JP2010277169A - Information code reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information code reader for discriminating the color of each cell of an information code by an appropriate method corresponding to the imaging state of the information code. <P>SOLUTION: An information code reader includes an "allocation size detection means" and a "size determination means", and the "allocation size detection means" is configured to detect the size of an allocation area allocated to the cell image in the code image of an information code imaged by an imaging means. Also, the "size determination means" is configured to determine the size of a region used as the object of determination in discriminating the color of each cell image on the basis of the detected size of the allocation region. Furthermore, the information code reader includes a "cell color determination means" for discriminating the color of each of cell images configuring a code image by referring to a region equivalent to the size determined by the "size determination means" in each of the cell images, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an information code reader.

  At present, various information codes in which a plurality of cells are arranged in a matrix are widely provided. In this type of information code, each cell constituting the code area is given a color corresponding to the information to be represented in each cell, and when reading by a reader, the color of each cell is accurately recognized. Is required.

JP 2007-128524 A

  A reading apparatus that reads the information code generally has a configuration in which an information code to be read is captured by a light receiving sensor, and color determination is performed for each cell in the obtained code image. As a method of color discrimination, the pixel at each representative position (for example, the central position) of each cell is referred to, the color at each representative position (each reference pixel) is identified, and the identified color is referred to as each cell color. A method of judging can be considered.

  However, when the method of referring only to the pixel at a specific position of each cell as described above is used, the pixel at the reference position may not accurately reflect the cell color. In such a case, each cell color May not be properly determined. On the other hand, a method of distinguishing each cell color by referring to many pixels in each cell region is also conceivable, but pixel allocation to each cell (light-receiving element allocation to each cell) depends on the size of the two-dimensional code and image formation. Since this can change depending on the state, such a determination method becomes difficult when the number of pixels assigned to each cell is small.

  The present invention has been made to solve the above-described problems, and provides an information code reader capable of performing color discrimination of each cell of an information code by an appropriate method according to the imaging state of the information code. Objective.

  The invention according to claim 1 is an information code reading device for reading an information code in which a plurality of cells are arranged, the imaging means having a plurality of light receiving elements, and reflected light from the information code. An imaging unit that forms an image of a code in the imaging unit; an allocation size detection unit that detects a size of an allocation area allocated to a cell image in the code image of the information code captured by the imaging unit; A size determining unit that determines a size of an area to be used as a discrimination target in color discrimination of each cell image based on the size of the allocation area detected by the allocation size detection unit; and the code image that constitutes the code image In each cell image, the area corresponding to the size determined by the size determining means is referred to determine the color of each cell image. A cell color discriminating means, characterized by comprising a.

  According to a second aspect of the present invention, there is provided the information code reading device according to the first aspect, wherein the cell color discriminating unit detects a central pixel of the cell image constituting the code image, and the center pixel detecting unit. Based on the center pixel detected by the pixel detection means and the size determined by the size determination means, each cell image has a size corresponding to the determined size and the center pixel. Target area specifying means for specifying an area including the target area for color discrimination, and based on color information of each pixel constituting the target area specified by the target area specifying means, It is characterized by discriminating colors.

  According to a third aspect of the present invention, in the information code reading device according to the first or second aspect, the shape of a cell image constituting the code image from the code image of the information code imaged by the imaging means. Shape information acquisition means for acquiring information, and shape determination means for determining the shape of a region to be used as a determination target when determining the color of each cell image based on the shape information acquired by the shape information acquisition means, The cell color discrimination means is provided for each of the cell images constituting the code image, and corresponds to the size determined by the size determination means and has the shape determined by the shape determination means. The color of each cell image is discriminated by referring to the corresponding area.

  According to a fourth aspect of the present invention, there is provided an information code reading device for reading an information code in which a plurality of cells are arranged, the imaging means having a plurality of light receiving elements, and reflected light from the information code, An imaging means for forming an image of a code in the imaging means; and a shape information acquisition means for acquiring shape information of a cell image constituting the code image from a code image of the information code picked up by the imaging means; , Shape determining means for determining the shape of a region to be used as a discrimination target in color discrimination of each cell image based on the shape information acquired by the shape information acquiring means, and each cell image constituting the code image Cell color determination means for determining the color of each cell image with reference to the region corresponding to the shape determined by the shape determination means in each Characterized by comprising a.

  According to a fifth aspect of the present invention, in the information code reading device according to the third or fourth aspect, the shape determining means is adjacent to a predetermined center cell image and the periphery of the center cell image in the code image. A cell image detecting means for detecting an adjacent cell image, and a distance calculating means for calculating each distance from the central cell image to each adjacent cell image, and each of the calculated by the distance calculating means. Based on the distance, the shape of the region used for color discrimination of each cell image is determined.

  According to a sixth aspect of the present invention, in the information code reading device according to the fifth aspect, the center position of the center cell image detected by the cell image detecting means and the center position of the adjacent cell image are further detected. Center position detection means is provided, and the distance calculation means calculates each distance based on the center position of the center cell image and the center position of each adjacent cell image.

According to a seventh aspect of the present invention, in the information code reading device according to any one of the third to sixth aspects, the center position detecting means includes four first adjacent areas adjacent to each other in the vertical and horizontal directions of the central cell image. Detecting the center position of the cell image and the center positions of the four second adjacent cell images obliquely adjacent to the center cell image, respectively, and the distance calculating means includes the center position of the center cell image and the four A first interval between each center position of the first adjacent cell image is calculated as each distance.
Further, an adjacent cell interval calculation for calculating each second interval between the center position of each first adjacent cell image and the center position of each second adjacent cell image adjacent to both sides of each first adjacent cell image. Means is provided, and the shape determining means determines the shape based on the first interval calculated by the distance calculating means and the second interval calculated by the adjacent cell interval calculating means. It is characterized by that.

  The invention of claim 1 detects the size of the allocation area allocated to the cell image in the code image of the information code captured by the imaging means, and based on the detected size (allocation area size), The size of the area used as a discrimination target when the color of the cell image is discriminated is determined. In each cell image constituting the code image, an area corresponding to the determined size is referred to, and the color of each cell image is determined. This makes it possible to change the size of the region used as a discrimination target in color discrimination according to the size assigned to the cell image. Therefore, the discrimination method suitable for the imaging size is used for the color discrimination of each cell. Will be able to do it.

  The invention of claim 2 detects the center pixel of each cell image constituting the code image, and each cell image has a size corresponding to the size determined by the size determining means and includes the center pixel. This area is specified as a target area for color discrimination. Then, the color of each cell image is determined based on the color information of each pixel constituting the specified target area. In this way, an area near the central pixel with high reliability can be used as a color discrimination target area with an appropriate size corresponding to the recognized cell size.

  According to the third aspect of the present invention, shape information of the cell image constituting the code image is acquired from the code image of the imaged information code, and a discrimination target is determined when determining the color of each cell image based on the shape information. The shape of the region used as is determined. Then, in each of the cell images constituting the code image, the color corresponding to the size determined by the size determining unit and the region corresponding to the shape determined by the shape determining unit is referred to, and the color of each cell image is determined. Yes. In this way, since not only the size of the region used as a discrimination target in color discrimination but also the shape can be appropriately changed according to the imaging state, the color discrimination of each cell can be made more appropriate. It becomes possible to carry out by the discrimination method.

  According to the invention of claim 4, in the code image of the information code imaged by the imaging means, the shape information of the cell image constituting the code image is acquired, and the color discrimination of each cell image is performed based on the acquired shape information. In this case, the shape of the region used as a discrimination target is determined. Then, in each cell image constituting the code image, the color corresponding to each cell image is determined with reference to the region corresponding to the shape determined by the shape determining means. In this way, since the shape of the region used as a discrimination target in color discrimination can be changed according to the shape of the cell image, the color discrimination of each cell is performed by a discrimination method suitable for the imaging shape. Will be able to.

  The invention of claim 5 detects a predetermined center cell image and adjacent cell images adjacent to the periphery of the center cell image in the code image, and calculates each distance from the center cell image to each adjacent cell image. ing. And based on each calculated distance, the shape of the area | region used in the color discrimination of each cell image is determined. In this way, the shape of the cell image can be recognized without using a complicated processing method, and the shape information of each cell image can be acquired quickly and easily.

  The invention of claim 6 detects the center position of the center cell image and the center position of the adjacent cell image, and calculates each distance (each distance from the center cell image to each adjacent cell image) based on these center positions. is doing. In this way, it is possible to appropriately grasp the distance relationship between the center cell image and the adjacent cell image, and it is possible to appropriately identify the shape of each cell image based on the distance relationship.

  The invention according to claim 7 detects the center positions of the four first adjacent cell images adjacent to the center cell image vertically and horizontally, and the center positions of the four second adjacent cell images obliquely adjacent to the center cell image, respectively. is doing. And while calculating each 1st space | interval between the center position of a center cell image, and each center position of four 1st adjacent cell images, the center position of each 1st adjacent cell image and each said 1st The second intervals between the center positions of the second adjacent cell images adjacent to both sides of the adjacent cell image are calculated. Then, the cell shape is determined based on the first intervals and the second intervals calculated in this way. In this way, it is possible to appropriately grasp the positional relationship between the central cell, the adjacent cell (first adjacent cell) vertically adjacent to the central cell (first adjacent cell), and the diagonally adjacent cell (second adjacent cell). The shape of each cell image can be specified more appropriately based on the relationship.

FIG. 1 is a block diagram schematically illustrating an electrical configuration of the information code reader according to the first embodiment of the present invention. FIG. 2 is a flowchart illustrating a reading process performed by the information code reading device of FIG. FIG. 3 is a flowchart illustrating the decoding process performed in the reading process of FIG. FIG. 4 is a flowchart illustrating a cell color discrimination process performed in the decoding process of FIG. FIG. 5A is an explanatory diagram conceptually illustrating a cell array of information codes read by the information code reader of FIG. 1, and FIG. 5B images the information code of FIG. 5A. It is explanatory drawing which shows the example of an image. FIG. 6A is an explanatory diagram conceptually showing the target cell image and the surrounding cell images when any one of the code images in FIG. 5B is used as the target cell image. These are explanatory drawings explaining the space | interval (1st space | interval) between an attention cell image (center cell image) and each 1st adjacent cell image, and the space | interval (2nd space | interval) between adjacent cell images. FIG. 7A is an explanatory diagram illustrating distance values (first intervals) between a target cell image (center cell image) and each first adjacent cell image. FIG. 7B is an explanatory diagram conceptually illustrating a reference area that serves as a reference in determining the reference area. FIG. 7C illustrates each distance value (first interval) in FIG. 7A. FIG. 6 is an explanatory diagram illustrating an example in which a reference region is expanded based on (). FIG. 8A is an explanatory diagram illustrating each distance value (second interval) between adjacent cells, and FIG. 8B illustrates the center pixel, the top row, the bottom row, and the leftmost row for the extended region. It is explanatory drawing which shows relationships, such as a rightmost column. FIG. 8C is an explanatory diagram showing an example in which the extension region in FIG. 8B is further expanded and the reference region is determined based on the distance values (second intervals) in FIG. is there. FIG. 9 is an explanatory diagram illustrating a setting example in the case where the size of the reference area is determined based on the size of each cell image according to another embodiment.

[First embodiment]
Hereinafter, a first embodiment embodying the present invention will be described with reference to the drawings.
(overall structure)
First, the overall configuration of the information code reading apparatus according to the first embodiment will be outlined.
The information code reader 1 according to the present embodiment mainly includes an optical system such as an illumination light source 21, a light receiving sensor 23, a filter 25, and an imaging lens 27, a memory 35, a control circuit 40, an operation switch 42, and a liquid crystal display device. And a power supply system such as a power switch 41 and a battery 49.

  The optical system includes an illumination light source 21, a light receiving sensor 23, a filter 25, an imaging lens 27, and the like. The illumination light source 21 functions as an illumination light source capable of emitting the illumination light Lf, and includes, for example, an LED and a diffusing lens, a condensing lens, and the like provided on the emission side of the LED. In this embodiment, the illumination light Lf can be irradiated toward the reading object R through a reading port (not shown in FIG. 1) of the housing. The reading object R corresponds to, for example, a display medium such as a packaging container, wrapping paper, or label, and a two-dimensional code 100 to be read is formed on the reading object R by printing or the like.

  The light receiving sensor 23 is configured to receive the reflected light Lr irradiated and reflected on the reading object R or the two-dimensional code 100. For example, the light receiving sensor 23 is a solid-state image sensor such as a C-MOS or CCD. An area sensor arranged in two dimensions corresponds to this. The light receiving sensor 23 is mounted on a printed wiring board (not shown) in such a configuration that incident light incident through the imaging lens 27 can be received by the light receiving surface 23a. In the present embodiment, the light receiving sensor 23 corresponds to an example of “imaging means”.

  The filter 25 is an optical low-pass filter that allows passage of light that is less than or equal to the wavelength of the reflected light Lr and blocks passage of light that exceeds that of the reflected light Lr. Unnecessary light that exceeds the wavelength of the reflected light Lr Is prevented from entering the light receiving sensor 23. The imaging lens 27 functions as an imaging optical system that collects incident light incident from the outside via a reading port and forms an image on the light receiving surface 23a of the light receiving sensor 23. It is comprised by the cylinder and the some condensing lens accommodated in this barrel. In the present embodiment, the imaging lens 27 corresponds to an example of an “imaging unit”. The reflected light from the two-dimensional code 100 (information code) is taken in, and the image of the two-dimensional code 100 is received by the light receiving sensor 23 ( The imaging means) functions to form an image.

  Next, a configuration outline of the microcomputer system will be described. The microcomputer system includes an amplification circuit 31, an A / D conversion circuit 33, a memory 35, an address generation circuit 36, a synchronization signal generation circuit 38, a control circuit 40, an operation switch 42, an LED 43, a buzzer 44, a liquid crystal display device 46, and a communication interface 48. Etc. As the name suggests, this microcomputer system is composed mainly of a control circuit 40 and a memory 35 that can function as a microcomputer (information processing apparatus). The image signal of the two-dimensional code 100 imaged by the optical system described above. Can be processed in hardware and software. The control circuit 40 also performs control related to the entire system of the information code reader 1.

  In this microcomputer system, an image signal (analog signal) output from the light receiving sensor 23 of the optical system is amplified by the amplification circuit 31 with a predetermined gain, and the amplified signal is converted from an analog signal to a digital signal by the A / D conversion circuit 33. Has been converted. The digitized image signal (that is, image data) is input to the memory 35 and stored in the image data storage area. The synchronization signal generation circuit 38 is configured to generate a synchronization signal for the light receiving sensor 23 and the address generation circuit 36. The address generation circuit 36 is based on the synchronization signal supplied from the synchronization signal generation circuit 38. Thus, the storage address of the image data stored in the memory 35 can be generated.

  The memory 35 is configured as a semiconductor memory device, and corresponds to, for example, a RAM (DRAM, SRAM, etc.) or a ROM (EPROM, EEPROM, etc.). In addition to the above-described image data storage area, the RAM of the memory 35 is configured so as to be able to secure a work area, a reading condition table, and the like that are used by the control circuit 40 at each processing such as arithmetic operation and logical operation. Yes. The ROM stores in advance a predetermined program that can execute a reading process and the like that will be described later, and a system program that can control each hardware such as the illumination light source 21 and the light receiving sensor 23.

  The control circuit 40 is capable of controlling the entire information code reader 1 and is constituted by a microcomputer including, for example, a CPU, a system bus, an input / output interface, and the like. The control circuit 40 has an information processing function, and various input / output devices (peripheral devices) can be connected via a built-in input / output interface. In the present embodiment, as shown in FIG. 1, a power switch 41, an operation switch 42, an LED 43, a buzzer 44, a liquid crystal display device 46, a communication interface 48, and the like are connected to the control circuit 40. The communication interface 48 can be connected to a host computer HST or the like corresponding to the host system of the information code reader 1.

  The power supply system includes a power switch 41, a battery 49, and the like, and the on / off control of the control circuit 40 controls the conduction and interruption of the drive voltage supplied from the battery 49 to the above-described devices and circuits. ing.

(Two-dimensional code)
Next, a two-dimensional code to be read by the information code reader 1 will be described. FIG. 5A is an explanatory diagram conceptually illustrating the cell arrangement of information codes read by the information code reader 1 according to the first embodiment, and FIG. 5B is a diagram illustrating FIG. It is explanatory drawing which shows the example of an image which imaged the information code of ().

  The two-dimensional code 100 is configured as a cell aggregate in which cells C having a square outer shape are aggregated and arranged in a matrix. In the example of FIG. 5A, the number of cells is the same in the vertical and horizontal directions (12 cells). × 12 cells). The code area of the two-dimensional code 100 (area where the cell C is arranged) is a rectangular area whose outer shape is rectangular (in the example of FIG. 5A, the outer shape is a square area having a square shape). In FIG. 5 (a), only some of the cells are denoted by reference symbol C, and the reference numerals of other cells are omitted. In FIG. 5A, a specific cell configuration is omitted.

  The two-dimensional code 100 shown in FIG. 5A is configured as a so-called color code using, for example, three or more types of cells having different colors, densities, or luminances. A specific pattern (related to data) is included in the code area. A predetermined pattern) and a plurality of code blocks (a data code block representing data, an error correction code block for error correction, etc.) are arranged. In the code block, the numerical value and the cell display color are associated with each other. For example, the first color “white” with respect to the data value “0” and the second color “with respect to the data value“ 1 ”. The third color “green” for the data value “2”, the fourth color “blue” for the data value “3”, and the fifth color “magenta” for the data value “4”. The sixth color “yellow” for the data value “5”, the seventh color “cyan” for the data value “6”, and the eighth color “black” for the data value “7”. Are associated with each other.

(Reading treatment)
Next, a reading process performed by the information code reading device 1 will be described.
FIG. 2 is a flowchart illustrating the flow of reading processing performed by the information code reading device 1. The reading process shown in FIG. 2 is started, for example, when a worker performs a predetermined operation (for example, turning on the operation switch 42), and first, an image acquisition process is performed (S1). In this process, the reading object R (FIG. 1) to which the two-dimensional code 100 is attached is imaged by the light receiving sensor 23, and the image data of the two-dimensional code 100 is stored in the memory 35.

  Thereafter, a process of specifying a code area (rectangular area) of the two-dimensional code 100 in the image data acquired in S1 is performed (S2). In this specifying process, for example, an area where the outer edge is a specific figure (for example, a substantially quadrilateral shape) is extracted, or an area where the outer edge is light and dark, or a color change is intense, is extracted. Specified area). Since various techniques for distinguishing different color areas are provided in the field of image processing, the areas may be specified using these known methods.

  After the specifying process of S2, it is determined whether or not the code area (rectangular area) can be specified in the process of S2 (S3). If it can be specified, the process proceeds to Yes in S3 and the decoding process is performed (S4). ). On the other hand, if it cannot be specified, the process proceeds to No in S3, and the reading process ends.

Next, the decoding process in S4 will be described. The decoding process of S4 is performed in the flow as shown in FIG. 3, for example. First, the code area (rectangular area) is divided into cell units, and the process of specifying the cell position is performed (S11). In the process of S11, the center pixel of each cell image constituting the code image is detected.
The control circuit 40 that executes the process of S11 corresponds to an example of “center pixel detection means”, “center position detection means”, and “cell image detection means”.

  After the process of S11, the process which selects the cell which is not selected among all the cells specified by S11 is performed (S12). In the present embodiment, the processes of S13 and S14 are performed on each cell constituting the code area. In the process of S12, any cell for which the processes of S13 and S14 have not been performed yet. Will be selected. After any cell is selected in S12, a process of determining the color of the selected cell is performed (S13).

  The cell color determination process in S13 is performed, for example, as shown in FIG. 4. First, each distance value between the cell selected in S12 (the current target cell) and neighboring cells around the target cell. Is performed (S21). In this process, the image of the cell of interest selected in S12 is used as a central cell image, adjacent cell images adjacent to the periphery of the central cell image are detected, and each distance value from the central cell image to each adjacent cell image is calculated. To do. Specifically, as shown in FIG. 6A, the center position P1 of the cell image (center cell image C1) selected in S12 from the coordinate data of the center position of each cell specified in S11. The coordinates and the coordinates of the center positions Q1, Q2, Q3, and Q4 of the four first adjacent cell images D1, D2, D3, and D4 that are adjacent in the vertical and horizontal directions of the central cell image C1 are read out as shown in FIG. Further, distance values A1, A2, A3, A4 (first intervals) between the center position P1 of the target cell image (center cell image C1) and the center positions Q1 to Q4 of the four first adjacent cell images. Is calculated.

The distance values A1 to A4 between the target cell image C1 (target cell image) and each of the first adjacent cell images D1, D2, D3, and D4 reflect the size of the target cell image C1, and in S21 The control circuit 40 that executes processing corresponds to an example of “allocation size detection means”, and is assigned to each cell image in the code image of the two-dimensional code 100 (information code) imaged by the light receiving sensor 23 (imaging means). It functions to detect the size of the allocated area.
The control circuit 40 that executes the process of S21 corresponds to an example of a “distance calculation unit”, and functions to calculate each distance value from the center cell image to each adjacent cell image.

  After the process of S21 in FIG. 4, a process of calculating a distance value between adjacent cells arranged around the target cell is performed (S22). In the present embodiment, as described above, by the processing of S11, the coordinates of the center positions Q1 to Q4 of the four first adjacent cell images D1 to D4 adjacent to the center cell image C1 in the vertical and horizontal directions, and the center cell image C1. The coordinates of the center positions R1 to R4 of the four second adjacent cell images E1 to E4 that are obliquely adjacent to each other are respectively specified. In S22, first, the center position Q1 of each of the first adjacent cell images D1 to D4 is specified. The coordinates of .about.Q4 and the coordinates of the center positions R1 to R4 of the second adjacent cell images E1 to E4 are read out. And in each center position Q1-Q4 and each center position R1-R4, each distance value B1-B8 (each 2nd space | interval) between adjacent cells is calculated, respectively.

The control circuit 40 that executes the process of S22 corresponds to an example of “adjacent cell interval calculation means”.
Further, the distance values A1 to A4 between the target cell image (center cell image C1) and the first adjacent cell images D1 to D4 and the distance values B1 to B4 between the adjacent cell images are the same as the target cell image (center cell). This corresponds to “shape information” reflecting the shape of the image C1). The control circuit 40 that executes the processes of S21 and S22 corresponds to an example of “shape information acquisition unit”, and is based on a code image of the two-dimensional code 100 (information code) captured by the light receiving sensor 23 (imaging unit). , And functions to acquire “shape information” of each cell image constituting the code image.

After the process of S22 in FIG. 4, a process for determining the size and shape of the reference area to be referred to when the color of the cell of interest is determined (S23).
In this process, based on the distance values A1 to A4 (first interval) calculated in S21 and the distance values B1 to B8 (second interval) calculated in S23, the target cell (center cell) The size and shape of the reference area are determined.

  In this embodiment, for example, a reference area as shown in FIG. 7B is determined in advance. In the process of S23, first, based on the distance calculation results in S21 and S22, a size larger than this reference area is set. An extended area is set. Specifically, based on the distance relationship between the center cell image C1 and the upper first adjacent cell image D1, it is determined how much the reference region in FIG. Based on the distance relationship between the center cell image C1 and the lower first adjacent cell image D2, it is determined how much the reference region is expanded downward. Further, based on the distance relationship between the center cell image C1 and the first adjacent cell image D3 on the left side, the extent to which the center cell image C1 and the first cell on the right side are expanded is determined. Based on the distance relationship with the adjacent cell image D4, it is determined how much the reference area is expanded to the left.

  In the present embodiment, the unit size (unit length) serving as a reference in calculating the distance value in S21 and S22 is N, and each distance value A1 to A4 is such that the distance between the centers is N. It is obtained as a value indicating how many times it is. For example, when the actual distance from the center position P1 of the center cell image C1 to the center position Q1 of the first adjacent cell image D1 is A1 ′, the value of the integer part of A1 ′ / N (that is, A1 ′ / N The value obtained by discarding the decimal part) is the value of the distance A1. Similarly, the value of the integer part of A2 ′ / N when the actual distance from the center position P1 to the center position Q2 is A2 ′ is A2, and the actual distance from the center position P1 to the center position Q3 is A3 ′. The value of the integer part of A3 ′ / N is determined as A3, and the value of the integer part of A4 ′ / N is determined as A4 when the actual distance from the center position P1 to the center position Q4 is A4 ′. Yes.

  In S23, the reference area is expanded vertically and horizontally by the distance values A1, A2, A3, and A4 thus obtained. For the upper part, the upper column G2 of the center pixel W1 is expanded upward A1 times, and for the lower part, the lower column G2 of the center pixel F1 is expanded downward A2 times. For the left, the left column G3 of the center pixel W1 is expanded A3 times to the left, and for the right, the right column G4 of the center pixel F1 is expanded A4 times to the right. Therefore, the A1 column is arranged above the center pixel G1, and the A2 column is arranged below the center pixel F1. Further, A3 columns are arranged to the left of the center pixel F1, and A4 columns are arranged to the right of the center pixel F1. As a whole, an extended region of X rows and Y columns (X × Y) is obtained (where X = A1 + A2 + 1, Y = A3 + A4 + 1).

  In the example of FIG. 7A, the case where the distance values A1 to A4 obtained in S21 are A1 = 1, A2 = 2, A3 = 2, and A4 = 2 is illustrated. When the reference area is 3 rows and 3 columns (FIG. 7B), the upper column is expanded 1 time (ie, there is no change), the lower column is expanded 2 times, and the left column is expanded 2 times. , The right column is doubled. As a whole, an extended region of 4 rows and 5 columns as shown in FIG. 7C is obtained.

  Furthermore, in this embodiment, the shape change degree of the extended region is determined based on the distance relationship between adjacent cells. Specifically, distance relationships between the first adjacent cell image D1 disposed above the center cell image C1 and the second adjacent cell images E1 and E3 are obtained, and based on these distance relationships, FIG. The shape change degree of the uppermost row H1 of the extended region shown in (b) is determined. Similarly, each distance relationship between the first adjacent cell image D2 and the second adjacent cell images E2 and E4 arranged below the center cell image C1 is obtained, and the lowest row H2 of the extension region is obtained based on these distance relationships. The degree of shape change is determined. Further, the distance relationship between the first adjacent cell image D3 and the second adjacent cell images E1 and E2 arranged on the left side of the center cell image C1 is obtained, and the leftmost column of the extension region is obtained based on these distance relationships. The degree of change in shape of H3 is determined. Further, the distance relationship between the first adjacent cell image D4 and the second adjacent cell images E3 and E4 arranged on the right side of the center cell image C1 is obtained, and the rightmost column of the extension region is determined based on these distance relationships. The degree of change in shape of H4 is determined.

  In this embodiment, in S22, each distance value B1-B8 is calculated | required by the method similar to the calculation method of each distance value A1-A4. That is, when the actual distances from the center position Q1 to the center positions R1 and R3 are B1 ′ and B2 ′, respectively, the value of the integer part of B1 ′ / N (that is, the value obtained by rounding down the decimal part of B1 ′ / N) ) Is the distance value B1, and the value of the integer part of B2 ′ / N (that is, the value obtained by discarding the decimal part of B2 ′ / N) is obtained as the distance value B2. Similarly, when the actual distances from the center position Q2 to the center positions R2 and R4 are B5 ′ and B6 ′, respectively, the value of the integer part of B5 ′ / N (that is, the decimal part of B5 ′ / N is rounded down) Value) is the distance value B5, and the value of the integer part of B6 ′ / N (that is, the value obtained by discarding the decimal part of B6 ′ / N) is obtained as the distance value B6. Further, when the actual distances from the center position Q3 to the center positions R1 and R2 are B3 ′ and B4 ′, respectively, the value of the integer part of B3 ′ / N (that is, the value obtained by rounding down the decimal part of B3 ′ / N) ) Is the distance value B3, and the value of the integer part of B4 ′ / N (that is, the value obtained by discarding the decimal part of B4 ′ / N) is the distance value B4. When the actual distances from the center position Q4 to the center positions R3 and R4 are B7 ′ and B8 ′, respectively, the value of the integer part of B7 ′ / N (ie, the value obtained by rounding down the decimal part of B7 ′ / N) ) Is the distance value B7, and the value of the integer part of B8 ′ / N (that is, the value obtained by discarding the decimal part of B8 ′ / N) is the distance value B8.

  In the process of S23, the number of pixels in the uppermost column H1, the lowermost column H2, the leftmost column H3, and the rightmost column H4 of the extended region is set based on the distance values B1 to B8 obtained in this way. For example, for the uppermost column, the number of pixels to be arranged to the left of the upper end pixel J1 in the column of the central pixel F1 is set to a value obtained by multiplying the reference number (1) by B1, and the upper end pixel J1 in the column of the central pixel F1. The shape (pixel arrangement) of the uppermost column H1 is newly set so that the number of pixels to be arranged on the right side is a value obtained by multiplying the reference number (1) by B2. On the lower side, the number of pixels to be arranged to the left of the lower end pixel J2 in the column of the central pixel F1 is set to a value obtained by multiplying the reference number (1) by B5, and the lower pixel J2 in the column of the central pixel F1. Also, the shape (pixel arrangement) of the lowermost row H2 is newly set so that the number of pixels to be arranged on the right side is a value obtained by multiplying the reference number (1) by B6. On the left side, the number of pixels to be arranged above the left end pixel J3 in the column of the center pixel F1 is set to a value obtained by multiplying the reference number (1) by B3, and from the left end pixel J3 in the column of the center pixel F1. Also, the shape (pixel arrangement) of the leftmost column H3 is newly set so that the number of pixels to be arranged below is a value obtained by multiplying the reference number (1) by B4. Further, regarding the right side, the number of pixels to be arranged above the right end pixel J4 in the column of the center pixel F1 is set to a value obtained by multiplying the reference number (1) by B7, and the right end pixel F4 in the column of the center pixel F1. In addition, the shape (pixel arrangement) of the leftmost column H4 is newly set so that the number of pixels to be arranged below is a value obtained by multiplying the reference number (1) by B8.

  In the example of FIG. 8A, the distance values B1 to B8 obtained in S22 are B1 = 2, B2 = 2, B3 = 1, B4 = 2, B5 = 3, B6 = 3, B7 = 1, FIG. 8C illustrates an example in which B8 = 2. In FIG. 8C, based on the second intervals B1 to B8 as illustrated in FIG. 7 (c) shows an example in which the shape of the extended region) is changed.

  In this example, first, a value (ie, “2”) obtained by doubling the number of pixels to be arranged to the left of the upper end pixel J1 of the vertical pixel row including the center pixel F1 from the reference number (1). To do. Note that the position of the extended region shown in FIG. 8B (that is, the position on the left side of the upper end pixel J1) has the same value, and therefore the shape of this position is not changed. Similarly, the number of pixels to be arranged to the right of the upper end pixel J1 in the vertical pixel row including the center pixel F1 is set to a value (ie, “2”) that is twice the reference number (1). Also in this case, since the position of the extended region in FIG. 8B (that is, the position on the right side of the upper end pixel J1) has the same value, the shape of this position is not changed.

  For the bottom row, the number of pixels to be arranged to the left of the lower end pixel J2 of the vertical pixel row including the center pixel F1 is a value obtained by multiplying the reference number (1) by three (ie, “3”). ). In the extended region in FIG. 8B, the number of pixels at the position (that is, the position on the left side of the lower end pixel J2) is “2”. Extend to Further, the number of pixels that should be arranged to the right of the lower end pixel J2 of the vertical pixel row including the center pixel F1 is set to a value that is three times the reference number (1). In the extended region of FIG. 8B, the number of pixels at this position (that is, the position on the right side of the lower end pixel J2) is “2”, so that it is one pixel to the right as shown in FIG. Expand.

  For the leftmost column, the number of pixels that should be arranged above the leftmost pixel J3 in the pixel column in the horizontal direction including the center pixel F1 is set to a value obtained by multiplying the reference number (1) by one. Note that the position of the extended region in FIG. 8B (that is, the position above the left end pixel J3) has the same value, so the shape of this position is not changed. Further, the number of pixels to be arranged below the left end pixel J3 of the pixel column in the left and right direction including the center pixel F1 is set to a value obtained by doubling the reference number (1). Also in this case, since the position of the extended region in FIG. 8B (that is, the position below the left end pixel J3) has the same value, the shape of this position is not changed.

  For the rightmost column, the number of pixels that should be arranged above the right end pixel J4 of the pixel column in the left-right direction including the center pixel F1 is set to a value obtained by multiplying the reference number (1) by one. Since the position (that is, the position above the right end pixel J4) in the extended region in FIG. 8B has the same value, the shape of this position is not changed. Further, the number of pixels to be arranged below the right end pixel J4 of the pixel column in the left-right direction including the center pixel F1 is set to a value obtained by doubling the reference number (1). Also in this case, since the position of the extended region in FIG. 8B (that is, the position below the right end pixel J4) has the same value, the shape of this position is not changed.

  Thus, by setting the number of pixels in the uppermost column H1, the lowermost column H2, the leftmost column H3, and the rightmost column H4 of the extended region, a pixel region (reference region) as shown in FIG. 8C is obtained. It will be. Of the columns extending in the left-right direction, intermediate columns other than the left-right column including the center pixel F1, the uppermost column, and the lowermost column are closest to the left-right column including the center pixel F1, the uppermost column, and the lowermost column. The number of pixels in the pixel column and the pixel arrangement may be the same, and the number of pixels in the intermediate column may be the same as the number of columns arranged on the upper and lower sides of the intermediate column among the horizontal column, the uppermost column, and the lowermost column including the central pixel F1. It may be an intermediate value. For example, in the example of FIG. 8C, there is an intermediate column between the horizontal column including the central pixel and the lowermost column. The number of pixels in the intermediate column is the horizontal column closest to the intermediate column. The number of pixels may be the same as (the left-right column including the center pixel or the lowermost column), and the number of pixels in the intermediate column is set to each column (the left-right column including the center pixel F1) arranged on both upper and lower sides of the intermediate column. And the bottom row) may be an intermediate value (a value obtained by rounding up, rounding down, or rounding off the decimal number when the intermediate value includes a small number).

The control circuit 40 that executes the process of S23 corresponds to an example of a “size determining unit”, and performs color discrimination of each cell image based on the size of the allocation area detected by the “allocation size detection unit”. It functions to determine the size of the area used as the discrimination target.
The control circuit 40 that executes the process of S23 corresponds to an example of a “shape determination unit”, and performs color determination of each cell image based on the “shape information” acquired by the “shape information acquisition unit”. It functions to determine the shape of the region used as the discrimination target. Specifically, it functions to determine the shape of the region used for color discrimination of each cell image based on each distance calculated by the “distance calculation means”.
The control circuit 40 that executes the process of S23 corresponds to an example of “target region specifying unit”, and the center pixel detected by the “center pixel detecting unit” and the size determined by the “size determining unit”. Based on the above, in each cell image, the area corresponding to the determined size and including the center pixel functions to be specified as a color discrimination target area.

  After the process of S23 in FIG. 4, a process of determining the cell color of the target cell is performed (S24). In S24, in the cell image of the target cell (the target cell selected in S12), the area corresponding to the reference area determined in S23 is referred to as the target area, and based on the color information of each pixel constituting the control area. To determine the color of each cell image. For example, in the case of FIGS. 8A and 8C, the pixel as shown in FIG. 8C in which the center position P1 is the center pixel F1 in the target cell image (that is, the center cell image C1). An area is specified as a “target area”, and color information of each pixel in such a target area is acquired. For example, the R component average value for all pixels in the target region, the G component average value for all pixels in the target region, and the B component average value for all pixels in the target region are obtained, and the obtained R component average value, G Based on the component average value and the B component average value, one of the colors for which the color of the target cell (the cell of interest selected in S12) is a candidate is determined. Note that various known methods can be used as a method of performing color discrimination based on the R component value, the G component value, and the B component value of the cell image.

  The control circuit 40 that executes the process of S24 corresponds to an example of a “cell color determination unit” and corresponds to the size determined by the “size determination unit” in each cell image constituting the code image. It functions to refer to the area and determine the color of each cell image. Specifically, in each of the cell images constituting the code image, referring to the area corresponding to the size determined by the “size determining means” and the shape determined by the “shape determining means”, It functions to discriminate the color of each cell image.

  After the cell color determination process of FIG. 3 is performed for the target cell (the target cell selected in S12) as described above, the color of the target cell determined in S13 is set to a value associated with the color. The data is converted and stored as binary data in the memory 35 (S14). Thereafter, it is determined whether or not the processes of S13 and S14 have been performed for all the cells (S15). If there is a cell that has not yet been performed, the process proceeds to No in S15, returns to S12, and remains. Any one cell is selected and the processes of S13 and S14 are repeated. On the other hand, if the processes of S13 and S14 have been performed for all the cells, the process proceeds to Yes in S15 to perform error correction processing and output the decoding result.

(Main effects of this embodiment)
Further, in the code image of the information code imaged by the imaging means, the size of the allocation area allocated to the cell image is detected, and the color discrimination of each cell image is performed based on the detected size (allocation area size). In this case, the size of the area used as a discrimination target is determined. In each cell image constituting the code image, an area corresponding to the determined size is referred to, and the color of each cell image is determined. This makes it possible to change the size of the region used as a discrimination target in color discrimination according to the size assigned to the cell image. Therefore, the discrimination method suitable for the imaging size is used for the color discrimination of each cell. Will be able to do it.

  In addition, the center pixel of each cell image constituting the code image is detected. In each cell image, an area having a size corresponding to the size determined by the size determining means and including the center pixel is color-determined. It is specified as the target area. Then, the color of each cell image is determined based on the color information of each pixel constituting the specified target area. In this way, an area near the central pixel with high reliability can be used as a color discrimination target area with an appropriate size corresponding to the recognized cell size.

  Further, the shape information of the cell image constituting the code image is acquired from the code image of the captured information code, and the shape of the region used as a discrimination target in the color discrimination of each cell image based on the shape information Is determined. Then, in each of the cell images constituting the code image, the color corresponding to the size determined by the size determining unit and the region corresponding to the shape determined by the shape determining unit is referred to, and the color of each cell image is determined. Yes. In this way, since not only the size of the region used as a discrimination target in color discrimination but also the shape can be appropriately changed according to the imaging state, the color discrimination of each cell can be made more appropriate. It becomes possible to carry out by the discrimination method.

  Further, in the code image, a predetermined center cell image and adjacent cell images adjacent to the periphery of the center cell image are detected, and each distance from the center cell image to each adjacent cell image is calculated. And based on each calculated distance, the shape of the area | region used in the color discrimination of each cell image is determined. In this way, the shape of the cell image can be recognized without using a complicated processing method, and the shape information of each cell image can be acquired quickly and easily.

  Further, the center position of the center cell image and the center position of the adjacent cell image are detected, and each distance (each distance from the center cell image to each adjacent cell image) is calculated based on these center positions. In this way, it is possible to appropriately grasp the distance relationship between the center cell image and the adjacent cell image, and it is possible to appropriately identify the shape of each cell image based on the distance relationship.

  Further, the center positions of the four first adjacent cell images adjacent to the top, bottom, left, and right of the center cell image and the center positions of the four second adjacent cell images obliquely adjacent to the center cell image are detected. And while calculating each 1st space | interval between the center position of a center cell image, and each center position of four 1st adjacent cell images, the center position of each 1st adjacent cell image and each said 1st The second intervals between the center positions of the second adjacent cell images adjacent to both sides of the adjacent cell image are calculated. Then, the cell shape is determined based on the first intervals and the second intervals calculated in this way. In this way, it is possible to appropriately grasp the positional relationship between the central cell, the adjacent cell (first adjacent cell) vertically adjacent to the central cell (first adjacent cell), and the diagonally adjacent cell (second adjacent cell). The shape of each cell image can be specified more appropriately based on the relationship.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  In the above embodiment, after setting the extension area, the shape of the extension area is further changed as shown in FIG. 8C, but the extension area obtained as shown in FIG. 7C is used as the reference area. It may be used.

  In the above embodiment, the reference region is a pixel region of 3 rows and 3 columns, but is not limited thereto. For example, one pixel (a pixel region of 1 row and 1 column) may be used as a reference region, and a pixel region of another size such as 5 rows and 5 columns may be used as a reference region.

  In the above embodiment, both the size and shape of the pixel area assigned to each cell are detected, but only the size of the pixel area assigned to each cell may be detected. For example, the number of pixels assigned to each cell image may be detected as a value indicating the size of the pixel area assigned to each cell image, and the size of the reference area may be determined according to the number of pixels. As an example of this, as shown in FIG. 9, there is a method in which the number of pixels and the reference area size are associated with each other in advance so that the reference area increases as the number of assigned pixels increases. In this case, when performing color discrimination of each cell, the number of pixels of the cell to be subjected to color discrimination may be detected, and the reference area size corresponding to the number of pixels may be read out. Then, color discrimination may be performed with reference to a region of a corresponding size (read size) including the center position of the cell image to be subjected to the color discrimination.

DESCRIPTION OF SYMBOLS 1 ... Information code reader 23 ... Light receiving sensor (imaging means)
27. Imaging lens (imaging means)
40... Control circuit (allocation size detection means, size determination means, cell color discrimination means, center pixel detection means, target area identification means, shape information acquisition means, shape determination means, cell image detection means, distance calculation means, center position detection Means, adjacent cell interval calculation means)

Claims (7)

An information code reading device for reading an information code in which a plurality of cells are arranged,
An imaging means comprising a plurality of light receiving elements;
Imaging means for capturing reflected light from the information code and forming an image of the information code in the imaging means;
In the code image of the information code imaged by the imaging means, an allocation size detection means for detecting the size of the allocation area allocated to the cell image;
Based on the size of the allocation area detected by the allocation size detection means, a size determination means for determining the size of the area to be used as a determination target when determining the color of each cell image;
Cell color determination means for determining the color of each cell image with reference to the area corresponding to the size determined by the size determination means in each of the cell images constituting the code image;
An information code reading device comprising: The cell color discrimination means
Center pixel detecting means for detecting a center pixel of each cell image constituting the code image;
Based on the center pixel detected by the center pixel detection means and the size determined by the size determination means, each cell image has a size corresponding to the determined size and the Target area specifying means for specifying the area including the center pixel as a target area for color discrimination;
With
The information code reading apparatus according to claim 1, wherein the color of each cell image is determined based on color information of each pixel constituting the target area specified by the target area specifying unit. Shape information acquisition means for acquiring shape information of a cell image constituting the code image from a code image of the information code imaged by the imaging means;
Based on the shape information acquired by the shape information acquisition means, a shape determination means for determining the shape of a region to be used as a determination target when determining the color of each cell image;
With
The cell color determining means refers to an area corresponding to the size determined by the size determining means and corresponding to the shape determined by the shape determining means in each of the cell images constituting the code image. 3. The information code reading apparatus according to claim 1, wherein a color of each cell image is discriminated. An information code reading device for reading an information code in which a plurality of cells are arranged,
An imaging means comprising a plurality of light receiving elements;
Imaging means for capturing reflected light from the information code and forming an image of the information code in the imaging means;
Shape information acquisition means for acquiring shape information of a cell image constituting the code image from a code image of the information code imaged by the imaging means;
Based on the shape information acquired by the shape information acquisition means, a shape determination means for determining the shape of a region to be used as a determination target when determining the color of each cell image;
Cell color determination means for determining the color of each cell image with reference to the region corresponding to the shape determined by the shape determination means in each of the cell images constituting the code image;
An information code reading device comprising: The shape determining means includes
Cell image detection means for detecting a predetermined center cell image and adjacent cell images adjacent to the periphery of the center cell image in the code image;
Distance calculating means for calculating each distance from the central cell image to each adjacent cell image;
With
5. The information code according to claim 3, wherein the shape of the region used for color determination of each cell image is determined based on each distance calculated by the distance calculation unit. Reader. A center position detecting means for detecting a center position of the center cell image detected by the cell image detecting means and a center position of the adjacent cell image;
6. The information code reading apparatus according to claim 5, wherein the distance calculating unit calculates the distances based on a center position of the center cell image and a center position of each adjacent cell image. The center position detecting means is configured to determine a center position of four first adjacent cell images adjacent to the top, bottom, left and right of the center cell image, and a center position of four second adjacent cell images diagonally adjacent to the center cell image. Detect each
The distance calculation means calculates a first interval between the center position of the center cell image and each center position of the four first adjacent cell images as the distance, respectively.
Further, an adjacent cell interval calculation for calculating each second interval between the center position of each first adjacent cell image and the center position of each second adjacent cell image adjacent to both sides of each first adjacent cell image. With means,
The shape determining unit determines the shape based on the first interval calculated by the distance calculating unit and the second interval calculated by the adjacent cell interval calculating unit. The information code reading device according to any one of claims 3 to 6.