# US 2010/0166306 A1 · Color conversion table creating device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166306 A1 - Document ID: US20100166306A1 - Status: Published application - Kind: A1 - Application number: 12/633,650 - Filed: 2009-12-08 - Published: 2010-07-01 - Earliest claimed: 2008-12-25 - Assignees: Brother Kogyo Kabushiki Kaisha - Inventors: Masashi Kuno - Web page: https://patentgrep.com/patent/US20100166306A1 ## CPC - H04N 1/6033: {using test pattern analysis (H04N1/6055 takes precedence)} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A color conversion table creating device for creating a color conversion table for converting first color data defined in a first color space to second color data defined in a second color space different from the first color space, includes a first data acquiring unit, a reference value determining unit, a lightness judging unit, a third data determining unit, and a creating unit. The first data acquiring unit is configured to acquire a plurality of sets of first data defined in the first color space. The first data sets are determined by measuring test patches each corresponding to a set of second data defined in the second color space. The first data sets include a set of black color data corresponding to data representing black in the second color space. Each first data set has a lightness value. The reference value determining unit is configured to determine a reference value based on a lightness value of the black color data set. The lightness judging unit is configured to judge, for each first data set, whether or not a lightness value of the subject first data set is smaller than the reference value. The third data determining unit is configured to determine the first data set as a set of third data when the lightness judging unit judges that the lightness value of the first data set is smaller than the reference value. The creating unit creates a color conversion table based on the first data sets excluding the third data set. ## Claims ### Claim 1 A color conversion table creating device for creating a color conversion table for converting first color data defined in a first color space to second color data defined in a second color space different from the first color space, comprising: a first data acquiring unit that is configured to acquire a plurality of sets of first data defined in the first color space, the first data sets being determined by measuring test patches each corresponding to a set of second data defined in the second color space, the first data sets including a set of black color data corresponding to data representing black in the second color space, each first data set having a lightness value; a reference value determining unit that is configured to determine a reference value based on a lightness value of the black color data set; a lightness judging unit that is configured to judge, for each first data set, whether or not a lightness value of the subject first data set is smaller than the reference value; a third data determining unit that is configured to determine the first data set as a set of third data when the lightness judging unit judges that the lightness value of the first data set is smaller than the reference value; and a creating unit that creates a color conversion table based on the first data sets excluding the third data set. ### Claim 2 (depends on 1) The color conversion table creating device according to claim 1, wherein the reference value determining unit determines the lightness value of the black color data set as the reference value. ### Claim 3 (depends on 1) The color conversion table creating device according to claim 1, wherein a plurality of grid points are defined in the first color space, each grid point having a set of grid data defined in the first color space, wherein the color conversion table creating device further comprises: a grid point selecting unit that is configured to select, for each of the first data sets excluding the third data set, a single grid point whose grid data set is closest to the subject first data set, the grid points including a black grid point whose grid data is closest to the black color data set; and a grid data corresponding unit that is configured to correspond, to each selected grid point, the second data set corresponding to the first data set that is closest to the grid data set of the subject grid point, and wherein the creating unit creates the color conversion table based on the grid data sets and the second data sets. ### Claim 4 (depends on 3) The color conversion table creating device according to claim 3, wherein the each grid data set has a lightness value, and wherein the reference value determining unit is configured to determine, as the reference value, a lightness value with a prescribed range from the lightness value of the grid data set of black grid point. ### Claim 5 (depends on 3) The color conversion table creating device according to claim 3, wherein the reference value determining unit is configured to determine, as the reference value, a lightness value that is smaller than the lightness value of the black color data set by a prescribed value. ### Claim 6 (depends on 1) The color conversion table creating device according to claim 1, further comprising a hue judging unit that is configured to judge, for each first data set, whether or not the subject first data set represents blue hue, and wherein the third data determining unit determines, for each first data set, the subject first data set as the third data set when the hue judging unit judges the subject first data set represents blue hue and the lightness judging unit judges that a lightness value of the subject first data set is smaller than the reference value. ### Claim 7 A color conversion table creating method for creating a color conversion table for converting first color data defined in a first color space to second color data defined in a second color space different from the first color space, the color conversion table creating method comprising: (a) acquiring a plurality of sets of first data defined in the first color space, the first data sets being determined by measuring test patches each corresponding to a set of second data defined in the second color space, the first data sets including a set of black color data corresponding to data representing black in the second color space, each first data set having a lightness value; (b) determining a reference value based on a lightness value of the black color data set; (c) judging, for each first data set, whether or not a lightness value of the subject first data set is smaller than the reference value; (d) determining the first data set as a set of third data when the lightness value of the first data set is smaller than the reference value; and (e) creating a color conversion table based on the first data sets excluding the third data set. ### Claim 8 (depends on 7) The color conversion table creating method according to claim 7, wherein the (b) determining determines the lightness value of the black color data set as the reference value. ### Claim 9 (depends on 1) The color conversion table creating method according to claim 1, wherein a plurality of grid points are defined in the first color space, each grid point having a set of grid data defined in the first color space, wherein the color conversion table creating method further comprises: (f) selecting, for each of the first data sets excluding the third data set, a single grid point whose grid data set is closest to the subject set of first data, the grid points including a black grid point whose grid data is closest to the black color data set; and (g) corresponding, to each selected grid point, the second data set corresponding to the first data set that is closest to the subject grid point, and wherein the (e) creating creates the color conversion table based on the grid data sets and the second data sets. ### Claim 10 (depends on 9) The color conversion table creating method according to claim 9, wherein the each grid data set has a lightness value, and wherein the (b) determining determines, as the reference value, a lightness value with a prescribed range from the lightness value of the grid data set of black grid point. ### Claim 11 (depends on 9) The color conversion table creating method according to claim 9, wherein the (b) determining determines, as the reference value, a lightness value that is smaller than the lightness value of the black color data set by a prescribed value. ### Claim 12 (depends on 7) The color conversion table creating method according to claim 7, further comprising (h) judging, for each first data set, whether or not the subject first data set represents blue hue, and wherein the (d) determining determines, for each first data set, the subject first data set as the third data set when the (h) judging judges that the subject first data set represents blue hue and the (c) judging judges that a lightness value of the subject first data set is smaller than the reference value. ### Claim 13 A computer-readable recording medium that stores a color conversion table creating program for creating a color conversion table for converting first color data defined in a first color space to second color data defined in a second color space different from the first color space, the color conversion table creating program comprising instructions for: (a) acquiring a plurality of sets of first data defined in the first color space, the first data sets being determined by measuring test patches each corresponding to a set of second data defined in the second color space, the first data sets including a set of black color data corresponding to data representing black in the second color space, each first data set having a lightness value; (b) determining a reference value based on a lightness value of the black color data set; (c) judging, for each first data set, whether or not a lightness value of the subject first data set is smaller than the reference value; (d) determining the first data set as a set of third data when the lightness value of the first data set is smaller than the reference value; and (e) creating a color conversion table based on the first data sets excluding the third data set. ### Claim 14 (depends on 13) The computer-readable recording medium according to claim 13, wherein the (b) determining determines the lightness value of the black color data set as the reference value. ### Claim 15 (depends on 13) The computer-readable recording medium according to claim 13, wherein a plurality of grid points are defined in the first color space, each grid point having a set of grid data defined in the first color space, wherein the color conversion table creating program further comprises instructions for: (f) selecting, for each of the first data sets excluding the third data set, a single grid point whose grid data set is closest to the subject set of first data, the grid points including a black grid point whose grid data is closest to the black color data set; and (g) corresponding, to each selected grid point, the second data set corresponding to the first data set that is closest to the subject grid point, and wherein the (e) creating creates the color conversion table based on the grid data sets and the second data sets. ### Claim 16 (depends on 15) The computer-readable recording medium according to claim 15, wherein the each grid data set has a lightness value, and wherein the (b) determining determines, as the reference value, a lightness value with a prescribed range from the lightness value of the grid data set of black grid point. ### Claim 17 (depends on 15) The computer-readable recording medium according to claim 15, wherein the (b) determining determines, as the reference value, a lightness value that is smaller than the lightness value of the black color data set by a prescribed value. ### Claim 18 (depends on 13) The computer-readable recording medium according to claim 13, the color conversion table creating program further comprises instructions for: (h) judging, for each first data set, whether or not the subject first data set represents blue hue, and wherein the (d) determining determines, for each first data set, the subject first data set as the third data set when the (h) judging judges that the subject first data set represents blue hue and the (c) judging judges that a lightness value of the subject first data set is smaller than the reference value.