Author: Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages :
Book Description
Image Compression Using Trellis Coded Quantization
Author: A Study of Trellis Coded Quantization for Image Compression
Author: Kannan PanchapakesanPublisher:
ISBN:
Category : Coding theory
Languages : en
Pages : 166
Book Description
"Trellis coded quantization has recently evolved as a powerful quantization technique in the world of lossy image compression. The aim of this thesis is to investigate the potential of trellis coded quantization in conjunction with two of the most popular image transforms today; the discrete cosine transform and the discrete wavelet trans form. Trellis coded quantization is compared with traditional scalar quantization. The 4-state and the 8-state trellis coded quantizers are compared in an attempt to come up with a quantifiable difference in their performances. The use of pdf-optimized quantizers for trellis coded quantization is also studied. Results for the simulations performed on two gray-scale images at an uncoded bit rate of 0.48 bits/pixel are presented by way of reconstructed images and the respective peak signal-to-noise ratios. It is evident from the results obtained that trellis coded quantization outperforms scalar quantization in both the discrete cosine transform and the discrete wavelet transform domains. The reconstructed images suggest that there does not seem to be any considerable gain in going from a 4-state to a 8-state trellis coded quantizer. Results also suggest that considerable gain can be had by employing pdf-optimized quantizers for trellis coded quantization instead of uniform quantizers."--Abstract.
Image compression using wavelet transform and trellis code vector quantization with entropy constraint
Author: Publisher:
ISBN:
Category :
Languages : pt-BR
Pages :
Book Description
Essa dissertação apresenta um codificador de imagens para baixas taxas de bits utilizando a decomposição da imagem em 10 sub-bandas através da aplicação da transformada wavelet. Uma técnica de redução de irrelevância visual é usada para descartar blocos de coeficientes das sub-bandas de alta freqüência (2 a 10). Os blocos remanescentes são classificados em bordas e não bordas e codificados através da técnica ECTCVQ (Entropy-Constrained Trellis Coded Vector Quantization). Já a primeira sub-banda é codificada através da técnica PTCQ(Predictive Trellis Coded Quantization) com preservação de bordas. Na alocação de bits entre as sub-bandas é utilizado o algoritmo de Wersterink et al. Os resultados obtidos mostram um desempenho muito superior ao padrão JPEG, e bons resultados quando comparados a técnica de codificação de imagens recentes.
Robust Source Coding of Images with Predictive Trellis - Coded Quantization
Author: Lisa M. MarvelPublisher:
ISBN: 9781423585046
Category :
Languages : en
Pages : 75
Book Description
The ability to transmit images over narrow bandwidth noisy channels has become desirable for many applications. Image integrity and timely transmission are imperative in many scenarios. The traditional method of image transmission requires a multistage process. The first stage is source coding, or the removal of redundancy, to compress the image for the narrow bandwidth channel. The second stage is channel coding, or the adding of redundant characters to protect the information from noise. This report pursues a method to perform robust source coding, providing both compression and noise mitigation. Specifically, Predictive Trellis Coding Quantization (PTCQ) incorporating various types of prediction filters is investigated. Trellis Coded Quanitization (TCQ) implies using an expanded set of quantization levels and the Viterbi algorithm to determine the minimal distortion path through a trellis, whose structure allows for low bit rate encoding. The prediction filter supplies correlation of the prediction differences and thereby provides the protection from noise at the decoder. PTCQ combines TCQ's encoding efficiency with predictive coding compression merits. Linear and nonlinear filter performance within the PTCQ scheme is shown under various channel conditions. Findings show that nonlinear filter implementation provides the highest noise immunity of those tested. The resulting algorithm is implementable in near real-time, allowing for the fast, efficient transmission of images over noisy channels.
Trellis coded quantization
Author: Michael W. MarcellinPublisher:
ISBN:
Category :
Languages : en
Pages : 116
Book Description
Wavelet Image and Video Compression
Author: Pankaj N. TopiwalaPublisher: Springer Science & Business Media
ISBN: 0306470438
Category : Science
Languages : en
Pages : 434
Book Description
An exciting new development has taken place in the digital era that has captured the imagination and talent of researchers around the globe - wavelet image compression. This technology has deep roots in theories of vision, and promises performance improvements over all other compression methods, such as those based on Fourier transforms, vectors quantizers, fractals, neural nets, and many others. It is this revolutionary new technology that is presented in Wavelet Image and Video Compression, in a form that is accessible to the largest audience possible. Wavelet Image and Video Compression is divided into four parts. Part I, Background Material, introduces the basic mathematical structures that underly image compression algorithms with the intention of providing an easy introduction to the mathematical concepts that are prerequisites for the remainder of the book. It explains such topics as change of bases, scalar and vector quantization, bit allocation and rate-distortion theory, entropy coding, the discrete-cosine transform, wavelet filters and other related topics. Part II, Still Image Coding, presents a spectrum of wavelet still image coding techniques. Part III, Special Topics in Still Image Coding, provides a variety of example coding schemes with a special flavor in either approach or application domain. Part IV, Video Coding, examines wavelet and pyramidal coding techniques for video data. Wavelet Image and Video Compression serves as an excellent reference and may be used as a text for advanced courses covering the subject.
JPEG2000 Image Compression Fundamentals, Standards and Practice
Author: David TaubmanPublisher: Springer Science & Business Media
ISBN: 1461507995
Category : Computers
Languages : en
Pages : 780
Book Description
This is nothing less than a totally essential reference for engineers and researchers in any field of work that involves the use of compressed imagery. Beginning with a thorough and up-to-date overview of the fundamentals of image compression, the authors move on to provide a complete description of the JPEG2000 standard. They then devote space to the implementation and exploitation of that standard. The final section describes other key image compression systems. This work has specific applications for those involved in the development of software and hardware solutions for multimedia, internet, and medical imaging applications.
Subband Image Coding Using Classification and Trellis Coded Quantization
Author: Rajan Laxman JoshiPublisher:
ISBN:
Category : Image compression
Languages : en
Pages : 260
Book Description
Document and Image Compression
Author: Mauro BarniPublisher: CRC Press
ISBN: 1420018833
Category : Technology & Engineering
Languages : en
Pages : 456
Book Description
Although it's true that image compression research is a mature field, continued improvements in computing power and image representation tools keep the field spry. Faster processors enable previously intractable compression algorithms and schemes, and certainly the demand for highly portable high-quality images will not abate. Document and Image Compression highlights the current state of the field along with the most probable and promising future research directions for image coding. Organized into three broad sections, the book examines the currently available techniques, future directions, and techniques for specific classes of images. It begins with an introduction to multiresolution image representation, advanced coding and modeling techniques, and the basics of perceptual image coding. This leads to discussions of the JPEG 2000 and JPEG-LS standards, lossless coding, and fractal image compression. New directions are highlighted that involve image coding and representation paradigms beyond the wavelet-based framework, the use of redundant dictionaries, the distributed source coding paradigm, and novel data-hiding techniques. The book concludes with techniques developed for classes of images where the general-purpose algorithms fail, such as for binary images and shapes, compound documents, remote sensing images, medical images, and VLSI layout image data. Contributed by international experts, Document and Image Compression gathers the latest and most important developments in image coding into a single, convenient, and authoritative source.
Author: Chung-Yen Chiu