The invention provides a method and an apparatus for dithering, and inversely dithering an image. The apparatus makes use of a pixel address and a pixel data to locate a dither reference value from a dither matrix and use the dither reference value to convert an original pixel data having N bits into a dithered pixel data having M bits (N>M). On the other hand, the apparatus for performing an inversely dithering process makes use of the pixel address and the dithered pixel data (M bits) to locate a dither reference value from a dither matrix. Then, the dither reference value is employed to perform an inversely dithering process to recover the dithered pixel data into original pixel data.
A method and apparatus for dithering may provide filtering M bit data and performing a temporal/spatial compensation based on LSB of the filtered M bit data. The dithering may be performed on a selected frame. M-2 bits of the M bit data may be specified as a reference gray scale value resulting from the filtered M bit data. Temporal compensation may provide adding a weight of `0` or `1` to the reference gray scale value, for example M-2 bit data. Spatial compensation may include horizontal or vertical mirroring, and may be performed to represent whole gray scales without saturation.
