Patent ID: 6020921
Filing Date: 2000-02-01
Classification: H04N

Abstract:
A gamma correction circuit comprising circuit means for approximating in linear translation circuits successive nonlinear portions of a gamma correction curve, means for applying an input luminance (Y) signal to the circuit means, and selection means for selecting signals translated by any of the circuit means as a gamma corrected output signal depending on whether the input signal falls within predetermined ranges approximately corresponding to said nonlinear portions of the gamma correction curve, in which the number of circuit means is three, and in which the number of successive nonlinear portions of the gamma correction curve is three, and in which transfer functions of each of the circuit means isYg=4*Y-48 for Y<=34Yg=Y+54 for 34<Y<=127Yg=Y/2+118 for 127<Ywhere Yg represents the gamma corrected output signal and Y represents the input signal.