Performance of the JPEG Estimated Spectrum Adaptive Postfilter (JPEG-ESAP) for Low Bit Rates

摘要

Frequency-based, pixel-adaptive filtering using the JPEG-ESAP algorithm for low bit rate JPEG formatted color images may allow for more compressed images while maintaining equivalent quality at a smaller file size or bitrate. For RGB, an image is decomposed into three color bands—red, green, and blue. The JPEG-ESAP algorithm is then applied to each band (e.g., once for red, once for green, and once for blue) and the output of each application of the algorithm is rebuilt as a single color image. The ESAP algorithm may be repeatedly applied to MPEG-2 video frames to reduce their bit rate by a factor of 2 or 3, while maintaining equivalent video quality, both perceptually, and objectively, as recorded in the computed PSNR values.

主权项

1. A computer-implemented method, comprising:
creating JPEG quantization coefficients, by a computing system, for each respective color plane of a plurality of color planes; JPEG decoding each color plane, by the computing system, to generate YCbCr discrete cosine transform (DCT) coefficients for estimated spectrum adaptive postfilter (ESAP) postfiltering; ESAP postfiltering each of the color planes, by the computing system; and outputting a JPEG image file and an ESAP postfiltered image file, by the computing system.