We proposed a novel method for 2d image compression-encryption whose quality is demonstrated through accurate 2dimage reconstruction at higher compression ratios. The method is based on the dWT-discrete Wavelet Trans...
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We proposed a novel method for 2d image compression-encryption whose quality is demonstrated through accurate 2dimage reconstruction at higher compression ratios. The method is based on the dWT-discrete Wavelet Transform where high frequency sub-bands are connected with a novel Hexadata crypto-compression algorithm at compression stage and a new fast matching search algorithm at decoding stage. The novel crypto-compression method consists of four main steps: 1) A five-level dWT is applied to an image to zoom out the low frequency sub-band and increase the number of high frequency sub-bands to facilitate the compression process;2) The Hexa data compression algorithm is applied to each high frequency sub-band independently by using five different keys to reduce each sub-band to1/6of its original size;3) Build a look up table of probability data to enable decoding of the original high frequency sub-bands, and 4) Apply arithmetic coding to the outputs of steps (2) and (3). At decompression stage a fast matching search algorithm is used to reconstruct all high frequency sub-bands. We have tested the technique on 2dimages including streaming from videos (YouTube). Results show that the proposed crypto-compression method yields high compression ratios up to 99% with high perceptual quality images.
In this paper, a new method for imagecompression is proposed whose quality is demonstrated through accurate 3d reconstruction from 2dimages. The method is based on the discrete cosine transform (dCT) together with a...
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In this paper, a new method for imagecompression is proposed whose quality is demonstrated through accurate 3d reconstruction from 2dimages. The method is based on the discrete cosine transform (dCT) together with a high-frequency minimization encoding algorithm at compression stage and a new concurrent binary search algorithm at decompression stage. The proposedcompression method consists of five main steps: (1) divide the image into blocks and apply dCT to each block;(2) apply a high-frequency minimization method to the AC-coefficients reducing each block by 2/3 resulting in a minimized array;(3) build a look up table of probability data to enable the recovery of the original high frequencies at decompression stage;(4) apply a delta or differential operator to the list of dC-components;and (5) apply arithmetic encoding to the outputs of steps (2) and (4). At decompression stage, the look up table and the concurrent binary search algorithm are used to reconstruct all high-frequency AC-coefficients while the dC-components are decoded by reversing the arithmetic coding. Finally, the inverse dCT recovers the original image. We tested the technique by compressing anddecompressing 2dimages including images with structured light patterns for 3d reconstruction. The technique is compared with JPEG and JPEG2000 through 2d and 3d RMSE. Results demonstrate that the proposedcompression method is perceptually superior to JPEG with equivalent quality to JPEG2000. Concerning 3d surface reconstruction from images, it is demonstrated that the proposed method is superior to both JPEG and JPEG2000.
A fine-grain scalable and efficient audio compression scheme based oil adaptive significance-trees is presented. Common approaches for 2-dimagecompression like EZW (embedded wavelet zero tree) and SPIHT (set partiti...
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ISBN:
(纸本)0780391543
A fine-grain scalable and efficient audio compression scheme based oil adaptive significance-trees is presented. Common approaches for 2-dimagecompression like EZW (embedded wavelet zero tree) and SPIHT (set partitioning in hierarchical trees) use a fixed significance-tree that captures well the inter- and intra-band cot-relations of wavelet coefficients. For 1-d audio signals, such rigid coefficient correlations are not present. We address this problem by dynamically selecting an optimal significance-tree for the actual audio frame from a given set of possible trees. Experimental results ire given. showing that this coding scheme outperforms single-type tree coding schemes and performs comparable to the MPEG AAC coder while additionally achieving fine-grain scalability.
We present a novel robust and secure steganography technique to hide images into audio files aiming at increasing the carrier medium capacity. The audio files are in the standard WAV format, which is based on the LSB ...
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