Color table look-up having last value memory

• US 6,075,514 A
• Filed: 02/05/1998
• Issued: 06/13/2000
• Est. Priority Date: 02/05/1998
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Ryan, Dennis L.
• Primary Examiner(s): Wu, Xiao
• Application Number:
  US09/019,191
• Time in Patent Office: 859 Days
• Field of Search: 345/150, 345/153, 345/154, 345/155, 345/199, 382/167, 382/162, 382/163, 382/166, 358/518, 358/520, 347/43, 395/109
• US Class Current: 345/601
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables
• CPC Class Codes: H04N 1/6019 using look-up tables H04N1/6025 takes precedence

Abstract

A system for correcting pixel color values, with each color value represented by a byte of data, includes applying look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data, simultaneously comparing the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data. The first, second, third, and fourth bytes of corrected output data are stored as outputs corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if all comparisons in the comparing step indicate equality, and look-up table correction is applied to obtain corrected output data corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if any of the comparisons in the comparing step indicate inequality.

Claims

1. A method for correcting pixel color values, with each color value represented by a byte of data, comprising:

applying look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data;

simultaneously comparing the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data;

storing the first, second, third, and fourth bytes of corrected output data as outputs corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if all comparisons in said comparing step indicate equality; and

applying look-up table correction to obtain corrected output data corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if any of the comparisons in said comparing step indicate inequality.

2. A computer-readable medium storing computer-executable process steps to apply a look-up table to correct pixel color values, with each color value represented by a byte of data, the process steps comprising:

an applying step to apply look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data;

a comparing step to simultaneously compare the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data;

a storing step to store the first, second, third, and fourth bytes of corrected output data as outputs corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if all comparisons in said comparing step indicate equality; and

an applying step to apply look-up table correction to obtain corrected output data corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if any of the comparisons in said comparing step indicate inequality.

3. Computer-executable process steps stored on a computer-readable medium, the process steps to apply a look-up table to correct pixel color values, with each color value represented by a byte of data, the process steps comprising:

an applying step to apply look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data;

a comparing step to simultaneously compare the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data;

a storing step to store the first, second, third, and fourth bytes of corrected output data as outputs corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if all comparisons in said comparing step indicate equality; and

an applying step to apply look-up table correction to obtain corrected output data corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if any of the comparisons in said comparing step indicate inequality.

4. A method for applying a look-up table to correct pixel color values, with each color value represented by a byte of data, comprising:

applying look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data;

comparing the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data;

storing the first, second, third, and fourth bytes of corrected output data as outputs corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if all comparisons in said comparing step indicate equality; and

applying look-up table correction to the fifth, sixth, seventh, and eighth bytes of input color value data if any of the comparisons in said comparing step indicate inequality.

5. A method according to claim 4, wherein the comparisons in said comparing step are performed simultaneously using a dword compare function.

6. A method according to claim 4, wherein a process of comparing four bytes of new input color value data to four bytes of previously-input color value data and copying the corrected output data corresponding to the previously-input color value data as corrected output data for the new input color value data is repeated until the four bytes of new input color value data are not equal to the four bytes of previously-input color value data.

7. A computer-readable medium storing computer-executable process steps to apply a look-up table to correct pixel color values, with each color value represented by a byte of data, the process steps comprising:

an applying step to apply look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data;

a comparing step to compare the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data;

a storing step to store the first, second, third, and fourth bytes of corrected output data as outputs corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if all comparisons in said comparing step indicate equality; and

an applying step to apply look-up table correction to the fifth, sixth, seventh, and eighth bytes of input color value data if any of the comparisons in said comparing step indicate inequality.

8. A computer-readable medium according to claim 7, wherein the comparisons in said comparing step are performed simultaneously using a dword compare function.

9. A computer-readable medium according to claim 7, the process steps further comprising a comparing step to compare four bytes of new input color value data to four bytes of previously-input color value data and a comparing step to copy corrected output data corresponding to the previously-input color value data as corrected output data for the new input color value data until the four bytes of new input color value data are not equal to the four bytes of previously-input color value data.

10. Computer-executable process steps stored on a computer-readable medium, the process steps to apply a look-up table to correct pixel color values, with each color value represented by a byte of data, the process steps comprising:

an applying step to apply look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data;

a comparing step to compare the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data;

an storing step to store the first, second, third, and fourth bytes of corrected output data as outputs corresponding to the fifth, sixth, seventh, and eighth bytes of input color value data if all comparisons in said comparing step indicate equality; and

an applying step to apply look-up table correction to the fifth, sixth, seventh, and eighth bytes of input color value data if any of the comparisons in said comparing step indicate inequality.

11. Computer-executable process steps according to claim 10, wherein the comparisons in said comparing step are performed simultaneously using a dword compare function.

12. Computer-executable process steps according to claim 10, further comprising process steps to compare four bytes of new input color value data to four bytes of previously-input color value data and to copy corrected output data corresponding to the previously-input color value data as corrected output data for the new input color value data until the four bytes of new input color value data are not equal to the four bytes of previously-input color value data.

13. A method for correcting N-bit pixel values with a processor using X-bit processing, the method comprising:

applying look-up table correction to X/N pixel values to obtain X/N corrected output values;

determining whether a next X/N pixel values are identical to the X/N pixel values; and

storing the X/N corrected output values as output values corresponding to the next X/N pixel values.

14. A method according to claim 13, further comprising applying look-up table correction to the next X/N pixel values to obtain next corresponding X/N corrected output values if it is determined that the X/N pixel values are not identical to the next X/N pixel values.

15. Computer-executable process steps stored on a computer-readable medium to correct N-bit pixel values with a processor using X-bit processing, the proces steps comprising:

an applying step to apply look-up table correction to X/N pixel values to obtain X/N corrected output values;

a determining step to determine whether a next X/N pixel values are identical to the X/N corrected output values as output values corresponding to the next X/N pixel values.

16. Computer-executable process steps according to claim 15, further comprising a step to apply look-up table correction to the next X/N corrected output values if it is determined that the X/N pixel values are not identical to the next X/N pixel values.

17. A computer-readable medium storing computer-executable process steps to correct N-bit pixel values with a processor using X-bit processing, the process steps comprising:

an applying step to apply look-up table correction to X/N pixel values to obtain X/N corrected output values;

a determining step to determine whether a next X/N pixel values are identical to the X/N picel values; and

a storing step to store the X/N corrected output values as output values corresponding to the next X/N pixel values.

18. A computer-readable medium according to claim 17, further comprising an applying step to apply look-up table correction to the next X/N pixel values to obtain next corresponding X/N corrected output values if it is determined that the X/N pixel values are not identical to the next X/N pixel values.