JP5267323B2 - Two-dimensional code reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly perform the color decision of each cell with high accuracy, in a two-dimensional code configured as a color code. <P>SOLUTION: A two-dimensional code reading apparatus includes: an imaging means for imaging a two-dimensional code including a color reference pattern; and a color decision means for determining the display color of each cell image based on color information to be obtained from each cell image and color information to be obtained from the image of the color reference pattern. The two-dimensional code reading apparatus further includes a setting means for setting the "contribution degree" of each color reference pattern used for determining the display color of each cell image for each cell image. The color decision means generates cell-by-cell reference data for use in the color decision of each cell image based on the color information to be obtained from each image of the plurality of color reference patterns and the "contribution degree" to be set for each cell image, and determines the display color of each cell image based on the color information to be obtained from each cell image and the cell-by-cell reference data corresponding to each cell image. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a two-dimensional code reader.

  Conventionally provided two-dimensional codes generally have a configuration in which white cells and black cells are arranged in a matrix, but such two-dimensional codes have a situation that it is difficult to increase the amount of information to be recorded. . Therefore, various color two-dimensional codes for expressing the cell display in color have been proposed at present, and the recording information has been densified. As a technique relating to such a color two-dimensional code, for example, there is a technique as described in Patent Document 1.

Japanese Patent No. 3923696

  In the color two-dimensional code as described above, it is required to accurately determine each color displayed in the cell. However, the reading result of each color is likely to vary depending on the printing environment and the reading environment, and if no measures are taken, an erroneous determination due to the variation is caused. In order to prevent such an erroneous determination, it is desirable to arrange a color reference pattern to be a color determination standard in a specific area and determine each color based on the reference result of the color reference pattern.

  In order to perform more appropriate color determination, it is desirable to provide a plurality of the color reference patterns in the color two-dimensional code. However, how to refer to the color reference pattern in the color determination of each cell is a problem. For example, if the color determination of all cells is performed based on a uniform standard value (for example, an average value generated based on all color reference patterns), the state of each cell and the state of each color reference pattern are taken into consideration. It is difficult to perform appropriate color determination, and as a result, the accuracy of color determination may be reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a two-dimensional code reading apparatus and a two-dimensional code reading method capable of accurately and appropriately performing color determination of each cell.

According to the first aspect of the present invention, a plurality of cells are two-dimensionally arranged in a rectangular area, information encoded by the color, density, or luminance of each cell is expressed in color, and the rectangular area is A two-dimensional code reader capable of reading a two-dimensional code provided with a plurality of color reference patterns serving as a standard of cell display colors used for each cell, the imaging means for imaging the two-dimensional code, and the imaging means In the code image of the two-dimensional code imaged by the color, the display color of each cell image is discriminated based on the color information obtained from each cell image and the color information obtained from the color reference pattern image, respectively. comprising a determination unit, the contribution degree of each of the respective color reference pattern when said determining the display color of each cell image, a setting unit operable to set for each cell image, wherein the setting hand Calculates the distance from the cell image of interest to each of the plurality of color reference patterns in the setting for each cell image, and according to the distance from the cell image of interest for each color reference pattern The color determination unit is configured to set each contribution degree by weighting, and the color determination unit includes color information obtained from the images of the plurality of color reference patterns in the color reference pattern including images of a plurality of cells, respectively. , Based on the degree of contribution set for each cell image, generates cell-specific reference data used for color determination of each cell image, and determines the display color of each cell image from each cell image. The determination is based on the obtained color information and the reference data for each cell corresponding to each cell image.

The invention of claim 2 includes a selection unit that selects a reference pattern that contributes to color discrimination from among the plurality of color reference patterns for each of the cell images, and the color discrimination unit includes: The cell-specific reference data used for color determination of each cell image is generated based on the reference pattern selected for each cell image by the selection unit.

According to a third aspect of the present invention, for each of the cell images, the reference pattern that causes the selection unit to contribute to color determination of the cell image is a distance from the cell image from among the plurality of color reference patterns. It is characterized by selecting based on.

According to a fourth aspect of the present invention, the selection unit includes a determination unit that determines whether or not the color reference pattern is contaminated, and the determination unit among a plurality of the color reference patterns causes the contamination. A pattern determined not to be selected is selected as the reference pattern.

The invention of claim 5 is further provided with a judging means for judging whether or not the image of any cell of each color reference pattern is stained, and the color judging means is selected by the selecting means. In the reference pattern, when any cell is contaminated, the reference data for each cell is generated based on the color information of the portion excluding the dirty cell in the reference pattern.

According to a sixth aspect of the present invention, a fixed value for determining the stain is stored in advance in a storage unit, and the determination unit compares color information obtained from an image of each color reference pattern with the fixed value. It is characterized in that it is determined whether or not the stain is generated in each color reference pattern.

According to a seventh aspect of the present invention, the determination unit generates a reference value for determining the stain based on color information of a part or all of the color reference patterns existing in the two-dimensional code, and each color reference The color information obtained from the pattern image is compared with the reference value to determine whether or not the stain is generated in each color reference pattern.

In the invention of claim 8 , a plurality of cells are two-dimensionally arranged in the rectangular area, and information encoded by the color, density, or luminance of each cell is expressed in color, and the rectangular area includes A reading method for reading a two-dimensional code provided with a plurality of color reference patterns serving as a standard of cell display colors used for each cell, wherein the two-dimensional code is picked up by an image pickup means, and the image picked up by the image pickup means storing a code image of the two-dimensional code in the storage unit, the contribution degree of each of the color reference pattern when determining the display color of each cell images forming the code image, and more setting means, focusing said cell A distance from the image to each of the plurality of color reference patterns is calculated, and each of the color reference patterns is weighted according to the distance from the cell image of interest, and the offset is calculated. Set the at how to set the degree respectively for each cell image, further, the color discrimination means, in the color reference pattern consisting of images of a plurality of cells, respectively obtained from the images of a plurality of said color reference pattern color Based on the information and the contribution degree set for each cell image, the cell-specific reference data used for color discrimination of each cell image is generated, and the color information obtained from each cell image and each The display color of each cell image is determined based on the reference data for each cell corresponding to the cell image.

In the invention of claim 1, the degree of contribution of each color reference pattern when determining the display color of each cell image is set for each cell image, and in the color reference pattern composed of images of a plurality of cells , Based on the color information respectively obtained from the images of the plurality of color reference patterns and the degree of contribution set for each cell image, reference data for each cell used for color discrimination of each cell image is generated. Then, the display color of each cell image is determined based on the color information obtained from each cell image and the reference data for each cell corresponding to each cell image. In this way, it is possible to determine reference data (reference data for each cell) used for color discrimination for each cell image, and it is easy to accurately and appropriately perform color determination for each cell.

Also, in the setting for each cell image, the distance from the cell image to each of a plurality of color reference patterns is calculated, and the contribution degree is set by weighting each color reference pattern according to the distance from the cell image. ing. In this way, when setting the standard data (standard data for each cell) of each cell image, the degree of contribution of each color reference pattern can be determined by appropriately considering the distance to each color reference pattern, and closer. Appropriate standard setting that emphasizes the color reference pattern of the distance can be performed.

The invention according to claim 2 selects, for each cell image, a reference pattern that contributes to color determination from among a plurality of color reference patterns, and based on the selected reference pattern, determines the color of each cell image. Cell-specific reference data used in the above. In this way, the cell-specific standard data used for discrimination of each cell image can be generated based on the color reference pattern that should be contributed, and appropriate standard setting that eliminates the color reference pattern that should not be contributed is possible. Become.

According to a third aspect of the present invention, a reference pattern that contributes to color discrimination of each cell image is selected from a plurality of color reference patterns based on the distance from each cell image. In this way, it is possible to eliminate the color reference pattern at a distant distance that should not be contributed, and to generate standard data (standard data for each cell) used for discrimination of each cell image, thereby enabling more appropriate standard setting It becomes.

According to the fourth aspect of the present invention, a pattern that is determined not to be contaminated among a plurality of color reference patterns is selected as a standard pattern. In this way, since the cell-basis standard data can be generated except for the color reference pattern in which the stain is generated, it is possible to perform color discrimination with high accuracy without the influence of the stain.

According to the invention of claim 5 , it is possible to determine whether or not the image of any cell of each color reference pattern is stained. In the reference pattern selected by the selection means, any cell is stained. If it has occurred, the reference data for each cell is generated based on the color information of the portion excluding the dirty cell in the reference pattern. In this way, the reference data for each cell can be generated while reflecting the reference pattern to be contributed and eliminating the influence of the fouling cell. Therefore, when setting the standard of each cell image, it is possible to selectively incorporate only an appropriate portion of an appropriate color reference pattern (standard pattern) and generate more desirable cell-specific reference data.

According to the sixth aspect of the present invention, a fixed value for determining contamination is stored in advance in the storage means, and each color reference pattern is stained by comparing the color information obtained from the image of each color reference pattern with the fixed value. It is judged whether it has occurred. In this way, it is possible to appropriately determine whether or not each color reference pattern is soiled with a simple configuration.

According to the seventh aspect of the present invention, color information obtained from the image of each color reference pattern is generated by generating a reference value for judging stains based on the color information of a part or all of the color reference patterns existing in the two-dimensional code. Is compared with the reference value to determine whether or not each color reference pattern is contaminated. In this way, it is possible to relatively determine the stain of each color reference pattern based on the color information of the color reference pattern in the two-dimensional code, and to appropriately determine the stain even if the reading environment changes in various ways. .

According to the invention of claim 8 , it is possible to realize a reading method having the same effect as that of claim 1.

FIG. 1 is a block diagram schematically illustrating an electrical configuration of a two-dimensional code reader according to the first embodiment of the present invention. FIG. 2 is a schematic view schematically illustrating a two-dimensional code read by the two-dimensional code reading device of FIG. FIG. 3 is a schematic diagram conceptually illustrating an example of a color reference pattern. FIG. 4 is a flowchart illustrating a reading process performed by the two-dimensional code reading apparatus of FIG. FIG. 5 is a flowchart illustrating a decoding process in the reading process of FIG. FIG. 6 is a flowchart illustrating a cell color recognition process performed in the decoding process of FIG. FIG. 7 is a flowchart illustrating the reference creation process performed in the cell color recognition process of FIG. FIG. 8A is an explanatory diagram conceptually showing the component values of each color for any color reference pattern selected in S21, and FIG. 8B is different from FIG. 8A. It is explanatory drawing which shows each component value of each color about a color reference pattern notionally. FIG. 9 is an explanatory diagram conceptually illustrating an example in which the reference range for each component of each color is defined as a fixed value (fixed range). FIG. 10A is an explanatory diagram showing an example in which an average value for each component of each color is calculated based on a plurality of color reference patterns in the two-dimensional code, and FIG. It is explanatory drawing which shows the example which set the reference range about each component of each color based on each average value of (a). FIG. 11 is an explanatory diagram illustrating an example in which a plurality of color reference patterns close to a target cell (a cell in which color recognition is to be performed) are selected. FIG. 12A is an explanatory diagram illustrating another example 1 of the color reference pattern, and FIG. 12B is an explanatory diagram illustrating another example 2 of the color reference pattern. FIG. 13 is an explanatory diagram for explaining an example in which three color reference patterns are selected and cell-specific reference data is generated based on these three color reference patterns.

[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 two-dimensional code reader according to the first embodiment will be outlined.
The two-dimensional 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. A microcomputer (hereinafter referred to as “microcomputer”) system such as the device 46 and a power system such as a power switch 41 and a battery 49 are configured.

  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 be capable of receiving the reflected light Lr irradiated and reflected on the reading object R or the two-dimensional code 100. For example, the light receiving element 23 is a solid-state imaging device such as a C-MOS or CCD. This corresponds to an area sensor in which the two-dimensional array is arranged. 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 can block passage of light that exceeds that of the reflected light, and is unnecessary for exceeding the wavelength of the reflected light Lr. Light is prevented from entering the light receiving sensor 23. The imaging lens 27 functions as an imaging optical system capable of condensing incident light incident from the outside via a reading port and forming an image on the light receiving surface 23a of the light receiving sensor 23. For example, A lens barrel and a plurality of condensing lenses housed in the lens barrel are configured.

  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 two-dimensional code reader 1.

  An image signal (analog signal) output from the light receiving sensor 23 of the optical system is input to the amplification circuit 31 and amplified by a predetermined gain, and then input to the A / D conversion circuit 33. Converted into a digital signal. When the digitized image signal, that is, image data (image information) is input to the memory 35, it is 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 to be able to secure a work area and a reading condition table that are used by the control circuit 40 in each processing such as arithmetic operation and logical operation. . The ROM stores in advance a predetermined program that can execute reading processing, analysis processing, and the like, 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 a microcomputer that can control the entire two-dimensional code reader 1 and includes a CPU, a system bus, an input / output interface, and the like. The control circuit 40 can constitute an information processing device together with the memory 35 and has an information processing function. . The control circuit 40 is configured to be connectable to various input / output devices (peripheral devices) via a built-in input / output interface. In this embodiment, the control circuit 40 includes 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 two-dimensional code reader 1. The power supply system includes a power switch 41, a battery 49, and the like. When the power switch 41 is turned on and off by the control circuit 40, the conduction of the drive voltage supplied from the battery 49 to each device and each circuit described above is performed. Shut-off is controlled.

(Two-dimensional code)
Next, a two-dimensional code to be read by the two-dimensional code reader 1 will be described.
FIG. 2 schematically illustrates a two-dimensional code 100 read by the two-dimensional code reader 1. A two-dimensional code 100 shown in FIG. 2 includes a plurality of cells C arranged in a matrix, and includes a plurality of code blocks (a data code block 107 and an error correction code block 108) and a first specific pattern 102. The second specific patterns 103 and 104, and the color reference patterns 110, 120, 130, 140, 150, 160, 170, 180, and 190 (hereinafter, these color reference patterns are also referred to as color reference patterns 110 to 190). It has a prepared structure. 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, and in the example of FIG. 2, the number of cells is the same number (35 cells × 35 cells). ). In addition, the code area (area where the cell C is arranged) constituting the two-dimensional code 100 is a rectangular area whose outer shape is rectangular (in the example of FIG. 2, a square area whose outer shape is square).

  In FIG. 2, only some of the cells are denoted by reference symbol C, and the reference numerals of other cells are omitted. In FIG. 2, the positions of some error correction code blocks 108 are conceptually indicated by alternate long and short dash lines, and other error correction code blocks are not shown. Further, the positions of some data code blocks 107 are conceptually shown by two-dot chain lines, and the other data code blocks 107 are not shown. In FIG. 2, an area (data recording area) in which data is recorded is conceptually indicated by a broken line AR1, and a specific cell configuration in this data recording area AR1 (specific cell configuration of each code block, etc.) ) Is omitted.

  The two-dimensional code 100 of the present embodiment is configured as a so-called color code using three or more types of cells having different colors, densities, or luminances. In FIG. 2, as an example, a black cell, a white cell, A configuration using eight color cells of a red cell, a green cell, a blue cell, a cyan cell, a magenta cell, and a yellow cell is shown. Throughout this embodiment and other embodiments, the black cell is indicated by Cb, the white cell is indicated by Cw, the green cell is indicated by Cg, the red cell is Cr, the blue cell is Cu, the yellow cell is Cy, and the cyan cell. Is represented as Cn, and the magenta cell as Cm.

  The code block constituting a part of the two-dimensional code 100 is divided into a data code block 107 and an error correction code block 108 in the two-dimensional code 100 of FIG. It has a configuration.

  The data code block 107 is a block in which encoded data (data code word) obtained by encoding data to be decoded is expressed by a plurality of cells. Each cell constituting the data code block 107 is determined in advance. Any type of cell is selected from a plurality of types of cells (the above-described eight color cells in the example of FIG. 2). In FIG. 2, the data code block 107 in which eight cells are arranged in a matrix of 4 rows and 2 columns is conceptually illustrated by a two-dot chain line, but the number of cells and the block configuration of the data code block 107 are illustrated. May be other than this.

  Each data code block 107 is composed of an array of cells corresponding to encoded data (data code words) to be decoded. Specifically, the cell display color is associated with a numerical value. For example, the first color “white” for the data value “0” and the second color “red” for 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”, the eighth color “black” for the data value “7”, Are associated with each other.

  The error correction code block 108 is composed of error correction code words for performing error correction of the data code block 107. The error correction code word constituting the error correction code block 108 is generated based on the encoded data (data code word) constituting the data code block 107. As a method for generating an error correction code word based on a data code word, for example, a known Reed-Solomon error correction method can be used.

  The first specific pattern 102 is arranged at a prescribed corner 105a among four corners (portions constituting corners in the rectangular area) 105a to 105d provided in the rectangular area of the two-dimensional code 100. is there. In the example of FIG. 2, the outer shape of the first specific pattern 102 is formed in a rectangular shape (specifically, a square shape), and a predetermined corner portion 105 a in the rectangular region is defined by two sides that form the outer edge of the first specific pattern 102. The angular position of is determined. Specifically, one cell of the first color (black cell) is arranged at the center, and a plurality of types of cells surround the first color cell (black cell) in a rectangular shape. Further, the annular cell group (multi-color cell group) is surrounded by a first color cell (black cell 102a) in an annular and rectangular shape, which is configured as the outermost cell group. ing. The outermost cell group has a rectangular (square) outer shape, and the first specific pattern 102 as a whole has a rectangular (square) outer shape.

  The first specific pattern 102 functions as an element for specifying the position of each cell C in the rectangular area. Specifically, when the two-dimensional code 100 is read by the optical information reader. It is used to specify the position of the prescribed corner 105a in the obtained image data, and is used to specify the orientation of the two-dimensional code 100 in the image data. Throughout this specification, the first specific pattern 102, the second specific patterns 103 and 104, and color reference patterns 110 to 190 described later are included in data (data to be decoded) included in the two-dimensional code. Regardless of what is configured as a certain pattern.

  The second specific patterns 103 and 104 are arranged adjacent to the boundary side in contact with the first specific pattern 102 among the four sides (four boundary sides) forming the boundary of the code region (rectangular region). One pattern (second specific pattern 103) is arranged along one boundary side, and the other pattern (second specific pattern 104) is arranged along the other boundary side. These second specific patterns 103 and 104 are used to separate the code area (rectangular area) of the two-dimensional code 100 from the background, and the second specific patterns 103 and 104 are recognized at the time of reading to be described later. Thus, the position of the boundary side can be specified. In the example of FIG. 2, each of the second specific patterns 103 and 104 is configured by a black and white alternating pattern in which white cells and black cells are alternately arranged, but is configured by other patterns. It may be.

  Next, the color reference patterns 110 to 190 will be described. The color reference patterns 110 to 190 are patterns that serve as the standard of the cell display color used for each cell in the rectangular area, and in each case, a plurality of cells are arranged in a matrix (in the example of FIG. 2, a matrix of 3 rows and 3 columns). ). In the example of FIG. 2, all the color reference patterns 110 to 190 have the same configuration, and all the cell display colors (black, white, red, green, blue, magenta) used in the two-dimensional code 100 are used. , Cyan, yellow).

  FIG. 3 is an enlarged view of the color reference pattern 110. In this example, a black cell 110i is arranged at the center, and a plurality of cells surround the black cell 110i. These multi-colored cells will be described clockwise from the white cell 110a arranged at the corner. The white cell 110a, the cyan cell 110b, the red cell 110c, the green cell 110g, the white cell 110e, the magenta cell 110f, and blue Cells 110g and yellow cells 110h are arranged in this order. In FIG. 3, only the color reference pattern 110 is shown, but the other color reference patterns 120 to 190 have the same configuration as the color reference pattern 110, so that the color reference patterns 120 to 190 are enlarged. The drawings and detailed description are omitted. In the example of FIG. 2, the color reference patterns 110 to 190 are arranged at the four corners 105 a, 105 b, 105 c, 105 d, etc. of the rectangular area, but the color reference pattern placement location and the number of color reference patterns Is not limited to the configuration of FIG.

(Reading treatment)
Next, a reading process performed by the two-dimensional code reader 1 will be described.
FIG. 4 is a flowchart illustrating the flow of reading processing performed by the two-dimensional code reading device 1. The reading process shown in FIG. 4 is started, for example, when a worker performs a predetermined operation (for example, an ON operation of 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). This identification process can be performed, for example, by extracting a region whose outer edge is a specific figure (for example, a quadrangle), or by extracting a region where the outer edge has a sharp change in brightness and color. 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, for example, as shown in FIG. 5. First, the code area (rectangular area) is divided into cell units, and the process of specifying the cell position is performed (S11). By the processing of S11, each cell position is specified in the code area.

  After the process of S11, the process which selects the cell which is not selected among all the cells specified by S11 is performed. 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, processing for recognizing the color of the selected cell is performed (S13). The cell color recognition process of S13 is performed, for example, as shown in FIG. 6. First, a process of selecting K patterns close to the cell selected in S12 (the current target cell) is performed (S21). The value of K can vary, and may be the number of color reference patterns existing in the two-dimensional code (“9” in the example of FIG. 2). It is good also as a value smaller than a number. For example, when the two-dimensional code 100 as shown in FIG. 2 is read, if the value of K is “4”, four of all color reference patterns 110 to 190 are selected in order from the one closest to the cell selected in S12. Will do.

  In S21, after K color reference patterns close to the currently focused cell (the cell selected in S12) are selected, any unprocessed color reference pattern is selected from the K color reference patterns. (S22). In this embodiment, the processes of S23 and S24 are performed for each color reference pattern selected in S21. In S22, a color reference pattern for which the processes of S23 and S24 have not yet been performed is selected. It will be.

  After any color reference pattern is selected in S22, the distance to the selected color reference pattern is calculated and stored in the memory 35 (S23), and the color components of each cell of the color reference pattern are further calculated. (S24).

  For example, if the currently focused cell (the cell selected in S12) is the cell C1 shown in FIG. 2 and the color reference pattern selected in S22 is the color reference pattern 110, first, in S23 The distance from the cell C1 to the color reference pattern 110 is calculated and stored in the memory 35. For calculating this distance, various known methods such as Euclidean distance and Manhattan distance can be employed. Further, in S24, the color components of the cells 110a to 110i of the color reference pattern 110 are acquired. Specifically, the R component value, the G component value, and the B component value are obtained and stored in the memory 35 for the cells 110 a to 110 i of the respective colors. In addition, when there are a plurality of cells of any color (white in FIG. 3) as shown in FIG. 3, each component value may be acquired only by any one of the plurality of cells for that color. You may obtain | require the average value of each component in a some cell. By performing such processing, data as shown in FIG. 8A is obtained for the color reference pattern currently focused on.

  After the processing of FIG. 24, whether or not the processing of S23 and S24 for the Kth color reference pattern is completed (that is, the processing of S23 and S24 is performed for all the K color reference patterns selected in S21). It is determined whether or not the process has been completed (S25). If the process has been completed, the process proceeds to Yes in S25, and a reference creation process is performed (S26). On the other hand, if the Kth color reference pattern has not been completed, the process proceeds to No in S25, and the processing from S22 onward is repeated for any remaining color reference pattern, and FIG. Data like b) is acquired. Such processing is repeated for all K color reference patterns, and when the processing is completed for all K color reference patterns, data as shown in FIGS. 8A and 8B is obtained for all K color reference patterns. Will be.

  Next, the reference creation process of S26 will be described. The reference creation process of S26 is performed in the flow as shown in FIG. 7, for example. In this process, first, an unselected color reference pattern is selected from the K color reference patterns selected in S21 (S31). In the present embodiment, the processes of S32 to S36 are performed for all K color reference patterns selected in S21. In the process of S31, the process is still out of the K colors selected in S21. Any color reference pattern for which the processing of S33 to S36 has not been performed is selected.

  After the process of S31, one of the unselected colors is selected in the color reference pattern selected in S31 (S32). In the present embodiment, the processing of S33 to S36 is performed for all the colors of the color reference pattern selected in S31. In the processing of S32, all the colors in the color reference pattern selected in S31 are processed. Any color that has not yet been subjected to the processing of S33 to S36 is selected from the colors.

  Then, the data (the component values generated by the processing of S21 to S25 in FIG. 6) for the color selected in S32 in the color reference pattern selected in S31 is referred to, and the R component value and G component in the data are referred to. It is determined whether the value and the B component value are within the standard (S33).

  The reference range for performing the determination process of S33 may be set in advance as a fixed value, and the calculation and setting process may be performed at a predetermined time before S33. In the case where the fixed values are set in advance, the reference ranges of the R component value, the G component value, and the B component value may be set as fixed ranges as shown in FIG. 9 for each assumed color. In the example of FIG. 9, for example, for a black cell, the R component reference range is defined as Rbmin or more and less than Rbmax, the G component reference range is defined as Gbmin or more and less than Gbmax, the B component reference range is defined as Bbmin or more, and Bbmax. The reference ranges of the R component, the G component, and the B component are also determined for cells of other colors.

  Further, when the reference range is calculated and set at a predetermined time before S3, it is based on the color information of some or all of the nine color reference patterns 110 to 190 provided in the two-dimensional code 100. A reference range may be defined. Specifically, for example, after proceeding to Yes in S25 of FIG. 6 and before performing the reference creation process of S26, based on the data obtained in the processes of S21 to S25, A reference range setting process for setting the reference range may be performed.

  As an example of this, first, an average value of each component value of each color is obtained based on the data of the K color reference patterns selected in S21. For example, because of the processing of S21 to S25, K R component values, K G component values, and K B component values are obtained based on each black cell of the K color reference patterns. Average values Rbave, Rgave, and Bbave of these K R component values, K G component values, and K B component values are obtained. Similarly, because of the processing of S21 to S25, K R component values, K G component values, and K B component values are obtained based on the white cells of the K color reference patterns. Then, average values Rwave, Rwave, and Bwave of these K R component values, K G component values, and K B component values are obtained. The same applies to the other colors. As shown in FIG. 10A, the average value of the R component value, the average value of the G component value, and the average value of the B component value for each color of the K color reference patterns. Ask for.

  Then, based on each component average value of each color obtained as shown in FIG. 10A, a reference range (reference value) for each component of each color is set. There are various methods for setting the reference range, but in the example of FIG. 10B, a certain range of the average value of each component of each color is set as the reference range for each component of each color. For example, for the R component of the black cell, the R component average value Rbave of the K black cells is set as the median value, and the range of “Rbave−α or more and less than Rbave + α” is set as the reference range (reference value). Similarly, the reference range is set for the G component and B component of the black cell, and the sub-range is set similarly for the R component, G component, and B component of the other colors. In this example, the reference range for each component of each color shown in FIG. 10B corresponds to an example of “reference value for determining contamination”.

  In S33 of FIG. 7, based on the standard range set as shown in FIG. 9 or 10 (b), the target color (the color reference pattern selected in S31) of the target color (selected in S32) is selected. It is determined whether each component value of (color) is within the standard.

  For example, a standard range as shown in FIG. 10B is defined, and when the color reference pattern K1 as shown in FIG. 8A is selected in S31 and black is selected in S32, Whether the R component value Rb1 of the black cell of the color reference pattern K1 is within the range of Rbave−α or more and less than Rbave + α, whether the G component value Gb1 is within the range of Gbave−α or more and less than Gbave + α, B component It is determined whether or not the value Bb1 is within the range of Bbave−α or more and less than Bbave + α. If any of the component values Rb1, Gb1, and Bb1 are within the standard range, it is determined that the black cell of the color reference pattern K1 is within the standard, and the process proceeds to Yes in S33. On the other hand, if any one of the component values Rb1, Gb1, and Bb1 is not within the standard range, it is determined that the black cell of the color reference pattern K1 is not within the standard, and No in S33. Will proceed to.

When the process proceeds to Yes in S33, a process of calculating a weight value is performed (S34).
In the present embodiment, in the process of S23 of FIG. 6, a plurality of color reference patterns (K pieces selected in S21) are selected from the target cell image (that is, the cell selected in S12) to be subjected to color recognition (color discrimination). Color reference patterns), and the weights corresponding to the distance from the cell image are calculated for each color reference pattern in S34 of FIG. For example, the weighting is calculated by the following formula 1.

  In Equation 1, Wn is a value indicating the weight of the nth color reference pattern of interest. Ln is the distance from the cell in which color recognition is to be performed (the cell selected in S12 in FIG. 5) to the nth color reference pattern of interest. Further, Lmax is the distance from the cell to be color-recognized among the K color reference patterns selected in S21 (the cell selected in S12 in FIG. 5) to the farthest color reference pattern.

  For example, as shown in FIG. 11, when the cell C1 is a cell that performs color recognition, and four color reference patterns 110, 120, 180, and 190 near the cell C1 are selected in S21 of FIG. The weight value calculated in S34 when the color reference pattern 110 is selected is L4 / L1. Similarly, when the color reference pattern 120 is selected in S31, the weight value calculated in S34 is L4 / L2, and when the color reference pattern 180 is selected in S31, the weight value calculated in S34 is L4 / L3, and when the color reference pattern 190 is selected in S31, the weight value calculated in S34 is L4 / L4. Thus, the color reference pattern closer to the cell of interest C1 is weighted so that the weighting value becomes larger.

  On the other hand, when the process proceeds to No in S33, the weight for the target color of the target color reference pattern is set to “0”. In this case, each component value of the color selected in S32 in the color reference pattern selected in S31 is not reflected in the standard creation.

After the process of S34 or after the process of S35, a value obtained by multiplying each component value of the target color selected in S32 by the weight value set in S34 or S35 is calculated (S36). For example, in the case shown in FIG. 11, when the color reference pattern 110 is selected in S31 and the black cell is selected in S32, the component values of each color of the color reference pattern 110 are as shown in FIG. In this case, when the process proceeds to Yes in S33 (that is, when the component values of the black cells are within the reference), the calculation is performed for the component values Rb1, Gb1, Bb1 of the black cells in S34. Each of the weights L4 / L1 is multiplied to obtain the multiplication values “Rb1 × L4 / L1”, “Gb1 × L4 / L1”, and “Bb1 × L4 / L1”. When the process proceeds to No in S33, the component values Rb1, Gb1, and Bb1 of the black cells are multiplied by “0”, so that the multiplication values of the components are all 0.

  After obtaining the multiplication value in S36, it is determined whether or not the processing of S33 to S36 has been performed for all the colors of the color reference pattern of interest (the color reference pattern selected in S31) (S37). If a color that has not been subjected to the processing of S33 to S36 remains, the process proceeds to No in S37, selects one of the remaining colors (S32), and repeats the processing after S33. . When the processing of S33 to S36 is performed for all the colors of the color reference pattern of interest (the color reference pattern selected in S31), the process proceeds to Yes in S37, and all the K selected in S21 are processed. It is determined whether or not the processes of S32 to S37 have been performed for the color reference pattern (S38). If the color reference patterns that have not been subjected to the processing of S32 to S37 remain among the K color reference patterns selected in S21, the process proceeds to No in S38, and the remaining color reference patterns. One of the color reference patterns is selected from the inside (S31), and the processes of S32 to S37 are repeated.

  When the processes of S32 to S37 have been performed for all K color reference patterns selected in S21, the process proceeds to Yes in S38, and the process of calculating the reference data (cell-specific reference data) for each component for each color is performed. Do. In this process, for each component of each color, the sum of the multiplication values calculated in S36 and the sum of the weights calculated in S34 and S35 and the value obtained by dividing the sum of the multiplication values by the sum of the weights are obtained. This is used as reference data for each component of each color. For example, when generating standard data for each component for a black cell, first, by adding all the calculation results of S34 or S35 performed for each black cell of each color reference pattern, weighting for the black cell Find the sum of values. In addition, by adding all the calculation results of the process of S36 performed for each black cell of each color reference pattern for each R component, for each G component, and for each B component, The sum of the multiplication values, the sum of the multiplication values for the G component of the black cell, and the sum of the multiplication values for the B component of the black cell are obtained. Then, by dividing the sum of the multiplication values obtained for the R component of the black cell by the sum of the weighted values for the black cell, reference data for the R component of the black cell can be obtained. Similarly, the reference data for the G component of the black cell can be obtained by dividing the sum of the multiplication values for the G component of the black cell by the sum of the weighting values for the black cell. By dividing the sum of the multiplication values by the sum of the weight values for the black cells, the reference data for the B component of the black cells can be obtained. The reference data of each component can be acquired for other colors in the same manner.

  Next, a specific calculation example of the reference data will be described with reference to FIG. In the following, a method for calculating R component reference data, G component reference data, and B component reference data for a red cell will be described as a representative example. FIG. 11 shows an example in which four color reference patterns 110, 120, 180, and 190 are selected in S21 during the cell color recognition process (S13) for the cell C1, and each of these color reference patterns 110 and 120 is shown. , 180 and 190, the R component value, the B component value, and the B component value detected in the vicinity of each color reference pattern. In the following description, the distances L1, L2, L3, and L4 from the target cell C1 to be color-recognized to the respective color reference patterns 110, 120, 180, and 190 are represented by L1 = 30, L2 = 60, and L3 =, respectively. 80 and L4 = 120. In the following description, it is assumed that the R component reference range, the G component reference range, and the B component reference range for the red cell are set to “150 or more”, “less than 130”, and “less than 130”, respectively.

  In the example of FIG. 11, when the color reference pattern 110 is selected in S31 of FIG. 7 and the red cell is selected in S32, all the component values of the red cell are within the reference range. Proceed to Yes. In S34, the weighting value is calculated as L4 / L1 = 120/30 = 4. Further, when the color reference pattern 120 is selected in S31 and the red cell is selected in S32, since all the component values of the red cell are within the standard range, the process proceeds to Yes in S33. Become. In S34, the weighting value is calculated as L4 / L2 = 120/60 = 2. On the other hand, when the color reference pattern 180 is selected in S31 and the red cell is selected in S32, the B component value of the red cell does not fall within the reference range, so the process proceeds to No in S33. In this case, the weighting value is 0. On the other hand, when the color reference pattern 190 is selected in S31 and the red cell is selected in S32, since all the component values of the red cell are within the standard range, the process proceeds to Yes in S33. In S34, the weighting value is calculated as L4 / L4 = 120/120 = 1. In this case, the sum of the weight values for the red cell is 4 + 2 + 0 + 1 = 7.

  Further, when the color reference pattern 110 is selected in S31 of FIG. 7 and the red cell is selected in S32, the weight value “4” is obtained in S34 as described above. 110 R component value “200”, G component value “100”, and B component value “80” are each multiplied by “4” to obtain an R component multiplication value “200 × 4” and a G component multiplication value “100 × 4”. , B component multiplication value “80 × 4” is obtained. Similarly, when the color reference pattern 120 is selected in S31 of FIG. 7 and the red cell is selected in S32, the R component multiplication value “210 × 2” and the G component multiplication value “60” for the color reference pattern 120 are selected. × 2 ”and the B component multiplication value“ 70 × 2 ”are obtained. When the color reference pattern 190 is selected in S31 of FIG. 7 and the red cell is selected in S32, the R component multiplication value “220 × 1” and the G component multiplication value “80 ×” for the color reference pattern 190 are selected. 1 ”and the B component multiplication value“ 80 × 1 ”are obtained. When the color reference pattern 180 is selected in S31 of FIG. 7 and the red cell is selected in S32, the process proceeds to No in S33, so that the R component multiplication value and the G component multiplication value for the color reference pattern 180 are processed. , B component multiplication values are both “0”.

  The R component standard data of the red cell is obtained by dividing the sum of the R component multiplication values (200 × 4 + 210 × 2 + 220 × 1 = 1440) of the color reference patterns 110, 120, 180, and 190 by the sum “7” of the weight values. Value, in this case “206”. Similarly, the G component standard data of the red cell is the sum (100 × 4 + 60 × 2 + 80 × 1 = 600) of the G component multiplication values of the color reference patterns 110, 120, 180, and 190, and the sum of the weight values is “7”. In this case, “86” is determined. Further, the B component standard data of the red cell is the sum of the R component multiplication values (80 × 4 + 70 × 2 + 80 × 1 = 540) of the color reference patterns 110, 120, 180, and 190, and the sum of the weight values is “7”. It is a divided value, and in this case, it is determined as “77”.

  After the reference data (cell-specific reference data) for each component of each color is calculated as described above, a process for specifying the cell color is performed in S27 of FIG. In this process, for example, the R component value, the G component value, and the B component value of the cell to be color-recognized (that is, the cell selected in S12 of FIG. 5) are obtained from each color generated in S39 of FIG. Compared with the reference data (R component reference data, G component reference data, B component reference data), each component value of the reference data is the color closest to the R component value, G component value, and B component value of the target cell. It can be the color of the cell. There are various methods for determining the “closest” point. For example, for each color, R component reference data, G component reference data, and B component reference data, and the R component value and G component of the cell of interest. What is necessary is just to obtain | require the difference with each value and B component value, and to obtain | require the sum total of the absolute value of those differences. In this case, a color having a small sum of absolute values of differences can be set as the color of the target cell.

  After the cell color recognition process of FIG. 6 is completed, the color of the target cell (the color specified in S27) is converted into data associated with the color (S14). Then, it is determined whether or not the processes of S13 and S14 have been performed for all the cells, and in all the cells specified in S11, if cells that have not been subjected to the processes of S13 and S14 remain, S15 In S12, any of the remaining cells is selected in S12, and the processes in S13 and S14 are repeated. In the process of S13, a color reference pattern selection process (S21), a standard creation process (S26), and the like corresponding to the cell newly focused in S12 are performed. If the processes of S13 and S14 have been performed for all the cells specified in S11, the process proceeds to Yes in S15, and after performing a known error correction process (S16), the decoding process is terminated.

  In the present embodiment, the control circuit 40 that executes the processes of FIGS. 4 to 7 corresponds to an example of a “color determination unit”, and the code of the two-dimensional code 100 captured by the light receiving sensor 23 (imaging unit). In the image, the display color of each cell image functions to be discriminated based on the color information (each component value) obtained from each cell image and the color information obtained from the color reference pattern image.

  The control circuit 40 capable of performing the processing of S26 corresponds to an example of “setting means”, and determines the “contribution degree” of each color reference pattern when determining the display color of each cell image. It works to set every time.

  The control circuit 40 capable of performing the processes of S21 and S33 corresponds to an example of “selecting means”, and selects a reference pattern that contributes to color discrimination from a plurality of color reference patterns for each cell image. To work.

  The control circuit 40 capable of performing the process of S33 corresponds to an example of “determination means” and functions to determine whether any cell of each color reference pattern is contaminated.

  Further, the control circuit 40 corresponding to the “color discriminating means”, based on the color information obtained from each image of a plurality of color reference patterns and the contribution degree set for each cell image, Cell-specific reference data used for color discrimination is generated (S39: FIG. 7), the display color of each cell image is the color information (each component value) obtained from each cell image, and the cell-specific reference data corresponding to each cell image. It functions to discriminate based on (reference data generated in S39). Specifically, it functions to generate “cell-specific reference data” used for color determination of each cell image based on the reference pattern selected for each cell image by the “selecting means”. In addition, in the reference pattern selected by the “selecting means”, if any cell is contaminated, the cell is based on the color information of the portion excluding the contaminated cell in the reference pattern where the contamination is generated. It functions to generate different reference data.

(Main effects of this embodiment)
In the two-dimensional code reading device 1 according to the present embodiment, the degree of contribution of each color reference pattern when determining the display color of each cell image is set for each cell image, and a plurality of color reference patterns are displayed. Based on the color information obtained from each image and the contribution level set for each cell image, reference data for each cell used for color discrimination of each cell image is generated. Then, the display color of each cell image is determined based on the color information (each component value) obtained from each cell image and the reference data for each cell corresponding to each cell image. In this way, it is possible to determine reference data (reference data for each cell) used for color discrimination for each cell image, and it is easy to accurately and appropriately perform color determination for each cell.

  Also, in the setting for each cell image, the distance from the cell image to each of a plurality of color reference patterns is calculated, and the contribution degree is set by weighting each color reference pattern according to the distance from the cell image. ing. In this way, when setting the standard data (standard data for each cell) of each cell image, the degree of contribution of each color reference pattern can be determined by appropriately considering the distance to each color reference pattern, and closer. Appropriate standard setting that emphasizes the color reference pattern of the distance can be performed.

  In addition, for each cell image, a standard pattern that contributes to color discrimination is selected from among a plurality of color reference patterns. Based on the selected standard pattern, a cell-specific standard used for color discrimination of each cell image Data is being generated. In this way, the cell-specific standard data used for discrimination of each cell image can be generated based on the color reference pattern that should be contributed, and appropriate standard setting that eliminates the color reference pattern that should not be contributed is possible. Become.

  Specifically, as shown in S21 of FIG. 6, a reference pattern that contributes to the color discrimination of each cell image is selected from a plurality of color reference patterns based on the distance from each cell image. In this way, it is possible to eliminate the color reference pattern at a distant distance that should not be contributed, and to generate standard data (standard data for each cell) used for discrimination of each cell image, thereby enabling more appropriate standard setting It becomes.

  In the above embodiment, in the color reference pattern (standard pattern) selected in S21, if any cell is contaminated, the reference pattern in which the contamination is generated is a portion excluding the contaminated cell. Color information is reflected in the reference data for each cell. In this way, the reference data for each cell can be generated while reflecting the reference pattern to be contributed and eliminating the influence of the fouling cell. Therefore, when setting the standard of each cell image, it is possible to selectively incorporate only an appropriate portion of an appropriate color reference pattern (standard pattern) and generate more desirable cell-specific reference data.

  In addition, when using a method in which a fixed value for determining dirt (each standard range as shown in FIG. 9) is stored in the memory 35 (storage means) in advance, color information (each color of each color) obtained from the image of each color reference pattern is used. By comparing the (component value) with a fixed value, it is possible to determine whether each color reference pattern is contaminated. This makes it possible to appropriately determine whether or not each color reference pattern is contaminated with a simple configuration.

  In addition, when using a method for generating a reference value for determining a stain based on color information of a part of color reference patterns existing in the two-dimensional code, color information obtained from an image of each color reference pattern (for each color) Each component value) is compared with a reference value (for example, compared with a reference range (FIG. 10B) determined based on an average value as shown in FIG. 10A), so that each color reference pattern is stained. It can be determined whether or not. In this way, it is possible to relatively determine the stain of each color reference pattern based on the color information of the color reference pattern in the two-dimensional code, and to appropriately determine the stain even if the reading environment changes in various ways. .

[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-described embodiment, an example in which a color reference pattern having eight rows of cells configured in three rows and three columns is provided in the two-dimensional code 100 to be read has been described. However, the configuration of the color reference pattern is limited to this. However, the present invention can be similarly applied to other color reference patterns. For example, a color reference pattern of 3 colors of 2 rows and 2 columns as shown in FIG. 12A may be used, and a color reference pattern of 16 colors of 4 rows and 4 columns as shown in FIG. It may be used.

  In the above-described embodiment, an example in which four color reference patterns in the vicinity of a target cell are used in creating a standard is shown, but the present invention is not limited to this method. For example, as shown in FIG. 13, three color reference patterns in the vicinity of the cell of interest may be used for creating a standard. When creating a standard for each cell, all the color reference patterns in the two-dimensional code are used. Also good.

  In the above-described embodiment, if any cell is soiled in the color reference pattern (standard pattern) selected in S21, the cell-based standard is based on the color information of the portion of the standard pattern excluding the dirty cell. Although data has been generated, if any cell is contaminated, the entire color reference pattern may be excluded. In this case, in the process of FIG. 7, when S35 is omitted and the process proceeds to No in S33, a process of excluding the focused color reference pattern from the selection target (standard pattern) is performed, and the process returns to S31. The reference creation process may be changed as described above. In this way, since the cell-basis standard data can be generated except for the color reference pattern in which the stain is generated, it is possible to perform color discrimination with high accuracy without the influence of the stain.

  In the above embodiment, an average value as shown in FIG. 10A is obtained based on a part of the color reference patterns (color reference patterns selected in S21) in the two-dimensional code, as shown in FIG. An example of setting a standard range has been described, but an average value as shown in FIG. 10A is obtained based on all the color reference patterns in the two-dimensional code, and a standard range as shown in FIG. 10B is set. You may make it do.

DESCRIPTION OF SYMBOLS 1 ... Two-dimensional code reader 23 ... Light receiving sensor (imaging means)
35 ... Memory (storage means)
40. Control circuit (color discrimination means, setting means, selection means, determination means)
100 ... Two-dimensional code 110, 120, 130, 140, 150, 160, 170, 180, 190 ... Color reference pattern
C ... cell

Claims (8)

A plurality of cells are two-dimensionally arranged in the rectangular area, and the information encoded by the color, density or brightness of each cell is expressed in color, and the cell display used for each cell in the rectangular area A two-dimensional code reader capable of reading a two-dimensional code provided with a plurality of color reference patterns serving as color standards,
Imaging means for imaging the two-dimensional code;
In the code image of the two-dimensional code imaged by the imaging means, the display color of each cell image is based on color information obtained from each cell image and color information obtained from the image of the color reference pattern, respectively. Color discriminating means for discriminating;
Setting means for the contribution degree of each of the respective color reference pattern when determining the display color of each cell image, set the in each cell image,
With
In the setting for each cell image, the setting unit calculates a distance from the cell image of interest to each of the plurality of color reference patterns, and the distance from the cell image of interest for each color reference pattern Is configured to set the contribution degree by weighting according to
The color discrimination means
In the color reference pattern composed of images of a plurality of cells, each cell based on color information obtained from each of the images of the plurality of color reference patterns and the contribution set for each cell image Generate cell-specific reference data to be used for image color discrimination,
The two-dimensional code reading apparatus characterized in that the display color of each cell image is determined based on color information obtained from each cell image and the reference data for each cell corresponding to each cell image. The setting means includes a selection means for selecting a standard pattern that contributes to color discrimination from among the plurality of color reference patterns for each cell image,
The color discriminating unit generates the cell-specific reference data used for color discrimination of each cell image based on the reference pattern selected for each cell image by the selection unit. Item 2. The two-dimensional code reader according to Item 1 . The selection means selects, for each cell image, the reference pattern that contributes to color discrimination of each cell image based on a distance from each cell image from among the plurality of color reference patterns. The two-dimensional code reader according to claim 2 , wherein The selection means includes
A judging means for judging whether or not the color reference pattern is soiled;
Two-dimensional code reader according to pattern determined that is not occurring soiled by the determining means of the plurality of the color reference pattern to claim 2 or claim 3, characterized in that selected as the reference pattern . Comprising a determining means for determining whether said fouling on an image of one of the cells of each color reference pattern occurs,
In the reference pattern selected by the selection unit, the color determination unit, when any cell is contaminated, the color discrimination unit, based on the color information of the portion excluding the contamination cell in the reference pattern. two-dimensional code reading apparatus according to claim 2 or claim 3, characterized in that to generate the reference data. A fixed value for determining the dirt is stored in the storage means in advance,
Said determination means, said by the color information obtained from the image of each color reference pattern is compared with the fixed value, according to claim 4, characterized in that determining whether the dirt to the each color reference pattern occurs Or the two-dimensional code reader of Claim 5 . The determination means includes
Generating a reference value for determining the stain based on color information of a part or all of the color reference pattern existing in the two-dimensional code;
Wherein by the color information obtained from the image of each color reference pattern is compared with the reference value, to claim 4 or claim 5, characterized in that determining whether the dirt to the each color reference pattern occurs The two-dimensional code reading device described. A plurality of cells are two-dimensionally arranged in the rectangular area, and the information encoded by the color, density or brightness of each cell is expressed in color, and the cell display used for each cell in the rectangular area A reading method for reading a two-dimensional code provided with a plurality of color reference patterns serving as color standards,
Imaging the two-dimensional code by imaging means,
Storing the code image of the two-dimensional code imaged by the imaging means in a storage means;
The contribution degree of each of the color reference pattern when determining the display color of each cell images forming the code image, and more setting means, a distance from the focused the cell image to the plurality of said color reference pattern Calculating, for each color reference pattern, weighting according to the distance from the cell image of interest and setting the degree of contribution for each cell image,
Further, in the color reference pattern composed of images of a plurality of cells by the color discrimination means, color information obtained from the images of the plurality of color reference patterns, and the contribution degree set for each of the cell images, Based on the color information obtained from each cell image and the cell-specific reference data corresponding to each cell image A method for reading a two-dimensional code, wherein the display color of a cell image is determined.

Images