An algorithm for variable quality image compression is given. The idea is to encode di erent parts of an image with di erent bit rates depending on their importance. Variable quality image compression (VQIC) can be applied when a priori knowledge on some regions or details being more important than others is available. Our target application is digital mammography, where high compression rates ...

This paper presents the Discrete Wavelet based fusion techniques for combining perceptually important image features. SPIHT (Set Partitioning in Hierarchical Trees) algorithm is an efficient method for lossy and lossless coding of fused image. This paper presents some modifications on the SPIHT algorithm. It is based on the idea of insignificant correlation of wavelet coefficient among the medi...

We derive simple push-relabel algorithms for the matroid partitioning, matroid membership, and submodular flow feasibility problems. It turns out that, in order to have a strongly polynomial algorithm, the lexicographic rule used in all previous algorithms for the two latter problems can be avoided. Its proper role is that it helps speeding up the algorithm in the last problem.

The increased popularity of multimedia applications places a great demand on eecient data storage and transmission techniques. Network communication, especially over a wireless network , can easily be intercepted and must be protected from eavesdroppers. Unfortunately, en-cryption and decryption are slow and it is often diicult, if not impossible, to carry out real-time secure image and video c...

We carry out low bit-rate compression of multispectral images by means of the Said and Pearlman’s SPIHT algorithm, suitably modified to take into account the interband dependencies. Two techniques are proposed: in the first, a three-dimensional (3-D) transform is taken (wavelet in the spatial domain, Karhunen–Loeve in the spectral domain) and a simple 3-D SPIHT is used; in the second, after tak...

An efficient compression strategy is indispensable for 3-D digital echocardiography, which can provide more accurate diagnostic information than 2-D echocardiography without geometric assumption, but unfortunately requires a huge storage space. We describe a new set partitioning in hierarchical trees (SPIHT) algorithm that is based on the wavelet packet transform and use it to compress 3-D echo...

In this article we propose a new fast method with great potential for multiresolution pyramid decomposition of signals and images The method allows unusual exibility in choosing a lter for any task involving the multiresolution analysis and synthesis Using our method one can choose any low pass lter for the multiresolution ltering This method enabled us to choose the best lters for SPIHT image ...

Contourlet is a new image representation method, which can efficiently represent contours and textures in images. In this paper, we analyze the distribution of significant contourlet coefficients in different subbands and propose a contourlet image coding algorithm by constructing a virtual low frequency subband and adjusting coding method of SPIHT (Set Partitioning in Hierarchical Trees) algor...

A Joint source-channel coding (JSCC) scheme for SPIHT coded image transmission over OFDM systems with spatial diversity is proposed where no feedback channel is available. By using diversity techniques, the fading effects can be dramatically decreased and we show that subchannels in OFDM systems are indeed flat Rayleigh fading channels and approach Gaussian noisy channels when the diversity gai...

We consider two-dimensional partitioning of general sparse matrices for parallel sparse matrix-vector multiply operation. We present three hypergraph-partitioning based methods, each having unique advantages. The first one treats the nonzeros of the matrix individually and hence produces fine-grain partitions. The other two produce coarser partitions, where one of them imposes a limit on the nu...