Systems and methods for generating luminance look-up table based on color component values
Systems and methods are provided for generating at least one look-up table, wherein the look-up table holds at least one luminance value in a second color space. In some embodiments, the luminance value can be computed for distinct combinations of color component values corresponding to a plurality of color components in a first color space. The method comprises computing at least one luminance value in the second color space based on a portion of the color component value combination; deriving an address in a look-up table based on the portion of the color component combination; and storing the computed luminance value in the look-up table at the derived address.
1. A method for generating a look-up table, wherein the look-up table holds a luminance value in a second color space, the luminance value being computed for a combination of a plurality of color component values corresponding to a plurality of color components in a first color space, the method comprising:
generating a plurality of portion values by extracting, via a computer, one portion value from each of the plurality of color component values;
computing, via a computer, the luminance value in the second color space as a function of the plurality of portion values, the luminance value corresponding to an achromatic brightness associated with the plurality of portion values;
deriving, via the computer, an address in the look-up table by concatenating the plurality of portion values; and
recording the luminance value in the look-up table at the derived address.
2. The method of claim 1 , wherein the first color space is a CMYK color space.
3. The method of claim 1 , wherein the first color space is an RGB color space.
4. The method of claim 1 , wherein the second color space is a device independent color space.
5. The method of claim 4 , wherein the device independent color space is a CIEXYZ color space.
6. The method of claim 1 , wherein computing the luminance value further comprises extracting the plurality of portion values, each from a corresponding color component value.
7. The method of claim 6 , wherein the plurality of portion values have identical sizes.
8. The method of claim 6 , wherein the plurality of portion values do not have identical sizes.
9. The method of claim 1 , wherein the look-up table is stored in memory.
10. The method of claim 1 , wherein the look-up table is stored in firmware.
11. A method for retrieving a luminance value in a second color space from a look-up table, the luminance value being retrieved based on a plurality of color component values associated with an input pixel in a first color space, the method comprising:
generating a plurality of portion values by extracting, via a computer, one portion value from each of the plurality of color component values;
deriving, via the computer, an address in the look-up table, wherein the address is derived by concatenating the plurality of portion values; and
retrieving the luminance value from the look-up table at the derived address, wherein the luminance value corresponds to an achromatic brightness associated with the plurality of portion values.
12. The method of claim 11 , wherein the plurality of portion values have identical sizes.
13. The method of claim 11 , wherein the plurality of portion values do not have identical sizes.
14. A non-transitory computer-readable medium that contains instructions which, when executed by a processor, perform steps in a method for generating a look-up table, wherein the look-up table holds a luminance value in a second color space, the luminance value being computed for a combination of a plurality of color component values corresponding to a plurality of color components in a first color space, the method comprising:
generating a plurality of portion values by extracting one portion value from each of the plurality of color component values;
computing the luminance value in the second color space as a function of the plurality of portion values, the luminance value corresponding to an achromatic brightness associated with the plurality of portion values;
deriving an address in the look-up table by concatenating the plurality of portion values; and
recording the luminance value in the look-up table at the derived address.
15. The computer-readable medium of claim 14 , wherein computing the luminance value further comprises extracting the plurality of portion values, each from a corresponding color component value.
16. The computer-readable medium of claim 15 , wherein the plurality of portion values have identical sizes.
17. The computer-readable medium of claim 15 , wherein the plurality of portion values do not have identical sizes.
18. A non-transitory computer-readable medium that contains instructions which, when executed by a processor, perform steps in a method for retrieving a luminance value in a second color space from a look-up table, the luminance value being retrieved based on a plurality of color component values associated with an input pixel in a first color space, the method comprising:
generating a plurality of portion values by extracting one portion value from each of the plurality of color component values;
deriving an address in the look-up table, wherein the address is derived by concatenating the plurality of portion values; and
retrieving the luminance value from the look-up table at the derived address, wherein the luminance value corresponds to an achromatic brightness associated with the plurality of portion values.
19. The computer-readable medium of claim 18 , wherein the plurality of portion values have identical sizes.
20. The computer-readable medium of claim 18 , wherein the plurality of portion values do not have identical sizes.