JP6273807B2 - Optical code with image and method for producing the same - Google Patents

Description

  The present invention relates to an optical cord with an image formed by superimposing an optical code body composed of light and dark color modules on a visual image for visual observation.

  An optical code such as a bar code or a two-dimensional code, which is currently popular, records information by assigning a light color or a dark color to a module serving as a basic unit. These optical codes are standardized, and if they are standardized optical codes, anyone can know the recorded contents by optically identifying the light / dark pattern of the module with a reader such as a mobile phone. It is configured as follows.

  The optical code is inherently lacking in design, but Patent Document 1 proposes an optical code with an image in which design is imparted by superimposing the optical code on a visual image such as a logo mark. Such an optical code with an image is obtained by superimposing a two-dimensional code and a logo mark. The center of the module (cell) is colored with the color of the two-dimensional code (light or dark), and the periphery of the module is logo. By setting the color of the mark, it is possible to visually recognize the logo mark while making it possible to identify the light / dark pattern of the two-dimensional code by the reading device.

JP 2008-15642 A

  In recent years, optical codes are frequently used in product packages, advertisements, etc., but optical codes are not subject to visual inspection, so the optical codes attached to them impair the aesthetics of packages and advertisements. . On the other hand, like the optical code with an image of Patent Document 1, it is conceivable that the optical code is overlapped with a visual image such as a package image or an advertisement image to make it less noticeable. Since the optical code is painted in the center of the module with the color of the optical code (two-dimensional code), the image quality of the visual image is greatly reduced at the portion where the optical code is overlaid, and the original design of the visual image Will be damaged.

  The present invention has been made in view of the current situation, in the optical code with an image formed by superimposing the optical code and the visual image, the optical code overlaps without impairing the reading accuracy of the optical code, It aims at improving the visibility of a visual recognition image.

  The present invention relates to an optical with image formed by superimposing an optical code body composed of two types of modules, a light color module identified as a light color and a dark color module identified as a dark color, on a visual image for visual observation. The visual image is composed of pixels smaller than the light color module and the dark color module, and at least a part of the light color module overlaps the visual image, the color conversion including at least the central portion of the module. In the target region, among the pixels of the visual image, the color is changed so that a pixel that is less than the predetermined first brightness threshold is equal to or greater than the first brightness threshold, and is greater than or equal to the first brightness threshold. The color of a certain pixel is not changed, and at least a part of the dark color module overlaps the visual image, the color conversion target includes at least the center of the module. In the area, the color is changed so that the pixels of the visible image that exceed the second brightness threshold set to be less than the first brightness threshold are less than or equal to the second brightness threshold, and the first A pixel having a brightness threshold value of 2 or less is an optical code with an image characterized in that the color is not changed. Here, the “first brightness threshold” is the brightness that can be identified as a bright color by the reading device, and the “second brightness threshold” is the brightness that can be identified as a dark color by the reading device. Is proposed. The “brightness threshold” may be a predetermined brightness or brightness, but other brightness scales may be used.

  That is, in such a configuration, in the portion where the visual image and the light color module of the optical code main body overlap, all the pixels in the color conversion target region are changed to the first brightness threshold or more, and thus the module and The overlapping portion is identified as a bright color by the reading device. Then, in the portion where the visual image and the dark color module of the optical code body overlap, all the pixels in the color conversion target area are changed to the second brightness threshold or less, so that the portion overlapping the module is changed to the dark color by the reading device. Will be identified. Here, in this embodiment, in the color conversion target region, the color of all the pixels of the visual image is not changed, but the pixel equal to or higher than the first brightness threshold is set for the portion overlapping the light color module. As for the portion overlapping with the dark color module without changing it, the pixels below the second brightness threshold value are left without changing the color, so that it is possible to suppress degradation of the image quality of the visible image compared to the conventional configuration. There are advantages.

  In the present invention, the visual image is a color image, and in the portion where the optical code body and the visual image overlap, a configuration in which the hues of all the pixels of the visual image are maintained can be mentioned.

  The change in hue has a large effect on visual observation, but has a small effect on light / dark discrimination by the reading device. For this reason, when the visual image is a color image as in such a configuration, the brightness is changed while maintaining the hue even if the pixel is to be changed in color, and the optical code with the image is used for all the visual images. By maintaining the hue of the pixel, it is possible to further suppress the deterioration of the image quality of the visually recognized image. It should be noted that the pixels that change the brightness of the visually recognized image do not need to have the same hue before and after the change, and it is sufficient that the hue is maintained to the extent that it is recognized as the same system hue at the visual level.

  Further, in the present invention, the visual image is a monochrome image composed of white and black pixels, and in a portion where the light color module overlaps the visual image, the black pixel of the visual image is the first color conversion target region. In a portion where the color of the white pixel of the visual image is not changed and the dark color module overlaps the visual image, the white pixel of the visual image is the color conversion target area. However, a configuration is proposed in which the color is changed to gray below the second brightness threshold and the color of the black pixel is not changed.

  With such a configuration, the optical code body can be appropriately superimposed on a visual image made up of black and white binary pixels.

  Further, in the present invention, the optical code body is a two-dimensional code in which modules are arranged in a matrix, and it is determined in advance whether a light color module or a dark color module is used. A configuration is proposed in which a fixed area constituting a pattern for assisting reading is provided, and in a portion where a module that does not constitute the fixed area and a visual image overlap, the color conversion target area does not include a peripheral portion of the module. . Here, the “peripheral part of the module” refers to a part not inside the module but inside the module and close to the edge of the module.

  Usually, when reading a two-dimensional code, first, a module is cut out based on a light and dark pattern of a fixed area included in an image of the captured two-dimensional code. Then, whether each module cut out is light or dark is identified. At the time of discriminating between the light color and the dark color, the color information at the center of each module is emphasized, and the color information at the periphery is neglected. This is because the color information of the peripheral part is easily influenced by the color of the adjacent module. In this way, in the case of a two-dimensional code, the influence of the peripheral part of the module on the discrimination of light and dark is small, so by removing the peripheral part of the module from the color conversion target area, the reading accuracy of the optical code main body is secured. It becomes possible to improve the image quality of the visually recognized image.

  Further, as described above, when the visual image is a monochrome image composed of white and black pixels, the optical code body is a two-dimensional code in which modules are arranged in a matrix, and the light color module and dark color Which one of the modules is determined in advance, and includes a fixed region that forms a pattern that assists optical reading by the reading device. In a portion where the light color module that does not configure the fixed region overlaps the visual image, The color conversion target area of the module is only the central part of the module. In the peripheral part of the module, the black pixel of the visual image is changed to gray less than the first brightness threshold, and the white pixel of the visual image In the part where the color is not changed and the dark color module that does not constitute the fixed area overlaps the visible image, the color conversion target area of the module is the module. Only the central part of the module, and in the peripheral part of the module, the white pixels of the visible image are changed to gray exceeding the second brightness threshold, and the color of the black pixels of the visible image is not changed. A configuration is proposed.

  When the visual image is a monochrome binary monochrome image, as described above, when the peripheral portion of the module is removed from the color conversion target region, the contrast between the color conversion target region and the peripheral portion becomes high, so that the image is read by the reading device. Occasionally, the color information of the color conversion target area is affected by the color of the peripheral part, and the probability that an identification error will occur increases.However, as in this configuration, the contrast between the color conversion target area and the peripheral part can be kept low. For example, the brightness of the module can be accurately identified by the reader.

  Further, in the present invention, the optical code body is a two-dimensional code in which modules are arranged in a matrix, and it is determined in advance whether a light color module or a dark color module is used. A configuration is proposed in which a fixed area constituting a pattern for assisting reading is provided, and the color conversion target area is the entire module in a portion where the module constituting the fixed area and the visible image overlap.

  In such a configuration, in the portion overlapping with the light color module constituting the fixed region, all the pixels of the visually recognized image are equal to or higher than the first brightness threshold, and in the portion overlapping with the dark color module constituting the fixed region, Since the pixel is equal to or smaller than the second brightness threshold, the light / dark pattern of the fixed area can be reliably identified by the reading device. As described above, the light / dark pattern of the module in the fixed area is used to determine the position where the other module is cut out, and it is more necessary to accurately identify the module than the other module. If the identification of the module in the fixed area is made high as in this configuration, the reading accuracy of the optical code body can be increased.

  In another aspect of the present invention, an optical code body composed of two types of modules, a light color module identified as a light color by a reader and a dark color module identified as a dark color, is superimposed on a visual image for visual observation. A method of creating an optical code with an image for creating an optical code with an image, and at least a part of a light color module overlapping a visual image, in a color conversion target region including at least a central portion of the module, Among the pixels of the visual image, the color of a pixel that is less than the predetermined first brightness threshold is changed to be equal to or greater than the first brightness threshold, and the pixel that is equal to or greater than the first brightness threshold is a color In a portion where at least a part of the dark color module is overlapped with the visual image, the light conversion process is performed without changing the color in the color conversion target area including at least the central part of the module Among the pixels of the image, the color of a pixel that exceeds the second brightness threshold set to be less than the first brightness threshold is changed so as to be equal to or less than the second brightness threshold, and the second brightness The method of creating an optical code with an image is characterized in that a darkening process that does not change a color is executed for pixels that are equal to or greater than a threshold value. According to such a configuration, the optical code with an image can be easily created.

  Further, in the above-described method for creating an optical code with an image, the optical code body has an error correction function, and the color of the pixel of the visual image is determined with respect to a portion where the lightening process and the darkening process are performed. A color change evaluation process for calculating a module unit evaluation value indicating the degree of change in module units is performed, and for a module having a relatively high module unit evaluation value, a lightening process or a dark color is performed in a portion where the module and the visible image overlap. It is proposed to perform a color change cancellation process that cancels the conversion process.

  Here, the module unit evaluation value may be, for example, the total number of pixels of the visually recognized image whose color has been changed in a portion overlapping the module. When the color of a pixel is expressed by a numerical value such as an RGB value, the difference between the RGB values before and after the color change is used as an evaluation value indicating the degree of color change of the pixel, and the evaluation value is used for all the pixels of the module. The total is used as the module unit evaluation value.

  According to this method, the lightening process or the darkening process is canceled for a part in which the degree of change in the color of the pixel of the visual image is relatively high among the parts subjected to the lightening process or the darkening process. Thus, since the color of the pixel of the visually recognized image is reflected as it is in the optical code with an image, it is possible to suppress degradation of the image quality of the visually recognized image. If the optical code body has an error correction function, the reader can read the information stored in the optical code body without accurately identifying the brightness of all modules. If it is within the range correctable by the correction function, the color code cancel process does not make the optical code body unreadable.

  Further, in the above method for creating an optical code with an image, the error correction function performs error correction in symbol units constituted by a predetermined number of modules. In the color change cancellation processing, the module unit evaluation value It is proposed to cancel the lightening process or the darkening process for a module having a relatively high value and a module constituting the same symbol as the module.

  In an optical code that performs error correction in symbol units, basically, if even one module identification error occurs, it is considered that a module identification error has occurred in all the modules constituting the same symbol as that module. For this reason, if the color change cancellation processing is executed in units of symbols as in this method, it is possible to efficiently suppress deterioration in the image quality of the visually recognized image within a range where error correction is possible.

  Further, in the above method for creating an optical code with an image, a superposition position candidate determination process for determining a plurality of position and / or angle candidates for superimposing an optical code body on a visual image, and an optical code body for each candidate Candidate image data creation processing that obtains candidate image data that is a candidate for an optical code with an image by superimposing the visual images, and the color of the pixel of the visual image for the portion where the optical code body and the visual image overlap in each candidate image data It is proposed to include a candidate image evaluation process for calculating a candidate image evaluation value indicating the degree of change of the image, and an optical code determination process with an image for determining candidate image data with the smallest candidate image evaluation value as an optical code with an image. The

  According to such a method, for a plurality of candidates with different positions and angles to be overlapped, the optical code body and the visual image are actually overlapped, and a position and an angle with a small degree of change in the color of the visual image are selected. It is possible to further suppress the image quality deterioration of the image.

  As described above, according to the present invention, it is possible to realize an optical code with an image that has a higher visibility of a visually recognized image than the conventional configuration without impairing the reading accuracy of the optical code. For this reason, if the optical code with an image of the present invention is used, a package image and an advertisement image with an optical code having higher design than conventional ones can be realized.

1 is a conceptual diagram of an optical cord 1 with an image according to Embodiment 1. FIG. (A) is the optical code main body 3 which comprises the optical cord 1 with an image, (b) is explanatory drawing which shows each area | region of the optical code main body 3 according to the pattern classified by function. It is a table | surface which shows the color change aspect of the pixel of the visual recognition image 2 in the part which overlaps with the optical code main body 3. FIG. (A) is explanatory drawing which shows the color conversion object area | region 20a of the part which overlaps with the module 4 of the fixed area | region 7, (b) is explanatory drawing which shows the color conversion object area | region 20b of the part which overlaps with the module 4 of the variable area | region 8. is there. It is a flowchart which shows the preparation procedure of the optical code 1 with an image. It is a flowchart which shows the processing content of a superposition candidate creation process. It is a flowchart which shows the processing content of the lightening process. It is a flowchart which shows the processing content of a darkening process. FIG. 6 is a conceptual diagram of an optical cord with image 1a according to a second embodiment. It is explanatory drawing which shows the optical cord main body 3a which comprises the optical cord 1a with an image. 5 is an explanatory diagram illustrating a color conversion target area 20c of a module 28. FIG. It is a graph which shows the color change aspect of the pixel of the visual recognition image 2 in the part which overlaps with the optical code main body 3a. FIG. 6 is a conceptual diagram of an optical cord with image 1b of Example 3. It is a graph which shows the color change mode of the pixel of the visual recognition image 2a in the part which overlaps with the optical code main body 3. It is explanatory drawing which shows the color change aspect of the pixel of the visual recognition image 2a by superimposition with the optical code main body 3. FIG.

  Embodiments of the present invention are described according to the following examples.

  As shown in FIG. 1, the optical cord with image 1 of the present embodiment is obtained by superposing an optical code body 3 made of a two-dimensional code on a visual image 2 made of a photograph of a flower.

  The visual image 2 is an image composed of 800 × 700 pixel pixels. Although the colors are omitted in FIG. 1, the visual image 2 is a color image, and the color of each pixel is defined by RGB values.

  The optical code body 3 is made of a QR code (registered trademark). Specifically, as shown in FIG. 2 (a), the optical code body 3 is formed by arranging 21 square modules 4 in a matrix form, vertically and horizontally, and around it is a light color. A quiet zone 5 is provided. The quiet zone 5 is a light color area provided for the reading device to detect the optical code body 3, and has a width corresponding to four modules. The module 4 of the optical code body 3 includes a light color module 4a arranged in a light color (white) and a dark color module 4b arranged in a dark color (black). As shown in FIG. 2B, the area where the module 4 is arranged is composed of a fixed area (functional pattern) 7 and a variable area (encoding area) 8. The fixed area 7 is an area in which the color arrangement pattern of the module 4 is determined in advance, and includes a position detection pattern 11, a separation pattern 12, a timing pattern 13, and the like that assist optical reading of the optical code body 3. The variable area 8 is an area in which data is recorded according to the color arrangement pattern of each module 4, and a data code area 14 in which data code words and error correction code words are recorded, and a format in which codes indicating format information are arranged. And an information code area 15. The data code word and the error correction code word store information in symbol units constituted by eight modules 4, and the error correction code word is configured to perform error correction in symbol units by Reed-Solomon code. ing. Since these configurations conform to the JIS standard for JIS codes (JIS X 0510: 2004), detailed description is omitted.

The size of the optical cord main body 3 is about 3 cm square including the quiet zone 5, and one module is a square with a side of 1 mm. On the other hand, the size of the visual image 2 is 8 cm wide and 7 cm long, and is composed of 100 pixels per mm ² . That is, in the optical cord with image 1 of the present embodiment, 100 pixels of the visual image 2 overlap with one module 4 of the optical code body 3.

  The optical code 1 with an image of this embodiment is in a portion where the optical code body 3 and the visual image 2 overlap, and the light color portion of the optical code body 3 is identified as a light color by the reading device, and the dark color portion is identified as a dark color. As a result, the color of the pixel of the visual image 2 is changed. That is, the optical code with image 1 of the present embodiment is a color image composed of pixels of 800 × 700 pixels like the visual image 2.

  Specifically, in the optical cord with image 1, as shown in FIG. 3, the color of the pixel of the visual image 2 is changed. First, in a portion overlapping with the light-colored quiet zone 5, the luminance of the pixel having a luminance of less than 0.75 is changed to 0.75 while maintaining the hue of the pixel. Note that the color of the pixel having the luminance of 0.75 or more is not changed, and the pixel of the visual image 2 appears as it is. In this way, in the portion where the visual image 2 and the quiet zone 5 overlap, the pixel having the luminance less than 0.75 included in the visual image 2 is changed to the luminance 0.75, so that the entire portion has the luminance 0.75. The color is adjusted to be the above. As a result of the color change of the pixels, in the portion overlapping with the quiet zone 5, the visual image 2 is viewed brighter than the original image, but the color of the pixel having a luminance of 0.75 or more is maintained as it is in the portion. In addition, since the hues of all the pixels are maintained, the degradation of the image quality of the visual image 2 can be minimized.

  For the portion where the visual image 2 and the module 4 overlap, the color of the pixel 19 of the visual image 2 is changed in the portion overlapping the color conversion target areas 20 a and 20 b of the module 4. Specifically, when the module 4 is the light color module 4a, as shown in FIG. 3, among the pixels of the visual image 2 in the color conversion target areas 20a and 20b, pixels having a luminance of less than 0.75 are The color is changed so that the luminance becomes 0.75 while maintaining the hue of the original pixel. That is, in this embodiment, the luminance 0.75 corresponds to the “first brightness threshold” according to the present invention. In addition, among the pixels of the visual image 2 in the color conversion target areas 20a and 20b, the color of the original pixel whose luminance is 0.75 or more is not changed, and the color of the pixel appears as it is in the optical code with image 1. . On the other hand, when the module 4 is the dark color module 4b, among the pixels of the visual image 2 in the color conversion target areas 20a and 20b, the luminance of the pixel having a luminance of more than 0.25 is maintained while maintaining the hue of the original pixel. The color is changed to be 0.25. That is, in this embodiment, the luminance 0.25 corresponds to the “second brightness threshold” according to the present invention. And among the pixels of the visual image 2 in the color conversion target areas 20a and 20b, the color of the original pixel whose luminance is 0.25 or less is not changed, and the color of the pixel appears in the optical code with image 1 as it is. .

  The color conversion target area of the module 4 is different between the module 4 of the fixed area 7 and the variable area 8. In the module 4 in the fixed area 7, the shaded portion in FIG. 4A, that is, the entire module 4 becomes the color conversion target area 20a, and 100 pixels 19 of the visual image 2 overlapping the color conversion target area 20a are displayed. Subject to color change. Therefore, in the optical code with image 1, the entire portion where the light color module 4 a in the fixed region 7 overlaps is configured by the pixels 19 having a luminance of 0.75 or more, and the entire portion where the dark color module 4 b in the fixed region 7 overlaps. Is composed of the pixels 19 having a luminance of 0.25 or less.

  On the other hand, in the module 4 in the variable region 8, the shaded portion in FIG. 4B, that is, the square portion at the center of the module 4 becomes the color conversion target region 20b, and the visible image 2 overlapping the color conversion target region 20b. 36 (6 × 6 pixels) pixels 19 are subject to color change. For this reason, in the optical code with image 1 of the present embodiment, in the portion where the light color module 4a in the variable region 8 overlaps, the 36 pixels in the color conversion target region 20b have a luminance of 0.75 or more, and the color conversion target About 64 pixels of the peripheral part 21 of the area | region 20b, the pixel of the visual recognition image 2 appears without a color change. Similarly, in the portion where the dark color module 4b in the variable area 8 overlaps, all 36 pixels in the color conversion target area 20b have a luminance of 0.25 or less, and the 64 pixels in the peripheral portion 21 of the color conversion target area 20b. Is shown without the color of the pixels of the visual image 2 being changed.

  Note that in the optical code with image 1 of the present embodiment, in the portion corresponding to the module 4 constituting a partial symbol of the variable region 8, the color of the pixel of the visual image 2 appears as it is without any change. This is because the optical code body (QR code) 3 has an error correction function, and the information can be decoded even if the modules 4 of all symbols included in the variable area 8 cannot be read accurately. The purpose is to improve the image quality of the visual image 2 by representing the color of the pixel of the visual image 2 as it is for some symbols within a possible range. Note that, as will be described later, the symbol that directly represents the color of the pixel of the visual image 2 is intended for a symbol whose degree of color change increases when the color of the pixel of the visual image 2 is changed.

  The optical code 1 with an image according to the present embodiment can read information stored in the optical code main body 3 by a general-purpose reader (QR code reader). The reading procedure by the QR code reader is well known and will not be described in detail. First, the QR code reader takes an image of a portion where the visual image 2 and the optical code main body 3 overlap each other, and uses a quiet zone from the light and dark pattern of the taken image. 5 and fixed area 7 are searched. As described above, in the optical code with image 1, the portion corresponding to the quiet zone 5 is composed of pixels having a luminance of 0.75 or more, and the portion corresponding to the fixed region 7 is the portion of the light color module 4a being 0. .75 or more pixels, and the dark color module 4b is composed of pixels of 0.25 or less. Since the QR code reader reliably identifies a portion having a luminance of 0.75 or higher as a light color and reliably identifies a portion having a luminance of 0.25 or lower as a dark color, the QR code reader can detect a quiet zone 5 from a captured image. And the fixed area | region 7 can be detected reliably.

  When the QR code reader determines the position of the optical code main body 3 from the detected pattern of the quiet zone 5 and the fixed area 7, the QR code reader cuts out the module 4 in the variable area 8, and each module 4 is either light or dark. To identify. At this time, since the image of the peripheral part of the module 4 is easily influenced by the color of the adjacent module 4, the QR code reader recognizes the color by focusing on the color of the central part of each module 4. As described above, in the optical code with image 1, the central portion (color conversion target region 20 b) of the light color module 4 a in the variable region 8 is configured with pixels having a luminance of 0.75 or more, and the dark color module 4 b in the variable region 8 Since the central portion (color conversion target region 20b) is composed of pixels with a luminance of 0.25 or less, the module 4 in the cutout variable region 8 is accurately identified as light and dark colors by the QR code reader. . Based on the identification information, the QR code reader can decode the information stored in the optical code body 3.

  As described above, the optical code 1 with an image according to the present embodiment can identify the light / dark pattern of the optical code main body 3 and read the information stored in the optical code main body 3 with an existing QR code reader. On the other hand, the optical code with an image 1 of the present embodiment changes only the color of the pixel having a luminance of less than 0.75 among the pixels of the visual image 2 in the portion where the visual image 2 and the light color module 4a overlap. The portion is configured to be identified as a bright color by the reading device. Moreover, in the part where the visual image 2 and the dark color module 4b overlap, by changing only the color of the pixel whose luminance exceeds 0.25 among the pixels of the visual image 2, the relevant part is identified as a dark color by the reading device. It is configured as follows. As described above, in the optical code with image 1 of the present embodiment, the pixel color of the visual image 2 is reflected as it is without changing the pixel color of the visual image 2 that is equal to or higher than the predetermined luminance (or lower luminance) that matches the color of the module 4. Therefore, compared with the conventional configuration, there is an advantage that the visibility of the visual image 2 can be improved in a portion overlapping the optical code main body 3.

  In particular, in the optical cord with image 1 of the present embodiment, the hue of the original pixel is changed even in the portion where the optical code body 3 and the visual image 2 overlap and the color of the pixel of the visual image 2 is changed. Therefore, it is possible to suppress the deterioration of the image quality of the visually recognized image 2 due to the overlap with the optical code main body 3.

  In the present embodiment, for the portion corresponding to the module 4 in the variable region 8, the central portion of the module 4 is the color conversion target region 20 b, and the peripheral portion 21 of the module 4 is the pixel of the visual image 2. Since this is reflected as it is, deterioration of the image quality of the visually recognized image 2 can be suppressed due to this point.

  On the other hand, in the present embodiment, for the module 4 in the fixed area 7, the entire module 4 is set as the color conversion target area 20 a, and all the pixels of the visual image 2 overlapping the module 4 are equal to or higher than the reference luminance (or The visual image 2 is changed so that the luminance is equal to or lower than the luminance. As described above, in the present embodiment, the pixels of the visual image 2 are changed more preferentially than the variable region 8 in the fixed region 7 that is important for detecting the position of the optical code body 3, so that the image quality of the visual image 2 is degraded. The reading accuracy of the optical code body 3 can be maintained while suppressing the above.

Below, the preparation method of the said optical cord 1 with an image is demonstrated.
FIG. 5 is a flowchart showing a procedure for creating the optical code with image 1. The specific processing content of each step is as follows.
S101: The image data of the visual image 2 is loaded, and the process proceeds to step S102. The visual image 2 is raster data in which pixel colors are defined by RGB values.
S102: The data of the optical code body 3 is loaded, and the process proceeds to step S103. The data of the optical code body 3 includes information on the size of the optical code body 3 and information on the light / dark binary color arrangement pattern of each module 4.
S103: An overlay position candidate determination process is executed, and the process proceeds to step S104. In the overlapping position candidate determination process, a relative position candidate (overlapping position candidate) for overlapping the optical code body 3 and the visual image 2 is determined. The overlapping position candidate is determined by the position on the visual image 2 where the optical code body 3 is arranged and the angle of the optical code body 3 at the position. In the present embodiment, a total of five positions are selected as position candidates, that is, a reference position of the visual image 2 designated in advance and four positions shifted by 5 mm vertically and horizontally from the reference position. Then, for each position candidate, four angles obtained by rotating the optical code body 3 by 90 ° are selected as angle candidates. That is, in the overlapping position candidate determination process, a total of 20 types of overlapping position candidates are determined by combining five position candidates and four types of angle candidates.
S104: Of the 20 types of overlapping position candidates determined in step S103, select the one for which image data (candidate image data) in which the optical code body 3 and the visual image 2 are superimposed has not been created, and go to step S105. Transition.
S105: A candidate image data creation process for creating candidate image data for the overlay position candidate selected in step S104 is executed, and the process proceeds to step S106. The candidate image data creation process will be described later.
S106: A candidate image evaluation process for evaluating the candidate image data created in step S105 is executed, and the process proceeds to step S107. In the candidate image evaluation process, the degree of change of the RGB value of each pixel is calculated for the portion of the visual image 2 where the color of the pixel is changed. For example, when the RGB value of the pixel is changed from (0, 0, 0) to (255, 128, 117), the sum of the differences (absolute values) between the RGB values before and after the change is “500” ( 255 + 128 + 117) is an evaluation value indicating the degree of color change of the pixel. In the candidate image evaluation process, a numerical value obtained by adding the evaluation values of all the pixels is calculated as an evaluation value (candidate image evaluation value) of the candidate image data. That is, the smaller the candidate image evaluation value is, the smaller the degree of color change of the visual image 2 is, and the candidate image data is less image quality deterioration of the visual image 2.
S107: It is determined whether candidate image data has been created for all the overlay position candidates. If it is determined that there is an overlay position candidate for which candidate image data has not been created, the process proceeds to step S104. If it is determined that candidate image data has been created for all the overlay position candidates, the process proceeds to step S108. .
S108: Compare the candidate image evaluation values of all the created candidate image data, determine the one with the smallest candidate evaluation value as the optical code with image 1, and end the series of processing.

FIG. 6 is a flowchart showing the contents of the candidate image data creation process (FIG. 5: S105). The specific processing content of each step is as follows.
S201: Obtain pixel data of the visible image 2 in a portion overlapping the quiet zone 5, and proceed to step S202.
S202: Brightening processing is executed, and the process proceeds to step S203. In the brightening process, the color of the pixel of the visual image 2 is changed so that the portion overlapping the quiet zone 5 can be identified as a bright color by the reading device. The lightening process will be described later.
S203: Information on the module 4 located in the i row and the j column is acquired, and the process proceeds to step S204.
S204: The pixel data of the visible image 2 of the portion overlapping with the module 4 in i row and j column is acquired, and the process proceeds to step S205.
S205: It is determined whether or not the module 4 in the i row and the j column is the light color module 4a. If it is determined that the module is the light color module 4a, the process proceeds to step S206. If it is determined that the module is not the light color module 4a, the process proceeds to step S207.
S206: Brightening processing is executed, and the process proceeds to step S208. In the lightening process, the color of the pixel of the visual image 2 is changed so that a portion overlapping the light color module 4a can be identified as a light color by the reading device. The lightening process will be described later.
S207: Darkening processing is executed, and the process proceeds to step S208. In the darkening process, the color of the pixel of the visual image 2 is changed so that a portion overlapping the dark color module 4b can be identified as a dark color by the reading device. The darkening process will be described later.
S208: A color change evaluation process for evaluating the result of the lightening process or the darkening process is executed, and the process proceeds to step S209. In the color change evaluation process, the degree of change of the RGB value of each pixel is calculated for the portion of the visual image 2 where the color of the pixel is changed. For example, when the RGB value of the pixel is changed from (0, 0, 0) to (255, 128, 117), “500” is obtained by adding the difference (absolute value) between the RGB value before and after the change. This is an evaluation value indicating the degree of pixel change. In the color change evaluation process, a numerical value obtained by adding the evaluation values of all the pixels is calculated as an evaluation value (module unit evaluation value) of a portion corresponding to the module 4. That is, as the module unit evaluation value is smaller, the module 4 has a smaller degree of change in the color of the visual image 2 by the lightening process or the darkening process, and the image quality of the visual image 2 is less deteriorated.
S209: For all the modules 4, it is determined whether the lightening process or the darkening process has been completed. If it is determined that the processing has been completed for all modules 4, the process proceeds to step S210. If it is determined that there is an unprocessed module 4, the process proceeds to step S203, and the process for the unprocessed module 4 is executed.
S210: A color change cancellation process is executed, and the candidate image data creation process ends. In the color change cancellation process, a module 4 having a relatively large module unit evaluation value is selected from the modules 4 in the variable area 8. Then, with respect to the selected module 4 and the seven modules 4 constituting the same symbol as the module 4, the previously performed lightening process or darkening process is canceled, and the pixel color of the original visual image 2 is changed. To reflect.

FIG. 7 is a flowchart showing the processing contents of the bright color processing (FIG. 6: S206). The specific processing content of each step is as follows.
S301: Select pixels located in p rows and q columns from the processing target pixels of the visual image 2, and the process proceeds to step S302.
S302: It is determined whether or not the processing target is the quiet zone 5. If it is determined that the zone is the quiet zone 5, the process proceeds to step S305. If it is determined that the zone is not the quiet zone 5, the process proceeds to step S303.
S303: It is determined whether or not the processing target is the module 4 of the variable area 8. If it is determined that the area is the variable area 8, the process proceeds to step S304. If it is determined that the area is not the variable area 8, the process proceeds to step S305.
S304: It is determined whether or not the pixels in the p row and the q column are pixels in the central portion that is the color conversion target region 20b. If it is determined that the pixels are in the central portion, the process proceeds to step S305. If it is determined that the pixel is not, the process proceeds to step S307 because the color of the pixel is not changed.
S305: It is determined whether or not the pixels in the p row and the q column have a luminance of 0.75 or higher. If it is determined that the luminance is not higher than 0.75, the process proceeds to step S306, and the luminance is determined to be 0.75 or higher. In this case, since the color of the pixel is not changed, the process proceeds to step S307.
S306: The RGB values of the pixels in the p row and the q column are converted so that the luminance becomes 0.75 while maintaining the hue, and the process proceeds to step S307. The change in luminance while maintaining the hue can be converted by a known calculation formula. It is also possible to perform conversion using a table in which RGB values before conversion and after conversion are associated with each other.
S307: It is determined whether or not the processing has been completed for all the pixels to be processed. When it is determined that the processing has been completed for all the pixels, the lightening process is terminated, and when it is determined that there is an unprocessed pixel, the process proceeds to step S301, and the process for the unprocessed pixel is executed.

FIG. 8 is a flowchart showing the contents of the darkening process (FIG. 6: S207). The specific processing content of each step is as follows.
S401: Select pixels located in the p-th row and the q-th column from the pixels to be processed of the visual image 2, and the process proceeds to step S402.
S402: It is determined whether or not the processing target is the module 4 of the variable region 8. If it is determined that the processing target is the variable region 8, the process proceeds to step S403. If it is determined that the processing target is not the variable region 8, the process proceeds to step S404. .
S403: It is determined whether or not the pixels in the p row and the q column are the central pixel that is the color conversion target region 20, and if it is determined that the pixel is the central pixel, the process proceeds to step S404. If it is determined that the pixel is not, the process proceeds to step S406 because the color of the pixel is not changed.
S404: It is determined whether or not the pixels in the p row and the q column have a luminance of 0.25 or less. If it is determined that the luminance is not 0.25 or less, the process proceeds to step S405, and the luminance is 0.25 or less. If it is determined, the process proceeds to step S406 because the pixel color is not changed.
S405: The RGB values of the pixels in the p row and the q column are converted so that the luminance becomes 0.25 while maintaining the hue, and the process proceeds to step S406.
S406: It is determined whether the processing has been completed for all the pixels to be processed. When it is determined that the processing has been completed for all the pixels, the darkening process is terminated, and when it is determined that there is an unprocessed pixel, the process proceeds to step S401, and the process for the unprocessed pixel is executed.

  As described above, in the optical code 1 with an image according to the present embodiment, in the portion where the optical code main body 3 is overlapped, the light color module 4a portion is identified as light color by the reading device, and the dark color module 4b portion is read. It can be created by selectively changing the color of the pixel of the visual image 2 so that it can be identified as a dark color by the device.

  Further, in the above creation method, candidate image data creation processing is executed for a plurality of overlapping position candidates, and candidate image data having the smallest candidate image evaluation value (the lowest degree of change in the color of the visual image) is obtained. Since the optical code 1 with an image is selected, there is an advantage that the optical code 1 with an image excellent in the visibility of the visual image 2 can be created.

  In the above creation method, for the module 4 in which the degree of change of the pixels of the visual image 2 is relatively high in the lightening process and the darkening process, the lightening process and the darkening process are canceled and the visual image is displayed. Since the second color is reflected as it is, there is an advantage that the visibility of the visual image 2 can be improved by suppressing deterioration of the image quality of the visual image 2 in this respect. Further, in the above creation method, only the module 4 in which the degree of change of the pixels of the visual image 2 is relatively high is not canceled, but the seven symbols constituting the same symbol as the module 4 are not canceled. The module 4 also has the advantage that the image quality of the visual image 2 can be improved without increasing the error rate in symbol units because the lightening process and the darkening process are canceled.

  As shown in FIG. 9, the optical cord with image 1 a according to the present embodiment is formed by superimposing an optical code body 3 a made of a barcode on the visual image 2. The visual image 2 is a color image made up of the same flower photograph as in the first embodiment.

  As shown in FIG. 10, the optical code body 3a is an EAN / JAN code that is a product barcode. In FIG. 10, decimal numbers written at the bottom of the EAN / JAN code are omitted. Specifically, the optical code body 3a is arranged on both sides of the plurality of characters 24 arranged in a line in the reading direction, a center bar 25 arranged in the center of the character 24 line, and the character 24 line. A guard bar 26 and a quiet zone (margin) 27 provided on both sides of the guard bar 26 are provided. The character 24, the center bar 25, the guard bar 26, and the quiet zones 27 and 27 are configured by modules 28 and 28 having a predetermined width arranged in a light color (white) or a dark color (black). The character 24 records seven numbers by juxtaposing the seven modules 28 in accordance with the light / dark pattern of the modules 28. The center bar 25 and the guard bar 26 are used by the reading device to detect the optical code body 3a, and the color arrangement pattern is determined in advance. Specifically, the center bar 25 has a configuration in which modules 28 are juxtaposed in the order of light, dark, bright, dark, and light, and the guard bar 26 has a configuration in which modules 28 are juxtaposed in the order of dark color, light color, and dark color. It has become. The quiet zone 28 is an area necessary for the reading device to detect the optical code body 3a, and has a configuration in which nine light color modules 28 are juxtaposed. Since the optical cord main body 3a of the present embodiment conforms to the JIS standard (JIS X 0501: 1985), detailed description thereof is omitted.

  In this embodiment, the size of the optical cord main body 3a is about 4 cm in width including the quiet zone 28, and the width dimension of one module 28 is 4 mm. Therefore, in the optical cord with image 1a of the present embodiment, as shown in FIG. 11, four pixels 19 of the visual image 2 are overlapped in the width direction of one module 28 of the optical cord main body 3a.

  As in the first embodiment, the optical code 1a with an image of the present embodiment is a portion where the optical code main body 3a overlaps the visual image 2, and the light color portion of the optical code main body 3 is identified as a light color by the reading device. The color of the pixel of the visual image 2 is changed so that the portion can be identified as a dark color. That is, the optical code with image 1a of the present embodiment is a color image composed of pixels of 800 × 700 pixels similar to the visual image 2. Further, in this embodiment, the shaded portion of FIG. 11, that is, the entire module 28 is the color conversion target area 20c, and all the pixels of the visual image 2 overlapping the module 28 are the target of color change. .

  Specifically, as shown in FIG. 12, in the portion overlapping with the light color module 28, among the pixels of the visual image 2, the luminance of 0 is less than the pixel of luminance 0.75 while maintaining the hue of the original pixel. The color is changed to be .75, and the color of the original pixel whose luminance is 0.75 or higher is not changed, and the color of the pixel appears in the optical code with image 1 as it is. On the other hand, in the portion that overlaps the dark color module 28, the color of the pixels of the visual image 2 has been changed so that the luminance is 0.25 while maintaining the hue of the original pixel while maintaining the hue of the original pixel. Further, the color of the original pixel whose luminance is 0.25 or less is not changed, and the color of the pixel appears in the optical code with image 1 as it is.

  In the optical cord with image 1a of the present embodiment, the pixels of the visual image 2 are changed in color as described above in the portion where the optical code main body 3a and the visual image 2 overlap, so that all the light color portions of the optical code main body 3 are changed. It is composed of pixels with a luminance of 0.75 or more, and all dark portions of the optical code body 3a are composed of pixels with a luminance of 0.25 or less. A general-purpose reader (barcode reader) reliably identifies a portion with a luminance of 0.75 or higher as a light color, and reliably identifies a portion with a luminance of 0.25 or lower as a dark color. By scanning the portion of the optical code 1a where the optical code body 3a overlaps, the information stored in the optical code body 3a can be read.

  Also in the present embodiment, as in the first embodiment, in the portion corresponding to the light color module 28, the pixel having the luminance 0.75 or more of the visual image 2 is reflected as it is, and corresponds to the dark color module 28. In the portion to be viewed, pixels with a luminance of 0.25 or less of the visual image 2 are reflected as they are, and furthermore, the hue of the pixels of the visual image 2 is maintained for all the pixels. There is an advantage that image quality deterioration of the image 2 can be suppressed and visibility can be improved as compared with the conventional configuration.

  As shown in FIG. 13, the optical code with image 1b of the present embodiment is formed by superimposing an optical code body 3 made of a two-dimensional code on a monochrome binary visual image 2a. The optical code body 3 is composed of the same QR code as in the first embodiment.

  The visual image 2a is an image of about 4 cm square in which a 15-character alphabet from “a” to “n” is expressed in black on a white background, and is composed of 400 pixels square and monochrome binary pixels. Is.

  In the optical cord with image 1b of the present embodiment, 100 pixels of the visual image 2 overlap with one module 4 of the optical cord main body 3 as in the first embodiment. In the present embodiment, as in the first embodiment, in the portion where the optical code body 3 overlaps the visual image 2a, the light color portion of the optical code body 3 is identified as a light color by the reading device, and the dark color portion is a dark color. The color of the pixel of the visual image 2a is changed so that it can be identified. The optical code with image 1b according to the present embodiment is composed of the same 400 pixels and four pixels as the visual image 2a. However, as will be described later, the pixel of the visual image 2a is overlapped with the optical code body 3 as will be described later. Since the color is changed between dark gray (luminance 0.75) and light gray (luminance 0.25), the optical cord with image 1b is white (luminance 1), dark gray (luminance 0.75), and light gray. It is composed of pixels of four colors (luminance 0.25) and black (luminance 0).

  Specifically, in the optical cord with image 1b of the present embodiment, the color of the pixel of the visual image 2a is changed as shown in FIG. First, in a portion overlapping with the light quiet zone 5, the black pixel is changed to light gray with a luminance of 0.75, and the white pixel is not changed in color, and the pixel of the visual image 2a appears as it is.

  As for the portion where the visual image 2a and the module 4 in the fixed area 7 overlap, as in the first embodiment, the shaded portion in FIG. 4A, that is, the entire 100 pixels 19 overlapping the module 4 is color-converted. This is the target area 20a. Then, as shown in FIG. 14, in the portion where the light color module 4a of the fixed region 7 overlaps, the black pixel is changed to light gray with a luminance of 0.75, and the white pixel is changed in color as in the quiet zone 5. The pixels of the visually recognized image 2a appear as they are. On the other hand, in the portion where the dark color module 4b of the fixed region 7 overlaps, the white pixel is changed to dark gray with a luminance of 0.25, and the black pixel is not changed in color and the pixel of the visual image 2a appears as it is.

  On the other hand, as for the portion where the visible image 2a and the module 4 in the variable region 8 overlap, as in the first embodiment, 36 pixels corresponding to the shaded portion in FIG. 19 is the color conversion target area 20b.

  Specifically, in the portion of the variable area 8 that overlaps the light color module 4a, as shown in FIG. 14, in the color conversion target area 20b, the black pixels of the visual image 2a are changed to light gray with a luminance of 0.75. The white pixels are not changed in color, and the pixels of the visual image 2a appear as they are. On the other hand, in the peripheral portion 21 of the color conversion target area 20b, the black pixels of the visual image 2a are changed to dark gray with a luminance of 0.25, and the white pixels are not changed in color, and the pixels of the visual image 2a appear as they are. In the portion of the variable area 8 that overlaps the dark color module 4b, in the color conversion target area 20b, the white pixels of the visual image 2a are changed to dark gray with a luminance of 0.25, and the black pixels are not color-changed and are visible images. The pixel 2a appears as it is. On the other hand, in the peripheral portion 21 of the color conversion target area 20b, the white pixels of the visual image 2a are changed to light gray with a luminance of 0.75, and the black pixels are not changed in color, and the pixels of the visual image 2a appear as they are.

  FIG. 15 shows a specific example of the color change of the pixel of the visual image 2 a in the portion overlapping the optical code main body 3. FIG. 15A is an enlarged view of the visual image 2a of the portion overlapping the module 4 of the optical code body 3. FIG. Such a portion of the visual image 2 a is composed of approximately the same number of white pixels 19 and black pixels 19. When the light color module 4a of the fixed area 7 overlaps with the portion of the visual image 2a, as shown in FIG. 15B, the black pixel 19 of the visual image 2a is included in the portion of the optical code with image 1b. The color is changed to light gray with a luminance of 0.75. Further, when the dark color module 4b of the fixed region 7 overlaps with the portion of the visual image 2a, as shown in FIG. 15C, the white pixels of the visual image 2a are displayed in the portion of the optical code with image 1b. The color is changed to dark gray with a luminance of 0.25.

  On the other hand, when the light color module 4a of the variable area 8 overlaps with the corresponding part of the visual image 2a, as shown in FIG. 15D, in the corresponding part of the optical code with image 1b, the color conversion target area at the center part. In 20b, the black pixel 19 of the visual image 2a is changed to light gray with a luminance of 0.75, and the black pixel 19 of the visual image 2a is changed to dark gray with a luminance of 0.25 in the peripheral portion 21 of the color conversion target region 20b. Be changed. Further, when the dark color module 4b in the variable area 8 overlaps with the part of the visual image 2a, as shown in FIG. 15E, in the part of the optical code with image 1b, the color conversion target area 20b in the center part. The white pixel 19 of the visual image 2a is changed to a dark gray color with a luminance of 0.25, and the white pixel 19 of the visual image 2a is changed to a light gray color with a luminance of 0.75 in the peripheral portion 21 of the color conversion target area 20b. Is done.

  As described above, the optical code with an image of the present invention can be applied also to the visually recognized image 2a made up of monochrome binary pixels. Further, in this embodiment, the light color module 4a of the variable region 8 is overlapped, and the black pixel of the visual image 2a is changed to dark gray at the peripheral portion 21 of the color conversion target region 20b, and the dark color of the variable region 8 is changed. Since the white pixels of the visual image 2a are changed to light gray in the peripheral portion 21 of the color conversion target region 20b in the portion where the modules 4b overlap, the contrast between the color conversion target region 20b and the peripheral portion 21 is lowered. There is an advantage that the brightness of the module 4 in the variable region 8 can be accurately identified by the reader.

  The optical cord with an image of the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the gist of the present invention.

  For example, in the above embodiment, the “first brightness threshold” according to the present invention is set to the luminance 0.75, and the “second brightness threshold” is set to the luminance 0.25. The criterion of “threshold value” is not limited to the luminance 0.75 and 0.25, and can be changed as appropriate. In addition, the “brightness threshold” according to the present invention is not limited to luminance, and other brightness scales (such as brightness) can be used as a reference.

  In the above embodiment, a photograph and a document are exemplified as the visual image. However, the visual image according to the present invention is not limited to a photo and a document, and includes various images such as an illustration and a map.

  In the above embodiment, the optical code body is smaller than the visual image, and the entire optical code body is configured to overlap the visual image. However, the optical cord with an image of the present invention is such that the optical code body protrudes from the visual image. Alternatively, the entire visual image may overlap the optical code body. When the optical code body protrudes from the visually recognized image, for example, the protruding portion may be configured so that the color of the optical code body is displayed as it is.

1, 1a, 1b Optical code with image 2, 2a Visual image 3, 3a Optical code body 4 Module 5 Quiet zone 7 Fixed area 8 Variable area 11 Position detection pattern 12 Separation pattern 13 Timing pattern 14 Data code area 15 Format information code area 19 pixels 20a, 20b, 20c Color conversion target area 21 Peripheral area 24 Module 25 Center bar 26 Guard bar 27 Quiet zone 28 Module

Claims (8)

An optical code with an image formed by superposing an optical code body composed of two types of modules, a light color module identified as a light color by a reading device and a dark color module identified as a dark color, on a visual image for viewing. ,
The visual image is composed of smaller pixels than the light color module and the dark color module,
In a portion where at least a part of the light color module overlaps with the visual recognition image, pixels that are less than a predetermined first brightness threshold among the pixels of the visual recognition image in the color conversion target region including at least the central portion of the module, The color is changed so that it is equal to or higher than the first brightness threshold, and the color of pixels that are equal to or higher than the first brightness threshold is not changed,
In a portion where at least a part of the dark color module overlaps with the visually recognized image, the second brightness set to be less than the first brightness threshold among the pixels of the visually recognized image in the color conversion target region including at least the central portion of the module. The color is changed so that the pixels that are above the threshold are less than or equal to the second brightness threshold, and the pixels that are less than or equal to the second brightness threshold are not changed in color ,
The optical code body, the module comprising a two-dimensional code formed by arranging in a matrix, become one of the bright module and dark modules are predetermined, the pattern for assisting in optical reading by the reading device Comprising a fixed area to constitute,
The optical code with an image, wherein the color conversion target region does not include a peripheral portion of the module in a portion where the module that does not constitute the fixed region overlaps the visible image.   The optical code with an image according to claim 1, wherein the visual image is a color image, and the hue of all the pixels of the visual image is maintained in a portion where the optical code body and the visual image overlap. The visual image is a monochrome image consisting of white and black pixels,
In the portion where the light color module overlaps the visual image, the black pixel of the visual image is changed to gray equal to or higher than the first brightness threshold in the color conversion target area, and the white pixel of the visual image has a color. Unaltered,
In the portion where the dark color module overlaps with the visual image, the white pixel of the visual image is changed to gray below the second brightness threshold in the color conversion target area, and the color of the black pixel is not changed. The optical code with an image according to claim 1. An optical code with an image formed by superposing an optical code body composed of two types of modules, a light color module identified as a light color by a reading device and a dark color module identified as a dark color, on a visual image for viewing. ,
The visual image is composed of smaller pixels than the light color module and the dark color module,
In a portion where at least a part of the light color module overlaps with the visual recognition image, pixels that are less than a predetermined first brightness threshold among the pixels of the visual recognition image in the color conversion target region including at least the central portion of the module, The color is changed so that it is equal to or higher than the first brightness threshold, and the color of pixels that are equal to or higher than the first brightness threshold is not changed,
In a portion where at least a part of the dark color module overlaps with the visually recognized image, the second brightness set to be less than the first brightness threshold among the pixels of the visually recognized image in the color conversion target region including at least the central portion of the module. The color is changed so that the pixels that are above the threshold are less than or equal to the second brightness threshold, and the pixels that are less than or equal to the second brightness threshold are not changed in color ,
The visual image is a monochrome image consisting of white and black pixels,
In the portion where the light color module overlaps the visual image, the black pixel of the visual image is changed to gray equal to or higher than the first brightness threshold in the color conversion target area, and the white pixel of the visual image has a color. Unaltered,
In the portion where the dark color module overlaps with the visual image, the white pixel of the visual image is changed to gray below the second brightness threshold in the color conversion target area, and the color of the black pixel is not changed. Without
The optical code body is a two-dimensional code in which modules are arranged in a matrix, and it is determined in advance whether a light color module or a dark color module is used, and constitutes a pattern that assists optical reading by a reading device. A fixed area,
In a portion where the bright color module that does not constitute the fixed region overlaps with the visible image, the color conversion target region of the module is only the central portion of the module, and in the peripheral portion of the module, the black pixels of the visible image are the first pixels. It has been changed to gray below the brightness threshold, and the color of the white pixels in the viewing image has not changed,
In a portion where the dark color module that does not constitute the fixed region overlaps the visible image, the color conversion target region of the module is only the central portion of the module, and in the peripheral portion of the module, the white pixels of the visible image are the second brightness. An optical code with an image, wherein the color is changed to gray exceeding a threshold value, and the color of a black pixel of a visually recognized image is not changed. The optical code body is a two-dimensional code in which modules are arranged in a matrix, and it is determined in advance whether a light color module or a dark color module is used, and constitutes a pattern that assists optical reading by a reading device. A fixed area,
The optical code with an image according to any one of claims 1 to 3 , wherein the color conversion target area is the entire module in a portion where the module constituting the fixed area and the visible image overlap each other. . It consists of two types of modules, a light color module identified as light color by a reader and a dark color module identified as dark color, and an optical code body equipped with an error correction function is superimposed on a visual image for visual observation. A method for creating an optical code with an image for creating an optical code with an image,
For a portion where the bright color module overlaps the visual image, a pixel that is less than a predetermined first brightness threshold among the pixels of the visual image in the color conversion target region including at least the center of the module is set to the first brightness. A brightening process in which the color is changed so as to be equal to or greater than the threshold value, and the pixel that is equal to or greater than the first brightness threshold value is not changed in color;
For the portion where the dark color module overlaps the visual image, in the color conversion target region including at least the central portion of the module, the pixel of the visual image exceeds the second brightness threshold set below the first brightness threshold. pixel, changing the color to be the following second brightness threshold, and is the second brightness threshold or more pixels and dark Kasho sense to not change color,
The portion executing the lightening process and darkening process, a color change evaluation process for calculating the module unit evaluation value indicating the change degree of color pixels of the viewed image in module units,
Creation of an optical code with an image, comprising a module having a relatively high module unit evaluation value, and a color change canceling process for canceling the lightening process or the darkening process in a portion where the visual image overlaps with the module Method. The error correction function performs error correction in a symbol unit constituted by a predetermined number of modules,
7. The color change canceling process according to claim 6 , wherein the lightening process or the darkening process is canceled for a module having a relatively high module unit evaluation value and a module constituting the same symbol as the module. How to create an optical code with an image. An optical code with an image is created by superimposing an optical code body composed of two types of modules, a light color module identified as a light color and a dark color module identified as a dark color, on a visual image for viewing. A method of creating an optical code with an image,
For a portion where the bright color module overlaps the visual image, a pixel that is less than a predetermined first brightness threshold among the pixels of the visual image in the color conversion target region including at least the center of the module is set to the first brightness. A brightening process in which the color is changed so as to be equal to or greater than the threshold value, and the pixel that is equal to or greater than the first brightness threshold value is not changed in color;
For the portion where the dark color module overlaps the visual image, in the color conversion target region including at least the central portion of the module, the pixel of the visual image exceeds the second brightness threshold set below the first brightness threshold. A darkening process in which a pixel is changed in color so as to be equal to or lower than a second brightness threshold, and a pixel that is equal to or higher than the second brightness threshold is not changed in color ;
Overlay position candidate determination processing for determining a plurality of positions and / or angle candidates for superimposing the optical code body on the visual image;
A candidate image data creation process for obtaining candidate image data that is a candidate for an optical code with an image by superimposing a visual image on the optical code body for each candidate,
In each candidate image data, a candidate image evaluation process for calculating a candidate image evaluation value indicating a degree of change in the color of the pixel of the visible image for a portion where the optical code main body and the visible image overlap,
An image-attached optical code creation method comprising: an image-attached optical code determination process for determining candidate image data having the smallest candidate image evaluation value as an image-attached optical code.