نتایج جستجو برای: spiht
تعداد نتایج: 612 فیلتر نتایج به سال:
The set partitioning in hierarchical trees (SPIHT) wavelet image coding algorithm can be interpreted as implicitly using classification in its bit-plane coding procedure. The source distribution induced by this classification is studied and rate-distortion performance is evaluated. A quadtree sorting procedure, similar to SPIHT, is used to explicitly form classes of wavelet coefficients. The cl...
SPIHT (Set Partitioning In hierachical trees), being an efficient coding method for wavelet coefficients, has acquired more and more widely application, especially in image/video compression fields. But, conventional SPHIT have some obvious limitions. For example, when for the color image compression, polarmetric SAR image compression, or multispectrum image compression and other multi-channel ...
In this paper, we evaluate the performance of some wavelet based coding algorithms such as 3D QT-L, 3D SPIHT and JPEG2K. In the first step we achieve an objective comparison between three coders, namely 3D SPIHT, 3D QT-L and JPEG2K. For this purpose, eight MRI head scan test sets of 256 x 256x124 voxels have been used. Results show superior performance of 3D SPIHT algorithm, whereas 3D QT-L out...
An embedded image coder that provides very eeective progressive image transmission and a high degree of spatial scalability while achieving superior visual performance to SPIHT is presented. A new partitioning structure combined with scale-based wavelet weights achieves a signiicance reordering that codes more signiicant information belonging to the lower frequency bands earlier in the bitstrea...
Image compression is an important tool to reduce the bandwidth and storage requirements of practical image systems. It has been successfully implemented to provide high compression rates while maintaining good image quality. Wavelet transform is the latest method of compression where in ability to describe any type of signal both in time and frequency domain. To explore the effect of various im...
In this paper we propose a modification of the 3-D Set Partitioning in Hierarchical Trees (3-D SPIHT) algorithm for very low bit-rate wavelet-based video coding. The modified algorithm, called 3-D Virtual SPIHT (3-D VSPIHT), virtually decomposes the coarsest level of the wavelet coefficients to reduce the number of three-dimensional (spatio-temporal) sets in the 3-D SPIHT algorithm. Our simulat...
Because of excellent properties, people has paid more attention to SPIHI algorithm, which is based on the traditional wavelet transformation theory, but it also has its shortcomings. Combined the progress in the present wavelet domain and the human's visual characteristics, we propose an improved algorithm based on human visual characteristics of SPIHT in the base of analysis of SPIHI algorithm...
Among all wavelet transform and zero-tree quantization based image coding algorithms, set partitioning in hierarchical trees (SPIHT) is well known for its simplicity and efficiency. But theoretical analysis and experimental results have shown there are still some key points need to be further improved. This paper proposes a coefficient Statistic based Modified SPIHT Lossless Image Compression A...
An efficient, secure color image coder incorporating Color-SPIHT (C-SPIHT) compression and partial encryption is presented. Confidentiality of the image data is achieved by encrypting only the significance bits of individual wavelet coefficients for K iterations of the C-SPIHT algorithm. By varying K, the level of confidentiality vs. processing overhead can be controlled. For K=2, adequate secu...
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