Patent ID: 7580044

Claim:
A method of dithering an image at a first bit depth for display on a display device at a second bit depth, the second bit depth being less than the first bit depth, the method comprising: dividing a target curve of a predetermined function relating the first bit depth to the second bit depth into a plurality of intervals, the target curve spanning a predetermined range at least including original pixel values at the first bit depth being between two pixel values displayable at the second bit depth; obtaining an interval number for the original pixel values at the first bit depth that cannot be directly represented at the second bit depth according to the target curve; determining a plurality of appearance probabilities, one appearance probability being determined for each original pixel value according to a ratio between the interval number for that pixel value and a total number of intervals; generating a dithering matrix having a plurality of entries, wherein a probability of appearance of each particular entry in the dithering matrix is according to the appearance probability for the original pixel value for which that entry corresponds; and dithering pixels of the image according to the dithering matrix to thereby generate an output image for display on the display device at the second bit depth.