Applying the MDCT to image compression

[摘要] The replacement of the standard discrete cosine transform (DCT) of JPEG with thewindowed modifed DCT (MDCT) is investigated to determine whether improvementsin numerical quality can be achieved. To this end, we employ an existing algorithmfor optimal quantisation, for which we also propose improvements. This involves themodelling and prediction of quantisation tables to initialise the algorithm, a strategy thatis also thoroughly tested. Furthermore, the effects of various window functions on thecoding results are investigated, and we find that improved quality can indeed be achievedby modifying JPEG in this fashion.

[发布机构] Stellenbosch University