Patent ID: 7453610

Claim:
A color display system comprising: an image transforming device transforming X C , Y C , Z C of a XYZ image signal of a XYZ calorimetric system to an RGB image signal of a RGB calorimetric system and outputting the RGB image signal of the RGB calorimetric system; and a display receiving the image signal of the RGB calorimetric system which has been output from the image transforming device; wherein the image transforming device comprises: a converting part operable to convert X C , Y C , Z C of the XYZ image signal by taking a gradation value between 0 and (2 n −1) into RGB linear values using XYZ values corresponding to (2 n −1), wherein the XYZ values corresponding to (2 n −1) represent a maximum gradation value of each of RGB of the display, and further wherein the value, n, represents a number of bits of data being used to convert the X C , Y C , Z C of the XYZ image signal; a calculation part operable to calculate R d , G d and B d of the RGB image signal at gradation values d corresponding to the RGB linear values, wherein the calculating is performed by: using measurement data between gradation values and corresponding XYZ values of each of RGB of the display; obtaining (X rd , Y rd , Z rd ), (X gd , Y gd , Z gd ) and (X bd , Y bd , Z bd ) XYZ values at the gradation values d using the measurement data; and deriving values for a, b and c from X C =aX rd +bX gd +cX bd , Y C =aY rd +bY gd +cY bd , and Z C =aZ rd +bZ gd +cZ bd ; a determination part operable to determine whether the a, b and c found in the calculation part are all within a predefined tolerance range, wherein the predefined tolerance range includes 1, and, in case the a, b, and c found in the calculation part are within the range, outputting the R d , G d and B d as true values of the RGB image signal of the RGB colorimetric system corresponding to the XYZ image signal of the XYZ calorimetric system; and a feedback part for feeding back the calculation results a, b and c to the calculation part to perform the calculation again when determined to be out of the range by the determination part.