JP2012068691A - Optical information reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information reading device that reads a color code, with a configuration that allows a color of each cell to be determined more accurately.SOLUTION: The optical information reading device 1 sets reference values of cell colors to be used in a color code 100 on the basis of color reference patterns 110-190 included in a code image, and sets a temporary range for each of the cell colors on the basis of the set reference values of the cell colors. Each of the cells is classified into the temporary range of any cell color on the basis of the set temporary range of the each cell color and a detection value of the each cell. A cluster is set for the each cell color on the basis of the detection value of the each cell classified for each temporary range. A cell presumed to be stained is detected on the basis of the range of the set cluster for the each cell color and the detection value of the each cell.

Description

  The present invention relates to an optical information 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 problem that it is difficult to increase the amount of information to be recorded. . Therefore, various color codes in which cells of various colors are arranged have been proposed at present, and the density of recorded information has been increased. In addition, there exist a thing like patent document 1, 2 as a technique regarding such a color code, for example.

JP-A-10-55420 JP 2003-178277 A

  By the way, in the color code as described above, it is required to accurately determine each color displayed in the cell. However, the reading results of each color are likely to vary depending on the printing environment and the reading environment, and there is a problem in that if no measures are taken, erroneous determination due to the variation is caused. In order to prevent such erroneous determination, a reference pattern (reference pattern) to be a color determination reference is arranged in a specific area in the color code, and when the color code is read, the reference pattern reference result is displayed. It is effective to determine the color of each cell based on this. However, if the color of each cell is determined only by the above-described determination method, it is difficult to accurately determine the color of each cell when the reference pattern is dirty or there is uneven color in the color code. There is.

  On the other hand, as a technique related to such a problem, a technique such as Patent Document 2 has been proposed. In this technology, a deviation between a color detected in a reference pattern (reference pattern) and a preset reference color is used as a correction amount, and thereby variations caused by changes in the printing environment and the reading environment are corrected. It is trying to absorb and recognize the color of each cell more accurately. However, the correction method used in Patent Document 2 may not be effective, for example, when the conditions (printing, illumination, lens, etc.) are different between the reference pattern (reference pattern) area and the data recording area. In order to recognize the color of each cell more accurately, further ingenuity is required.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a configuration capable of more accurately discriminating the color of each cell in an optical information reader capable of reading a color code. To do.

According to the first aspect of the present invention, a plurality of types of cells having different colors, densities or luminances are arranged in the code area, and information of each cell is represented by each cell color, and is represented by one or a plurality of reference colors. The present invention relates to an optical information reading apparatus for reading a color code in which a reference pattern is provided in the code area.
Further, an imaging unit that images the color code, a cell color information acquisition unit that acquires a detection value indicating a degree of color for each cell in the code image of the color code captured by the imaging unit, and the code image A reference value setting means for detecting the reference pattern included in the color code and setting a reference value for each cell color used in the color code based on the reference pattern; and each cell color set by the reference value setting means Based on the reference value, for each cell color, a temporary range setting means for setting a numerical temporary range related to color, density or luminance, and the temporary range of each cell color set by the temporary range setting means, Classification means for classifying each cell into the temporary range of any cell color based on the detection value of each cell acquired by the cell color information acquisition means; Cluster setting means for setting a cluster that defines a numerical range related to color, density, or luminance for each cell color based on the detected value of each cell classified into the temporary range of each cell color by: A stain detection unit that detects a cell estimated to be a stain based on a cluster range for each cell color set by the cluster setting unit and the detection value of each cell acquired by the cell color information acquisition unit. It is characterized by having.

  According to a second aspect of the present invention, in the optical information reading apparatus according to the first aspect, the temporary range setting means is centered on a reference value of each cell color set by the reference value setting means and is predetermined. The temporary range of each cell color is set based on the determined temporary range size, and the cluster setting unit is configured to determine each cell based on the detected value of each cell classified into the temporary range of each cell color. The center value of the color cluster is calculated, and the range of each cell color cluster is set based on the calculated center value of each cell color cluster and a predetermined cluster size. .

According to a third aspect of the present invention, in the optical information reading apparatus according to the second aspect, the cluster setting means includes a range of each cell color cluster that has already been set and a cluster of each cell color that has already been set. Based on the detected value of each cell to which it belongs, center value resetting means for setting the center value of each cell color cluster, and the center value of each cell color cluster reset by the center value resetting means, Range resetting means for setting a cluster range of each cell color based on a predetermined cluster size.
Then, the contamination detection means estimates the contamination based on the cluster range of each cell color set by the range resetting means and the detection value of each cell acquired by the cell color information acquisition means. The detected cell is detected.

  According to a fourth aspect of the present invention, there is provided the optical information reading apparatus according to the third aspect, wherein the center value resetting unit is configured so that the number of times of setting the cluster range of each cell color by the range resetting unit reaches a predetermined number of times. Each time the range resetting means sets the range of each cell color cluster, the center value of each cell color cluster is reset, and the range resetting means sets the number of times the cluster range of each cell color is set. When the predetermined number of times is reached, the resetting of the center value is finished.

  According to a fifth aspect of the present invention, in the optical information reading apparatus according to the third aspect, the center value resetting unit assigns each cell to each cluster of each cell color set by the range resetting unit. Until each cell color cluster range is set by the range resetting means until the change from the assignment of each cell color to the respective cluster in the previous setting before the resetting, The center value of the cluster is reset, and the resetting of the center value is finished when the allocation does not change.

According to a sixth aspect of the present invention, in the optical information reading device according to any one of the third to fifth aspects, the stain detection unit is configured to set the temporary range and the range when the temporary range is set. When the cluster range is set by the resetting means, a cell that is estimated to be dirty is detected based on the detection value of each cell acquired by the cell color information acquisition means.
The center value resetting means refers to the detected values of the remaining cells excluding the cells estimated to be dirty by the dirt detecting means, and sets each of the remaining cells belonging to the cluster of each preset cell color. Based on the detected value of the cell, the center value of the cluster of each cell color is set.

A seventh aspect of the present invention is the optical information reading device according to any one of the first to sixth aspects, wherein the cell color information acquisition means is a code image of the color code imaged by the imaging means. In FIG. 5, each component value of the RGB component, each component value of the CMY component, or each component value of the HSV component is acquired as the detection value for each cell.
And the reference value setting means sets each component reference value of RGB component or CMY component or HSV component for each cell color used in the color code based on the reference pattern included in the code image, The tentative range setting means is determined in advance with each component reference value set by the reference value setting means as a central value for each cell color in virtual coordinates using RGB components, CMY components, or HSV components as parameters. A temporary range having a predetermined length as a radius is set.
Further, the classification unit includes the temporary range of each cell color set by the temporary range setting unit, and the RGB component, the CMY component, or the HSV component value of each cell acquired by the cell color information acquisition unit. Based on the above, each cell is classified into the temporary range of any cell color in the virtual coordinates, and the cluster setting unit is classified into the temporary range of each cell color by the classification unit, respectively. Based on each component value of the RGB component or CMY component or HSV component of each cell, a cluster range having a predetermined predetermined length as a radius is set for each cell color in the virtual coordinates.

According to the first aspect of the present invention, a reference pattern is detected in the code image of the color code imaged by the imaging means, a temporary range is set for each cell color based on the reference pattern, and each cell is set to any cell. It can be classified into a temporary range of colors. Since the temporary range is set for each cell color based on the reference pattern, each cell is appropriately classified based on an objective reference provided in the code.
Further, a cluster is set for each cell color based on the detection value of each cell classified into the temporary range of each cell color. Then, based on the set cluster range for each cell color and the detection value of each cell acquired by the cell color information acquisition unit, the cell that is estimated to be dirty is detected by the contamination detection unit. According to this configuration, it is possible to reset a more appropriate range (cluster range) reflecting the actual state for each cell color based on the detection value of each cell actually obtained. It is possible to more accurately determine which color each cell belongs to based on (range). Furthermore, it is possible to more accurately determine a cell that is estimated to be dirty based on a range (cluster range) appropriately determined for each cell color.

In the invention of claim 2, the temporary range setting means is centered on the reference value of each cell color set by the reference value setting means, and the temporary range of each cell color is determined based on a predetermined temporary range size. It is set. In this way, an appropriate provisional range is set, in which cells that are not separated from each reference value by a certain value or more are grouped with the reference value of each cell color obtained based on the reference pattern as the center. can do.
Then, the cluster setting means calculates the center value of each cell color cluster based on the detection value of each cell classified into the temporary range of each cell color, and the calculated cluster of each cell color A cluster range of each cell color is set on the basis of the center value of and the predetermined cluster size. In this way, the center value of the temporary range of each cell color can be corrected to a value reflecting the detection value of each cell classified into each temporary range. Then, the range of the cluster of each cell color can be appropriately determined so that each correction value corrected in consideration of the actual state in this way is set as the “center value of each cluster”.

In the invention of claim 3, the cluster setting means is configured to determine the cell color of each cell color based on the range of each cell color cluster that has already been set and the detection value of each cell that belongs to each of the previously set cell color clusters. The center value resetting means for setting the center value of the cluster, the center value of each cell color cluster reset by the center value resetting means, and the cluster size of each cell color based on the predefined cluster size Range resetting means for setting the range.
In this way, the center value of the cluster of each cell color once set can be corrected again to a value reflecting the detection value of each cell classified into each cluster. Accordingly, even if the reflection of the actual state is insufficient at the first setting of the cluster range, the cluster range of each cell color is more easily corrected by the setting again.
Then, based on the cluster range of each cell color set by the range resetting unit and the detection value of each cell acquired by the cell color information acquiring unit, a cell estimated to be dirty is detected. Thus, more accurate dirt detection can be performed.

In the invention of claim 4, the center value resetting means determines the range of the cluster of each cell color by the range resetting means until the number of times of setting the cluster range of each cell color by the range resetting means reaches a predetermined number. The center value of each cell color cluster is reset every time it is set, and the resetting of the center value is completed when the number of times the cluster range of each cell color is set by the range resetting means reaches a predetermined number. .
In this way, the center value of each cell color cluster once set is used every time the cell color cluster range is set until the number of times the cell color cluster range is set reaches a predetermined number. The center value of each cell color cluster can be reset. Accordingly, even if the reflection of the actual state is insufficient at the first setting of the cluster range, the cluster range of each cell color can be more appropriately corrected by resetting a predetermined number of times.

In the invention of claim 5, the assignment of each cell to each cell color cluster set by the range resetting means changes from the assignment to each cell color cluster in the previous setting before the resetting. Until the range disappears, the center value of each cell color cluster is reset every time the range reset means sets the range of each cell color cluster, and the center value is reset when the allocation does not change. It has ended.
In this way, the cluster range can be corrected until there is no change in the allocation within the cluster range before and after the resetting, and finally the cluster range that more appropriately reflects the actual detection value can be determined. .

According to the sixth aspect of the present invention, when the temporary range is set by the temporary range setting unit and the cluster range is set by the range resetting unit, the contamination is estimated based on the detection value of each cell acquired by the cell color information acquisition unit. A cell is detected. Then, the center value resetting means refers to the detection values of the remaining cells excluding the cells estimated to be dirty by the dirt detection means, and detects the remaining cells belonging to the cluster of each preset cell color. Based on the value, the center value of the cluster of each cell color is set.
In this way, since the detection value of the cell estimated to be dirty is not reflected in the setting of the cluster range, the detection value of the cell estimated to be dirty can be prevented from adversely affecting the setting of the cluster range. .

In the invention of claim 7, the reference value setting means sets each component reference value of the RGB component, CMY component or HSV component for each cell color used in the color code based on the reference pattern included in the code image, The tentative range setting means is a virtual coordinate having an RGB component, a CMY component, or an HSV component as a parameter, and for each cell color, each component reference value set by the reference value setting means is set as a central value and predetermined. A temporary range with a predetermined length as a radius is set. With this configuration, each component value of the RGB component, each component value of the CMY component, or each component value of the HSV component is detected for each cell, and each component value is determined based on an objective standard provided in the code. Cells can be properly classified.
Further, the classification means is based on the temporary range of each cell color set by the temporary range setting means and the component values of the RGB component, CMY component, or HSV component of each cell acquired by the cell color information acquisition means. , Each cell is classified into a temporary range of any cell color in virtual coordinates, and the cluster setting unit is configured to classify the RGB component or CMY component of each cell classified into the temporary range of each cell color by the classification unit, or Based on each component value of the HSV component, a cluster range having a predetermined predetermined length as a radius is set for each cell color in virtual coordinates. According to this configuration, a more appropriate range (cluster range) reflecting the actual state is set for each cell color based on the RGB component, CMY component, or HSV component value of each cell actually obtained. Based on this range (cluster range), it is possible to more accurately determine which color each cell belongs to.

FIG. 1 is a block diagram schematically illustrating an electrical configuration of the optical information reading apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic view schematically illustrating a color code read by the optical information reading apparatus of FIG. FIG. 3 is a schematic diagram conceptually showing an example of a standard pattern (color reference pattern) used for a color code. FIG. 4 is a flowchart illustrating a reading process performed by the optical information 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. 7A is an explanatory diagram illustrating a method for calculating an average value of reference patterns for each color as an example of calculating a reference value for each color. FIG. 7B is an explanatory diagram for specifically explaining a method for calculating a reference value of a predetermined cell color (black). FIG. 7C is an explanatory diagram conceptually illustrating detection values (R component value, G component value, and B component value) of each cell color. FIG. 8 is an explanatory diagram for conceptually explaining the provision of the temporary range based on the coordinates of the reference value for each color. FIG. 9 is an explanatory diagram for conceptually explaining a temporary range for any color, a cluster range set based on the temporary range, and a cluster range reset based on the cluster range.

[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 optical information reading apparatus according to the first embodiment will be outlined. FIG. 1 is a block diagram schematically illustrating the electrical configuration of the optical information reading apparatus according to the first embodiment of the invention.
The optical information reader 1 according to this 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 color 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 able to receive the reflected light Lr irradiated and reflected on the reading object R or the color code 100. For example, the light receiving sensor 2 is a solid-state imaging device such as a C-MOS or CCD. An area sensor arranged in a dimension 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 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 color code 100 imaged by the optical system described above is obtained. It can perform signal processing in terms of hardware and software. The control circuit 40 also performs control related to the entire system of the optical information reading apparatus 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 optical information reading apparatus 1 and includes a CPU, a system bus, an input / output interface, and the like. The control circuit 40 can constitute an information processing apparatus 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. Note that a host computer HST corresponding to the host system of the optical information reader 1 can be connected to the communication interface 48. 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.

(Color code)
Next, a color code to be read by the optical information reading apparatus 1 will be described with reference to FIGS. FIG. 2 is a schematic view schematically illustrating the color code 100 read by the optical information reading device 1. FIG. 3 is a schematic diagram conceptually showing an example of a standard pattern (color reference pattern) used for a color code.

  The color code 100 shown in FIG. 2 is formed by arranging a plurality of cells C in a matrix, and includes a plurality of code blocks (data code block 107, error correction code block 108), a first specific pattern 102, and the like. , Second specific patterns 103 and 104, and 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 color 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). It consists of an array that becomes. In addition, the code area (area where the cell C is arranged) constituting the color 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 color 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, and a red cell are used. A configuration using eight color cells, ie, a 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 color code 100 is divided into a data code block 107 and an error correction code block 108 in the color code 100 of FIG. There is no.

  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 predetermined corner 105a among four corners (portions constituting corners in the rectangular area) 105a to 105d provided in the rectangular area of the color code 100. . 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 color code 100 is read by the optical information reading device 1. 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 color code 100 in the image data. Throughout the present specification, the first specific pattern 102, the second specific patterns 103 and 104, and color reference patterns 110 to 190 described later relate to data included in the color code (data to be decoded). It is assumed that it is configured as a constant 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 color code 100 from the background, and the second specific patterns 103 and 104 are recognized at the time of reading to be described later. The position of the boundary side can be specified with. 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 used in the color code 100 (black, white, red, green, blue, magenta, Cyan, yellow). The color reference patterns 110 to 190 correspond to an example of “standard patterns”.

  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 110d, 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 optical information reading apparatus 1 will be described.
FIG. 4 is a flowchart illustrating the flow of reading processing performed by the optical information reading apparatus 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 color code 100 is attached is imaged by the light receiving sensor 23, and the image data of the color code 100 is stored in the memory 35.

  Thereafter, a process of specifying the code area (rectangular area) of the color 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 in S13 will be described in detail later. After the cell color recognition process in S13 is completed for the cell selected in S12 (target cell), the color of the target cell (color recognized in S13) 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 No. In this case, the process returns to S12, and any of the remaining cells is selected, and the processes of S13 and S14 are repeated. In this case, the cell color recognition process of S13 is performed on the cell newly focused in S12, and converted to data associated with the recognized color (S14). On the other hand, 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.

Next, the cell color recognition process in S13 will be described in detail.
FIG. 6 is a flowchart illustrating a cell color recognition process performed in the decoding process of FIG. FIG. 7A is an explanatory diagram illustrating a method for calculating an average value of reference patterns for each color as an example of calculating a reference value for each color. FIG. 7B is an explanatory diagram for specifically explaining a method for calculating a reference value of a predetermined cell color (black). FIG. 7C is an explanatory diagram conceptually illustrating detection values (R component value, G component value, and B component value) of each cell color. FIG. 8 is an explanatory diagram for conceptually explaining the provision of the temporary range based on the coordinates of the reference value for each color. FIG. 9 is an explanatory diagram for conceptually explaining a temporary range for any color, a cluster range set based on the temporary range, and a cluster range reset based on the cluster range.

  First, each cell of the color reference patterns 110 to 190 is specified based on the position information of each cell specified in S11. In the present embodiment, for example, position information indicating where the color reference pattern is present in the color code 100 to be read is stored in advance in the optical information reading apparatus 1, and based on this position information. Each cell of the color reference patterns 110 to 190 is specified. Then, R component, G component, and B component values are obtained for each cell of the color reference patterns 110 to 190. And the average value for every cell color in all the color reference patterns 110-190 is calculated.

  For example, for each cell color included in all the color reference patterns 110 to 190, an average value of the R component, an average value of the B component, and an average value of the G component are obtained, and these component values are obtained at the center of the temporary range of each cell color. Value (reference value). For example, an average value Brave of R components is obtained based on all R component values obtained from all black cells included in all color reference patterns 110 to 190, and similarly, all G component values obtained from all black cells. The average value Bgave of the G component and the average value Bbave of the B component are obtained based on the total B component value obtained from all black cells. Then, these component values Bave (Brave, Bgave, Bbave) are set as the center value (black reference value) of the temporary range of the cell color (black) (see FIG. 7B).

  The same applies to other colors. In the case of red, an average value Rrave of R components is obtained based on all R component values obtained from all red cells included in all color reference patterns 110 to 190, and similarly. The average value Rgave of the G component is obtained based on the total G component value obtained from the all red cell, and the average value Rbave of the B component is obtained based on the total B component value obtained from the all red cell. Then, these component values Rave (Rrav, Rgave, Rbave) are set as the center value (red reference value) of the temporary range of the cell color (red). In addition, although the example of the center value (black reference value) of the black temporary range and the center value (red reference value) of the red temporary range has been specifically described here, other colors (white, green, Similarly, the center value (reference value) of the temporary range of blue, yellow, cyan, and magenta is obtained (see FIG. 7A).

  In the present embodiment, the control circuit 40 that executes the process of S21 corresponds to an example of a “standard value setting unit”, detects the color reference patterns 110 to 190 included in the code image, and detects the color reference patterns 110 to 110. 190, and functions to set a reference value for each cell color used in the color code 100. More specifically, the color code 100 is used based on the color reference patterns 110 to 190 included in the code image. For each cell color, each component reference value of the RGB component is set.

  After S21, the value (detected value) of each color component (R component, G component, B component) is obtained for each cell whose position is specified in S11, and the detected value of each cell is mapped onto a virtual identification space. To do. In the present embodiment, for example, as shown in FIG. 8, a three-dimensional configuration in which an R component is an X coordinate (R coordinate), a G component is a Y coordinate (G coordinate), and a B component is a Z coordinate (B coordinate). A virtual identification space can be used, and in S22, the position for specifying the color component (R component, G component, B component) of each cell is mapped in such virtual three-dimensional coordinates. FIG. 7C conceptually illustrates detected values of color components (R component, G component, B component) of each cell existing in the color code, and FIG. The coordinates specified by the color components (R component, G component, B component) of each cell are conceptually indicated by x marks.

  In the present embodiment, the control circuit 40 corresponds to an example of a “cell color information acquisition unit”, and in the code image of the color code 100 captured by the light receiving sensor 23 (imaging unit), the degree of color is set for each cell. It functions to obtain the detected value shown.

  Then, a spherical area (temporary) in a range not exceeding the predetermined distance r from the center value (reference value) of each cell color (black, white, red, green, blue, yellow, cyan, magenta) obtained in S21. Range) is set, and cells of color components (R component, G component, B component) not included in any of the temporary ranges set for each cell color are extracted (S23).

  For example, when any one of all cell colors (black, white, red, green, blue, yellow, cyan, magenta) is the first cell color, the center value (reference value) of the first cell color ) Is expressed by (Xa.Ya, Za), the first cell color has a radius centered on the coordinate Pa (Xa.Ya, Za) in the XYZ coordinate system as shown in FIG. A spherical provisional range ARa of r is set. This temporary range includes a cell in which the coordinates (color component coordinates) specified by the detection values (the R component value, the G component value, and the B component value) are within the distance r from the center coordinate Pa. A cell whose coordinate (coordinate of color component) exceeds a distance r from the center coordinate Pa is out of the range. Similarly, the temporary range ARb is set for a second cell color different from the first cell color, and the temporary range ARc is set for a third cell color different from the first and second cell colors. FIG. 8 shows only the three cell color temporary ranges ARa to ARc, and other cell color temporary ranges are omitted, but the cell color temporary ranges other than the first to third cell colors are the same. Is set to

  After setting the temporary range of each cell color in this way, in S23, a cell whose coordinates specified by the detection value (each color component) are out of the temporary range of all cell colors is extracted (S23). In FIG. 8, coordinates (detection values) that deviate from the temporary range of all cell colors are conceptually illustrated by symbols Ca and Cb. In S23, the coordinates specified by the detection values (each color component) are A cell having such coordinates is extracted.

  In the present embodiment, the control circuit 40 that executes the process of S23 corresponds to an example of “temporary range setting unit”, and for each cell color, based on the reference value of each cell color set by the reference value setting unit. In addition, it functions to set a numerical temporary range related to color, density, or luminance. Specifically, the temporary range of each cell color is set based on a predetermined temporary range size, with the reference value of each cell color set by the reference value setting means as the center. , Virtual coordinates with RGB components as parameters (that is, virtual coordinates with R components as X-axis parameters, G components as Y-axis parameters, and B components as Z-axis parameters as shown in FIG. 8) , The coordinates specified by each component reference value (R component average value, G component average value, B component average value) set by the reference value setting means for each cell color are set as a center value and predetermined in advance. A spherical temporary range having a radius of length r is set.

  In S23, the cell color classification is assigned to each cell based on the detected value (component value) of each cell detected as shown in FIG. 7C. For example, a cell whose coordinates specified by the detection value (each component value) are within the temporary range ARa of the first cell color is classified as belonging to the temporary range of the first cell color, and the detected value (each component) A cell whose coordinates specified by (value) are within the temporary range ARb of the second cell color is classified as belonging to the temporary range of the second cell color. Specifically, cells whose coordinates specified by the detection value (each component value) are within the red temporary range are classified as belonging to the red temporary range and specified by the detection value (each component value). The cells whose coordinates are within the green temporary range are classified as belonging to the green temporary range, and the cells whose coordinates specified by the detection value (each component value) are within the blue temporary range And classified as belonging to the blue temporary range. The same applies to the classification of the other cell colors into the temporary range.

  In the present embodiment, the control circuit 40 that executes the process of S23 corresponds to an example of a “classification unit”, and each cell color temporary range (see FIG. 8) set by the temporary range setting unit and cell color information acquisition. Based on the detection value of each cell acquired by the means (see FIG. 7C), it functions to classify each cell into a temporary range of one of the cell colors. Based on the temporary range of each cell color set by the means and each RGB component value of each cell acquired by the cell color information acquisition means, each cell is selected as one of the cell colors in the virtual XYZ coordinate system. It is classified into the provisional range.

  After setting the temporary range of each cell color in S23, a cluster is set for each cell color based on the detection value of each cell classified into the temporary range of each cell color. Specifically, based on the detection value (each component value) of each cell classified into the temporary range of each cell color, the center value of each cell color cluster is calculated, and each calculated cell color A cluster range for each cell color is set based on the center value of the clusters and a predetermined cluster size.

  For example, as shown in FIG. 9, the central value of the temporary range ARn of a certain cell color is Pn (Xn, Yn, Zn), and the coordinates (detection values) of m cells are included in the temporary range ARn. Then, coordinates (Xn1, Yn1, Zn1) for specifying the center value Pn1 of the newly set cluster are obtained by the following expression.

  In Equations 1 to 3, the coordinates of the central value (standard value determined based on the color reference pattern) of the temporary range ARn of the cell color are (Xn, Yn, Zn). Further, the coordinates of the m cells included in the provisional range ARn (coordinates determined by the component values of each cell) are sequentially (X1, Y1, Z1) (X2, Y2, Z2) (X3, Y3, Z3). -(Xm, Ym, Zm). Then, each component value of each cell color is weighted A times with respect to each component value that determines the center value of the temporary range ARn, and a weighted average value is calculated for each component.

  The coordinates Pn1 (Xn1, Yn1, Zn1) of the center value of the cluster range are determined by Xn1, Yn1, and Zn1 calculated by the above formulas 1 to 3, and the range not exceeding the predetermined distance r from the coordinates Pn1 of the center value Is set as a cluster range of the cell color (cell color of the temporary range ARn).

  In the present embodiment, the control circuit 40 that executes the process of S24 corresponds to an example of “cluster setting means”, and the detection values (specifically, the specific values of the cells classified into the temporary ranges of the cell colors by the classification means. The function functions to set a cluster that defines a numerical range related to color, density, or luminance for each cell color based on each component value of RGB components. Based on the detection value (each component value of RGB components) of each cell classified into the range, the center value of each cell color cluster is calculated, and the calculated center value of each cell color cluster; Based on a predetermined cluster size (spherical size with radius r), a cluster range with a predetermined length r as a radius is set for each cell color in a virtual XYZ coordinate system. ing.

  After setting the cluster range in S24, it is determined whether or not the contents have been changed from the previous range setting. When the cluster range is set for the first time in S24, in S25, whether the temporary range is set in S23 or whether the cell belonging to each range has been changed in the case where the cluster range is set in S24. to decide. That is, cells belonging to the temporary range of each cell color when the temporary range of each cell color is set in S23, and cells belonging to the cluster range of each cell color when the cluster range of each cell color is set immediately after that in S24 If there is no change in the classification of each cell, the process proceeds to No in S25.

  On the other hand, if it is determined in S25 that the classification of each cell is changed, the process proceeds to Yes in S25, and it is determined whether or not the cluster range setting in S24 has been performed a predetermined number of times (for example, 5 times). . If it has been performed a predetermined number of times, the process proceeds to Yes in S26, and if not, the process proceeds to No in S26.

  When the process proceeds to Yes in S26, a cell that does not belong to any cluster range is extracted. That is, after setting a spherical region (temporary range) that does not exceed the predetermined distance r from the coordinates of the center value of the cluster range of each cell color obtained in the previous S24, it is set for each cell color in this way. Cells of color components (R component, G component, B component) that are not included in any of the cluster ranges are extracted (S23). In this process, cells whose coordinates specified by the detection values (each component value) are separated from the center value coordinates of the cluster range of all cell colors by a predetermined distance r are extracted.

  Then, after the processing of S23, the cluster range is reset (S24). In this cluster range setting, an average value of the detection values (each component value) of the cell to which it belongs is obtained for each cluster of each cell color set in the previous S24, and the average value is set as a new center value. Reset the current cluster range.

  The previous processing of S24 is the first cluster range setting. For example, the coordinates of t cells included in the first cluster range ARn1 set by the temporary range ARn (coordinates determined by the component values of each cell) ) In order (X11, Y11, Z11) (X12, Y12, Z12) (X13, Y13, Z13) (X1t, Y1t, Z1t), the average value Xn2 (Xn2) of the X component (R component) = (X11 + X12 + X13... X1t) / t), Y component (G component) average value Yn2 (Yn2 = (Y11 + Y12 + Y13... Y1t) / t), Z component (B component) average value Zn2 (Zn2 = ( Z11 + Z12 + Z13... Z1t) / t), and the coordinates Pn2 (Xn2, Yn2, Zn2) determined by these are set as a new cluster range.

  When the cluster range is reset in S24, the processing from S25 is performed again. In addition, when it becomes Yes by S25 and when it becomes No by S26, it is as above-mentioned. On the other hand, if No in S25 or Yes in S26, cells that are not included in each cluster range (final cluster range) are determined to be dirty. Then, the color of each cell is determined based on the final cluster range (S28). That is, each cell is recognized as the color of the final cluster range to which it belongs.

  In the present embodiment, the control circuit 40 that executes the processes of S24 to S26 corresponds to an example of a “center value resetting unit”, and the cluster range of each cell color that has already been set and the cell colors that have already been set. The center value of the cluster of each cell color is set based on the detection value (each component value) of each cell belonging to each cluster.

  Further, the control circuit 40 that executes the processes of S24 to S26 corresponds to an example of “range resetting unit”, and the center value of each cell color cluster reset by the center value resetting unit is defined in advance. It functions to reset the cluster range of each cell color based on the cluster size (spherical size with radius r).

  The “center value resetting unit” sets the cluster range of each cell color by the range resetting unit until the number of times of setting the cluster range of each cell color by the range resetting unit reaches a predetermined number. The center value of the cluster of each cell color is reset every time, and the resetting of the center value is completed when the number of times of setting the cluster range of each cell color by the range resetting means reaches a predetermined number. Further, as shown in S25, the assignment of each cell to each cell color cluster set by the range resetting means is determined from the assignment to each cell color cluster in the previous setting before the resetting. Until the range no longer changes, the range reset means resets the center value of each cell color cluster each time the cell color cluster range is set. The setting has been completed. Further, the center value resetting means refers to the detection values of the remaining cells except for the cells estimated to be dirty by the dirt detection means, as in S23 and S24 performed after S26, Based on the detection values of the remaining cells belonging to the color cluster, the center value of the cluster of each cell color is reset.

  In the present embodiment, the control circuit 40 that performs the processes of S23 and S27 corresponds to an example of “dirt detection unit”, and acquires a cluster range for each cell color set by the cluster setting unit and cell color information acquisition. It functions to detect cells estimated to be dirty based on the detection value of each cell acquired by the means. Specifically, when setting the temporary range and resetting the range by the temporary range setting means When the cluster range is set by the means, a cell that is estimated to be dirty is detected based on the detection value of each cell acquired by the cell color information acquisition means. Further, when the cluster range is reset by the range resetting means, based on the cluster range of each cell color set by the range resetting means and the detection value of each cell acquired by the cell color information acquiring means Thus, a cell that is estimated to be dirty is detected.

(Main effects of this embodiment)
In the optical information reading apparatus 1 according to the present embodiment, the color reference patterns 110 to 190 are detected in the code image of the color code 100 imaged by the imaging unit, and each cell color is detected based on the color reference patterns 110 to 190. After setting the temporary range, each cell can be classified into a temporary range of any cell color. Since the temporary range is set for each cell color based on the color reference patterns 110 to 190, each cell is appropriately classified based on an objective standard provided in the code.

  Further, a cluster is set for each cell color based on the detection value of each cell classified into the temporary range of each cell color. Then, based on the set cluster range for each cell color and the detection value of each cell acquired by the cell color information acquisition unit, the cell that is estimated to be dirty is detected by the contamination detection unit. According to this configuration, it is possible to reset a more appropriate range (cluster range) reflecting the actual state for each cell color based on the detection value of each cell actually obtained. It is possible to more accurately determine which color each cell belongs to based on (range). Furthermore, it is possible to more accurately determine a cell that is estimated to be dirty based on a range (cluster range) appropriately determined for each cell color.

In the present embodiment, as in S23, the reference value of each cell color set by the reference value setting unit is set as the center, and the temporary range of each cell color is set based on a predetermined temporary range size. is doing. By doing in this way, it is appropriate to group cells whose detection values are not separated from each reference value by a certain value around the reference value of each cell color obtained based on the color reference patterns 110 to 190. A temporary range can be set.
Then, as in S24, based on the detected values of the cells classified into the temporary ranges of the cell colors, the center value of the cluster of each cell color is calculated, and the calculated cluster of each cell color A cluster range of each cell color is set on the basis of the center value of and the predetermined cluster size. In this way, the center value of the temporary range of each cell color can be corrected to a value reflecting the detection value of each cell classified into each temporary range. Then, the range of the cluster of each cell color can be appropriately determined so that each correction value corrected in consideration of the actual state in this way is set as the “center value of each cluster”.

Further, in the present embodiment, as described in S24, each cell is determined based on the range of each cell color cluster that has already been set and the detection value of each cell that belongs to each of the previously set cell color clusters. The center value of the color cluster is set, and each of the cell color clusters is reset based on the center value of each cell color and the predetermined cluster size as in S23 and S24 when No in S26. The range of the cell color cluster is reset.
In this way, the center value of the cluster of each cell color once set can be corrected again to a value reflecting the detection value of each cell classified into each cluster. Accordingly, even if the reflection of the actual state is insufficient at the first setting of the cluster range, the cluster range of each cell color is more easily corrected by the setting again.
Then, based on the cluster range of each cell color set by the range resetting unit and the detection value of each cell acquired by the cell color information acquiring unit, a cell estimated to be dirty is detected. Thus, more accurate dirt detection can be performed.

In this embodiment, each cell color is set each time the cluster range of each cell color is set until the number of times of setting the cluster range of each cell color reaches a predetermined number as in S26, S23, and S24. The center value of the cluster is reset, and when the number of times of setting the cluster range of each cell color reaches a predetermined number, the resetting of the center value is completed.
In this way, the center value of each cell color cluster once set is used every time the cell color cluster range is set until the number of times the cell color cluster range is set reaches a predetermined number. The center value of each cell color cluster can be reset. Accordingly, even if the reflection of the actual state is insufficient at the first setting of the cluster range, the cluster range of each cell color can be more appropriately corrected by resetting a predetermined number of times.

In this embodiment, as in S25, S23, and S24, the allocation of each cell to each reset cluster of each cell color is assigned to each cluster of each cell color in the previous setting before the resetting. Each time the cluster range of each cell color is reset, the center value of each cell color cluster is reset until the allocation no longer changes. Has ended.
In this way, the cluster range can be corrected until there is no change in the allocation within the cluster range before and after the resetting, and finally the cluster range that more appropriately reflects the actual detection value can be determined. .

Further, in the present embodiment, as in S23, when setting the temporary range and setting the cluster range by the range resetting unit, the contamination is estimated based on the detection value of each cell acquired by the cell color information acquisition unit. A cell is detected. Then, as in S24, with reference to the detection values of the remaining cells excluding the cells estimated to be dirty, based on the detection values of the remaining cells belonging to the cluster of each preset cell color, The center value of the cell color cluster is set.
In this way, since the detection value of the cell estimated to be dirty is not reflected in the setting of the cluster range, the detection value of the cell estimated to be dirty can be prevented from adversely affecting the setting of the cluster range. .

In the present embodiment, based on the color reference patterns 110 to 190 included in the code image, each component standard value of the RGB component, the CMY component, or the HSV component is set for each cell color used in the color code 100. The range setting means has a predetermined predetermined value centered on each component reference value set by the reference value setting means for each cell color in virtual coordinates using RGB components, CMY components, or HSV components as parameters. A temporary range with the radius as the length is set. With this configuration, each component value of the RGB component, each component value of the CMY component, or each component value of the HSV component is detected for each cell, and each component value is determined based on an objective standard provided in the code. Cells can be properly classified.
Further, the classification means is based on the temporary range of each cell color set by the temporary range setting means and the component values of the RGB component, CMY component, or HSV component of each cell acquired by the cell color information acquisition means. , Each cell is classified into a temporary range of any cell color in virtual coordinates, and the cluster setting unit is configured to classify the RGB component or CMY component of each cell classified into the temporary range of each cell color by the classification unit, or Based on each component value of the HSV component, a cluster range having a predetermined predetermined length as a radius is set for each cell color in virtual coordinates. According to this configuration, a more appropriate range (cluster range) reflecting the actual state is set for each cell color based on the RGB component, CMY component, or HSV component value of each cell actually obtained. Based on this range (cluster range), it is possible to more accurately determine which color each cell belongs to.

[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, the color code (FIG. 2) in which eight cell colors of black, white, red, green, blue, yellow, cyan, and magenta are used as the cell colors is exemplified. The number and contents are not limited to the configuration of FIG. Further, the configuration of the color code is not limited to that shown in FIG. 2, and various known configurations can be employed.

  The configuration of the color reference pattern is not limited to the configuration of FIG. 3, and may be configured with a smaller number of colors than the number of cell colors, for example. In FIG. 3, a plurality of types of cells are provided for each color reference pattern. However, each color reference pattern may be configured by a single type of cell, and each color reference pattern may be configured by different colors. .

  In the above embodiment, RGB is used as the color expression method, but it may be expressed in CMY or HSV. For example, when expressed in CMY, the R component, G component, and B component of the above embodiment may be replaced with the C component, M component, and Y component.

  In the above embodiment, the plurality of color reference patterns 110 to 190 are referred to, and the detected value of each cell of the color reference patterns 110 to 190 is determined by the average R component value, the average G component value, and the B component value for each cell color. The average value is obtained, and the coordinates determined by the average value of the R component of each cell color, the average value of the G component, and the average value of the B component (each component reference value of the RGB component) are used as the center value of the temporary range of each cell color. Refers to only one of a plurality of color reference patterns provided in the code, and coordinates determined by detection values (R component value, G component value, B component value) for each cell color obtained from this color reference pattern. The center value of the temporary range of each cell color may be used.

DESCRIPTION OF SYMBOLS 1 ... Optical information reader 23 ... Light receiving sensor (imaging means)
40... Control circuit (cell color information acquisition means, reference value setting means, temporary range setting means, classification means, cluster setting means, dirt detection means, center value resetting means, range resetting means)
100 ... Color code 110 to 190 ... Color reference pattern (standard pattern)
C ... cell

Claims (7)

A plurality of types of cells having different colors or densities or luminances are arranged in the code area, information of each cell is represented by each cell color, and a reference pattern represented by one or more reference colors is the code. An optical information reader for reading a color code provided in an area,
Imaging means for imaging the color code;
Cell color information acquisition means for acquiring a detection value indicating the degree of color for each cell in the code image of the color code imaged by the imaging means;
A reference value setting means for detecting the reference pattern included in the code image and setting a reference value of each cell color used in the color code based on the reference pattern;
Temporary range setting means for setting a numerical temporary range related to color, density or luminance for each cell color based on the reference value of each cell color set by the reference value setting means;
Based on the temporary range of each cell color set by the temporary range setting means and the detected value of each cell acquired by the cell color information acquisition means, each cell is converted to the temporary color of any cell color. A classification means for classifying into a range;
Cluster setting for setting a cluster that defines a numerical range related to color, density, or luminance for each cell color based on the detected value of each cell classified into the temporary range of each cell color by the classification means Means,
A stain detection unit that detects a cell estimated to be a stain based on a cluster range for each cell color set by the cluster setting unit and the detection value of each cell acquired by the cell color information acquisition unit. When,
An optical information reading apparatus comprising: The temporary range setting means sets the temporary range of each cell color based on a predetermined temporary range size, with the reference value of each cell color set by the reference value setting means as a center.
The cluster setting means calculates the center value of each cell color cluster based on the detected value of each cell classified into the temporary range of each cell color, and the calculated cell color of each cell color 2. The optical information reading apparatus according to claim 1, wherein a range of clusters of each cell color is set based on a cluster center value and a predetermined cluster size. The cluster setting means includes
Center value reset that sets the center value of each cell color cluster based on the range of each cell color cluster that has already been set and the detected value of each cell that belongs to each of the cell color clusters that have already been set Means,
Range resetting means for setting the range of the cluster of each cell color based on the center value of the cluster of each cell color reset by the center value resetting means and a predefined cluster size;
Have
The stain detection means is estimated to be dirty based on the cluster range of each cell color set by the range resetting means and the detection value of each cell acquired by the cell color information acquisition means. The optical information reader according to claim 2, wherein the cell is detected.   The center value resetting means is configured so that each range of cell colors is set by the range resetting means until the number of times of setting the cluster range of each cell color by the range resetting means reaches a predetermined number. The center value of each cell color cluster is reset, and the resetting of the center value is terminated when the number of times of setting the cluster range of each cell color by the range resetting means reaches the predetermined number of times. The optical information reader according to claim 3.   The center value resetting means is configured to assign each cell to each cell color cluster set by the range resetting means from assignment to each cell color cluster in the previous setting before the resetting. The center value of each cell color cluster is reset every time the range reset means sets the range of each cell color cluster until the range no longer changes. 4. The optical information reading apparatus according to claim 3, wherein the resetting is terminated. The stain detection means is based on the detection value of each cell acquired by the cell color information acquisition means when the temporary range is set by the temporary range setting means and when the cluster range is set by the range resetting means. Cell that is estimated to be dirty,
The center value resetting means refers to the detected values of the remaining cells excluding the cells estimated to be dirty by the dirt detecting means, and sets the remaining cells belonging to the cluster of the set cell colors. 6. The optical information reading apparatus according to claim 3, wherein a center value of the cluster of each cell color is set based on the detection value. The cell color information acquisition unit obtains the RGB component value, the CMY component value, or the HSV component value for each cell in the color code image captured by the imaging unit. As a detection value,
The reference value setting means sets each component reference value of RGB component or CMY component or HSV component for each cell color used in the color code based on the reference pattern included in the code image,
The provisional range setting means uses a virtual coordinate having an RGB component, a CMY component, or an HSV component as a parameter, and for each cell color, sets each component reference value set by the reference value setting means as a center value and is predetermined. Set a temporary range with the specified length as the radius,
The classification unit includes the temporary range of each cell color set by the temporary range setting unit and the RGB component, CMY component, or HSV component value of each cell acquired by the cell color information acquisition unit. Based on each cell, the virtual coordinates are classified into the temporary range of any cell color in the virtual coordinates,
The cluster setting unit is configured to determine, for each cell color, in the virtual coordinates based on the RGB component, CMY component, or HSV component value of each cell classified by the classification unit in the temporary range of each cell color. 7. The optical information reading apparatus according to claim 1, wherein a cluster range having a radius of the predetermined length set in advance is set.

Images