Patent ID: 7440015

Claim:
A gamma correction method, which performs a gamma correction on an n-bit video signal to thus generate a gamma correction value, the method comprising the steps: a virtual index computation step, which obtains a virtual index by dividing a value of the n-bit video signal by a first constant and accordingly performing a floor operation, and adding a second constant; a first primary index and first sub-index computation step, which obtains a first primary index by dividing the virtual index by a third constant and accordingly performing the floor operation, and a first sub-index by multiplying the first primary index by the third constant to thus generate a first inter-median and then subtracting the first inter-median from the virtual index; a first gamma construction step, which uses the first primary index and the first sub-index to construct a first gamma value; a second primary index and second sub-index computation step, which obtains a second primary index by dividing the first gamma value with a fourth constant and accordingly performing the floor operation, and a second sub-index by multiplying the second primary index with the fourth constant to thus generate a second inter-median and then subtracting the second inter-median from the first gamma value; a multi-threshold generation step, which uses the second primary index and the second sub-index to construct multiple thresholds; and a correction step, which compares the n-bit video signal with the thresholds for correcting the first gamma value and thus generating the gamma correction value.