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26th IEEE International Conference on Image Processing (ICIP)

作者： Filali, Amira Ricordel, Vincent Normand, Nicolas Hamidouche, Wassim Nantes Univ LS2N Lab Rue Christian Pauc F-44306 Nantes France Rennes Univ IETR Lab INSA 20 Buttes Coesmes F-35708 Rennes France

ISBN: (纸本)9781538662496

This paper deals with the current trends of new compression methods for 3-D point cloud contents required to ensure efficient transmission and storage. The representation of 3D point clouds geometry remains a challenging problem, since this signal is unstructured. In this paper, we introduce a new hierarchical geometry representation based on adaptive Tree-Structured Point-lattice vector quantization (TSPLVQ). This representation enables hierarchically structured 3D content that improves the compression performance for static point clouds. The novelty of the proposed scheme lies in adaptive selection of the optimal quantization scheme of the geometric information, that better leverage the intrinsic correlations in point cloud. Based on its adaptive and multiscale structure, two quantization schemes are dedicated to project recursively the 3D point clouds into a series of embedded truncated cubic lattices. At each step of the process, the optimal quantization scheme is selected according to a rate-distortion cost in order to achieve the best tradeoff between coding rate and geometry distortion, such that the compression flexibility and performance can be greatly improved. Experimental results show the interest of the proposed multi-scale method for lossy compression of geometry.

关键词： 3D point cloud geometry lattice vector quantization rate-distortion optimization

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Low Bit Rate Speech Coding Using lattice vector quantization and Time-Scale Modification

Low Bit Rate Speech Coding Using Lattice Vector Quantization...

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International Conference on Manufacturing Science and Technology (ICMST 2011)

作者： Xiao, Qiang Chen, Liang Geng, Chao PLA Univ Sci & Tech Inst Commun Engn Nanjing Jiangsu Peoples R China PLA Ruian Unit 92985 Ruian Peoples R China

ISBN: (纸本)9783037852958

This paper presents a low bit rate speech coder based on predictive lattice vector quantization (PLVQ) and time-scale modification (TSM). The coding model of proposed vocoder is built on the MELP, in which bit rate reduction is achieved by taking advantage of PLVQ and TSM techniques. PLVQ is used to encode the speech line spectrum pair (LSP) parameters, which has the advantage of lower implementation complexity than multi-stage vector quantization (MSVQ), moreover, it does not require memory for codebook storage. With our speech data base, PLVQ can save up to 4 bits/frame compared to unstructured codebook MSVQ. TSM can change the speed of speech signal with its perceptual characteristics remained. Through appending TSM as previous and post process, speech coding at bit rate about 1.1 kbps could be easily achieved without modifying the vocoder structure.

关键词： Low bit rate speech coding lattice vector quantization Time-scale modification LSP parameters

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A MULTISACLE BASED MULTISTAGE lattice vector quantization VIDEO CODING FOR ROBUST TRANSMISSION OVER WIRELESS CHANNELS

A MULTISACLE BASED MULTISTAGE LATTICE VECTOR QUANTIZATION VI...

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IEEE International Conference on Signal Processing and Communications

作者： Salleh, M. F. M. Soraghan, J. J. Univ Sains Malaysia Sch Elect & Elect Engn Seberang Prai Selatan 14300 Pulau Pinang Malaysia Univ Strathclyde Inst Commun & Signal Proc Dept Elect & Elect Engn Glasgow GI IXW Lanark Scotland

ISBN: (纸本)9781424412358

In this paper a new non-predictive video codec for mobile applications is presented. The non-predictive scheme omits prediction step in the temporal axis. Hence, it increases robustness for transmission at low bit rate in mobile channel. The video sequence is grouped into a number of frames (GOP) and the same subband from each frame in the GOP are joined together to exploit their spatial-temporal redundancies. The significant vectors of the joined subband within the GOP arc quantized using a novel multistage lattice vector quantization (MLVQ). This process reduces quantization errors and enhances the reconstruction quality of the frames. Experimental results of the new video codec are shown to be significantly better than H.263 and comparable to the current H.264 standard in erroneous Hilly Terrain mobile environment, simulated using TETRA channel simulator for some test video sequences.

关键词： Error resilient lattice vector quantization RS codes TETRA channels

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Analysis and application of lattice vector quantization using mixture models and bit-plane coding

Analysis and application of lattice vector quantization usin...

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作者： Patchoo, Wisarn Washington State University

学位级别：Ph.D.

This thesis studies lattice vector quantization (LVQ) with application to audio and im- age sources. The performance of nonzero pulse amplitude quantization implicit in alge- braic codebook code-excited linear prediction (ACELP) is examined and it is demonstrated that the quantization used in ACELP is effective in a rate-distortion sense at the encoding rates commonly used. A block-based Gaussian mixture model (GMM) is used to model the marginal distribution and the block energy distribution of transform audio data. The expectation-maximization algorithm is used to estimate the GMM parameters. A GMM- based rate-distortion function is derived and shown to closely match the observed spherical LVQ performance. Then, we move forward to the lattice VQ on transformed image. The GMM is used to motivate a subband image coding algorithm based on lattice-based spher- ical VQ and lattice-based pyramid VQ. The algorithm partitions a subband image into blocks of various sizes, depending on their energy and complexity constraints on the enu- meration encoding of lattice codevectors. Using the cubic lattice, the algorithm provides performance competitive with the set partitioning in hierarchical trees (SPIHT) algorithm. A bit-plane coding method is developed for the encoding of binary lattice codevectors as binary codewords, yieldingan embedded bitstream. In sign-magnituderepresentation, only a few least significant bit-planes are constrained due to the structure of the lattice, while there is no restriction on other more significant bit-planes. Simple encoding methods for the lattice-defining bit-planes of the D4, RE8, and Barnes-Wall 16-dimensional lattices are described. Simulation results for these lattices show that partial decoding of the resulting embedded bitstream provides about the same performance as for the integer lattice. When the entire bitstream is fully decoded, the granular gain of the lattice is realized.

关键词： Electrical engineering Bit-plane Coding lattice lattice vector quantization Mixture Models

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EMBEDDED VORONOI CODES FOR SUCCESSIVE REFINEMENT lattice vector quantization

EMBEDDED VORONOI CODES FOR SUCCESSIVE REFINEMENT LATTICE VEC...

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IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Guillaume Fuchs Fraunhofer Institut Integrierte Schaltungen

ISBN: (纸本)9781479903573

lattice vector quantization (LVQ) is an interesting tool in source coding which can take advantage of a higher dimension than the scalar case while overcoming complexity limitations of conventional vector quantization. However, the high dimension and the relatively complex indexing of the codebooks make LVQ often unsuitable for getting a successive refinement of the source. For addressing this problem, the paper proposes a new class of LVQ called the embedded Voronoi codes. The new codes can gradually describe the source with a granularity of 1 bit/dimension by properly combining differently scaled Voronoi codes. A rate-distortion evaluation for a Gaussian source shows that the embedding of the codes comes at a minimal cost at low bit-rates while preserving LVQ advantages over scalar quantization.

关键词： lattice vector quantization Embedded quantization learning vector quantization lattice vector quantization Codes scalar quantization source coding embedding vector quantization codebook Bit rate New classes quantization

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AN ANALYTICAL GAMMA MIXTURE BASED RATE-DISTORTION MODEL FOR lattice vector quantization

AN ANALYTICAL GAMMA MIXTURE BASED RATE-DISTORTION MODEL FOR ...

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European Signal Processing Conference

作者： Ludovic Guillemot Yann Gaudeau Said Moussaoui Jean-Marie Moureaux CRAN – CNRS UMR 7039 Universit′e Henri Poincar′e Nancy 1 BP 239 F-54506 Vand?uvre-l`es-Nancy Cedex Tel.: +33 3 83 68 44 76 Fax: +33 3 83 68 44 62 e-mail: firstname.lastname@cran.uhp-nancy.fr

Here we propose a new blockwise Rate-Distortion (R-D) model dedicated to lattice vector quantization (LVQ) of sparse and structured signals. We first show that the clus- tering properties leads to a distribution of the norm L? of source vectors close to a mixture of Gamma density. From this issue, we derive the joint distribution of vectors as a mix- ture of multidimensional generalized gaussian densities. This data modelling not only allows us to compute more accurate analytical R-D model for LVQ but provides a new theoretical framework to the design of codebooks better suited to data like dead zone LVQ [5, 12].

关键词： learning vector quantization quantization Cloning vectors lattice vector quantization

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A Unified Framework for ACELP Codebook Search Based on Low-complexity Multi-rate lattice vector quantization

A Unified Framework for ACELP Codebook Search Based on Low-c...

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2007 International Symposium on Communications and Information Technologies (ISCIT 2007), vol.3

作者： Cheng Zhou Ruimin Hu Yong Zhang School of Computer Science Wuhan University of China Hubei China National Engineering Research Center for Multimedia Software Wuhan University of China Hubei China

Speech codec with ACELP structure are widely used due to their high performance for the bit rates between 4kbps and 16kbps. In ACELP codec, searching for the best codevector from a huge codebook is the crucial pan in both performance and complexity. In some cases, the effect of codebook search does not fit our expectation. Furthermore, there is no unified method for ACELP codebook search;rather different method is developed for each ACELP codec. In this paper, a unified framework for fixed codebook search based on Low-complexity multi-rate lattice vector quantization is proposed, and is applied to a standard ACELP codec AMR-WB+. It is confirmed that the proposed method enhances the performance especially at lower bit rates.

关键词： ACELP Fixed codebook search lattice vector quantization AMR-WB+

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lattice labeling algorithms for vector quantization

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1998年第2期8卷 206-220页

作者： Wang, C Cao, HQ Li, WP Tzeng, KK Lehigh Univ Dept Comp Sci & Elect Engn Bethlehem PA 18015 USA

Labeling algorithms for Construction-A and Construction-B lattices with respect to pyramid boundaries are presented, The algorithms are developed based on relations between lattices and linear block codes as well as on transformations among several specifically defined lattices and their translations, The mechanism for the construction of these algorithms can be considered as an extension of that given by Fischer, The algorithms are noted to achieve 100% efficiency in utilizing index bits for binary representations. Furthermore, it is determined that many important lattices (E-8, Lambda(16),...) san be indexed to arbitrary norms and dimensions, The complexity of these algorithms in terms of both memory and computation is quite. low and thus it is possible to develop practical lattice vector quantizers of large norms and high dimensions using these algorithms.

关键词： Construction-A Construction-B decoding encoding labeling lattice lattice vector quantization linear block code vector quantization

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Multiple description vector quantization with a coarse lattice

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IEEE TRANSACTIONS ON INFORMATION THEORY 2002年第3期48卷 781-788页

作者： Goyal, VK Kelner, JA Kovacevic, J Digital Fountain Inc Fremont CA 94538 USA Harvard Univ Cambridge MA 02138 USA Bell Labs Lucent Technol Murray Hill NJ 07974 USA

A multiple description (MD) lattice vector quantization technique for two descriptions was recently introduced in which fine and coarse codebooks are both lattices. The encoding begins with quantization to the nearest point in the fine lattice. This encoding is an inherent optimization for the decoder that receives both descriptions;performance can be improved! with little increase in complexity by considering all decoders in the initial encoding step. The altered encoding relies only on the symmetries of the coarse lattice. This allows us to further improve performance without a significant increase in complexity by replacing the fine lattice codebook with a nonlattice codebook that respects many of the symmetries of the coarse lattice. Examples constructed with the two-dimensional (2-D) hexagonal lattice demonstrate large improvement over time sharing between previously known quantizers.

关键词： codebook optimization high-rate source coding lattice vector quantization

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Regularized subband coding scheme

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IEEE TRANSACTIONS ON IMAGE PROCESSING 1999年第4期8卷 564-570页

作者： Prost, R Ding, Y Baskurt, A Benoit-Cattin, H Inst Natl Sci Appl 502 INSERM CNRS CREATISRes UnitUMR 5515 F-69621 Villeurbanne France

Two enhanced subband coding schemes using a regularized image restoration technique are proposed: the first controls the global regularity of the decompressed image, the second extends the first approach at each decomposition level. The quantization scheme incorporates scalar quantization (SQ) and pyramidal lattice vector quantization (VQ) with both optimal bit and quantizer allocation. Experimental results show that both the block effect due to VQ and the quantization noise are significantly reduced.

关键词： artifact reduction restoration regularization subband coding wavelets lattice vector quantization

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