Dithering

Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and digital video data, and is often one of the last analog stages of audio production to compact disc.

Ordered dithering is an image dithering algorithm. It is commonly used by programs that need to provide continuous image of higher colors on a display of less color depth. For example, Microsoft Windows uses it in 16-color graphics modes. It is easily distinguished by its noticeable crosshatch patterns.

The algorithm achieves dithering by applying a threshold map on the pixels displayed, causing some of the pixels to be rendered at a different color, depending on how far in between the color is of available color entries.

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