System and method for Gamma conversion

The invention provides a Gamma conversion system for a source of image pixel data which each has an M-bit value with a first gamma exponent. The Gamma conversion system includes a storage module, a processing module and a selecting module. The storage module stores I look-up tables. The processing module is coupled to the source and the storage module respectively. The processing module includes I converting modules which each corresponds to one of the I look-up tables. The selecting module is coupled to the source and the processing module respectively. The selecting module generates a selection signal in accordance with the M-bit pixel value. In response to the selection signal, the processing module assigns one from the I converting modules to convert the M-bit pixel value into an N-bit pixel value with a second gamma exponent by use of the look-up table corresponding to the assigned converting module.