Abstract: A method and apparatus for color quantization of an image employs a dynamic color map. Pixels of a first image are mapped into corresponding color space regions while incrementing counts in records of those color space regions. Associated colors of color space regions having largest non-zero counts are included in a color map. If the number of such associated colors is less than a maximum number of color indexes of the color map, the unassigned color indexes are reserved for later assignment. Pixels of subsequent images are also mapped into corresponding color space regions while incrementing counts in records of those color space regions. If unassigned color indexes are available in the color map, associated colors of these color space regions are added to the color map until all color indexes have been assigned.

Abstract: A method and apparatus for color quantization of an image employs a dynamic color map. Pixels of a first image are mapped into corresponding color space regions while incrementing counts in records of those color space regions. Associated colors of color space regions having largest non-zero counts are included in a color map. If the number of such associated colors is less than a maximum number of color indexes of the color map, the unassigned color indexes are reserved for later assignment. Pixels of subsequent images are also mapped into corresponding color space regions while incrementing counts in records of those color space regions. If unassigned color indexes are available in the color map, associated colors of these color space regions are added to the color map until all color indexes have been assigned.

Abstract: A method and apparatus for transmitting image updates employing high compression encoding are described. New and old image pixel values are compared at corresponding coordinate positions. For coordinate positions where the values are significantly different, the new image pixel values are assigned to those coordinates unless the new image pixel value is equal to a predefined transparent pixel value. In that case, a pixel value resulting in a color imperceptibly different than the new image pixel value is assigned. On the other hand, for coordinate positions where the values are not significantly different, then the predefined transparent pixel is assigned to those coordinates. Because of the high occurrence of the transparent pixel value in many applications, the pixel values assigned in such a manner are suitable for high compression encoding and consequently, high speed transmission.

Abstract: A method and apparatus for color quantization of an image employs a dynamic color map. Pixels of a first image are mapped into corresponding color space regions while incrementing counts in records of those color space regions. Associated colors of color space regions having largest non-zero counts are included in a color map. If the number of such associated colors is less than a maximum number of color indexes of the color map, the unassigned color indexes are reserved for later assignment. Pixels of subsequent images are also mapped into corresponding color space regions while incrementing counts in records of those color space regions. If unassigned color indexes are available in the color map, associated colors of these color space regions are added to the color map until all color indexes have been assigned.

Abstract: A method and apparatus for transmitting image updates employing high compression encoding are described. New and old image pixel values are compared at corresponding coordinate positions. For coordinate positions where the values are significantly different, the new image pixel values are assigned to those coordinates unless the new image pixel value is equal to a predefined transparent pixel value. In that case, a pixel value resulting in a color imperceptibly different than the new image pixel value is assigned. On the other hand, for coordinate positions where the values are not significantly different, then the predefined transparent pixel is assigned to those coordinates. Because of the high occurrence of the transparent pixel value in many applications, the pixel values assigned in such a manner are suitable for high compression encoding and consequently, high speed transmission.