GenLOT-design and application for transform-based image coding

Abstract

Wavelet transform with symmetric basis functions has emerged as the next-generation standard for still-image compression. Wavelet methods outperform the current JPEG standard (block transform based on DCT) at low bit rates, since the DCT-based transform suffers from blocking effects due to its short basis functions. GenLOT is a new linear-phase block orthogonal transform which drastically reduces the blocking effects at low bit rates. We present the theory, structure and design methods for GenLOT. In particular, GenLOTs that perform well in image compression are discussed. We compare the performance of GenLOTs, in both objective and subjective measures, to the symmetric wavelet transforms. For a certain class of images, GenLOTs outperform the symmetric wavelet transforms.