The Experts below are selected from a list of 39108 Experts worldwide ranked by ideXlab platform
K R Rao - One of the best experts on this subject based on the ideXlab platform.
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Variable Block size lapped transforms
IEEE Transactions on Signal Processing, 1996Co-Authors: R L De Queiroz, K R RaoAbstract:A structure for implementing lapped transforms with time-varying Block sizes that allows full orthogonality of the transient transforms is presented. The formulation is based on a factorization of the transfer matrix into orthogonal factors. Such an approach can be viewed as a sequence of stages with Variable-Block-size transforms separated by sample-shuffling (delay) stages. Details and design examples for a first-order system are presented.
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Variable Block-size interpolative vector quantization
Visual Communications and Image Processing '96, 1996Co-Authors: Krit Panusopone, K R RaoAbstract:The conventional fixed Block-size vector quantization (VQ) usually copes with a small dimension data to alleviate computation load. This technique suffers from the Blocking effect at low bit rates. To handle this problem, input data is arranged to form a Variable dimension vector so that correlation between two vectors is weak. This paper uses quadtree partitioning to form Variable Block-size regions. Instead of taking all data of segmented area directly, only constant amount of pixels are selectively subsampled from each terminal node to form an input vector of VQ. With this improvement, only single universal codebook can take care of all kinds of image data. At the decoder, reduced dimension vector will be interpolated back to its full resolution information. Simulation results show that the reconstructed images preserve fine and pleasant qualities in both edge and background regions. The search time for VQ coder also reduces significantly. Furthermore, the comparison of the PSNR of the reconstructed images also reveals better performance of the proposed method than the traditional fixed Block-size scheme at low bit rates.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Variable Block size coding of images with hybrid quantization
IEEE Transactions on Circuits and Systems for Video Technology, 1996Co-Authors: Y. Huh, Krit Panusopone, K R RaoAbstract:This paper describes a progressive image transmission (PIT) scheme using a Variable Block size coding technique in conjunction with a variety of quantization schemes in the transform domain. The proposed scheme uses a region growing technique to partition the images so that regions of different sizes can be addressed using a small amount of side information. This segmentation divides the image into five different regions that vary in size based on the details within the image. High detail Blocks are classified into four different categories based on the energy distribution followed by vector quantization (VQ), and low-detail Blocks are encoded with scalar quantization (SQ). Progressive refinement is achieved by proper masking of the information in the transform domain. Simulation results show that the reconstructed images preserve fine and pleasant qualities based on both subjective and mean square error criteria. Also, the receiver reconstructs more details in each stage so that the observer can recognize the image quickly.
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Variable Block size lapped transforms
International Conference on Image Processing, 1995Co-Authors: R L De Queiroz, K R RaoAbstract:A structure for implementing lapped transforms with time-varying Block sizes is discussed. It allows full orthogonality in the transitions based on a factorization of the transfer matrix into orthogonal factors. Such an approach can be viewed as a sequence of stages with Variable-Block-size transforms intermediated by sample-shuffling (delay) stages. Details for a first order system are given and a design example is presented.
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ICIP - Variable Block size lapped transforms
Proceedings. International Conference on Image Processing, 1Co-Authors: R L De Queiroz, K R RaoAbstract:A structure for implementing lapped transforms with time-varying Block sizes is discussed. It allows full orthogonality in the transitions based on a factorization of the transfer matrix into orthogonal factors. Such an approach can be viewed as a sequence of stages with Variable-Block-size transforms intermediated by sample-shuffling (delay) stages. Details for a first order system are given and a design example is presented.
Ozlem Koctas Cotur - One of the best experts on this subject based on the ideXlab platform.
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Variable Block insertion heuristic for the quadratic assignment problem
Congress on Evolutionary Computation, 2017Co-Authors: Fatih M Tasgetiren, Yucel Ozturkoglu, Ozlem Koctas CoturAbstract:The aim of this paper is to apply the Variable Block insertion heuristic (VBIH) algorithm recently proposed in the literature for solving the quadratic assignment problem (QAP). The VBIH algorithm is concerned with making Block moves in a given solution. As a local search in this paper, the VNST is employed from the literature to be applied to a solution obtained after several Block moves. Besides the single-solution based VBIH, we also propose a populated VBIH (PVBIH) in this paper. The proposed algorithms were evaluated on quadratic assignment problem instances arising from real life problems as well as on a number of benchmark instances from the QAPLIB. The computational results show that the proposed algorithms are very effective in solving both types of instances. All PCB instances are further improved.
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CEC - Variable Block insertion heuristic for the quadratic assignment problem
2017 IEEE Congress on Evolutionary Computation (CEC), 2017Co-Authors: M. Fatih Tasgetiren, Yucel Ozturkoglu, Quan-ke Pan, Ozlem Koctas CoturAbstract:The aim of this paper is to apply the Variable Block insertion heuristic (VBIH) algorithm recently proposed in the literature for solving the quadratic assignment problem (QAP). The VBIH algorithm is concerned with making Block moves in a given solution. As a local search in this paper, the VNST is employed from the literature to be applied to a solution obtained after several Block moves. Besides the single-solution based VBIH, we also propose a populated VBIH (PVBIH) in this paper. The proposed algorithms were evaluated on quadratic assignment problem instances arising from real life problems as well as on a number of benchmark instances from the QAPLIB. The computational results show that the proposed algorithms are very effective in solving both types of instances. All PCB instances are further improved.
Mathias Wien - One of the best experts on this subject based on the ideXlab platform.
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Variable Block size transforms for h 264 avc
IEEE Transactions on Circuits and Systems for Video Technology, 2003Co-Authors: Mathias WienAbstract:A concept for Variable Block-size transform coding is presented. It is called adaptive Block-size transforms (ABT) and was proposed for coding of high resolution and interlaced video in the emerging video coding standard H.264/AVC. The basic idea of inter ABT is to align the Block size used for transform coding of the prediction error to the Block size used for motion compensation. Intra ABT employs Variable Block-size prediction and transforms for encoding. With ABT, the maximum feasible signal length is exploited for transform coding. Simulation results reveal a performance increase up to 12% overall rate savings and 0.9 dB in peak signal-to-noise ratio.
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Variable Block-size transforms for H.264/AVC
IEEE Transactions on Circuits and Systems for Video Technology, 2003Co-Authors: Mathias WienAbstract:A concept for Variable Block-size transform coding is presented. It is called adaptive Block-size transforms (ABT) and was proposed for coding of high resolution and interlaced video in the emerging video coding standard H.264/AVC. The basic idea of inter ABT is to align the Block size used for transform coding of the prediction error to the Block size used for motion compensation. Intra ABT employs Variable Block-size prediction and transforms for encoding. With ABT, the maximum feasible signal length is exploited for transform coding. Simulation results reveal a performance increase up to 12% overall rate savings and 0.9 dB in peak signal-to-noise ratio.
L. Guan - One of the best experts on this subject based on the ideXlab platform.
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Image compression by Variable Block truncation coding with optimal threshold
IEEE Transactions on Signal Processing, 1991Co-Authors: Mohamed S. Kamel, C.t. Sun, L. GuanAbstract:A Variable Block truncation coding (BTC) algorithm is proposed for image compression. It is shown that there exists an optimal threshold for the quantization in BTC algorithms (fixed and Variable) that minimizes the errors. Compared to the fixed BTC (fBTC), the Variable BTC (vBTC) gives better performance on all the tested images. The use of vBTC with optimal threshold leads to a reduction of the error in the reconstructed images by almost 40% of the error in the reconstructed images obtained by fBTC. This enhanced performance suggests that the vBTC with optimal threshold is a better alternative to the fixed Block truncation coding. >
R L De Queiroz - One of the best experts on this subject based on the ideXlab platform.
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Variable Block size lapped transforms
IEEE Transactions on Signal Processing, 1996Co-Authors: R L De Queiroz, K R RaoAbstract:A structure for implementing lapped transforms with time-varying Block sizes that allows full orthogonality of the transient transforms is presented. The formulation is based on a factorization of the transfer matrix into orthogonal factors. Such an approach can be viewed as a sequence of stages with Variable-Block-size transforms separated by sample-shuffling (delay) stages. Details and design examples for a first-order system are presented.
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Variable Block size lapped transforms
International Conference on Image Processing, 1995Co-Authors: R L De Queiroz, K R RaoAbstract:A structure for implementing lapped transforms with time-varying Block sizes is discussed. It allows full orthogonality in the transitions based on a factorization of the transfer matrix into orthogonal factors. Such an approach can be viewed as a sequence of stages with Variable-Block-size transforms intermediated by sample-shuffling (delay) stages. Details for a first order system are given and a design example is presented.
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ICIP - Variable Block size lapped transforms
Proceedings. International Conference on Image Processing, 1Co-Authors: R L De Queiroz, K R RaoAbstract:A structure for implementing lapped transforms with time-varying Block sizes is discussed. It allows full orthogonality in the transitions based on a factorization of the transfer matrix into orthogonal factors. Such an approach can be viewed as a sequence of stages with Variable-Block-size transforms intermediated by sample-shuffling (delay) stages. Details for a first order system are given and a design example is presented.
