DCC '97 Proceedings of the Conference on Data Compression
Embedded Image Coding Using ZeroBlocks of Subband/Wavelet Coefficients and Context Modeling
DCC '01 Proceedings of the Data Compression Conference
An investigation of wavelet-based image coding using anentropy-constrained quantization framework
IEEE Transactions on Signal Processing
Space-frequency quantization for wavelet image coding
IEEE Transactions on Image Processing
Comparison of different methods of classification in subband coding of images
IEEE Transactions on Image Processing
High performance scalable image compression with EBCOT
IEEE Transactions on Image Processing
A new, fast, and efficient image codec based on set partitioning in hierarchical trees
IEEE Transactions on Circuits and Systems for Video Technology
Hierarchical quantization indexing for wavelet and wavelet packet image coding
Image Communication
Improved wavelet feature extraction using kernel analysis for text independent speaker recognition
Digital Signal Processing
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In recent literature, there exist many high-performance wavelet coders that use different spatially adaptive coding techniques in order to exploit the spatial energy compaction property of the wavelet transform. Two crucial issues in adaptive methods are the level of flexibility and the coding efficiency achieved while modeling different image regions and allocating bitrate within the wavelet subbands. In this paper, we introduce the "spherical coder," which provides a new adaptive framework for handling these issues in a simple and effective manner. The coder uses local energy as a direct measure to differentiate between parts of the wavelet subband and to decide how to allocate the available bitrate. As local energy becomes available at finer resolutions, i.e., in smaller size windows, the coder automatically updates its decisions about how to spend the bitrate. We use a hierarchical set of variables to specify and code the local energy up to the highest resolution, i.e., the energy of individual wavelet coefficients. The overall scheme is nonredundant, meaning that the subband information is conveyed using this equivalent set of variables without the need for any side parameters. Despite its simplicity, the algorithm produces PSNR results that are competitive with the state-of-art coders in literature.