The three-dimensional wavelet transform (3D-WT) has been proposed for volumetric data coding, since it can provide lossless coding and top-quality reconstruction: two key features highly relevant to medical imaging applications. In this paper, we present experimental results for four new algorithms based on the Classic 3D-WT. The proposed algorithms are capable of obtaining the wavelet coefficients after the spatial and, mainly, the temporal decomposition processes, reducing most redundancies in the video sequence and getting lower entropy values than the Classic algorithm. The new algorithms are based on the Temporal-Window method for carrying out the temporal decomposition. We have conducted a set of experimental evaluations for a representative data set of a modality of intrinsically volumetric medical imaging: angiography sequences.

Three-dimensional wavelet transform (3D-WT) has been proposed as basis for volumetric data coding, because it can provide lossless coding and top-quality reconstruction. These functionalities are very important for medical imaging. There are two different ways to perform the WT: the Non Standard or Classic WT versus the Standard WT. The last one is practically rejected for state-of-the-art coders because its high computational demands. However, by slightly changing its operation, it is possible to substantially reduce its computational requirements and improve its coding efficiency. In this paper we propose two 3D Standard WT-based decomposition algorithms capable of obtaining the wavelet coefficients during the spatial and temporal decomposition processes and therefore reducing the redundancy present in the video sequence. The new algorithms perform the novel Temporal-Window methodology to carry out the temporal decomposition in 3D-WT. We have conducted a set of experimental evaluations for a representative data set of a modality of intrinsically volumetric medical imaging: angiography sequences.

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We introduce and evaluate the implementations of three parallel video-sequences decorrelation algorithms. The proposed algorithms are based on the nonalternating classic three-dimensional wavelet transform (3D-WT). The parallel implementations of the algorithms are developed and tested on a shared memory system, an SGI origin 3800 supercomputer making use of a messagepassing paradigm. We evaluate and analyze the performance of the implementations in terms of the response time and speed-up factor by varying the number of processors and various video coding parameters. The key points enabling the development of highly efficient implementations rely on the partitioning of the video sequences into groups of frames and a workload distribution strategy supplemented by the use of parallel I/O primitives, for better exploiting the inherent features of the application and computing platform. We also evaluate the effectiveness of our algorithms in terms of the first-order entropy.

In this paper, we introduce and evaluate the parallel implementations of two video sequences decorrelation algorithms having been developed based on the nonalternating three-dimensional wavelet transform (3D-WT) and the temporal-window method. The proposed algorithms have been proven to outperform the classic 3D-WT algorithm in terms of a better coding efficiency and lower computational requirements while enabling a lossless coding and a top-quality reconstruction: the two most highly relevant features to medical imaging applications. The parallel implementations of the algorithms are developed and tested on a shared memory system, a SGI Origin 3800 supercomputer, making use of a message-passing paradigm. We evaluate and analyze the performance of the implementations in terms of the response time and speed-up factor by varying the number of processors and various video coding parameters. The key point enabling the development of highly efficient implementations rely on a workload distribution strategy supplemented by the use of parallel I/O primitives, for better exploiting the inherent features of the application and computing platform. Two sets of I/O primitives are tested and evaluated: the ones provided by the C compiler and the ones belonging to the MPI/IO library.