Patent ID: 6295379
Filing Date: 2001-09-25
Classification: G06T

Abstract:
A method for encoding a digital image, the method comprising:calculating an intra-frame difference between a first sample associated with a first element of a current scan line and a second sample associated with a second element of a previous scan line, the second element located immediately above the first element in a frame, wherein the frame comprises a plurality of scan lines and the current scan line and the previous scan line represent a portion of the plurality of scan lines;providing a first quantization table including a plurality of levels, each level including a plurality of quantizers;selecting one of the plurality of levels according to the calculated intra-frame difference between the first sample and the second sample;if a level switch occurs, placing information identifying the selected level into an information stream;selecting one of the plurality of quantizers according to the calculated intra-frame difference between the first sample and the second sample;placing information corresponding to the selected quantizer into the information stream; and,restricting the encoding to intra-frame differences by repeating the above for each sample in each scan line of the plurality of scan lines until the frame is completely encoded.