Adaptive lapped transform-based image and video coding
Timothy J. Klausutis, Vijay Krishna Madisetti · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1997
We propose a design framework for perfectly reconstructed time-varying linear-phase paraunitary filter bands using a novel adaptive lapped transform (ALT). The ALT is based on the Generalized Lapped Orthogonal Transform (GenLOT) proposed by Queiroz. A time-varying filter bank is constructed through the factorization of the GenLOT into cascaded matrix stages. Variable length lapped transforms are subsequently generated by cascading a number of these matrix stages to build specific length filters. Several constraints on the design ensure perfect reconstruction and a fast implementation. An embedded ALT images codec is presented and the application of the ALT to the H.263 video coding standard is discussed. Preliminary results show that the ALT-based embedded image codec has a 1.61-2.35 and a 2.37-4.04 dB increase in peak signal-to-noise ratios (PSNR) compared to the JPEG image coding standard for the Lenna and Barbara test images, respectively.