Video processing method and device

Abstract

A video processing method comprises the steps of dividing an entire input data region into three of first, second and third regions in order from the low level side thereof; setting, as an output data characteristic to input data, a trapezoidal characteristic which is nonlinear and continuous as a whole and consists of a linear portion in the first region where the gain is greater than one, a linear portion in the second region where the gain is equal to one exactly or approximately, and a linear portion in the third region where the gain is smaller than one; setting, as another output data characteristic to the input data, an S-shaped characteristic which is nonlinear and continuous as a whole and consists of linear portions in the first and third regions where the gain is smaller than one, and a linear portion in the second region where the gain is greater than one; selecting either the trapezoidal characteristic or the S-shaped characteristic; and correcting the digital luminance data in accordance with the selected characteristic. This method eliminates the known disadvantages and increases the luminance of a reproduced image while raising the contrast of its dark portion.