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A numerical simulation of a prechamber autoignition gas engine has been performed based on an experimental test case. With a simplified finite-rate/eddy-dissipation model for the combustion of natural gas, it was possible to properly reproduce the experiment considering the combustion duration, ignition timing and overall energy balance. However the predefined empiric constant of the eddy-dissipation model had to be increased by a factor of 10. A modification of the original cylindrical-conical prechamber g

Perceptual prefiltering is the process of enhancing relevant portions of an image or of a video, and of simplifying contextual information in order to improve the perceived quality or the compression ratio. In this paper, we discuss the results of subjective quality evaluation experiments performed to assess the impact of perceptual prefiltering on video coding and we propose an objective quality metric that mimics the behavior of human observers. The predicted performance of the proposed metric is consiste

The new Motion JPEG 2000 standard is providing with some compelling features. It is based on an intra-frame wavelet coding, which makes it very well suited for wireless applications. Indeed, the state-of-the-art wavelet coding scheme achieves very high coding efficiency. In addition, Motion JPEG 2000 is very resilient to transmission errors as frames are coded independently (intra coding). Furthermore, it requires low complexity and introduces minimal coding delay. Finally, it supports very efficient scalab

In this work, we study the effect of inserting spatially local temporal adaptivity to motion compensated frame adaptive transforms for video coding. Motion compensation aligns the temporal wavelet decomposition along motion trajectories. However, valid trajectories for an efficient multi-scale filtering have a finite duration in time. This is due to well known effects like occlusions or inaccurate motion estimation. Hence, the signal encountered by the temporal wavelet transform can be seen as a piecewise-s

In this paper, we discuss a framework for the distributed compression of vector sources, based on our previous work on distributed transform coding. In particular, our goal is to develop a strategy of first applying a suitable distributed Karhunen-Loeve transform, whereafter each component can be andled by standard distributed compression techniques. In the present paper, we first study the scenario where all but one terminal furnish a noisy approximation of their observation. For the case where the underly

Color image quality depends on many factors, such as the initial capture system and its color image processing, compression, transmission, the output device, media and associated viewing conditions. In this paper, we are primarily concerned with color image quality in relation to compression and transmission. We review the typical visual artifacts that occur due to high compression ratios and/or transmission errors. We discuss color image quality metrics and present no-reference artifact metrics for blockin

The Joint Photographic Experts Group (JPEG) has recently rolled out a new still image coding standard called JPEG 2000. This standard integrates an efficient image compression scheme with functionalities required by multimedia applications, such as progressiveness up to lossless coding, region of interest coding, and error resiliency. Security is a concern in many applications, and therefore also a desired functionality. This paper provides readers with insights and examples of how to combine security solut

I. Introduction Wavelets are the result of collective efforts that recognized common threads between ideas and concepts that had been independently developed and investigated by distinct research communities. They provide a unifying framework for decomposing images, volumes, and time-series data into their elementary constituents across scale. Although a relatively recent construct, wavelets have become a tool of choice for engineers, physicists, and mathematicians, leading to efficient solutions in time a

We propose a fully three-dimensional object-based coding system exploiting the diagnostic relevance of the different regions of the volumetric data for rate allocation. The data are first decorrelated via a 3D discrete wavelet transform. The implementation via the lifting steps scheme allows to map integer-to-integer values, enabling lossless coding, and facilitates the definition of the object-based inverse transform. The coding process assigns disjoint segments of the bitstream to the different objects, w

Over the last decade or so, wavelets have had a growing impact on signal processing theory and practice, both because of the unifying role and their successes in applications. Filter banks, which lie at the heart of wavelet-based algorithms, have become standard signal processing operators, used routinely in applications ranging from compression to modems. The contributions of wavelets have often been in the subtle interplay between discrete-time and continuous-time signal processing. The purpose of this ar

The JPEG 2000 is a new image coding standard that specifies only the decoding algorithm and the compressed data format—the encoder algorithm is deliberately left up to you.

The ridgelet transform (Candes and Donoho, 1999) was introduced as a new multiscale representation for functions on continuous spaces that are smooth away from discontinuities along lines. In this paper, we present several discrete versions of the ridgelet transform that lead to algorithmic implementations. The resulting transforms are invertible, non-redundant and computed via fast algorithms. Furthermore, this construction leads to a family of directional orthonormal bases for digital images. Numerical re

Scrambling for Video Surveillance with Privacy

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Numerical simulations of a prechamber autoignition cogeneration engine operating on natural gas

Evaluating Perceptually Prefiltered Video

Error-Resilient Video Coding Performance Analysis of Motion JPEG 2000 and MPEG-4

Intra-Adaptive Motion-Compensated Lifted Wavelets for Video Coding

On Compression Using the Distributed Karhunen-Loeve Transform

Color image quality on the Internet

Secure JPEG 2000 - JPSEC

Guest Editorial: Wavelets in Medical Imaging

Lossy to lossless object-based coding of 3-D MRI data

Wavelets, approximation, and compression

The JPEG 2000 Image Coding Standard

Discrete Ridgelet Transforms for Image Representation