EXTENDED LAPPED TRANSFORM IN IMAGE-CODING

A modulated lapped transform with extended overlap (ELT) is investigat ed in image coding with the objective of verifying its potential to re place the discrete cosine transform (DCT) in specific applications. So me of the criteria utilized for the performance comparison are reconst ructed image quality (both objective and subjective), reduction of blo cking artifacts, robustness against transmission errors, and filtering (for scalability). Also, a fast implementation algorithm for finite-l ength-signals using symmetric extensions is developed specially for th e ELT with overlap factor 2 (ELT-2). This comparison shows that ELT-2 is superior to both DCT and the lapped orthogonal transform (LOT).