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2-Step Scalar Deadzone Quantization for bitplane image coding

IEEE TRANSACTIONS ON image PROCESSING 2013年第12期22卷 4678-4688页

作者： Auli-Llinas, Francesc Univ Autonoma Barcelona Dept Informat & Commun Engn Cerdanyola Del Valles 08290 Spain

Modern lossy image coding systems generate a quality progressive codestream that, truncated at increasing rates, produces an image with decreasing distortion. Quality progressivity is commonly provided by an embedded quantizer that employs uniform scalar deadzone quantization (USDQ) together with a bitplane coding strategy. This paper introduces a 2-step scalar deadzone quantization (2SDQ) scheme that achieves same coding performance as that of USDQ while reducing the coding passes and the emitted symbols of the bitplane coding engine. This serves to reduce the computational costs of the codec and/or to code high dynamic range images. The main insights behind 2SDQ are the use of two quantization step sizes that approximate wavelet coefficients with more or less precision depending on their density, and a rate-distortion optimization technique that adjusts the distortion decreases produced when coding 2SDQ indexes. The integration of 2SDQ in current codecs is straightforward. The applicability and efficiency of 2SDQ are demonstrated within the framework of JPEG2000.

关键词： 2-step scalar deadzone quantization general embedded quantization bitplane image coding JPEG2000

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bitplane image coding With Parallel Coefficient Processing

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IEEE TRANSACTIONS ON image PROCESSING 2016年第1期25卷 209-219页

作者： Auli-Llinas, Francesc Enfedaque, Pablo Moure, Juan C. Sanchez, Victor Univ Autonoma Barcelona Dept Informat & Commun Engn Bellaterra 08193 Spain Univ Autonoma Barcelona Dept Comp Architecture & Operating Syst Bellaterra 08193 Spain Univ Warwick Dept Comp Sci Coventry CV4 7AL W Midlands England

image coding systems have been traditionally tailored for multiple instruction, multiple data (MIMD) computing. In general, they partition the (transformed) image in codeblocks that can be coded in the cores of MIMD-based processors. Each core executes a sequential flow of instructions to process the coefficients in the codeblock, independently and asynchronously from the others cores. bitplane coding is a common strategy to code such data. Most of its mechanisms require sequential processing of the coefficients. The last years have seen the upraising of processing accelerators with enhanced computational performance and power efficiency whose architecture is mainly based on the single instruction, multiple data (SIMD) principle. SIMD computing refers to the execution of the same instruction to multiple data in a lockstep synchronous way. Unfortunately, current bitplane coding strategies cannot fully profit from such processors due to inherently sequential coding task. This paper presents bitplane image coding with parallel coefficient (BPC-PaCo) processing, a coding method that can process many coefficients within a codeblock in parallel and synchronously. To this end, the scanning order, the context formation, the probability model, and the arithmetic coder of the coding engine have been re-formulated. The experimental results suggest that the penalization in coding performance of BPC-PaCo with respect to the traditional strategies is almost negligible.

关键词： bitplane image coding single instruction multiple data (SIMD) JPEG2000

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Strategy of Microscopic Parallelism for bitplane image coding

Strategy of Microscopic Parallelism for Bitplane Image Codin...

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Data Compression Conference (DCC)

作者： Auli-Llinas, Francesc Enfedaque, Pablo Moure, Juan C. Blanes, Ian Sanchez, Victor Univ Autonoma Barcelona Dept Informat & Commun Engn E-08193 Barcelona Spain Univ Autonoma Barcelona Dept Comp Architecture & Operating Syst E-08193 Barcelona Spain Univ Warwick Dept Comp Sci Coventry CV4 7AL W Midlands England

ISBN: (纸本)9781479984305

Recent years have seen the upraising of a new type of processors strongly relying on the Single Instruction, Multiple Data (SIMD) architectural principle. The main idea behind SIMD computing is to apply a flow of instructions to multiple pieces of data in parallel and synchronously. This permits the execution of thousands of operations in parallel, achieving higher computational performance than with traditional Multiple Instruction, Multiple Data (MIMD) architectures. The level of parallelism required in SIMD computing can only be achieved in image coding systems via microscopic parallel strategies that code multiple coefficients in parallel. Until now, the only way to achieve microscopic parallelism in bitplane coding engines was by executing multiple coding passes in parallel. Such a strategy does not suit well SIMD computing because each thread executes different instructions. This paper introduces the first bitplane coding engine devised for the fine grain of parallelism required in SIMD computing. Its main insight is to allow parallel coefficient processing in a coding pass. Experimental tests show coding performance results similar to those of JPEG2000.

关键词： bitplane image coding JPEG2000 single instruction multiple data

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Scanning Order Strategies for bitplane image coding

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IEEE TRANSACTIONS ON image PROCESSING 2012年第4期21卷 1920-1933页

作者： Auli-Llinas, Francesc Marcellin, Michael W. Univ Autonoma Barcelona Dept Informat & Commun Engn Bellaterra 08193 Spain Univ Arizona Dept Elect & Comp Engn Tucson AZ 85721 USA

Scanning orders of bitplane image coding engines are commonly envisaged from theoretical or experimental insights and assessed in practice in terms of coding performance. This paper evaluates classic scanning strategies of modern bitplane image codecs using several theoretical-practical mechanisms conceived from rate-distortion theory. The use of these mechanisms allows distinguishing those features of the bitplane coder that are essential from those that are not. This discernment can aid the design of new bitplane coding engines with some special purposes and/or requirements. To emphasize this point, a low-complexity scanning strategy is proposed. Experimental evidence illustrates, assesses, and validates the proposed mechanisms and scanning orders.

关键词： bitplane image coding JPEG2000 probability models scanning orders

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Entropy-Based Evaluation of Context Models for Wavelet-Transformed images

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IEEE TRANSACTIONS ON image PROCESSING 2015年第1期24卷 57-67页

作者： Auli-Llinas, Francesc Univ Autonoma Barcelona Dept Informat & Commun Engn Bellaterra 08193 Spain

Entropy is a measure of a message uncertainty. Among others aspects, it serves to determine the minimum coding rate that practical systems may attain. This paper defines an entropy-based measure to evaluate context models employed in wavelet-based image coding. The proposed measure is defined considering the mechanisms utilized by modern coding systems. It establishes the maximum performance achievable with each context model. This helps to determine the adequateness of the model under different coding conditions and serves to predict with high precision the coding rate achieved by practical systems. Experimental results evaluate four well-known context models using different types of images, coding rates, and transform strategies. They reveal that, under specific coding conditions, some widely-spread context models may not be as adequate as it is generally thought. The hints provided by this analysis may help to design simpler and more efficient wavelet-based image codecs.

关键词： Context models image entropy wavelet transform bitplane image coding JPEG2000

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Lossy-to-lossless 3D image coding through prior coefficient lookup tables

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INFORMATION SCIENCES 2013年 239卷 266-282页

作者： Auli-Llinas, Frances Marcellin, Michael W. Serra-Sagrista, Joan Bartrina-Rapesta, Joan Univ Autonoma Barcelona Dept Informat & Commun Engn Bellaterra 08193 Spain Univ Arizona Dept Elect & Comp Engn Tucson AZ 85721 USA

This paper describes a low-complexity, high-efficiency, lossy-to-lossless 3D image coding system. The proposed system is based on a novel probability model for the symbols that are emitted by bitplane coding engines. This probability model uses partially reconstructed coefficients from previous components together with a mathematical framework that captures the statistical behavior of the image. An important aspect of this mathematical framework is its generality, which makes the proposed scheme suitable for different types of 3D images. The main advantages of the proposed scheme are competitive coding performance, low computational load, very low memory requirements, straightforward implementation, and simple adaptation to most sensors. (C) 2013 Elsevier Inc. All rights reserved.

关键词： 3D image coding Entropy coding bitplane image coding JPEG2000

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Stationary Probability Model for Microscopic Parallelism in JPEG2000

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IEEE TRANSACTIONS ON MULTIMEDIA 2014年第4期16卷 960-970页

作者： Auli-Llinas, Francesc Marcellin, Michael W. Univ Autonoma Barcelona Dept Informat & Commun Engn Bellaterra 08193 Spain Univ Arizona Dept Elect & Comp Engn Tucson AZ 85721 USA

Parallel processing is key to augmenting the throughput of image codecs. Despite numerous efforts to parallelize wavelet-based image coding systems, most attempts fail at the parallelization of the bitplane coding engine, which is the most computationally intensive stage of the coding pipeline. The main reason for this failure is the causality with which current coding strategies are devised, which assumes that one coefficient is coded after another. This work analyzes the mechanisms employed in bitplane coding and proposes alternatives to enhance opportunities for parallelism. We describe a stationary probability model that, without sacrificing the advantages of current approaches, removes the main obstacle to the parallelization of most coding strategies. Experimental tests evaluate the coding performance achieved by the proposed method in the framework of JPEG2000 when coding different types of images. Results indicate that the stationary probability model achieves similar coding performance, with slight increments or decrements depending on the image type and the desired level of parallelism.

关键词： bitplane image coding JPEG2000 parallel architectures probability models

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HIGH THROUGHPUT image CODEC FOR HIGH-RESOLUTION SATELLITE imageS 38

HIGH THROUGHPUT IMAGE CODEC FOR HIGH-RESOLUTION SATELLITE IM...

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38th IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： de Cea-Dominguez, Carlos Enfedaque, P. Moure, Juan C. Bartrina-Rapesta, Joan Auli-Llinas, Francesc Univ Autonoma Barcelona Dept Informat & Commun Engn Barcelona Spain Univ Autonoma Barcelona Dept Comp Architecture & Operating Syst Barcelona Spain Lawrence Berkeley Natl Lab Computat Res Div Berkeley CA USA

ISBN: (纸本)9781538671504

The growth in the use of satellite images has generated the need for their fast compression, processing, and distribution. JPEG2000 is a widespread standard for the compression and transmission of such images once they are in the ground. Despite its advanced features and excellent coding performance, JPEG2000 demands significant computational resources. This paper introduces a wavelet-based codec that uses the JPEG2000 framework, but replaces its most computationally demanding coding stage by a highly parallel engine. When executed in Graphics Processing Units to code high-resolution satellite images, the proposed codec achieves speed-ups of up to 8x when compared to the fastest implementation of JPEG2000 executed in a multi-core platform.

关键词： High throughput image coding bitplane image coding JPEG2000

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HIGH THROUGHPUT image CODEC FOR HIGH-RESOLUTION SATELLITE imageS

HIGH THROUGHPUT IMAGE CODEC FOR HIGH-RESOLUTION SATELLITE IM...

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IEEE International Geoscience and Remote Sensing Symposium

作者： Carlos de Cea-Dominguez P. Enfedaque Juan C. Moure Joan Bartrina-Rapesta Francesc Auli-Llinas Department of Information and Communications Engineering Universitat Autònoma de Barcelona Spain Department of Computer Architecture and Operating Systems Universitat Autònoma de Barcelona Spain Computational Research Division Lawrence Berkeley National Laboratory

The growth in the use of satellite images has generated the need for their fast compression, processing, and distribution. JPEG2000 is a widespread standard for the compression and transmission of such images once they are in the ground. Despite its advanced features and excellent coding performance, JPEG2000 demands significant computational resources. This paper introduces a wavelet-based codec that uses the JPEG2000 framework, but replaces its most computationally demanding coding stage by a highly parallel engine. When executed in Graphics Processing Units to code high-resolution satellite images, the proposed codec achieves speed-ups of up to 8× when compared to the fastest implementation of JPEG2000 executed in a multi-core platform.

关键词： High throughput image coding bitplane image coding JPEG2000

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