39,964 research outputs found
Data compression techniques applied to high resolution high frame rate video technology
An investigation is presented of video data compression applied to microgravity space experiments using High Resolution High Frame Rate Video Technology (HHVT). An extensive survey of methods of video data compression, described in the open literature, was conducted. The survey examines compression methods employing digital computing. The results of the survey are presented. They include a description of each method and assessment of image degradation and video data parameters. An assessment is made of present and near term future technology for implementation of video data compression in high speed imaging system. Results of the assessment are discussed and summarized. The results of a study of a baseline HHVT video system, and approaches for implementation of video data compression, are presented. Case studies of three microgravity experiments are presented and specific compression techniques and implementations are recommended
Combined wavelet domain and motion compensated filtering compliant with video codecs
In this paper, we introduce the idea of using motion estimation resources from a video codec for video denoising. This is not straightforward because the motion estimators aimed for video compression and coding, tolerate errors in the estimated motion field and hence are not directly applicable to video denoising. To solve this problem, we propose a novel motion field filtering step that refines the accuracy of the motion estimates to a degree that is required for denoising.
We illustrate the use of the proposed motion estimation method within a wavelet-based video denoising scheme. The resulting video denoising method is of low-complexity and receives comparable results with respect to the latest video denoising methods
Recovery from Linear Measurements with Complexity-Matching Universal Signal Estimation
We study the compressed sensing (CS) signal estimation problem where an input
signal is measured via a linear matrix multiplication under additive noise.
While this setup usually assumes sparsity or compressibility in the input
signal during recovery, the signal structure that can be leveraged is often not
known a priori. In this paper, we consider universal CS recovery, where the
statistics of a stationary ergodic signal source are estimated simultaneously
with the signal itself. Inspired by Kolmogorov complexity and minimum
description length, we focus on a maximum a posteriori (MAP) estimation
framework that leverages universal priors to match the complexity of the
source. Our framework can also be applied to general linear inverse problems
where more measurements than in CS might be needed. We provide theoretical
results that support the algorithmic feasibility of universal MAP estimation
using a Markov chain Monte Carlo implementation, which is computationally
challenging. We incorporate some techniques to accelerate the algorithm while
providing comparable and in many cases better reconstruction quality than
existing algorithms. Experimental results show the promise of universality in
CS, particularly for low-complexity sources that do not exhibit standard
sparsity or compressibility.Comment: 29 pages, 8 figure
Frame Theory for Signal Processing in Psychoacoustics
This review chapter aims to strengthen the link between frame theory and
signal processing tasks in psychoacoustics. On the one side, the basic concepts
of frame theory are presented and some proofs are provided to explain those
concepts in some detail. The goal is to reveal to hearing scientists how this
mathematical theory could be relevant for their research. In particular, we
focus on frame theory in a filter bank approach, which is probably the most
relevant view-point for audio signal processing. On the other side, basic
psychoacoustic concepts are presented to stimulate mathematicians to apply
their knowledge in this field
Dynamic Rate Adaptation for Improved Throughput and Delay in Wireless Network Coded Broadcast
In this paper we provide theoretical and simulation-based study of the
delivery delay performance of a number of existing throughput optimal coding
schemes and use the results to design a new dynamic rate adaptation scheme that
achieves improved overall throughput-delay performance.
Under a baseline rate control scheme, the receivers' delay performance is
examined. Based on their Markov states, the knowledge difference between the
sender and receiver, three distinct methods for packet delivery are identified:
zero state, leader state and coefficient-based delivery. We provide analyses of
each of these and show that, in many cases, zero state delivery alone presents
a tractable approximation of the expected packet delivery behaviour.
Interestingly, while coefficient-based delivery has so far been treated as a
secondary effect in the literature, we find that the choice of coefficients is
extremely important in determining the delay, and a well chosen encoding scheme
can, in fact, contribute a significant improvement to the delivery delay.
Based on our delivery delay model, we develop a dynamic rate adaptation
scheme which uses performance prediction models to determine the sender
transmission rate. Surprisingly, taking this approach leads us to the simple
conclusion that the sender should regulate its addition rate based on the total
number of undelivered packets stored at the receivers. We show that despite its
simplicity, our proposed dynamic rate adaptation scheme results in noticeably
improved throughput-delay performance over existing schemes in the literature.Comment: 14 pages, 15 figure
Color space adaptation for video coding
Processament d'imatges abans de ser codificades pel codificador HEVC amb la finalitat d'augmentar la qualitat i la fidelitat.[ANGLÈS] Project on the objective and subjective improvements by pre-processing images to be encoded into a video.[CASTELLÀ] Proyecto sobre la repercusión en la mejora de calidad objetiva y subjetiva del pre-procesado de imágenes a codificar con vídeo.[CATALÀ] Projecte sobre la repercussió en la millora de la qualitat objectiva i subjectiva del pre-processament d'imatges a codificar amb vídeo
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