9:30, IMDSP-P6.1
IMPROVED LOSSLESS COMPRESSION OF COLOR-MAPPED IMAGES BY AN APPROXIMATE SOLUTION OF THE TRAVELING SALESMAN PROBLEM
A. SPIRA, D. MALAH
A color-mapped image is composed of a palette and an image of indices. The color of each pixel is the palette color referenced by the pixel’s index. The indices image is usually far from being smooth. This affects its compressibility by lossless image compression methods, due to their reliance on the natural smoothness of images. The indices images can be smoothed by re-ordering the palette, i.e., assigning the indices to the colors in a better way. In this paper we propose a new method for palette ordering based on an approximate solution of the Traveling Salesman Problem. The proposed method has low complexity dependent only on the size of the palette. It is found to significantly improve the compression ratios of color-mapped images coded with the JPEG-LS lossless compression standard. The resulting compression ratios are better than those achieved by the popular GIF image file format.

9:30, IMDSP-P6.2
FINE-GRANULARITY SPATIALLY SCALABLE VIDEO CODING
Q. WANG, F. WU, S. LI, Y. ZHONG, Y. ZHANG
In this paper, we proposed a novel architecture for spatially scalable video coding, namely, Fine-Granularity Spatially Scalable (FGSS) coding. The traditional layered spatially scalable coding provides only coarse scalability in which bit-stream can be decoded only at a few fixed resolution, but not something in between. The proposed FGSS scheme provides fine-granularity property to the spatial scalability. In this scheme, bit plane technique is combined with spatial scalability, thus a fine granularity increase in the image quality from low-resolution to high-resolution can be obtained. In addition, the proposed scheme provides a flexible embedded bitstream that can be decoded up to any point in the enhancement layer bitstream from low-resolution to high-resolution. This feature further enables efficient video streaming over the Internet where the scalable bitstream can adapt to the widely fluctuated bandwidth. The FGSS coding scheme extends new functionalities such as the multi-resolution, fine granularity, channel adaptation and error-recovery properties to scalable video coding, thus can satisfy different user clients with a wide range of channel bandwidth and screen resolution.

9:30, IMDSP-P6.3
ADAPTIVE FILTER BANKS FOR LOSSLESS IMAGE COMPRESSION
R. OKTEM, O. GEREK, E. CETIN, L. OKTEM, K. EGIAZARIAN
A subband decomposition based lossless image compression algorithm based on adaptive is described. The decomposition is achieved by a two-channel adaptive filter bank. The resulting coefficients are lossy coded first, and th en the residual error between the lossy and error free coefficients are compressed. The locations and the magnitudes of the nonzero coefficients are encoded separately by a hierarchical enumerative coding method. The locations of the nonzero coefficients in children bands are predicted from those in the parent band. The proposed compression algorithm, on the average, provides higher compression ratios than the state-of-the-art methods.

9:30, IMDSP-P6.4
PROGRESSIVE TEXTURE VIDEO CODING
T. STOCKHAMMER, D. MARPE, C. BUCHNER, G. HEISING, G. BLAETTERMANN
In this paper, we present a novel video coding approach which provides the functionality of fine granular bitstream scalability. The proposed progressive texture video coding scheme (PTVC) consists of two parts, the current ITU-T H.26L test model for coding macroblock mode and motion information only and a new technique for progressively coding all intra and inter texture information thus providing an embedded bitstream. It can still be decoded with moderate quality degradation in case of partial loss of the bitstream. It is therefore well suited for multicast or broadcast scenarios where time varying or different fixed bitrates shall be provided to the clients as no transcoding or multiple coding process is required.

9:30, IMDSP-P6.5
A UNIFORM TRANSFORM DOMAIN VIDEO CODEC BASED ON DUAL TREE COMPLEX WAVELET TRANSFORM
K. SIVARAMAKRISHNAN, T. NGUYEN
This paper describes a uniform transform domain Video Codec where the motion estimation/compensation (ME) is performed in the transform domain. The estimation technique discussed here is a subpixel transform domain ME based on the Dual Tree Complex Wavelet Transform (DT CWT) and a maximum phase correlation technique. The DT CWT is a multiresolution fine-to-coarse bandpass filtered decomposition of each still frame and has desirable properties of \textbf{\emph{shiftablility}}, directional selectivity and perfect reconstruction (PR). Estimation is first performed at the finest resolution and successively proceeds to the coarse resolutions using a fine-to-coarse strategy. This gives multiresolution motion estimates enabling estimation of current frame transform coefficients from the corresponding ones in previous frame. The key difference of this approach is the transform domain error frames - a uniform transform domain Video Codec. This further simplifies the encoder and decoder resulting in computational savings with comparable performance to the standards.

9:30, IMDSP-P6.6
CONFIGURABLE VARIABLE LENGTH CODE FOR VIDEO CODING
N. CHEUNG, Y. ITOH
The variable length code (VLC) tables in the MPEG-1/2/4 and H.263 are fixed and optimized for a limited range of bit-rates, and they cannot handle a variety of applications. The universal variable length code (UVLC) is a new scheme to encode syntax elements and has some configurable capabilities. It is also being considered in the ITU-T H.26L. However, the configurable feature of the UVLC has not been well explored. In this paper we propose configuring the UVLC with the additional code configuration (ACC). The ACC is used to adapt UVLC to different symbol distributions by adjusting the partitioning of the symbols into different categories, and the code size assignment to different categories. Experimental results show that the UVLC with ACC outperforms the current proposed scheme in H.26L and the VLC tables of existing standards, while drastically simplifying the encoding and decoding process, and is applicable to a variety of applications.

9:30, IMDSP-P6.7
LOSSLESS CODING FOR PROGRESSIVE ARCHIVAL OF MULTISPECTRAL IMAGES
A. BENAZZA-BENYAHIA, J. PESQUET, M. HAMDI
In this paper, a nonlinear subband decomposition scheme with perfect reconstruction is proposed for lossless coding of multispectral images. The merit of this new scheme is to exploit efficiently both the spatial and the spectral redundancies contained in a multispectral image sequence. Besides, it is suitable for progressive coding, which constitutes a desirable feature for telebrowsing applications. Simulation tests performed on real scenes allow to assess the performances of this new multiresolution coding algorithm. They demonstrate that the achieved compression ratios are higher than those obtained with currently used lossless coders.