Color picture signal processing method and color picture using the method

Claim 2

A color picture signal processing method, comprising the steps of: (a) inputting picture signal data of primary colors or complementary colors; (b) converting said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and (c) executing a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+C×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K (iii), and Cr′=Cr×A+Cb×B, Cb′= ( Cr×C+Cb×D ) ×K ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and also a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction.

Claim 3

A color picture signal processing method according to claim 1 , further comprising the steps of: (x) calculating dependency of the color difference ratio H=Cr/Cb on the luminance Y by changing an amount of exposure, and executing said color difference matrix calculation by using K calculated by an equation (v), wherein K =( Cr/Cb )/( Cr/Cb ) Y=Y0 ( v ), where (Cr/Cb) Y=Y0 is a color difference ratio at a proper exposure.

Claim 4

A color picture signal processing method according to claim 1 , wherein at least one of the executing steps of said equations (i) to (iv) is performed by referring to a look-up table representing a correlation between the coefficients and/or the variables in said equations (i) to (iv).

Claim 5

A color picture signal processing method according to claim 2 , wherein at least one of the executing steps of said equations (i) to (v) is performed by referring to a look-up table representing a correlation between the coefficients and/or the variables described in said equations (i) to (v).

Claim 6

A color picture signal processing method according to claim 1 , wherein said executing step is performed only for a flesh color.

Claim 7

A color picture signal processing method according to claim 2 , wherein said executing step is performed only for a flesh color.

Claim 8

A color picture signal processing apparatus, comprising: a data input device that inputs picture signal data of primary colors or complementary colors; a data converter that converts said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and a processor that executes a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D )× K ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction.

Claim 9

A color picture signal processing apparatus, comprising: a data input device that inputs picture signal data of primary colors or complementary colors; a data converter that converts said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and a processor that executes a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D )× K ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction.

Claim 10

A color picture signal processing apparatus according to claim 7 , further comprising: a preparatory processor that calculates dependency of the color difference ratio H=Cr/Cb on the luminance Y by changing an amount of exposure, and executes said color difference matrix calculation by using K calculated by an equation (v), wherein K =( Cr/Cb )/( Cr/Cb ) Y=Y0 ( v ) where (Cr/Cb) Y=Y0 is a color difference ratio at a proper exposure.

Claim 11

A color picture signal processing apparatus according to claim 7 , wherein at least one of said processors refers to a look-up table representing a correlation between the coefficients and/or the variables in said equations (i) to (iv).

Claim 12

A color picture signal processing apparatus according to claim 8 , wherein at least one of said processors refers to a look-up table representing a correlation between the coefficients and/or the variables in said equations (i) to (v).

Claim 13

A color printer, comprising: a picture data inputting device; a picture data processor comprising a color picture signal processing apparatus comprising: a data input device that inputs picture signal data of primary colors or complementary colors; a data converter that converts said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and a processor that executes a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr′ =( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D )×K  ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction; and a picture printing device that prints out a picture in accordance with picture data processed by said picture data processor.

Claim 14

A color printer, comprising: a picture data inputting device; a picture data processor comprising a color picture signal processing apparatus comprising: a data input device that inputs picture signal data of primary colors or complementary colors; a data converter that converts said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and a processor that executes a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr′ =( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D )×K  ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction; and a picture printing device that prints out a picture in accordance with picture data processed by said picture data processor.

Claim 15

A color picture display apparatus, comprising: a picture data inputting device; a picture data processor comprising a color picture signal processing apparatus comprising: a data input device that inputs picture signal data of primary colors or complementary colors; a data converter that converts said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and a processor that executes a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D)×K ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Gb′ are color differences after correction; and a picture data display device that displays picture data in accordance with picture data processed by said picture data processor.

Claim 16

A color picture display apparatus, comprising: a picture data inputting device; a picture data processor comprising a color picture signal processing apparatus comprising: a data input device that inputs picture signal data of primary colors or complementary colors; a data converter that converts said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and a processor that executes a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D)×K ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Gb′ are color differences after correction; and a picture data display device that displays picture data in accordance with picture data processed by said picture data processor.

Claim 17

A program stored on a computer readable medium for a computer to execute color picture signal processing, the program comprising the instructions of: (a) inputting picture signal data of primary colors or complementary colors; (b) converting said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and (c) executing a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D )×K  ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction.

Claim 18

A program stored on a computer readable medium for a computer to execute color picture signal processing, the program comprising the instructions of: (a) inputting picture signal data of primary colors or complementary colors; (b) converting said picture signal data to data of luminance Y and data of color differences Cr and Cb on a Y-Cr-Cb space; and (c) executing a color difference matrix calculation by using at least one pair of equations (i) to (iv), wherein Cr′=Cr×A/K+Cb×B, Cb′=Cr×C+Cb×D ( i ), Cr ′=( Cr×A+Cb×B ) /K, Cb′=Cr×C+Cb×D ( ii ), Cr′=Cr×A+Cb×B, Cb′=Cr×C+Cb×D×K ( iii ), and Cr′=Cr×A+Cb×B, Cb ′=( Cr×C+Cb×D )×K  ( iv ), where A, B, C and D are color difference matrix coefficients, K is a function of Y and a correction coefficient larger than 0, K is determined to fix a color difference ratio H (=Cr′/Cb′) regardless of the luminance Y, and Cr′ and Cb′ are color differences after correction.

Claim 19

A program according to claim 13 , further comprising the instruction of: (x) calculating dependency of the color difference ratio H=Cr/Cb on the luminance Y by changing an amount of exposure, and executing said color difference matrix calculation by using K calculated by an equation (v), wherein K =( Cr/Cb )/( Cr/Cb ) Y=Y0 ( v ), where (Cr/Cb) Y=Y0 is a color difference ratio at a proper exposure.