HIGH-PRECISION LOOK-UP TABLE FROM LOW-PRECISION LOOK-UP TABLE FOR IMPROVED TYPE COLOR GRADATION ADJUSTMENT

摘要

PROBLEM TO BE SOLVED: To realize emphasis of better contrast without correcting software operated on a host computer. SOLUTION: An image reception system 100 includes a scanner 140 having a 10-bit A/D converter 106. The scanner 140 is operated under an environment including a host computer 145 configured to receive 8-bit data. The emphasis of contrast of the scanner 140 is attained by applying improved tonal adjustment on a scanned image. The host computer 145 connecting to the scanner 140 provides a lookup table (that is, 8-bit color tone map) from 256 values to 256 values to the scanner 140. The scanner 140 generates an interpolated lookup table from 1024 level to 256 level from the lookup table from 256 level to 256 level (that is, 10-bit color tone map). The lookup table from 1024 values to 256 values is generated by using linear interpolation or linear correction.