Color conversion device and color conversion method

Claim 2

A color conversion device for performing pixel-by-pixel color conversion of image data, the device comprising: calculating means for calculating a maximum value β and a minimum value α of said image data for each pixel; hue data calculating means for calculating hue data r, g, b, y, m and c based on said image data and said maximum and minimum values β and α outputted from said calculating means; means for generating comparison-result data based on each hue data outputted from said hue data calculating means; arithmetic means for performing calculation using each hue data outputted from said hue data calculating means; coefficient generating means for generating specified matrix coefficients; and a matrix calculator for performing matrix calculation based on the coefficients from said coefficient generating means, using the comparison-result data from said comparison-result data generating means, the output from said arithmetic means, the hue data from said hue data calculating means and said minimum value α from said calculating means, thereby to obtain color-converted image data.

Claim 3

The color conversion device according to claim 1 , wherein said calculating means for calculating said maximum and minimum values β and α calculates a maximum value β and α minimum value α of the image data R, G and B, said hue data calculating means calculates hue data r, g, b, y, m and c by subtraction in accordance with: r=R−α, g=G−α, b=B−α, y=β−B, m=β−G, and c=β−R; based on inputted image data R, G and B and said maximum and minimum values β and α outputted from said calculating means, said comparison-result data generating means includes multiplying means for multiplying respective hue data by calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 ; means for obtaining comparison-result data based on outputs from said multiplying means, said comparison-result data being hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m), with min(A, B) indicating a minimum value of A and B; and means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data; said arithmetic means includes means for obtaining product terms and fraction terms based on each of said hue data, and the matrix calculator performs the matrix calculation using said comparison-result data from said comparison-result data generating means, said outputs from said arithmetic means, said hue data from said hue data calculating means and said minimum value α from said calculating means, to thereby obtain color-converted image data.

Claim 4

The color conversion device according to claim 2 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (1) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) ] + [ α α α ] ( 1 ) to thereby obtain color-converted image data.

Claim 5

The color conversion device according to claim 2 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (3) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) α ] ( 3 ) to thereby obtain color-converted image data.

Claim 6

The color conversion device according to claim 2 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (5) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) ] + [ α α α ] ( 5 ) to thereby obtain color-converted image data.

Claim 7

The color conversion device according to claim 2 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (7) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) α ] ( 7 ) to thereby obtain color-converted image data.

Claim 8

The color conversion device according to claim 2 , wherein said multiplying means for multiplying said hue data by specified calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 , in said comparison-result data generating means, performs calculation on said hue data and said calculation coefficients by setting said calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 to integral values of 2 n , with n being an integer, and by bit shifting.

Claim 9

The color conversion device according to claim 1 , wherein said calculating means for calculating said maximum and minimum value β and α includes means for obtaining complementary color data C, M and Y of cyan, magenta and yellow from image data R, G and B and calculating a maximum value β and a minimum value α of said complementary color data C, M and Y, said hue data calculating means determines complementary color data C, M and Y from image data R, G and B and calculating hue data r, g, b, y, m and c by subtraction in accordance with: r=β−C, g=β−M, b=β−Y, y=Y−α, m=M−α, and c=C−α based on said complementary color data and said maximum and minimum values β and α, said comparison-result data generating means includes multiplying means for multiplying respective hue data by calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 ; means for obtaining comparison-result data based on outputs from said multiplying means, said comparison-result data being hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m), with min(A, B) indicating a minimum value of A and B; and means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, said arithmetic means includes means for obtaining product terms and fraction terms based on each of said hue data, and said matrix calculator performs the matrix calculation using said comparison-result data from said comparison-result data generating means, said outputs from said arithmetic means, said hue data from said hue data calculating means and said minimum value α from said calculating means, to thereby obtain color-converted image data.

Claim 10

The color conversion device according to claim 8 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and FiJ (i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (2) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) ] + [ α α α ] ( 2 ) to thereby obtain color-converted image data.

Claim 11

The color conversion device according to claim 8 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (4) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) α ] ( 4 ) to thereby obtain color-converted image data.

Claim 12

The color conversion device according to claim 8 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (6) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) ] + [ α α α ] ( 6 ) to thereby obtain color-converted image data.

Claim 13

The color conversion device according to claim 8 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (8) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r c * m / ( c + m ) m * y / ( m + y ) y * c / ( y + c ) r * g / ( r + g ) g * b / ( g + b ) b * r / ( b + r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) α ] ( 8 ) to thereby obtain color-converted image data.

Claim 14

The color conversion device according to claim 1 , wherein said calculating means for calculating said maximum and minimum value β and α calculates a maximum value β and α minimum value α of the image data R, G and B, said hue data calculating means calculates hue data r, g, b, y, m and c by subtraction in accordance with: r=R−α, g=G−α, b=B−α, y=β−B, m=β−G, and c=β−R; based on inputted image data R, G and B and said maximum and minimum value β and α outputted from said calculating means, said comparison-result data generating means includes multiplying means for multiplying respective hue data by calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 ; means for obtaining comparison-result data based on outputs from said multiplying means, said comparison-result data being hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m), with min(A, B) indicating a minimum value of A and B; means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, and means for obtaining comparison-result data between the hue data r, g, b and between the hue data y, m, c; said arithmetic means includes means for obtaining product terms based on each of said hue data, and said matrix calculator performs the matrix calculation using said comparison-result data from said comparison-result data generating means, said outputs from said arithmetic means, said hue data from said hue data calculating means and said minimum value α from said calculating means, to thereby obtain color-converted image data.

Claim 15

The color conversion device according to claim 13 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (9) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) ] + [ α α α ] ( 9 ) to thereby obtain color-converted image data.

Claim 16

The color conversion device according to claim 13 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (11) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) α ] ( 11 ) to thereby obtain color-converted image data.

Claim 17

The color conversion device according to claim 13 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (13) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) ] + [ α α α ] ( 13 ) to thereby obtain color-converted image data.

Claim 18

The color conversion device according to claim 13 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (15) below: [ R G B ] = ( Eij )  [ r g b ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) α ] ( 15 ) to thereby obtain color-converted image data.

Claim 19

The color conversion device according to claim 1 , wherein said calculating means for calculating said maximum and minimum values β and α includes means for obtaining complementary color data C, M and Y from image data R, G and B and calculating a maximum value β and a minimum value α of said complementary color data C, M and Y, said hue data calculating means determines complementary color data C, M and Y from image data R, G and B and calculating hue data r, g, b, y, m and c by subtraction in accordance with: r=β−C, g=β−M, b=β−Y, y=Y−α, m=M−α, and c=C−α based on said complementary color data and said maximum and minimum values β and α, said comparison-result data generating means includes multiplying means for multiplying respective hue data by calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 ; means for obtaining comparison-result data based on outputs from said multiplying means, said comparison-result data being hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m), with min(A, B) indicating a minimum value of A and B; means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data; and means for obtaining comparison-result data between the hue data r, g and b, and between the hue data y, m and c; said arithmetic means includes means for obtaining product terms based on each of said hue data, and said matrix calculator performs the matrix calculation using said comparison-result data from said comparison-result data generating means, said outputs from said arithmetic means, said hue data from said hue data calculating means and said minimum value α from said calculating means, to thereby obtain color-converted image data.

Claim 20

The color conversion device according to claim 18 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (10) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) ] + [ α α α ] ( 10 ) to thereby obtain color-converted image data.

Claim 21

The color conversion device according to claim 18 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (10) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( r , hry ) min  ( r , hrm ) min  ( g , hgy ) min  ( g , hgc ) min  ( b , hbm ) min  ( b , hbc ) α ] ( 12 ) to thereby obtain color-converted image data.

Claim 22

The color conversion device according to claim 18 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 18), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (14) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) ] + [ α α α ] ( 14 ) to thereby obtain color-converted image data.

Claim 23

The color conversion device according to claim 18 , wherein said means for obtaining comparison-result data based on comparison between each of said comparison-result data and each of said hue data, in said comparison-result data generating means, determines comparison-result data based on comparison between said comparison-result data hry, hrm, hgy, hgc, hbm and hbc, and said hue data r, g and b, said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) and Fij(i=1 to 3, j=1 to 19), said matrix calculator performs the matrix calculation on calculation terms in the form of said comparison-result data and said hue data and said minimum value α outputted from said calculating means by a matrix calculation formula (16) below: [ C M Y ] = ( Eij )  [ c m y ] + ( Fij )  [ c * m m * y y * c r * g g * b b * r min  ( c , m ) min  ( m , y ) min  ( y , c ) min  ( r , g ) min  ( g , b ) min  ( b , r ) min  ( y , hry ) min  ( y , hgy ) min  ( c , hgc ) min  ( c , hbc ) min  ( m , hbm ) min  ( m , hrm ) α ] ( 16 ) to thereby obtain color-converted image data.

Claim 24

The color conversion device according to claim 1 , wherein said coefficient generating means generates specified matrix coefficients Eij(i=1 to 3, j=1 to 3) based on a formula (17) below: ( Eij ) = [ 1 0 0 0 1 0 0 0 1 ] ( 17 ) and the matrix coefficients Fij(i=1 to 3, j=1 to 18, or j=1 to 19) are generated such that, of the coefficients Fij, the coefficients for said product term based on each hue data outputted from said calculating means are set to zero, and other coefficients are set to specified values.

Claim 25

The color conversion device according to claim 1 , wherein said calculating means for calculating a maximum value β and a maximum value α of said image data calculates a maximum value β and a minimum value α using said image data, and generating an identification code indicating the hue data which is of a value zero according to the image data or the complementary color data which are the largest and the smallest, and based on the identification code outputted from said calculation means, comparison-result data is generated by said comparison-result data generating means, and matrix coefficients are generated by said coefficient generating means, and matrix calculation is performed based on the coefficients from said coefficient generating means according to said identification code from said calculating means, to thereby obtain color-converted image data, or complementary color data.

Claim 26

A color conversion method for performing pixel-by-pixel conversion of image data, the method comprising the steps of: calculating a maximum value β and a minimum value α for each pixel of said image data; calculating hue data r, g, b, y, m and c based on said image data and said maximum and minimum values β and α, and generating comparison-result data based on each of said calculated hue data; performing calculation using each of said calculated hue data; and performing matrix calculation using said comparison-result data, said calculation output, said hue data and said minimum value α and based on specified matrix coefficients, to thereby obtain color-converted image data.

Claim 27

A color conversion method for performing pixel-by-pixel conversion of image data, the method comprising the steps of: calculating a maximum value β and a minimum value α for each pixel of said image data; calculating hue data r, g, b, y, m and c based on said image data and said maximum and minimum values β and α, and generating comparison-result data based on each of said calculated hue data; performing calculation using each of said calculated hue data; and performing matrix calculation using said comparison-result data, said calculation output, said hue data and said minimum value α and based on specified matrix coefficients, to thereby obtain color-converted image data.

Claim 28

The color conversion method according to claim 25 , comprising the steps of: calculating a maximum value β and a minimum value for said image data R, G and B; calculating hue data r, g, b, y, m and c based on subtraction in accordance with: r=R−α, g=G−α, b=B−α, y=β−B, m=β−G, and c=β−R; on said inputted image data R, C and B and said maximum and minimum values β and α; multiplying said hue data by specified calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 , obtaining comparison-result data hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m) (where min(A, B) indicates the minimum value of A and B) using multiplied output and obtaining comparison-result data between said comparison-result data and said hue data; obtaining product terms and fraction terms based on each of said hue data; and performing matrix calculation using said comparison-result data, the calculation output, said hue data and said minimum value α, to thereby obtain color-converted image data.

Claim 29

The color conversion method according to claim 25 , comprising the steps of: calculating a maximum value β and a minimum value α of complementary color data C, M and Y of cyan, magenta and yellow from said image data R, G and B; calculating hue data r, g, b, y, m and c based on subtraction in accordance with: r=β−C, g=β−M, b=β−Y, y=Y−α, m=M−α, and c=C−α on said complementary color data C, M and Y and said maximum and minimum values β and α; using outputted results of multiplying said hue data by specified calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 , to obtain comparison-result data hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m) (where min(A, B) indicates the minimum value of A and B), and obtaining comparison-result data between said said comparison-result data and said hue data; obtaining product terms and fraction terms for each hue data; and performing matrix calculation using said comparison-result data, said calculation outputs, said hue data and said minimum value α, to thereby obtain color-converted complementary color data.

Claim 30

The color conversion method according to claim 25 , comprising the steps of: calculating a maximum value β and a minimum value for said image data R, G and B; calculating hue data r, g, b, y, m and c based on subtraction in accordance with: r=R−α, g=G−α, b=B−α, y=β−B, m=β−G, and c=β−R; on said image data R, G and B and said maximum and minimum values β and α; multiplying said hue data by specified calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 , obtaining comparison-result data hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m) (where min(A, B) indicates the minimum value of A and B) using multiplied output, obtaining comparison-result data between said comparison-result data and said hue data; obtaining comparison-result data between the hue data r, g, b and between the hue data y, m, c; obtaining product terms based on each of said hue data; and performing matrix calculation using said comparison-result data, the calculation output, said hue data and said minimum value α, to thereby obtain color-converted image data.

Claim 31

The color converting method according to claim 25 , comprising the steps of: obtaining complementary color data C, M and Y from said image data R, G and B, and calculating a maximum value β and a minimum value α of said complementary color data; obtaining complementary color data from said image data R, G and B; calculating hue data r, g, b, y, m and c based on subtraction in accordance with: r=β−C, g=β−M, b=β−Y, y=Y−α, m=M−α, and c=C−α on said complementary color data and said maximum and minimum values β and α; multiplying said hue data by specified calculation coefficients aq 1 to aq 6 and ap 1 to ap 6 ; using outputs of said multiplication to obtain comparison-result data hry=min(aq 1 *g, ap 1 *m), hrm=min(aq 2 *b, ap 2 *y), hgy=min(aq 3 *r, ap 3 *c), hgc=min(aq 4 *b, ap 4 *y), hbm=min(aq 5 *r, ap 5 *c) and hbc=min(aq 6 *g, ap 6 *m) (where min(A, B) indicates the minimum value of A and B); obtaining comparison-result data based on comparison between each said comparison-result data and said hue data; obtaining comparison-result data based on comparison among said hue data r, g and b and among said hue data y, m and c; obtaining a product term for each of said hue data; and performing matrix calculation by using said comparison-result data, said calculated outputs, said hue data and said minimum value α, and thereby obtaining color-converted complementary color data.