JP2010140311A - Bar code reading apparatus, bar code reading program, and bar code reading method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bar code reading apparatus for properly detecting the position of a bar code from a captured image. <P>SOLUTION: The bar code reading apparatus is provided with: an image pickup part 1 for imaging a region including at least a bar code; a bright/dark region identification part 2 for creating bright/dark data for identifying a bright region and a dark region on an image differentiated on the basis of a concentration value from an image obtained by differentiating the captured image; an expansion/contraction part 3 for expanding the bright region at least until a space between the bars of the bar code becomes the bright region with respect to the bright/dark data, and for contracting the expanded bright region at least until the contact between the bar code whose space between the bars has become the bright region and the other bright region is eliminated, and for creating the bright/dark data by changing the size of the contracted bright region to the pre-expansion size; and a position extraction part 4 for selecting the bright region whose area is the maximum from among the bright regions of the bright/dark data created by the expansion/contraction part 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a barcode reading apparatus, a barcode reading program, and a barcode reading method that capture an image of an area including a barcode and read the barcode from the captured image.

  Conventionally, a method has been disclosed in which a region including a barcode is captured by a camera, and the barcode is decoded based on the captured image.

  Also, a method is known in which a captured image is differentiated twice in order to decode a waveform, and a zero cross point is obtained from the obtained image.

As a related art related to the present invention, a barcode recognition apparatus and method capable of recognizing information even if a barcode image is unclear is disclosed (for example, Patent Document 1).
JP 2007-226328 A

  However, in order to decipher the waveform at the sub-pixel for a picked-up image with noise or for a bar code with a narrow bar width, the method of obtaining the zero cross point by performing the above-described two-time differentiation process. Therefore, it is difficult to obtain an accurate bar width, and thus accurate barcode reading cannot be performed.

  The present invention has been made to solve the above-described problems. Even when the captured image is rough, the captured image is blurred, noisy, or the barcode has a narrow bar width, etc. An object of the present invention is to provide a barcode reading apparatus, a barcode reading program, and a barcode reading method capable of accurately detecting the position of a barcode and accurately decoding the barcode based on the detected barcode position. .

  In order to solve the above-described problem, a barcode reader according to one embodiment of the present invention includes an imaging unit that captures at least a region including a barcode, and an image captured by the imaging unit in a barcode scanning direction. At least a differentiation process is performed, and based on a density value of the image subjected to the differentiation process, a bright area on the image subjected to the differentiation process and a dark area on the image subjected to the differentiation process are identified. Bright and dark area identification unit for creating data, and the bright area obtained by expanding the bright area until the dark part sandwiched by at least the bright part becomes a bright area with respect to the bright and dark data created by the bright and dark area identification unit At least until the bar code where the space between the bars becomes a bright area and contact with other bright areas disappears, and the reduced bright area is returned to the size before expansion. An expansion degeneracy unit for creating data, in contrast data created by the expansion degeneracy unit, characterized in that it comprises a selection unit, a selecting a bright region with the largest area among the respective bright areas.

  In addition, the barcode reading program according to one aspect of the present invention includes an acquisition step of acquiring an image in which at least a region including a barcode is captured, and differential processing in the barcode scan direction on the image acquired by the acquisition step At least, and based on the density value of the image subjected to the differentiation process, brightness data that identifies the bright area on the image subjected to the differentiation process and the dark area on the image subjected to the differentiation process The bright region is expanded until the dark portion sandwiched between at least the bright portions becomes the bright region with respect to the bright / dark data generated by the bright / dark region identification step and the bright / dark region identification step, At least, the bar code in which the space between the bars becomes a bright area is degenerated until there is no longer any contact with other bright areas, and the degenerated bright area is expanded. An expansion / reduction step for creating brightness / darkness data returned to the previous size, a selection step for selecting a bright area of the maximum area from each of the bright areas of the brightness / darkness data created by the expansion / reduction step, and selection by the selection step The computer is caused to execute a barcode decoding step of decoding the barcode in the image acquired by the acquisition step based on the barcode position, with the bright region as a barcode position.

  Furthermore, the barcode reading method according to one aspect of the present invention includes an acquisition step of acquiring an image in which an area including at least a barcode is captured, and differential processing in the barcode scan direction on the image acquired by the acquisition step At least, and based on the density value of the image subjected to the differentiation process, brightness data that identifies the bright area on the image subjected to the differentiation process and the dark area on the image subjected to the differentiation process The bright region is expanded until the dark portion sandwiched between at least the bright portions becomes the bright region with respect to the bright / dark data created by the bright / dark region identification step and the bright / dark region identification step, At least before the bar code where the space between the bars is a bright area and the other bright areas are no longer in contact with each other, the degenerated bright area is not expanded. An expansion / reduction step for creating brightness / darkness data returned to a size, a selection step for selecting a bright area of the maximum area from each of the bright areas of the brightness / darkness data created by the expansion / reduction step, and a selection step selected And a barcode decoding step of decoding a barcode in the image acquired by the acquisition step based on the barcode position based on the barcode position.

  It is possible to accurately detect the position of the barcode from the captured image.

  In the present embodiment, a barcode that conforms to the specifications of the NW-7 code system is the target of processing. Here, NW-7 will be described. Note that the barcode reading apparatus, barcode reading program, and barcode reading method disclosed in the present embodiment can be applied to code systems other than NW-7 (for example, Code-39).

  In the NW-7 code system, one character is composed of a total of seven bars of four bars and three spaces. Also, it is assumed that there is a wide space portion called a character gap between characters.

  Bars and spaces are narrow (narrow bar / narrow space) and thick (wide bar / wide space). The ratio between narrow and wide is 2 to 3 times.

Further, the density of the barcode width is as follows. In this embodiment, it is possible to cope with high density.
・ Low density: narrow width = 0.40mm, ratio 2.5 times ・ Medium density: narrow width = 0.26mm ratio 2.5 times ・ High density: narrow width = 0.19mm ratio 2.25 times

  Narrow bar and narrow space represent 0 of the binary code, and wide bar and wide space represent 1 of the binary code. That is, one character is expressed by 7 bits.

The NW-7 code system has the following specifications.
-The bar code's left and right margins require more than 10 times the narrow space.
• The data field length is 96 bits and represents 12 characters.
・ Start character and end character are “a” only.

  In the following description, the form of the barcode reader specialized for barcode position detection will be described as “Embodiment 1”, and the form of the barcode reader specialized for barcode interpretation will be described as “implementation”. This will be described as “Mode 2”. Further, in the following description, an image having the horizontal axis (X axis) in the barcode arrangement direction, that is, the scanning direction is targeted.

(Embodiment 1)
A functional configuration of the barcode reading apparatus according to the first embodiment will be described with reference to FIG. The barcode reader 100 includes an imaging unit 1, a light / dark region identification unit 2, an expansion / reduction unit 3, a position extraction unit 4 (selection unit), and a barcode decoding unit 5.

  The imaging unit 1 is a camera that captures an area including at least a barcode as a moving image through a lens, forms an image on the imaging element, and outputs the image as a video signal. The imaging unit 1 is a portable terminal device having a moving image imaging function represented by, for example, a mobile phone, and the user can perform work while confirming a moving image of the captured image while continuously capturing the vicinity of the barcode. it can.

  The light / dark region identifying unit 2 performs image processing such as shading correction and X-direction differentiation processing on one frame (one still image) of the captured moving image, and performs a bright region (hereinafter referred to as an image processed image). , A white region (bright region)) and a dark region (hereinafter referred to as a black region (dark region)) are generated. In the first embodiment, it is assumed that an image in which the white area and the black area are binarized is generated.

  The expansion / reduction unit 3 applies to the image binarized by the light / dark region identification unit 2 until at least a black portion sandwiched between white portions becomes a white region (a black gap between bars (with a density value of 0)). The white area is expanded until the space is filled, i.e., the space between the bars disappears. Further, the expansion / reduction unit 3 reduces the white area in order to cut the white area of the barcode in contact with the surrounding white area.

  Further, the expansion / reduction unit 3 expands the contracted white area again, and returns the barcode to the original size. The expansion / reduction unit 3 stores data obtained in each step of expansion processing, reduction processing, and expansion processing for returning to the original barcode size in the memory as image data.

  The position extraction unit 4 performs a labeling process on the image data that has been subjected to the expansion process, the contraction process, and the expansion process for returning to the original barcode size by the expansion / reduction unit 3 to extract a white region. Thereafter, the position extraction unit 4 selects the largest area in the white region. This maximum area is the bar code position.

  The barcode decoding unit 5 sets the white area of the maximum area extracted by the position extraction unit 4 as the barcode position, and decodes the barcode in the image captured by the imaging unit 1 based on the barcode position ( Barcode decoding process).

  Next, the operation of the barcode reading apparatus 100 in the present embodiment will be described with reference to the flowchart of FIG.

  First, the imaging unit 1 captures an area including at least a barcode and acquires a captured image (S1). Next, the bright / dark region identifying unit 2 calculates the average density of the captured image, and if the average density is not within a certain range, changes the gain value and corrects the average density to be within the certain range (S2).

  The bright / dark region identifying unit 2 performs shading correction on the image whose gain has been changed (S3). The light / dark area identifying unit 2 averages the maximum density value of a predetermined area in the X direction (the horizontal component direction with respect to the image) as shading correction, and averages the density for each pixel. Divide the density value of the original image by the value. The bright / dark region identifying unit 2 then adds a constant value to the divided value to obtain the density value of each pixel.

  Here, the barcode portion of the original image obtained by the imaging unit 1 is shown in FIG. 3, and the image subjected to the shading correction is shown in FIG. In this way, by performing gain change processing and shading correction, the influence of extraneous light such as illumination can be alleviated, and the distinction between the bar portion of the original image and the space between the bars can be made clear to some extent. . 3 and 4 show barcode images (X-axis and Y-axis two-dimensional images). However, in order to increase the processing speed, processing is actually performed in one dimension only in the X direction as described above. .

  Next, the light / dark region identifying unit 2 performs X-direction differentiation processing on the image subjected to the shading correction to obtain the density value of each pixel by taking the difference between the density values of pixels adjacent in the X direction (S4). . FIG. 5 shows an image subjected to the X-direction differentiation process. As shown in FIG. 5, the light / dark region identifying unit 2 emphasizes the bar portion by performing X-direction differentiation processing. In the present embodiment, as shown in FIG. 5, the image after the X-direction differentiation process has a low density value in the vicinity of the originally bright area and a high density value in the vicinity of the originally dark area. Keep in mind.

  Subsequently, the light / dark region identifying unit 2 performs binarization processing on the image after the X-direction differentiation processing is performed (S5).

  A method of selecting a threshold value when performing binarization processing will be described with reference to FIGS. First, FIG. 6A shows a density cross-sectional view of an image that has been subjected to X-direction differentiation processing (the vertical axis is the density value, and the horizontal axis is the position on the image in units of pixels). Here, for example, the light / dark region identifying unit 2 creates a density value histogram of a local region (see FIG. 6B) of, for example, 20 pixels. In the first embodiment, for example, when the density peak is about 2 pixels, 10 peaks are set as the range of the local region.

  FIG. 7 shows a local area density value histogram in which the vertical axis represents the number of pixels in the local area (number) and the horizontal axis represents the density value. The light / dark region identifying unit 2 sets a density value that maximizes the variance between the two waveforms when the density waveform is divided into two classes (interclass variance). The light / dark region identifying unit 2 thus calculates a threshold value for each local region, and compares each pixel in the local region with the calculated threshold value. When the density value of the pixel is equal to or greater than the calculated threshold value, the light / dark region identification unit 2 sets the pixel to white (density value 255), and if the density value is less than the threshold value, sets the pixel to black (density value 0). (See also FIG. 6B).

  It should be noted that the light / dark region identifying unit 2 may naturally adopt a method in which a predetermined threshold value or more provided in advance is white (density value 255) and a value less than the threshold value is black (density value 0). FIG. 8 shows an image that has been binarized.

  The expansion / reduction unit 3 expands the white area in the binarized image until all the black gaps (density value 0) between the bars in the barcode portion are filled (the density value becomes 255) (S6). ). FIG. 9 shows an image in which the white region is expanded.

  In general, a barcode is printed with a number indicated by an array of bars at the bottom of the bar area. As shown in FIG. 9, in the image in which the white region is expanded, the printed numbers are also expanded, and the number portions are in contact with the expanded barcode portion as noise. In addition, depending on the quality of barcode printing and the adhesion of dirt, noise other than the printed numbers may occur. Therefore, in order to cut | disconnect contact with these noises, the expansion / contraction part 3 contracts a white area | region until there is no contact with noise (S7). FIG. 10 shows an image after the reduction process is performed.

  Subsequently, the expansion / reduction unit 3 performs the expansion process again on the image subjected to the expansion / reduction process in steps S6 and S7, thereby returning the white area to the original size before the expansion / reduction process is performed (S8). ). The image returned to the original size is shown in FIG.

  The position extraction unit 4 performs a labeling process on the image that has been subjected to the process of S8 (S9). That is, the position extraction unit 4 extracts a closed region of the white region including the barcode part, and attaches a label to the extracted closed region. Thereafter, the position extraction unit 4 extracts the largest area among the labeled closed areas as the barcode position (S10). Note that the barcode position is extracted by extracting the X-coordinate value and Y-coordinate value of the feature point (each vertex in the case of a rectangular area).

  If the area of the extracted barcode position is not equal to or greater than a predetermined threshold, the position extraction unit 4 does not use the barcode, or does not use the barcode if the extracted area includes a black area. When the provided conditions are not satisfied, the process is returned to the imaging process (S1) by the imaging unit 1 (S11, No). If the condition is satisfied (S11, Yes), the barcode decoding unit 5 reads the barcode from the original image or the image subjected to the shading correction of S3 described above based on the barcode position information extracted by the position extraction unit 4. The bar code is decoded by cutting out the code and scanning the cut out image (S12). Note that the barcode decoding process by the barcode decoding unit 5 may be a process according to a second embodiment to be described later, or may be a conventional barcode decoding process.

  The expansion / reduction unit 3 may perform the expansion / reduction process of S6, S7, and S8 by adding the values provided in advance as the expansion rate and the reduction rate to the area of the white region.

  The bar code reader 100 may notify the user by sounding a dial tone or the like when the bar code position can be extracted.

  As described above, the barcode reader 100 according to the first embodiment can accurately detect the barcode position.

(Embodiment 2)
In the first embodiment, the barcode reader specialized in the function of extracting the barcode position has been described. In the second embodiment, the barcode reader having a function of accurately decoding the extracted barcode. Will be described.

  FIG. 12 shows a barcode reader according to the second embodiment. The barcode reader 200 includes a barcode position extraction unit 11, a scan data acquisition unit 12 (density array data acquisition unit), a bar width calculation unit 13, a bar determination unit 14, and a code extraction unit 15.

  The barcode position extraction unit 11 extracts a barcode position from at least an image of the barcode imaged.

  The scan data acquisition unit 12 scans the barcode portion whose position is extracted by the barcode position extraction unit 11 in the X direction with a predetermined Y coordinate, and acquires a density value for each position (for each pixel) as scan data. To do.

  The bar width calculation unit 13 acquires each position where the density value becomes the peak value from the scan data. Further, the bar width calculation unit 13 calculates the average density value within a predetermined range of the scan data centered on the position that becomes the peak value for each position that becomes the peak value. The bar width calculator 13 calculates the bar width of the barcode and the width of the space between the bars based on the average density value.

  Based on the width of the bar calculated by the bar width calculation unit 13 and the width of the space between the bars, the bar determination unit 14 determines whether the value indicated by the bar or the space is 1 or 0, and consists of 0 and 1 Create a bit array.

  The code extraction unit 15 extracts characters corresponding to the array of 0 and 1 created by the bar determination unit 14.

  Next, the operation of the barcode reader 200 will be described with reference to the flowchart of FIG.

  The barcode position extraction unit 11 extracts a barcode position from at least an image of the barcode imaged (S51). For example, the barcode position extraction unit 11 may have the configuration shown in the first embodiment, or may have a conventional barcode position extraction processing function.

  The scan data acquisition unit 12 cuts out a barcode from the captured image based on the position extracted by the barcode position extraction unit 11, scans the cut barcode part in the X direction with a predetermined Y coordinate value, A density value (hereinafter referred to as scan data) for each (pixel) is acquired (S52). In this embodiment, the center value of the Y coordinate of the detected barcode position is set as the scan position.

  The bar width calculation unit 13 specifies the position where the density value reaches a peak in the acquired scan data (S53). The peak position is, for example, on the waveform graph with the horizontal axis representing the scan data array (ie, position data) and the vertical axis representing the density value, from the rising edge (upward slope) to the falling edge (lower slope). ) Or a position that changes from a falling edge to a rising edge (in other words, a position where the slope of the tangent line that contacts the waveform graph is 0 or in the vicinity thereof). At this time, if the falling amount or the rising amount is not equal to or greater than a certain ratio of the average height of the waveform graph, the bar width calculation unit 13 ignores it as noise in the local portion.

  In addition, the bar width calculation unit 13 sets a constant pixel before and after the peak position specified as described above as a local region, and calculates an average value of density values in the local region (hereinafter, local average density value) (S54). Note that the interclass variance used in the binarization process (S5) of the first embodiment may be used, and the value obtained by the interclass variance may be used as the local average density value. Or it is good also as an average of the peak density value before and behind.

  Further, the bar width calculation unit 13 calculates a point at which the waveform graph for the above-described local region having the horizontal axis (X axis) as position data and the vertical axis (Y axis) as the density value intersects with the calculated local average density value. The X coordinate value is obtained up to the decimal point level, the X coordinate value at the point where the rising portion of the waveform graph intersects with the local average density value, and the X coordinate value at the point where the falling portion of the waveform graph intersects with the local average density value Is calculated at the decimal point level, and the calculated difference is set as a bar width or a space width between bars (S55).

  Based on the calculated bar width and space width, the bar determination unit 14 determines whether the value indicated by the bar (or space) is 1 or 0, and creates an array of 0 and 1. The bar determination unit 14 sets 1 when the bar width (or space width) is larger than a predetermined threshold, and sets 0 when it is smaller (see also the barcode specification described later).

  Note that the bar determination unit 14 may calculate the threshold using the interclass variance of the binarization process (S5) of the first embodiment. FIG. 14 is a graph in which the vertical axis indicates the number of bars and spaces between bars, and the horizontal axis indicates the bar width or space width (number of pixels). The bar determination unit 14 sets a value that maximizes the variance between the two waveforms when the waveform is divided into two classes as a threshold for the width determination. If the width is larger than the threshold, the bar determination unit 14 determines 1. Judge as 0.

  The code extraction unit 15 extracts a corresponding character from the array of 0 and 1 created by the bar determination unit 14 (S57). FIG. 15 shows the correspondence between codes and characters. FIG. 15A shows the correspondence between 7-bit codes and characters, and FIG. 15B shows the correspondence between barcodes and characters.

  The code extraction unit 15 determines whether there is an unregistered character in NW-7 (that is, a character that does not comply with the above-described NW-7 specification) (S58). Here, when there is no unregistered character, that is, it is a valid code (S58, No), the code extraction unit 15 next determines whether the start and end characters are correct (S59). If the start and end characters are correct (S59, Yes), the decoded character string is displayed to the user (S60), and the process ends.

  On the other hand, if there is an unregistered character (S58, Yes), or if the start and end characters are incorrect (S59, No), the read barcode data is invalid, so the barcode position extraction processing image The input process is performed again (S61). That is, the process is performed again from S51.

  It should be noted that the result of decoding the barcode is compared between the image before and after the predetermined frame and the next frame of the moving image. For example, if two or more of the three results are the same, the result may be normal. .

  In the above description, the barcode position is extracted and the operation after that is mainly described. However, hereinafter, the case where the barcode position extraction process is not used will be described.

  For the entire original image, the scan data acquiring unit 12 scans several lines in the X-axis direction with a large interval between Y coordinate values. For example, the scan data acquisition unit 12 scans with Y coordinate values of 1/4, 1/2, and 3/4 of the Y coordinate maximum value. The bar width calculation unit 13, the bar determination unit 14, and the code extraction unit 15 perform the processes up to S57 described above for each scan data.

  The barcode reading apparatus 200 includes data that conforms to the above-described NW-7 specifications, such as a start code and an end code among the scan data extracted by the code extraction unit 15, and the number of characters between them is 12 characters. It is determined that the barcode is included in the included scan data. Further, the scan data acquisition unit 12 scans a plurality of locations (for example, three locations) around the Y coordinate value obtained by scanning the scan data including the barcode, and the bar width calculation unit 13, the bar determination unit 14, the code The extraction unit 15 further performs the processing up to S57 described above for each scan data. As a result, if the same code is extracted a plurality of times (for example, twice) or more, it is regarded as a normal code.

  In this case, on the waveform of the density cross section of the scan data, a portion (dark region) where the density value falls at a certain rate from the end in the X direction may be determined as the end of the barcode. If the next peak (bright area) is more than a certain pixel away from the position (pixel) determined to be the barcode end, the portion where the next density value falls is the barcode end. This process is repeated until a true bar code edge is found. In addition, because of the specification, the white part continues for a certain number of pixels before the part where the barcode begins, so it is more accurate to add the condition that the bar code end is the depressed part after the bright area continues for a certain number of pixels. Increase.

  Further, the scan data acquisition unit 12 scans one frame image a plurality of times while shifting the Y coordinate by several pixels within the barcode position. If the result of decoding is the same decoding result more than a predetermined number of times, the result is normalized. The code may be For example, when scanning is performed three times, if two or more of the three decoded results are the same code, the result is assumed to be normal.

  When the imaging unit 1 is a mobile terminal, the barcode arrangement may be reversed depending on how the user holds the mobile terminal. The bar code reader shown in the above embodiment can read bar codes in the left-to-right, right-to-left, horizontal and vertical directions. For example, when the left and right are reversed, the barcode reader reverses the position of the scanned data array.

  The bar code reader shown in the above-described embodiment may be a single computer having at least a CPU (Central Processing Unit), a main storage device that is a volatile storage device, and a nonvolatile storage device as hardware resources. Alternatively, the imaging unit 1 of the first embodiment may be provided as a mobile terminal, and the other functional blocks may be provided as a computer. Further, all the functional blocks may be provided in a state where they are integrated into one mobile terminal (a device having at least hardware such as a CPU and a storage device).

  Each functional block described above is realized by software previously installed in a nonvolatile storage device cooperating with hardware resources such as a CPU and a main storage device.

  In the above-described embodiment, the barcode reading program is described as being installed in advance in the above-described barcode reading apparatus. However, the barcode reading program according to the present invention includes that stored in a storage medium. . Here, the storage medium is a magnetic tape, a magnetic disk (floppy (registered trademark) disk, hard disk drive, etc.), an optical disk (CD-ROM, DVD disk, etc.), a magneto-optical disk (MO, etc.), a flash memory, etc. It refers to all media that can be read and executed by a computer in the barcode reader described above, such as media that can be attached to and detached from the reader, and media that can be transmitted via a network.

3 is a diagram illustrating an example of functional blocks of the barcode reading apparatus according to Embodiment 1. FIG. 3 is a flowchart showing the operation of the barcode reading apparatus according to the first embodiment. 4 is a diagram illustrating a barcode portion of an original image obtained by an imaging portion according to Embodiment 1. FIG. 6 is a diagram illustrating an image that has been subjected to shading correction according to Embodiment 1. FIG. 6 is a diagram illustrating an image subjected to X-direction differentiation processing according to Embodiment 1. FIG. 6 is a diagram for explaining processing of a light / dark region identifying unit according to Embodiment 1. FIG. It is a figure for demonstrating the process of the light and dark area | region identification part based on Embodiment 1 (interclass dispersion | distribution). 6 is a diagram illustrating an image subjected to binarization processing according to Embodiment 1. FIG. 6 is a diagram illustrating an image in which a white region is expanded according to Embodiment 1. FIG. FIG. 6 is a diagram showing an image after performing a reduction process according to the first embodiment. It is a figure which shows the image which returned the white area | region to the original size based on Embodiment 1. FIG. 6 is a diagram illustrating an example of functional blocks of a barcode reading apparatus according to Embodiment 2. FIG. 6 is a flowchart showing the operation of the barcode reading apparatus according to the second embodiment. It is a figure which shows the graph which made the vertical axis | shaft the number of the bars and the space between bars, and made the horizontal axis | shaft bar width or space width (number of pixels) based on Embodiment 2. FIG. FIG. 10 is a diagram illustrating a specification of a code system according to the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Image pick-up part, 2 Light / dark area identification part, 3 Expansion / reduction part, 4 Position extraction part, 5 Bar code decoding part, 11 Bar code position extraction part, 12 Scan data acquisition part, Bar width calculation part, 14 Bar determination part, 15 Code extraction unit, 100, 200 Bar code reader.

Claims (5)

An imaging unit for imaging an area including at least a barcode;
At least a differentiation process in the barcode scan direction is performed on the image captured by the imaging unit, and based on a density value of the image subjected to the differentiation process, a bright region on the image subjected to the differentiation process, A light / dark region identifying unit for creating light / dark data that identifies a dark region on an image subjected to differentiation processing;
With respect to the light / dark data created by the light / dark area identifying unit, the light area is expanded until at least the dark part sandwiched between the light parts becomes the light area, and at least the space between the bars is brightened in the expanded light area. An expansion / reduction unit that creates light / dark data in which the bar code that has become an area is degenerated until there is no contact with the other bright areas, and the degenerated bright area is returned to the size before expansion, and
In the brightness / darkness data created by the expansion / reduction part, a selection part that selects a bright area of the maximum area from each of the bright areas,
A barcode reader. The barcode reader according to claim 1, wherein
A barcode decoding unit that decodes a barcode in an image captured by the imaging unit based on the barcode position, with the bright region selected by the selection unit as a barcode position;
A barcode reader. The barcode reader according to claim 1 or 2,
The light and dark area identification unit performs shading correction on the image captured by the imaging unit, performs a differentiation process in the barcode scan direction on the image after the shading correction, and performs an operation on the image after the differentiation process. A bar code reading apparatus characterized in that by performing binarization processing, light / dark data in which a bright area and a dark area are identified is created. An acquisition step of acquiring an image in which an area including at least a barcode is captured;
The image acquired by the acquisition step is at least subjected to differentiation processing in the barcode scanning direction, and based on the density value of the image subjected to the differentiation processing, a bright region on the image subjected to the differentiation processing, and the differentiation A light / dark region identifying step for creating light / dark data identifying dark regions on the processed image;
With respect to the light / dark data created by the light / dark area identifying step, the light area is expanded until at least the dark part sandwiched between the light parts becomes the light area, and at least the space between the bars is brightened in the expanded light area. An expansion / reduction step of creating light / dark data in which the bar code that has become an area is degenerated until there is no contact with the other bright areas, and the degenerated bright area is returned to the size before expansion, and
A selection step of selecting a bright area of the maximum area from each of the bright areas of the brightness data generated by the expansion / reduction step;
A barcode decoding step for decoding the barcode in the image acquired by the acquisition step based on the barcode position, with the bright area selected by the selection step as a barcode position;
Barcode reading program that causes a computer to execute. An acquisition step of acquiring an image in which an area including at least a barcode is captured;
The image acquired by the acquisition step is at least subjected to differentiation processing in the barcode scanning direction, and based on the density value of the image subjected to the differentiation processing, a bright region on the image subjected to the differentiation processing, and the differentiation A light / dark region identifying step for creating light / dark data identifying dark regions on the processed image;
With respect to the light / dark data created by the light / dark area identifying step, the light area is expanded until at least the dark part sandwiched between the light parts becomes the light area, and at least the space between the bars is brightened. An expansion / reduction step of creating light / dark data in which the bar code that has become an area is degenerated until there is no contact with the other bright areas, and the degenerated bright area is returned to the size before expansion, and
A selection step of selecting a bright area of the maximum area from each of the bright areas of the brightness data generated by the expansion / reduction step;
A barcode decoding step for decoding the barcode in the image acquired by the acquisition step based on the barcode position, with the bright area selected by the selection step as a barcode position;
Bar code reading method to execute.

Images