Apparatus and method mapping a look-up table in an imaging system

1. A scanner, comprising:

a photoelectric sensing element adapted to sense an optical signal:

circuitry adapted to form a digital signal having a high-bit portion and a low-bit portion based at least in part on the sensed optical signal; and

a memory communicatively coupled to the circuitry, and adapted to receive said digital signal,

wherein the circuitry is further adapted to:

map the high-bit portion of said digital signal to a curve table to provide a high-bit signal:

determine a low-bit signal based at least in part on said low-bit portion and said high-bit portion; and

combine said high-bit signal with said low-bit signal to produce an output signal.

2. The scanner of claim 1 , wherein the photoelectric sensing element comprises a charge-coupled device (CCD).

3. The scanner of claim 1 , wherein the memory comprises a scanner random access memory (RAM).

4. The scanner of claim 1 , said circuitry further adapted to:

map said high-bit portion to a slope table to provide a factor and

determine the low-bit signal based at least in part on said low-bit portion and said factor.

5. The scanner of claim 1 , said circuitry further adapted to:

access a curve divided into a plurality of differential zones, said curve related to a plurality of mapping values in said curve table;

generate a plurality of slope values according to said differential zones; and

store said slope values in said slope table for mapping a portion of said high-bit portion.

6. The scanner of claim 5 , wherein said curve comprises a gamma curve adapted to be used for gamma correction.

7. The scanner of claim 1 , wherein said digital signal further comprises a plurality of bits, wherein the plurality of bits comprise a most significant bit (MSB) and a least significant bit (LSB).

8. The scanner of claim 7 , wherein the high-bit portion includes the MSB and the low-bit portion includes the LSB.

9. A method, comprising:

accessing a digital signal obtained from a scanning operation, said digital signal having a high-bit portion and a low-bit portion;

mapping said high-bit portion of said digital signal to a curve table to obtain a high-bit signal;

determining a low-bit signal based at least in part on said low-bit portion and said high-bit portion; and

combining said high-bit signal with said low-bit signal to produce an output signal.

10. The method of claim 9 , further comprising:

mapping said high-bit portion to a slope table to provide a factor; and

determining the low-bit signal based at least in part on said low-bit portion and said factor.

11. The method of claim 9 , wherein the digital signal comprises a signal obtained from a photoelectric sensing element of a scanner.

12. The method of claim 9 , wherein said mapping further comprises:

accessing a curve divided into a plurality of differential zones, said curve related to a plurality of mapping values in said curve table;

generating a plurality of slope values according to said differential zones; and

storing said slope values in said slope table for mapping a portion of said high-bit portion.

13. The method of claim 12 , wherein said curve comprises a gamma curve adapted to be used for gamma correction.

14. The method of claim 9 , wherein said high bit portion comprises a most significant bit (MSB) of said digital signal.

15. The method of claim 9 , wherein said low-but portion includes a least significant bit (LSB).

16. The method of claim 9 , wherein the digital signal comprises a 16-bit digital signal.

17. An article comprising: a computer readable storage medium having stored thereon instructions that, if executed, result in:

accessing a digital signal obtained from a scanning operation of a scanner, said digital signal having a high-bit portion and a low-bit portion;

mapping said high-bit portion of said digital signal to a curve table to obtain a high-bit signal;

mapping said high-bit portion to a slope table to provide a factor;

determining the low-bit signal based at least in part on said low-bit portion and said factor; and

combining said high-bit signal with said low-bit signal to produce an output signal.

18. The article of claim 17 , wherein said computer readable storage medium further includes instructions that, if executed, further results in mapping by:

accessing a curve divided into a plurality of differential zones, said curve related to a plurality of mapping values in said curve table;

generating a plurality of slope values according to said differential zones; and

storing said slope values in said slope table for mapping a portion of said high-bit portion.

19. The article of claim 18 , wherein said curve comprises a gamma curve adapted to be used for gamma correction.

20. The article of claim 17 , wherein said high bit portion comprises a most significant bit (MSB) of said digital signal.

21. The article of claim 17 , wherein said low-but portion includes a least significant bit (LSB).