the position of the barcode label image in the frame memory. Next, j is initialized to perform 2 i scans for one loop i (step S53). Then, it is determined whether or not j is "0" (step S54). Here, if j is not 0, that is, if the proposition of step S54 is true (NO), a value obtained by doubling the scan interval nn obtained in step S52 is added to the row number n (step S55). If j is "0", that is, if the proposition of step S54 is false (YEA), step S55 is skipped, the process proceeds to step S56, and the image data of the n-th row is fetched (step S56).
[0059]
Next, the start code 22 is detected from the fetched image data (step S57). Next, it is determined whether or not the start code 22 has been detected (step S58). If the start code 22 does not exist (NO), the process proceeds to step S62. If the start code 22 exists (YES), the detected coordinates are stored in the coordinate array start. pos (step S59). And the variable start One is added to num (step S60).
[0060]
Next, the variable start It is determined whether or not num exceeds a predetermined number (step S61). Here, if it has exceeded (YES), the process proceeds to step S66. However, if not exceeded (NO), the variable j is incremented (step S62), and it is determined whether j is smaller than 2 to the power of i (step S63). If j is smaller (YES), the process returns to step S54. However, if j is not smaller than 2 to the power of i (NO), the variable i is incremented (step S64), and it is determined whether or not i is smaller than a specified constant Loop (step S65). If i is smaller (YES), the process returns to step S52. However, if i is not smaller than the specified constant Loop (NO), the process returns with the bar code label non-detection information. Therefore, in this subroutine, a maximum of (2 to the power of Loop) -1 scans are performed.
[0061]
Also, in step S61, start If num exceeds the specified number, a routine for calculating the maximum and minimum values of the Y coordinate, which will be described later, is called (step S66). Then, the process returns with the barcode label detection information. As described above, when a predetermined number or more of the start codes can be detected, the processing can be speeded up by returning the control to the upper routine even during the loop processing.
[0062]
Next, the start code detection routine called in step S57 in the scan and detection routine in FIG. 14 will be described with reference to the flowchart shown in FIG.
[0063]
First, the fetched image data is converted into width information (step S71). Next, the converted width information is normalized (step S72), and matching is performed (step S73). Then, it is determined whether or not the width information matches the start code (step S74). If it is determined that the width is the start code (YES), the process returns with the information indicating that the start code is present. If it is not a start code (NO), the process returns with information indicating that there is no start code.
[0064]
Next, a routine for converting into width information called in step S71 will be described with reference to a series of flowcharts shown in FIGS. This routine finds the width between the bar and the space of the bar code label, finds the boundary between the bar and the space using the differential signal, and then finds the peak of the data by approximating a quadratic curve. It is. Then, the width is obtained by sequentially obtaining peaks and obtaining the difference between the positions.
[0065]
First, the capture buffer array scan captured by the upper routine The line is an array of line data, and the value taken in and stored in the variable num is defined as the number of data (step S81). Next, the result of decrementing the value of the variable num is stored in the position indicator counter i, and the variable j is initialized to "0" (step S82).
[0066]
Then, the capture buffer array scan The fetch buffer array scan from the value of the i-th position (indicated by the position indicator counter i) of the line Subtract the value at the (i-1) th position of line, take in the solution, and retrieve the buffer array scan The line is reset to the i-th position (step S83). Thereafter, the position indicator counter i is decremented (step S84), and it is determined whether or not the result i is greater than "0" (step S85). If i is not greater than 0 (NO), the process returns to the step S83, that is, in steps S81 to S85, the line data is first differentiated. If the result i is larger than "0" (YES), the position indicator counter i is initialized to 2 (step S86).
[0067]
Then, the capture buffer array scan The value of the i-th position of line is larger than the value of the threshold variable THRESHOLD, and the capture buffer array scan line is larger than the value of the (i-1) th position of the line and the capture buffer array scan It is determined whether or not the value is equal to or more than the value of the (i + 1) th position of the line (step S87). If so (YES), the code index flag is set to UP (step S88). However, if not (NO), the procedure moves to the next step S89.
[0068]
Here, the capture buffer array scan The value of the i-th position of line is smaller than the value of the threshold variable THRESHOLD (-THRESHOLD) with a negative sign, and the capture buffer array scan line is smaller than the value of the (i-1) th position of the line and the capture buffer array scan It is determined whether or not the value is equal to or less than the value of the (i + 1) th position of the line (step S89). If so (YES), the code index flag is set to DOWN (step S90). Otherwise (NO), the procedure moves to the next step S91.
[0069]
Here, the position indicator counter i is incremented (step S91). It is determined whether i is smaller than a value obtained by subtracting 1 from the value of the variable num (step S92). If it is smaller (YES), the process returns to step S87. If it is not smaller (NO), the process returns to the routine of step 72.
[0070]
That is, in steps S87 to S92, the first peak exceeding the value of the threshold variable THRESHOLD, that is, the first peak in FIG. 19 is detected. If the sign of the detected peak is positive, the code index flag is set to UP, and the process proceeds to the next step S93. If the sign of the detected peak is negative, the code index flag is set to DOWN, and step S94 is performed. Move to If no peak is detected even after scanning the line data, the control is returned to a higher-level routine.
[0071]
If the code index flag is set in this way, then the value of the position indicator counter i is set to x1, and the fetch buffer array scan The value of the (i-1) th position of the line is y1, the capture buffer array scan The value of the i-th position of line is y2, the capture buffer array scan By setting the value of the (i + 1) th position of the line as y3, the detected peak position and data on both sides thereof are fitted with a quadratic curve (step S93). Then, a calculation of -0.5 (-y1-2x1y1 + 4x1y2 + y3-2x1y3) / y1-2y2 + y3 is performed to obtain the peak position of the quadratic curve, and this is stored in the variable lastpos (step S94).
[0072]
Thereafter, the value of the position indicator counter i is smaller than the value obtained by subtracting 2 from the value of the variable num, and the variable j is WIDTH. It is determined whether or not the variable j is smaller than NUM (step S95). If the variable j is not smaller (NO), the process returns to the upper routine.
[0073]
Where the variable j is WIDTH The proposition that it is smaller than NUM will be described. WIDTH NUM is a constant storing the number of widths to be obtained, and j is a variable storing the number of obtained peaks. Here, in order to detect the position of the start code 22, a condition that the start code 22 is always located on the left side of the frame memory 6 and a condition that there is no information other than the bar code label in the frame memory 6 If there is, the array scan It is not necessary to convert all the differential information stored in the line into width information.
[0074]
That is, since the minimum number of peaks required to detect eight pieces of width information is nine, the constant WIDTH This means that NUM should be larger than that. Normally, WIDTH NUM is determined by the SN ratio of the image. That is, if there is no information other than the bar code label in the frame memory 6, WIDTH NUM can be set to "9". Otherwise, WIDTH NUM must be a number greater than or equal to nine.
[0075]
For the reasons described above, the above proposition is included in the determination in step S95. When this proposition enters the judgment, the routine can be terminated without obtaining all the width information, so that the processing can be sped up. As will be described later, when it is desired to obtain all the width information from the differential information, it is only necessary to remove this proposition.
[0076]
If the proposition in step S95 is satisfied (YES), the position indicator counter i is incremented (step S96). The code index flag is DOWN, and the capture buffer array scan When the value of the i-th position of the line is larger than the value of the threshold variable THRESHOLD and the capture buffer array scan capture buffer array scan larger than the value of the (i-1) th position of line It is determined whether the value is equal to or greater than the value of the (i + 1) th position of the line (step S97). If all the terms hold (YES), the code index flag is set to UP (step S98).
[0077]
However, if all the terms do not hold in step S98 (NO), then the sign index flag is UP and the fetch buffer array scan The value of the i-th position of line is smaller than the value of the threshold variable THRESHOLD with a negative sign, and the capture buffer array scan capture buffer array scan smaller than the value at the (i-1) th position of line It is determined whether the value is equal to or less than the value of the (i + 1) th position of the line (step S99). If all the terms do not hold (NO), the process returns to step S95, and if all the terms hold (YES), the code index flag is set to DOWN (step S100).
[0078]
When the code index flag is reset in this way, the value of the position indicator counter i is set to x1, and the fetch buffer array scan The value of the (i-1) th position of the line is y1, the capture buffer array scan The value of the i-th position of line is y2, the capture buffer array scan By setting the value of the (i + 1) th position of the line as y3, the detected peak position and data on both sides thereof are fitted with a quadratic curve (step S101).
[0079]
Then, a calculation of -0.5 (-y1-2x1y1 + 4x1y2 + y3-2x1y3) / y1-2y2 + y3 is performed to obtain the peak position of the quadratic curve, and the obtained peak position is stored in a variable nowpos (step S102).
[0080]
As a result, as shown in FIG. 20, the previous peak position lastpos and the currently obtained peak position nowpos are obtained. Then, the peak-to-peak distance is obtained by taking the difference between the two peak positions thus obtained, and is stored in the position indicated by the variable j of the width information storage array variable width (step S103).
[0081]
Thereafter, the peak position variable lastpos is updated to the value of the peak position variable nowpos (step S104), the variable j is incremented (step S105), and the process proceeds to step S95.
[0082]
As described above, in steps S95 to S105, peaks are sequentially detected, and the distance between the peaks is stored in the width information storage array variable width. Here, the difference from the first peak detection in steps S87 to S92 is that, for example, when the current code index flag is DOWN, the next peak that cannot be found is a positive sign peak. is there.
[0083]
Next, the normalization routine called in step S82 in the above-described start code detection routine will be described with reference to the flowchart shown in FIG. First, "0" is substituted for the loop count variable i and the variable sum, and the initialization is performed (step S111). Next, an array width [i] storing the width information obtained by the conversion routine to the width information is added to the variable sum, and the sum is stored again in the sum (step S112).
[0084]
Next, the variable i is incremented (step S113). Next, it is determined whether or not the variable i is smaller than "8" (step S114). If the variable i is smaller than "8" (YES), the process returns to step S112. If the variable i is larger than "8" (NO), the process moves to the next step S115. Here, the reason that the variable i changes from “0” to “7” is that the code word of the PDF 417 is composed of a total of eight pieces of width information of four bars and four spaces. This is for normalizing the start code using all the width information.
[0085]
Next, "0" is substituted for the variable i again to initialize (step S115). Next, "17" is divided by the variable sum, and the value multiplied by the value stored in the i-th width [i] of the width information array is rounded to the nearest integer to the value (step S116). Here, round in FIG. 21 means rounding. Then, the variable i is incremented (step S117), and it is determined whether the variable i is smaller than "8" (step S118). If the variable i is smaller than "8" (YES), the process returns to the step S116, and if the variable i is larger than "8" (NO), the process returns to the upper routine.
[0086]
Next, the start code matching in step S73 in the start code detection routine shown in FIG. 16 as described above will be described.
Although any matching method may be used, a bar portion often becomes thicker than intended when printing a barcode label. If the bar portion is too thick, the decoding performance is significantly reduced. However, in such a case, the space portion becomes thinner as the bar becomes thicker. Therefore, it is better to adopt a method of matching the width information obtained by adding the bar thickness and the space thickness to the matching.
[0087]
Next, the routine for detecting the maximum and minimum values of the Y coordinate called in step S66 in the detection routine of FIG. 14 will be described with reference to the flowchart shown in FIG. The maximum / minimum value detection routine of the Y coordinate is a routine for finding the maximum and minimum Y coordinates among the coordinates of the start code detected by the specified number.
[0088]
First, the Start value stored in the 0th position of the array of the detected coordinates of the start code detected in step S57 (FIG. 14) is stored in the coordinate variable MAX and the value of the Y coordinate of MIN (MAXy and MINy). value of the Y coordinate of pos [0] (start pos [0] y) is substituted (step S121). Next, 1 is substituted for a variable i necessary for looping by the number of data (step S122).
[0089]
Next, the start stored at the i-th position in the array pos [i] Y coordinate value (start It is determined whether or not pos [i] y) is greater than MAXy (step S123). If it is larger than MAXy (YES), that is, if the proposition in step S123 is true, the i-th start of the coordinate array pos [i] is substituted for the coordinate variable MAX (step S124), and the process proceeds to step S127. However, if it is smaller than MAXy (NO), that is, if the proposition in step S123 is false, the process moves to step S125.
[0090]
Next, the start stored at the i-th position in the array pos [i] Y coordinate value (start It is determined whether or not pos [i] y) is smaller than MINy (step S125). If it is smaller than MINy (YES), that is, if the proposition in step S125 is true, the i-th start of the coordinate array pos [i] is substituted for the coordinate variable MIN (step S126), and the process proceeds to step S127. However, if it is larger than MINy (NO), that is, if the proposition in step S125 is false, the process moves to step S127.
[0091]
Next, the variable i is incremented (step S127). Next, the variable i is the start obtained in step S57. It is determined whether or not the variable i is larger than num (step S128). If the variable i is smaller (NO), that is, if the proposition in step S128 is false, the process proceeds to step S123. However, if the variable i is larger (YES), that is, if the proposition in step S128 is true, the coordinate variable MAX is stored in the coordinate g in FIG. 10 and the coordinate variable MIN is stored in the coordinate e in FIG. Step S129), and return to the upper routine of FIG.
[0092]
Next, the routine for determining the range of the label called in step S35 in the label detection routine of FIG. 9 as described above will be described with reference to the flowchart shown in FIG.
[0093]
First, an equation of a straight line parallel to the line segment e-g is defined, for example, an equation y = ax + b of the line segment e-g is obtained (step S131). Next, an intercept b is defined so that this straight line crosses the start big bar 22A (step S132). The structure of the start code 22 includes, for example, a start big bar 22A including eight bars, three pairs of white bars and black bars, and three white bars, for a total of 17 bars. It is assumed that the imaging result is N pixels. It is known that a straight line represented by the equation y = ax + b moves in parallel by changing the intercept b. Therefore, in order to obtain a straight line that crosses the big bar 22A, it is sufficient that the line segment e-g is set to an intercept b that is moved to the left by {(17−8 / 2) / 17} × N pixels. Become.
[0094]
When a straight line crossing the start big bar 22A is obtained in this way, the intersections of the straight line and the equations defining the screen are respectively set to A and A '(see FIG. 10) (step S133). ).
[0095]
Then, the data is sequentially viewed from the midpoint of the line AA ′ to the point A (step S134), and it is checked whether or not an edge exists (step S135). This check can be performed by, for example, an intensity comparison for observing a change in luminance, a differentiation method, a second differentiation method, or the like. If an edge is thus detected, the detected coordinates are stored in a coordinate variable i (step S136). That is, the detected coordinates are set to point i.
[0096]
Next, the data is viewed from the midpoint of the line AA 'to A' next (step S137), and it is checked whether an edge exists (step S138). When an edge is thus detected, the detected coordinates are stored in a coordinate variable m (step S139). That is, the detected coordinates are set to the point m.
[0097]
Then, a perpendicular is drawn from the point i indicated by the coordinate variable i to a straight line passing through the points e and g indicated by the coordinate variables e and g, and the coordinates of the intersection are stored in the coordinate variable a (step S140). That is, an equation of a straight line orthogonal to the line A-A 'passing through the point i is obtained, and an intersection of the equation and a straight line passing through the points e and g is obtained.
[0098]
Similarly, a perpendicular is drawn from the point m indicated by the coordinate variable m to a straight line passing through the points e and g indicated by the coordinate variables e and g, and the coordinates of the intersection are stored in the coordinate variable d (step S141). That is, an equation of a straight line orthogonal to the line A-A 'passing through the point m is obtained, an intersection of the equation and a straight line passing through the points e and g is obtained, and the intersection is defined as a point d.
[0099]
After the value of the coordinate variable a thus obtained is stored in the coordinate variable STARTTOP and the value of the coordinate variable d is stored in the coordinate variable STARTBOTTOM (step S142), the control is returned to the upper routine.
[0100]
Next, a routine for determining the inclination of the label called in step S36 in the above-described label detection routine will be described with reference to a flowchart shown in FIG. 24 and an explanatory diagram for obtaining the inclination of the label shown in FIG. I do.
[0101]
First, the value of the x coordinate of the coordinate variable STARTBOTTOM is divided by the value obtained by subtracting the value of the y coordinate of the coordinate variable STARTTOP from the value of the y coordinate of the coordinate variable STARTBOTTOM, and the value of the x coordinate of the coordinate variable STARTTOP is calculated as the coordinate. The value obtained by subtracting the value of the y coordinate of the coordinate variable STARTTOP from the value of the y coordinate of the variable STARTBOTTOM is divided, and the difference between these two quotients is stored in the slope variable Slope (step S151).
[0102]
Next, the result of multiplying the y coordinate of the coordinate variable STARTBOTTOM by the x coordinate of the coordinate variable STARTTOP is divided by the value obtained by subtracting the y coordinate value of the coordinate variable STARTTOP from the y coordinate value of the coordinate variable STARTBOTTOM, and The result of multiplying the x coordinate of the coordinate variable STARTBOTTOM by the y coordinate of the coordinate variable STARTTOP is divided by the value obtained by subtracting the value of the y coordinate of the coordinate variable STARTTOP from the value of the y coordinate of the coordinate variable STARTBOTTOM, and these two quotients are obtained. Is stored in the intercept variable intersect (step S152). In addition, the superscript of the asterisk * in the figure means the multiplication symbol x.
[0103]
Next, the threshold determination routine called in step S5 in FIG. 4 will be described with reference to the flowchart shown in FIG. 25 and the explanatory diagram for calculating the threshold shown in FIG.
[0104]
First, a value corresponding to the point e shown in FIG. 10 is substituted for the point p (step S161). Next, the line indicated by the y-coordinate value of the coordinate variable p, that is, the data of the data fetch line as shown in FIG. 26A is fetched from the frame memory 6 (step S162), and the end x-coordinate of the start code 22 is obtained. The x coordinate of the point q is set (step S163).
[0105]
Then, the data from the point p to the point q is differentiated (step S164). Thus, for example, in the case of the data capture line shown in FIG. 26A, a differentiated waveform of the start code 22 as shown in FIG. 26B is obtained. Then, the absolute value of the third peak of the differential data is set as a variable MAX (step S165).
[0106]
Here, the reason for looking at the third of the differential data is that, conceptually, it is desired to determine the threshold value where the contrast is lowest in the barcode area (that is, the edge has the lowest differential peak). The reason is that the third edge of the start or stop code where the space between the start code and the space is narrowest is selected. This enables stable decoding regardless of the label size or the lighting conditions of the label.
[0107]
Then, the value of the variable MAX obtained in this manner is converted into a constant THRESHOLD of the ratio to the peak. It divides by RATIO, and substitutes the result into a threshold variable THRESHOLD (step S166). That is, a threshold is temporarily obtained from the obtained data. Note that the variable THRESHOLD RATIO is a value indicating what percentage of the peak is selected as the threshold, and is usually set to “2” or “3”.
[0108]
Next, the value of the temporarily determined threshold value THRESHOLD is the minimum threshold value constant THRESHOLD. It is larger than SMALL (step S167) and the maximum threshold constant THRESHOLD It is determined whether it is smaller than BIG (step S168). That is, it is determined whether or not the temporarily determined threshold value is within a range that the threshold value can take. Constant THERESHOLD If it exceeds the maximum value indicated by SMALL (YES), the constant THRESHOLD The maximum value indicated by SMALL is substituted for the threshold variable THERESHOLD, that is, the threshold is set to the minimum value (step S169).
[0109]
Also, the variable THRESHOLD If less than the minimum value indicated by BIG (YES), THERESHOLD The minimum value represented by BIG is substituted for the threshold variable THRESHOLD, that is, the threshold is set to the maximum value (step S170).
[0110]
Next, the indicator information determination routine called in step S6 of FIG. 4 will be described with reference to the flowchart shown in FIG. 27 and the projection image onto the frame memory shown in FIG.
[0111]
First, the value of the top coordinate TOP of the label is stored in the coordinate variable WORK as a starting point of the reference coordinates for reading the row indicator information (step S171). Next, a straight line I passing through the coordinate variable WORK and having a slope represented by the slope variable Slope of the label is defined (step S172), and points W1 and W2 where the straight line I crosses the screen frame are defined (step S173). ).
[0112]
Then, the image data on the line segment W1-W2 is fetched (step S174), and the row indicator information contained therein is read (step S175).
Here, the reading of the row indicator information is performed, for example, as follows. That is, an edge is detected from the image data on the target line fetched in step S174, that is, a monochrome pixel value, and is converted into width information. Then, the start code 22 is detected from the width information, and since it is known that the code following the start code 22 is the row indicator 21A, it is read.
[0113]
Similarly, the stop code 23 is detected, and since the code immediately before the stop code 23 is also known to be the row indicator 21A, it is read. When the row indicator 21A is read in this way, it is compared with a bar code table (not shown), and the corresponding part is converted into a code, that is, information such as the number of rows, the number of columns, and a security level. Note that there are various methods for conversion to width information. For example, the conversion to width information can be performed by calling a conversion routine for width information as described later.
[0114]
Next, it is checked whether or not the row indicator information has been established (step S176). If it is determined (YES), the process proceeds to step S180. If not fixed (NO), the process moves to step S177. Here, "confirmed" means that the row indicator 21A is read several times and the reliability of the information is sufficiently increased. For example, if the information (the number of rows, the number of columns, and the security level) written in the row indicator 21A is read ten times, if the same information is obtained in all of the ten times, it is assumed that the information is determined.
[0115]
If the row indicator information is not determined in the determination in step S176 (NO), a predetermined increment L is added to the value of the y coordinate of the coordinate variable WORK. INC is added, and the result is substituted as the y coordinate value of a new coordinate variable WORK (step S177). Further, the value of the label slope variable Slope is multiplied by the value of the y coordinate of the coordinate variable WORK, the intercept variable intersect of the label is added to the result, and the result is substituted as the x coordinate value of the new coordinate variable WORK (step S178). Thus, the reference coordinates for the new scan are reset to the coordinate variables WORK.
[0116]
Then, it is determined whether or not the reset y-coordinate value of the coordinate variable WORK exceeds the y-coordinate value of the bottom coordinate variable BOTTOM of the label, that is, whether or not the label is within the label area (step S179). If it is, the process is repeated from the step S172. If it is out of the label area, the process returns to the upper routine with the undefined information of the matrix.
[0117]
On the other hand, if it is determined in step S176 that the row indicator 21A has been determined (YES), the number of recoverable data is calculated from the security level obtained from the row indicator information, and REST It is stored in NUM (step S180). Further, the number of rows of the label obtained from the row indicator information is equal to the row number variable ROW of the label. It is stored in NUMBER (step S181). Also, the number of label columns is extracted from the row indicator information, and the number of label column variables COLUMN It is stored in NUMBER (step S182). Thereafter, control is returned to a higher-level routine with information that the matrix has been defined.
[0118]
Next, the tilt redefinition routine called in step S8 in FIG. 4 will be described with reference to a flowchart shown in FIG. 29 and an explanatory diagram for redefining the tilt shown in FIG. Here, the reason for redefining the inclination will be described below.
[0119]
The inclination obtained from e and g in FIG. 10, that is, the inclination obtained from only the information of the start code 22, is not an accurate value due to problems such as print quality and CCD accuracy. Therefore, after the indicator information is determined in step S8, the stop code 23 is detected from a position close to the stop code 23, and the inclination is obtained from both the information of the start code 22 and the stop code 23. The value is determined. Obtaining a more accurate slope value before the optimum scan in step SC leads to a higher scan speed.
[0120]
First, the detection start point p is determined (step S191). p is the distance obtained by the above-mentioned indicator information determination routine, which divides a straight line I connecting the upper end point u and the lower end point v of the left end of the column of the right-hand indicator into four equal parts, and divides u from u by four equal parts It is a point that has advanced. Next, data between p and p 'is fetched (step S192). p 'is a point that advances from the point p in parallel with the x-axis and intersects a straight line of y = the number of columns.
[0121]
Next, a stop code detection routine to be described later is called (step S193). Then, it is determined whether or not a stop code has been detected (step S194). If the stop code has not been detected (NO), the process returns with information indicating that the slope has not been redefined. If detected (YES), the coordinates of the detected point are stored in f shown in FIG. 10, and f is defined (step S195).
[0122]
Next, the detection start point q is determined (step S196). This point q is obtained by dividing the straight line I connecting the upper end point u and the lower end point v of the left end of the column of the right row indicator obtained by the indicator information determination routine into four equal parts, and dividing the straight line from v into four equal parts. It is a point that has advanced the distance. Next, data between points q and q 'is fetched (step S197). The point q 'is a point which advances from the point q in parallel with the x-axis and intersects a straight line of y = the number of columns. Next, the stop code detection routine in step S193 is called to detect the stop code (step S198). Then, it is determined whether or not a stop code has been detected (step S199). If the stop code has not been detected (NO), the process returns with information indicating that the slope has not been redefined. If detected (YES), the coordinates of the detected point are stored in h shown in FIG. 10, and h is defined (step S200).
[0123]
Next, a label range detection routine, which will be described in detail later, is called (step S201), and the inclination is calculated (step S202). Then, the process returns with the information on redefining the inclination.
[0124]
The stop code detection routine called in steps S193 and S198 will be described with reference to the flowchart shown in FIG.
This routine is basically the same as the start code detection shown in FIG. 16, but differs from FIG. 16 in the matching part. This is because the start code 22 and the step code 23 of the PDF 417 have different width information. As for the matching method, as described above, a matching method that is not affected by the printing accuracy of the barcode label is desirable.
[0125]
Next, the label range detection routine called in step S201 of FIG. 29 will be described with reference to the flowchart shown in FIG.
First, an equation of a straight line parallel to the line segment fh is defined, for example, an equation y = ax + b of the line segment fh is obtained (step S221).
[0126]
Next, an intercept b is defined so that this straight line crosses the stop big bar 23A (step S222). The structure of the stop code 23 includes, for example, a stop big bar 23A including eight bars, three pairs of white bars and black bars, and three white bars, for a total of 17 bars. It is assumed that the imaging result is N pixels. It is known that a straight line represented by the equation y = ax + b moves in parallel by changing the intercept b.
[0127]
Therefore, in order to obtain a straight line that crosses the big bar 23A, it is sufficient that the line segment fh is set to an intercept b that is moved to the left by {(17−8 / 2) / 17} × N pixels. Become.
[0128]
When a straight line crossing the stop big bar 23A is obtained in this way, the intersections of the straight line and the equations defining the screen are respectively set to B and B '(see FIG. 10) (step S223).
[0129]
Then, the data is sequentially viewed from the middle point of the line BB 'to the point B (step S224), and it is checked whether or not an edge exists (step S225). This check can be performed by, for example, an intensity comparison for observing a change in luminance, a differentiation method, a second differentiation method, or the like. When an edge is detected in this way, the detected coordinates are stored in a coordinate variable j (step S226). That is, the detected coordinates are set to a point j.
[0130]
Next, the data is sequentially viewed from the middle point of the line BB 'to the point B' (step S227), and it is checked whether an edge exists (step S228). When an edge is detected in this way, the detected coordinates are stored in a coordinate variable k (step S229). That is, the detected coordinates are set to a point k.
[0131]
Then, a perpendicular is drawn from the point j indicated by the coordinate variable j to a straight line passing through the points f and h indicated by the coordinate variables f and h, and the coordinates of the intersection are stored in the coordinate variable b (step S230). That is, an equation of a straight line orthogonal to the line BB 'passing through the point j is obtained, an intersection of the equation and a straight line passing through the points f and h is obtained, and the intersection is defined as a point b.
[0132]
Similarly, a perpendicular line is drawn from the point k indicated by the coordinate variable k to a straight line passing through the points f and h indicated by the coordinate variables f and h, and the coordinates of the intersection are stored in the coordinate variable c (step S231). That is, an equation of a straight line orthogonal to the line BB 'passing through the point k is obtained, and an intersection of the equation and a straight line passing through the points f and h is obtained.
[0133]
Then, after storing the value of the coordinate variable b thus obtained in the coordinate variable STOPTOP and the value of the coordinate variable c in the coordinate variable STOPBOTTOM (step S232), the process returns to the upper routine of FIG.
[0134]
Next, the label inclination recalculation routine called in step S202 of FIG. 29 will be described with reference to the flowchart shown in FIG.
First, the value of the y-coordinate of the coordinate variable STOPTOP is divided by the value obtained by subtracting the value of the x-coordinate of the coordinate variable STARTTOP from the value of the x-coordinate of the coordinate variable STOPTOP. The x-coordinate value of the coordinate variable STARTTOP is divided by the value obtained by subtracting the x-coordinate value of the coordinate variable STARTTOP, and the difference between these two quotients is stored in the slope variable Slope1 (step S241).
[0135]
Next, the value of the y-coordinate of the coordinate variable STOPBOTTOM is divided by the value obtained by subtracting the value of the x-coordinate of the coordinate variable STARTBOTTOM from the value of the x-coordinate of the coordinate variable STOPBOTTOM, and the value of the y coordinate of the coordinate variable STARTBOTTOM is The value obtained by subtracting the value of the x-coordinate of the coordinate variable STARTBOTTOM from the value of the x-coordinate of the coordinate variable STOPBOTTOM is divided, and the difference between these two quotients is stored in the slope variable Slope2 (step S242).
[0136]
Next, it is determined whether or not the absolute value of the difference between the slope variable Slope1 and the slope variable Slope obtained in step S36 is smaller than the threshold constant SLOPETHRESH1, and whether the absolute value of the difference between the slope variables Slope2 and Slope is smaller than the threshold constant SLOPETHRESH1. (Step S243). Here, abs in the figure means an absolute value. If the proposition in step S243 is false (NO), the process returns with information without recalculation. If not (YES), the absolute value of the difference between the variables Slope1 and Slope2 is taken, and it is determined whether or not it is greater than a threshold constant SLOPETHRESH2 (step S244).
[0137]
If the absolute value is smaller at this step S244 (NO), the process moves to step S250, and if it is larger, the process moves to the next step S245.
Next, the absolute value of the difference between the slope variable Slope obtained in step S36 and the variable Slope1 is stored in a variable a (step S245). Next, the absolute value of the difference between the slope variable Slope obtained in step S36 and the variable Slope2 is stored in a variable b (step S246).
[0138]
Then, it is determined whether or not the variable b is larger than the variable a (step S247). If the variable b is large (YES), Slope1 is substituted for the slope variable Slope (step S248). If the variable b is small (NO), Slope2 is substituted for the slope variable Slope (step S249). If the absolute value of the difference between the slope variables Slope and Slope2 is smaller than the threshold constant (NO) in step S244, the slope variable Slope is obtained by dividing the sum of the slope variables Slope1 and Slope2 by 2, ie, Slope1. And the average of Slope2 is substituted (step S250). Then, the process returns with the information indicating that there is recalculation.
[0139]
In the series of steps S244 to S249, as shown in FIG. 34, a case is considered in which either the start code 22 or the stop code 23 of the PDF417 barcode label has a defect and the label range is not correctly determined. are doing. In the case of FIG. 34, the value of the slope Slope1 of the straight line n and the value of the slope Slope2 of n ′ are significantly different. This is detected by this routine, and a value close to the slope Slope of the label calculated from points e and g in FIG. 10 is adopted as a new slope. By using such a method, it is possible to obtain a more accurate label inclination even when there is a defect in either the start code 22 or the stop code 23.
[0140]
The case where the determination in step S243 is false is a case where there is a defect above or below one of the start code 22 and the stop code 23. In this case, the inclination is not recalculated.
[0141]
Next, the scan equation determination routine called in step S9 in FIG. 4 will be described with reference to the flowchart shown in FIG. 36 and the projection image onto the frame memory shown in FIG. FIG. 35 shows an example in which the start code 22 is selected based on the row scan.
[0142]
That is, first, the variable counter is initialized to "0" (step S251), and the reference coordinate variable WORK is initialized to the value of the top coordinate variable TOP of the label (step S252).
[0143]
Next, the difference between the y-coordinate value of the bottom coordinate variable BOTTOM of the label and the y-coordinate value of the top coordinate variable TOP of the label is calculated by a variable count. is assigned to end (step S253). That is, the number of patterns to be determined (the number of pixels in the column direction of the label in the case of FIG. 36) is obtained, and the variable count Store in end. That is, the number of patterns is a number for scanning the entire label surface.
[0144]
Next, the value of the variable counter is added to the y coordinate value of the top coordinate variable TOP of the label, and the result is substituted as the y coordinate value of the reference coordinate variable WORK (step S254). Further, the value of the label slope variable Slope is multiplied by the value of the y coordinate of the reference coordinate variable WORK, the intercept variable intersect of the label is added to the result, and the result is substituted as the x coordinate value of the new reference coordinate variable WORK. (Step S255). As described above, the reference coordinate variable WORK is reset with the increase in the variable counter.
[0145]
Next, a straight line I passing through the reset coordinate variable WORK and having a slope represented by the slope variable Slope of the label is defined (step S256), and two points at which the straight line I intersects the screen frame are obtained. Array of coordinate variables DIM POINT P and DIM POINT It is stored in the Qth counter (the array number indicated by the value of the variable counter) (step S257).
[0146]
Thereafter, the variable counter value is incremented (step S258), and the resulting reset variable counter value becomes the required number, that is, the variable counter. It is checked whether the end has been reached (step S259). If the required number has not been reached (YES), the process returns to step S254, and if the required number has been reached (NO), the process proceeds to step S260. By the above operation, the combination of the start point and the end point when sequentially scanning the label is defined.
[0147]
Next, the variable counter is initialized to "0" again (step S260), and the value of the slope variable Slope of the label is multiplied by the value of the variable counter, whereby the calculated increment by the position of the slope Slope of the label is calculated. Is calculated, and this calculation result is stored in an array LINE of variables. It is stored in a predetermined position of INC (position indicated by the variable counter) (step S261).
[0148]
After that, the variable counter is incremented (step S262), and the reset variable counter becomes the maximum size constant MAX of the array. It is checked whether or not NUM has been reached (step S263). If not reached (YES), the process returns to step S261, and if reached (NO), the process returns to the routine of FIG.
[0149]
Through the loop from step S260 to step S263 described above, a tilt pattern when one line of label information is captured is obtained. The maximum size constant MAX of the array NUM indicates the size of a variable determined when the program is created. For example, assuming that the size of the frame memory 6 is "640 × 480 pixels", it may be set to "about 1000".
[0150]
Next, the embedding check routine called in step S10 in FIG. 4 will be described with reference to the flowchart shown in FIG. 37 and the diagram of the image projected on the frame memory shown in FIG. FIG. 38 shows an example in which the start code 22 is selected based on the row scan. The label size is “4 × 3”.
[0151]
First, when a ROW detection routine, which will be described later, is called and a label is scanned, various information (detection line number, code length, row number, detection position, etc.) of the first and last rows found are detected (step S271). , Each variable ROW FIRST, ROW Store in LAST.
[0152]
Next, the variable ROW FIRST and ROW It is determined whether or not the LAST is also determined (step S272). If the LAST is determined (YES), the process proceeds to step S273. However, if it is not determined (NO), it is determined that decoding is impossible and the process returns to the upper routine of FIG.
[0153]
Thus, the variable ROW is determined in step S272. FIRST and ROW If LAST is also determined (YES), the start position coordinates of each code in the code word matrix are estimated, and the two-dimensional array variable CODE is estimated. The POS code is stored in the row number and column number order of each code (step S273). Here, as shown in FIG. 38, the estimation of the start coordinate position of each codeword is based on the inclination of the label, the detection line number of the first and last rows, the code length, the row number, the detection position, and the matrix size (ROW NUMBER × COLUMN NUMBER).
[0154]
Next, among the coordinates estimated in the above step, the number of the codes whose code may run off the screen is counted, and the variable error It is stored in num (step S274). In the example shown in FIG. 38, five codes of (row number, column number) = (0, 2), (1, 2), (2, 2), (3, 1), (3, 2) are Unreadable and determined to be error 5 is stored in num.
[0155]
Further, the error num is a variable REST of the number of recoverable codes obtained in step S180 of FIG. NUM (step S275), and error num is REST If it is not more than NUM (YES), it is determined that decoding is possible and the process returns to the upper routine of FIG. On the other hand, error num is REST If it exceeds NUM (NO), decoding is disabled and the process returns to the upper routine of FIG.
[0156]
With such a routine, the position of each code can be estimated, and the number of codes estimated to be out of the screen can be counted. Therefore, it can be determined at this stage whether or not decoding is possible. As a result, the worst pattern in which decoding is not performed despite processing for a long time is drastically reduced.
[0157]
Next, the ROW detection routine called in step S271 of FIG. 37 will be described with reference to the flowchart shown in FIG. 39 and the projection image onto the frame memory shown in FIG.
[0158]
First, the difference between the y coordinate value of the bottom coordinate variable BOTTOM of the label and the y coordinate value of the top coordinate variable TOP of the label, that is, the number of pixels in the y direction of the label is calculated. It is stored in num (step S281).
[0159]
Next, the value of the variable “inc” is set to “1” (step S282), the value of the variable “counter” is set to “0” (step S283), and the value of the variable “end” is determined by the pos obtained in step S282 or S283. num (step S284).
[0160]
Then, a ROW number detection routine to be described later is called using each of the variables (initial value counter, increment inc, end position end) obtained in steps S282 to S284 (step S285). If the row number can be correctly detected from the indicator information, the variable ROW Information such as a detection line number, a code length, a row number, and a detection position is stored in the POS.
[0161]
That is, it is determined whether or not the row number has been correctly detected from the indicator information in the routine (step S286). If the row number has been detected (YES), the process proceeds to step S287. If the row number has not been detected (NO), Return to upper routine as decoding impossible.
[0162]
Next, the data ROW obtained in step S285 POS ROW It is stored in FIRST (step S287). That is, in steps S282 to S287, scan lines are successively set from the TOP of the label to BOTTOM, and the first detected indicator position is ROW. Stored in FIRST.
[0163]
Further, in steps S288 to S293, the scan lines are sequentially set from the BOTTOM to the TOP, and the first detected indicator position is ROW. Stored in LAST.
[0164]
With such a routine, it is possible to determine whether or not a part of the row has become unprocessable (for example, jumping out of the screen). Because the row number is 4 and the ROW Row number 0 is detected by FIRST and ROW When row number 2 is detected in the LAST, row number 3 cannot be detected, so that it cannot be processed.
[0165]
Next, the ROW number detection routine called in step S285 of FIG. 39 will be described with reference to the flowchart shown in FIG.
First, the scan start point and end point at the current variable counter value are set in the coordinate variable array DIM. POINT P, DIM POINT Q, the x-direction increment is “1” and the y-direction increment is the inclination increment array LINE. In the INC, one line of image data is taken out from the frame memory 6 and taken in by the take-in buffer The data is stored in a line, and the number of data is stored in a variable num (step S301).
[0166]
Then, a conversion routine is called for width information described later (step S302), and the extracted data is converted to width information. Next, based on the width information, a portion corresponding to a barcode table (not shown) is converted into a code, and indicator information is extracted from the information and stored (step S303). Here, it is determined whether or not the indicator information has been read (step S304). If the indicator information has not been read (NO), the variable counter is incremented, that is, reset with the value of the interval variable inc (step S305). It is determined whether or not the reset variable counter value exceeds the variable end, that is, the label range (step S306). If not exceeded (NO), the process returns to step S301. If exceeded (YES), it is determined that decoding is impossible, and the process returns to the upper routine of FIG.
[0167]
On the other hand, if it is determined in step S304 that the data can be read (YES), the detected line number, code length, row number, and detected position at that time are stored in the variable ROW. It is stored in the POS (step S307), and the process returns to the upper routine of FIG. Therefore, various information of the indicator detected first after entering this routine is stored in ROW. It will be stored in the POS.
[0168]
Next, the optimal scan routine called in step S13 in FIG. 4 will be described with reference to the flowchart shown in FIG. 41 and the projection image onto the frame memory shown in FIG.
[0169]
First, the indicator information variable ROW of the label LAST detection position y coordinate value and ROW The difference from the FIRST detection position y coordinate value, that is, the number of pixels in the y direction of the label is calculated, and the calculation result is stored in a variable end (step S311).
[0170]
Next, the value of the variable end is set to the number of lines of the label (variable ROW). LAST row number-variable ROW By dividing by the FIRST row number (absolute value), an interval for scanning the center of each row only once is calculated as shown in FIG. 42, and the calculated interval is stored in a variable inc (step S312). And the variable ROW The detection line number of FIRST is set as the initial value of the variable counter (step S313).
[0171]
Next, the scan start point and end point at the current variable counter value are set in the coordinate variable array DIM. POINT P, DIM POINT Q, the x-direction increment is “1” and the y-direction increment is the inclination increment array LINE. The INC fetches one line of image data from the frame memory 6 and fetches it, and fetches it in the buffer array scan. The data is stored in a line, and the number of the data is stored in a variable num (step S314).
[0172]
Then, a conversion routine for width information is called as in step S302 described later (step S315), and the extracted data is converted into width information. Next, based on the width information, a portion corresponding to a barcode table (not shown) is converted into a code, and the information is stored (step S316).
[0173]
Thereafter, the variable counter is incremented, that is, reset with the value of the interval variable inc (step S317), and it is determined whether or not the reset variable counter value exceeds the variable end, that is, the label range (step S318). ). If it does not exceed (YES), the process returns to step S314, and if it does (NO), it is determined whether the information described in the label of the stored code information can be completely decoded (step S314). S318). If decoding is possible (YES), the process returns to the upper routine of FIG. 4 with information indicating that decoding is possible. However, when decoding is impossible (NO), the process returns to the upper routine of FIG.
[0174]
Next, the intelligent scan routine called in step S14 of FIG. 4 will be described with reference to the flowchart shown in FIG. This skip scan routine is a routine that scans only code positions missed in the optimal scan.
[0175]
First, among the code words that cannot be embedded by the optimal scan, the number of codes considered to be in the screen is defined as i (step S321). Further, the row number and column number of each code are stored in arrays R and C, respectively (step S322). As described above, the number and positions of the code words that could not be embedded by the optimal scan are obtained. As will be described later, if the column number and the row number are known, the position is determined by the CODE obtained in step S10. The coordinates are known from the POS.
[0176]
Next, the variable counter and the inclination pattern counter n are initialized to “0” (step S323). Then, the coordinates CODE of the counter-th undetected location A straight line I passing through POS [[R [counter]] [C [counter]] and having a slope of Slope + dt [n] is defined (step S324). Points W3 and W4 at which this straight line I crosses the screen frame are defined, and image data on the line segment W3-W4 is captured (step S325).
[0177]
Then, a conversion routine for width information is called as in step S302 described later (step S326), and the extracted data is converted to width information. Next, based on the width information, a portion corresponding to a barcode table (not shown) predetermined according to the use of the barcode is converted into a code, and the information is stored (step S327).
[0178]
Further, it is determined whether or not the code at the target location in steps S324 to S326 has been embedded (step S328). If it cannot be filled (NO), the inclination pattern counter n is incremented (step S329), and the number of inclination patterns is incremented by N. It is checked whether or not PAT is smaller than PAT (for example, set to “10” when ten kinds of inclinations are prepared in the array dt in advance) (Step S330). Shifts to step S331.
[0179]
If it is determined in step S328 that the data has been embedded (YES), or the inclination pattern counter n indicates the number of inclination patterns N If the value is equal to or larger than the PAT, the variable counter is incremented, and the inclination pattern counter n is reset to “0” (step S331). It is checked whether or not the reset variable counter value exceeds the variable i, that is, the number of codes considered to be in the screen among the code words that could not be embedded by the optimal scan (step S332). If it does not exceed (YES), the process returns to step S324, and if it does (YES), it is determined whether or not the stored code information can completely decode the information described in the label (step S333). .
[0180]
If it is determined that decoding is possible (YES), the process returns to the upper routine of FIG. However, when decoding is impossible (NO), the process returns to the upper routine of FIG.
[0181]
Therefore, in steps S324 to S332, of the codewords that could not be embedded by the optimal scan, image data is fetched with a plurality of types of inclinations for each code considered to be in the screen, and the code is to be determined. As a result, the operation of taking in only a necessary part is performed, so that the codeword matrix is determined with the minimum number of tries.
[0182]
Next, a conversion routine to be called width information in step S302 or step S326 will be described with reference to a series of flowcharts in FIGS.
[0183]
This routine is basically the same as the routine described with reference to FIGS. 17 and 18, except for the steps S95 and S355. That is, in the routines of FIGS. 17 and 18, since the purpose is only to detect the start code 22, the width information is set to WIDTH. It is sufficient to obtain NUM, but in the routines of FIGS. 44 and 45, all the information of the label is required, so that all the widths must be obtained. Therefore, in step S355, the determination regarding j found in step S95 is removed.
[0184]
It is to be noted that the present invention is not limited to the above-described embodiment, and that various modifications can be made.
For example, the two-dimensional imaging device 5 is not limited to a device using an area sensor typified by a two-dimensional CCD or an imaging tube, but may be a combination of a one-dimensional imaging device and a one-dimensional scanning mechanism, or a photoelectric detector. A combination of a two-dimensional scanning mechanism may be used.
[0185]
In the above description, a label in the PDF-417 format is used as the barcode label. However, the present invention is not limited to this, and other stacked barcodes such as Code49 and one-dimensional barcodes such as JAN are used. But it's fine.
[0186]
Although the description has been given based on the above embodiments, the present invention includes the following inventions.
(1) imaging means for imaging a barcode consisting of a bar and a space as a two-dimensional image,
Storage means for temporarily storing a two-dimensional image obtained by the imaging means;
Transfer means for transferring a captured image from the imaging means to the storage means;
Recognition means for automatically recognizing the presence or absence of a barcode symbol from a two-dimensional barcode image obtained by the imaging means;
Position recognition means for recognizing the position of a barcode symbol from a two-dimensional barcode image obtained by the imaging means;
Reading means for sequentially reading the barcode information from a two-dimensional barcode image obtained by the imaging means;
A decoding unit for decoding the barcode information from the reading unit into original information.
[0187]
Therefore, a barcode consisting of a bar and a space is captured as a two-dimensional image, the obtained two-dimensional image is temporarily stored, the captured image is transferred to a storage unit, and the presence or absence of a barcode symbol is automatically recognized. The position of the barcode symbol is recognized, the barcode information is sequentially read, and the barcode information is decoded into the original information.
[0188]
(2) The symbol information reading device according to the first aspect, wherein the recognition unit recognizes a two-dimensional image of the moving barcode at a position where barcode information can be read on an imaged screen obtained by the imaging unit.
[0189]
Therefore, a two-dimensional image of the moving barcode is recognized at a position where the barcode information can be read on the imaging screen obtained by the imaging means.
Therefore, the effect is that when reading a moving barcode label, the process proceeds to the reading process only when the barcode label is completely inside the image, so that barcodes that protrude from the image can be read. This means that reading can be performed at high speed and reliability can be improved.
[0190]
(3) The symbol information reading device according to the first aspect, wherein the transfer unit compresses and transfers the two-dimensional image captured by the imaging unit.
Therefore, the two-dimensional image picked up by the image pickup means is compressed and transferred.
[0191]
Therefore, the effect is that, since the target image is compressed and transferred to the frame memory 6, the number of pixels to be processed is reduced, and barcode symbol information can be read at high speed.
[0192]
(4) The symbol information reading device according to (3), wherein the transfer unit transfers only one field component of the captured two-dimensional image to the storage unit.
Therefore, only one field component of the captured two-dimensional image is transferred to the storage means.
[0193]
Therefore, the effect is that when the barcode label image occupies a large proportion of the target image and the height of one line of the barcode label is sufficient, only the field image is transferred to the frame memory and the reading process is performed. Bar code information can be read by an inexpensive interlaced image sensor. The field image may be either an even component or an odd component.
[0194]
(5) The symbol information reading device according to (2), wherein the transfer unit separately transfers the two field components of the captured two-dimensional image to the storage unit.
Therefore, the two field components of the captured two-dimensional image are separately transferred to the storage unit.
[0195]
Therefore, the effect is that when the ratio of the barcode label image to the target image is small and the height of one line of the barcode label is not enough, two field images (even and odd components) are combined into one. That is, a reading process is performed on one field image separately in the frame memory, and if that fails, the reading process is performed on another field image, thereby improving the reliability of reading.
[0196]
(6) In the above item (2), the reading means performs reading processing on one field component stored by the storage means, and when the processing fails, reads again on another field component stored by the storage means. A symbol information reading device for reading barcode information, including a processing operation for processing.
[0197]
Accordingly, the bar code information includes a reading operation for one field component stored by the storage means and, when the processing fails, another reading for another field component stored by the storage means. Read.
[0198]
Therefore, the same effect as in the item (5) can be obtained.
(7) In the above item (2), the transfer means transfers one scan line of the field component of the two-dimensional image picked up by the image pickup means, and then transfers the scan line again with one line left in the storage means. A symbol information reading apparatus which repeats this process until image information for a field is transferred, and transfers and transfers the image information of one line above or below that line to a vacant line after completion of the transfer.
[0199]
Therefore, after transferring one scan line of the field component of the two-dimensional image picked up by the image pick-up means, one line is left in the storage means and the scan line is transferred again until the image information for one field is transferred. Repeating and transferring the image information including a processing operation of copying the image information of one line above or below the vacant line to the vacant line after the end.
[0200]
Therefore, the effect is that one field image is fetched into the frame memory 6 at intervals of one line, and the contents of the one line of the frame memory are copied to an empty line, and the reading process is performed. That is, reliability can be improved. Copying can be easily realized by hardware.
[0201]
(8) The symbol information reading device according to (3), wherein the transfer unit adds an arbitrary number of pieces of pixel information of the two-dimensional image captured by the imaging unit to form one pixel and transfers the pixel information.
[0202]
Therefore, in the above item 3, the transfer means adds an arbitrary number of pieces of pixel information of the two-dimensional image picked up by the image pick-up means and transfers it as one pixel.
Therefore, the effect is that if the height of one line of the barcode label is sufficient, an arbitrary number of pixels are added to all the pixel information and stored as one pixel in the frame memory. That is, symbol information can be read at high speed. This can also be easily realized by hardware, and has the effect of suppressing noise.
[0203]
(9) In the first aspect, the position recognizing means converts the pixel information of one row of the storage device into an arbitrary number of pieces of width information and recognizes symbol information for recognizing a position of a predetermined pattern determined by the type of the barcode. Reader.
[0204]
Therefore, the pixel information of one row of the storage device is converted into width information by an arbitrary number, and the position of a predetermined pattern determined by the type of the barcode is recognized.
Therefore, the effect is that if there is no information other than the barcode label in the target image and the start code of the PDF417 barcode label is located on the left side of the image, it is fetched line by line from the frame memory. Since only the width information enough to detect the start code is obtained without converting all the pixel information into the width information, the start code can be detected at high speed.
[0205]
(10) The symbol information reading device according to the first aspect, wherein the position recognizing means includes a processing operation for selectively selecting a row from the storage means, and recognizes a position of a predetermined pattern determined by the type of the barcode.
[0206]
Therefore, it includes a processing operation of selectively selecting a row from the storage means, and recognizes a position of a predetermined pattern determined by the type of the barcode.
Therefore, the effect is that, in the method of determining a row for capturing pixels, a method similar to the NEWTON method of repeatedly finding the solution of the equation is employed, and a method of gradually narrowing the space between rows is adopted. In addition, it can be detected at high speed.
[0207]
(11) In the first aspect, the reading unit detects at least two predetermined patterns defined by the type of the barcode, obtains the inclination of the barcode label, and determines the inclination of the barcode different from the already detected pattern. A symbol information reading apparatus for detecting a predetermined pattern determined by the type of the symbol information and redefining the inclination of the bar code label from both patterns, and reading bar code information.
[0208]
Therefore, a predetermined pattern defined by the type of the barcode is detected at least two places, the inclination of the barcode label is obtained, a predetermined pattern defined by the type of the barcode different from the already detected pattern is detected, It includes a processing operation for redefining the inclination of the barcode label from both patterns, and reads barcode information.
[0209]
Therefore, the effect is to estimate each code position from the bar code label indicator information after detecting the start code, detect the stop code from a position near the stop code, and determine the inclination of the bar code label from both the start code and the stop code. Is redefined, a more accurate inclination can be obtained, and the reliability of reading can be improved.
[0210]
(12) In the first aspect, when one corner of the barcode label is missing, the reading unit may read the barcode label obtained from only one piece of information of a predetermined pattern determined by the type of the barcode. A symbol information reading device that includes a processing operation for redefining the inclination with reference to the inclination and reads barcode information.
[0211]
Therefore, when one corner of the barcode label is missing, a processing operation for redefining the inclination with reference to the inclination of the barcode label obtained from only one information of the predetermined pattern determined by the type of the barcode. And reads barcode information.
[0212]
The same effects as in the above item (12) can be obtained.
(13) In the above item (2), the recognizing means vertically divides the two-dimensional image of the storage means into three equal parts, and arbitrarily selects the uppermost area determined by the size of the barcode label and the lowermost area. The bar code label can be read when the predetermined pattern defined by the type of the bar code cannot be detected in any line of the bar code and the predetermined pattern defined by the type of the bar code is detected in any line in the center area A symbol information reading apparatus that includes a processing operation of determining that the bar code label exists at a proper position and recognizes the presence or absence of a bar code label.
[0213]
Therefore, the two-dimensional image of the storage means is vertically divided into three equal parts, and the arbitrary line in the uppermost area and the arbitrary line in the lowermost area determined by the size of the barcode label depend on the type of the barcode. Including a processing operation for determining that a barcode label is present at a readable position when a predetermined pattern determined by the barcode type cannot be detected and a predetermined pattern determined by the type of the barcode is detected in an arbitrary line in the center area. , The presence or absence of the barcode label is recognized.
[0214]
Therefore, the effect is that when reading a moving barcode label, the process proceeds to the reading process only when the barcode label is completely inside the image, so that barcodes that protrude from the image can be read. This means that reading can be performed at high speed and reliability can be improved.
[0215]
(14) In the item (10), the position recognizing means first selects the center row of the two-dimensional image in the storage means, and then selects the center row of the upper half and the lower half of the two-dimensional image. A symbol information reading apparatus that includes a processing operation of selecting and subsequently selecting a center line of a divided image in the same manner, and recognizing a position of a predetermined pattern determined by the type of the barcode.
[0216]
Therefore, first, the center row of the two-dimensional image in the storage means is selected, and then the center row of the upper half and the center of the lower half of the two-dimensional image are selected. And sequentially recognizes the position of a predetermined pattern determined by the type of the barcode.
[0217]
The same effects as in the above item (10) can be obtained.
(15) In the twelfth aspect, the reading means obtains the inclination of the barcode label from two upper corners of the four corners of the two-dimensional barcode label image in the storage means, and then obtains the inclination of the lower part of the four corners. A symbol information reader for reading barcode information, including a processing operation for obtaining the inclination of a barcode label from two corners and obtaining the inclination of a barcode label from two inclinations.
[0218]
Accordingly, in the above paragraph 12, the reading means obtains the inclination of the barcode label from the upper two corners of the four corners of the two-dimensional barcode label image of the storage means, and then determines the lower two corners of the four corners. The barcode information is read out, including a processing operation for obtaining the inclination of the barcode label from the corner and obtaining the inclination of the barcode label from the two inclinations.
[0219]
(16) In the twelfth aspect, the reading means obtains the inclination of the barcode label from the upper two corners of the four corners of the two-dimensional barcode label image in the storage means, and then obtains the lower part of the four corners. The inclination of the barcode label is determined from the two corners, and if the difference between the two inclinations is equal to or greater than a predetermined threshold, the inclination determined by detecting at least two predetermined patterns defined by the type of the barcode. A symbol information reading device for reading bar code information, which includes a processing operation for setting a value close to the inclination of the bar code label.
[0220]
Therefore, the inclination of the barcode label is obtained from the upper two corners of the four corners of the two-dimensional barcode label image in the storage means, and then the inclination of the barcode label is obtained from the lower two corners of the four corners. If the difference between the two inclinations is equal to or greater than a predetermined threshold, a value close to the inclination obtained by detecting at least two locations of a predetermined pattern defined by the type of the barcode is set as the inclination of the barcode. Read barcode information, including operations.
[0221]
The same effects as in the above item (10) can be obtained.
(17) In the twelfth aspect, the reading means obtains the inclination of the barcode label from the upper two corners of the four corners of the two-dimensional barcode label image in the storage means, and then obtains the inclination of the lower part of the four corners. Calculating the inclination of the barcode label from the two corners, if the difference between the two inclinations is less than a predetermined threshold value, including a processing operation of setting the average of the two inclinations as the inclination of the barcode label; Symbol information reading device that reads code information.
[0222]
Therefore, the inclination of the barcode label is obtained from the upper two corners of the four corners of the two-dimensional barcode label image in the storage means, and then the inclination of the barcode label is obtained from the lower two corners of the four corners. If the difference between the two slopes is less than a predetermined threshold, the barcode information is read, including a processing operation of setting the average value of the two slopes as the slope of the barcode label.
[0223]
(18) The symbol information reading apparatus according to (6), wherein the reading unit includes a processing operation using the position information of the barcode label on the previous field screen when the reading process is performed again, and reads the barcode information.
[0224]
Therefore, the barcode information is read by including the processing operation using the position information of the barcode label of the previous field screen when going to the reading process again.
Therefore, the effect is that the barcode label position information of the previous field screen can be used when going to the reading process again, so that it is not necessary to detect the label again, and high-speed reading of the barcode information can be realized. . The new barcode label position can be calculated from the label speed and the scanning speed of the imaging device. If the speed of the barcode label is sufficiently negligible compared to the scanning speed of the imaging device, the position information of the barcode label on the previous field screen can be used as it is.
[0225]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to provide a symbol information reading device that reads barcode symbol information of a moving two-dimensional barcode quickly and reliably.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a symbol information reading device as a first embodiment.
FIG. 2 is a diagram illustrating a label structure of PDF-417 as an example of a stacked barcode.
FIG. 3 is a diagram showing a schematic diagram in which a label image of PDF-417 is virtually projected on a pixel array of a frame memory.
FIG. 4 is a flowchart for explaining label detection, label information reading, and decoding in the data processing device.
FIG. 5 is a diagram for explaining taking in only a field screen.
FIG. 6 is a flowchart illustrating an image capturing routine.
FIG. 7 is a diagram for describing capture of two field screens (an even component and an odd component).
FIG. 8 is a diagram for explaining that four pixels are added into one pixel.
FIG. 9 is a flowchart for explaining barcode label detection.
FIG. 10 is a diagram showing a projection image for explaining barcode label detection.
FIG. 11 is a diagram for explaining the inclination of a barcode label defined on a frame memory.
FIG. 12 is a flowchart for explaining detection within a barcode label screen.
FIG. 13 is a diagram showing a barcode label projection image for explaining detection within a barcode label screen.
FIG. 14 is a flowchart illustrating a scanning method.
FIG. 15 is a diagram showing a barcode label projection image for explaining a scanning method.
FIG. 16 is a flowchart for explaining start code detection.
FIG. 17 is a first half of a flowchart for describing a method of converting into width information.
FIG. 18 is a latter half of a flowchart for explaining a method of converting into width information.
FIG. 19 is a diagram for describing selection of a peak value.
FIG. 20 is a diagram for describing a method of calculating a distance between peaks.
FIG. 21 is a flowchart illustrating normalization.
FIG. 22 is a flowchart for describing detection of a maximum value and a minimum value of a Y coordinate.
FIG. 23 is a flowchart illustrating detection of a label range.
FIG. 24 is a flowchart illustrating detection of label inclination.
FIG. 25 is a flowchart for explaining threshold value determination.
26A is a diagram for explaining a threshold value calculation line, and FIG. 26B is a diagram illustrating a differential waveform of a start code.
FIG. 27 is a flowchart for explaining indicator information determination.
FIG. 28 is a diagram showing a barcode label projection image on a frame memory for indicator information determination.
FIG. 29 is a flowchart for describing redefinition of the inclination of a barcode label.
FIG. 30 is a diagram showing a barcode label projection image for explaining redefinition of the inclination of the barcode label.
FIG. 31 is a flowchart for describing stop code detection.
FIG. 32 is a flowchart for explaining barcode label range detection.
FIG. 33 is a flowchart for describing recalculation of the inclination of a barcode label.
FIG. 34 is a diagram for explaining the loss of a barcode label.
FIG. 35 is a diagram illustrating a barcode label projection image for describing calculation of a start point and an end point sequence of a barcode label.
FIG. 36 is a flowchart illustrating a scan equation determination.
FIG. 37 is a flowchart illustrating an embedding check.
FIG. 38 is a diagram illustrating a barcode label projection image for describing an embedding check.
FIG. 39 is a flowchart for describing ROW detection.
FIG. 40 is a flowchart for describing ROW number detection.
FIG. 41 is a flowchart illustrating an optimal scan.
FIG. 42 is a diagram illustrating a barcode label projection image onto a frame memory for describing optimal scanning.
FIG. 43 is a flowchart illustrating an intelligent scan.
FIG. 44 is the first half of a flowchart for explaining a method for converting into width information;
FIG. 45 is a second half of a flowchart for describing a method of converting into width information.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Article | item 2 ... Bar code label, 3 ... Conveying system, 4 ... Imaging optical system, 5 ... Two-dimensional imaging part, 6 ... Frame memory, 7 ... Data processing device, 8 ... Label detection part, 9 ... Reading part, Reference numerals 10: decoding determination unit, 11: decoding unit, 12: memory, 13: control unit, 14: position detection unit, 15: inclination detection unit, 16: host device.

Claims (4)

Imaging means for imaging a barcode consisting of a bar and a space and representing arbitrary information as a pattern as a two-dimensional image;
Storage means for temporarily storing two-dimensional images sequentially obtained by the imaging means;
Transfer means for transferring a two-dimensional image from the imaging means to the storage means;
A recognition unit for sequentially reading the two-dimensional images stored in the storage unit and recognizing the presence or absence of a barcode symbol within an imaging range;
Position detection means for detecting the position and inclination of the barcode recognized by the recognition means within the imaging range, and detecting the scan direction of the barcode;
Reading means for sequentially reading barcode information from a two-dimensional barcode image according to the scan direction detected by the position detection means;
Decoding means for decoding the barcode information from the reading means to the arbitrary information;
Equipped with,
The transfer unit compresses the two-dimensional image picked up by the image pickup unit, transfers one scan line of a field component of the two-dimensional image picked up by the image pickup unit, and then leaves one line in the storage unit open. In addition, the method includes a process of transferring a scan line, repeating the process until image information for one field is transferred, and copying the image information of one line above or below the line to an empty line after completion of the transfer. A symbol information reading device. Imaging means for imaging a barcode consisting of a bar and a space and representing arbitrary information as a pattern as a two-dimensional image;
Storage means for temporarily storing two-dimensional images sequentially obtained by the imaging means;
Transfer means for transferring a two-dimensional image from the imaging means to the storage means;
A recognition unit for sequentially reading the two-dimensional images stored in the storage unit and recognizing the presence or absence of a barcode symbol within an imaging range;
Position detection means for detecting the position and inclination of the barcode recognized by the recognition means within the imaging range, and detecting the scan direction of the barcode ;
Reading means for sequentially reading barcode information from a two-dimensional barcode image according to the scan direction detected by the position detection means;
Decoding means for decoding the barcode information from the reading means into the arbitrary information;
With
2. The symbol information reading device according to claim 1, wherein the transfer unit compresses the two-dimensional image captured by the imaging unit and transfers only one field component of the captured two-dimensional image to the storage unit. . 3. The symbol information reading device according to claim 2 , wherein the transfer unit separately transfers two field components of the captured two-dimensional image to the storage unit . Imaging means for imaging a barcode consisting of a bar and a space and representing arbitrary information as a pattern as a two-dimensional image;
Storage means for temporarily storing two-dimensional images sequentially obtained by the imaging means;
Transfer means for transferring a two-dimensional image from the imaging means to the storage means;
A recognition unit for sequentially reading the two-dimensional images stored in the storage unit and recognizing the presence or absence of a barcode symbol within an imaging range;
Position detection means for detecting the position and inclination of the barcode recognized by the recognition means within the imaging range, and detecting the scan direction of the barcode ;
Reading means for sequentially reading barcode information from a two-dimensional barcode image according to the scan direction detected by the position detection means;
Decoding means for decoding the barcode information from the reading means into the arbitrary information;
With
The symbol information reading device, wherein the transfer unit adds an arbitrary number of pieces of pixel information of the two-dimensional image captured by the image capturing unit and transfers the pixel information as one pixel.

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