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Digitization of the Battlespace III

作者： Saha, RK Chang, KC Lee, K Nova Res Corp Burlington MA 01803 USA

ISBN: (纸本)0819428426

Situation awareness systems must process and disseminate position information from widely dispersed maneuvering warfighters using combat net radios in restrictive environments. Such systems are important for effective monitoring, situation assessment, and mission planning. When information about the current location of friendly forces is combined with their identity, maneuver plans, and expected future locations, a complete situation awareness system is obtained. Due to the large volume of situation awareness data transmitted over the tactical communication links, it is essential to conserve bandwidth. This paper describes a bandwidth saving algorithm using the theory of Stochastic Approximation. Analysis of this algorithm is presented and its performance is validated by means of simulation.

关键词： situation awareness battlefield management bandwidth saving stochastic approximation predictive encoding

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A Speech predictive encoding Communication System for Multichannel Telephony

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IEEE Transactions on Communications 1973年第7期21卷 827-835页

作者： Sciulli, Joseph A. Campanella, S.J. COMSAT Laboratories Clarksburg Md. 20734 United States

This paper describes a speech predictive encoding communications (SPEC) system that is designed to accommodate the traffic of N PCM telephone trunks in the capacity of N/2 PCM telephone channels. The system exploits the statistics of multichannel voice communication in a manner significantly different from the technique employed in the well-known time-assignment speech interpolation (TASI) system. Specifically, the SPEC system operates at the transmitter by removing redundant speech samples during talk bursts as well as during silence intervals. The receiver remembers the most recent sample transmitted through each channel. As long as a new sample is not transmitted, the receiver simply repeats the sample value stored in its memory. Each sample from each incoming trunk is examined every 125 µs to determine which samples must be transmitted and which are redundant. Because the SPEC system operates at this high speed and predicts redundant or missing samples at the receiver, it does not produce the speech clipping effects typical of TASI-like systems. Any voice-quality degradation due to increased call load and/or speech activity is manifested as an increase in noise power. The subjective result is a graceful degradation that is virtually imperceptible to the listener. Copyright © 1973 by The Institute of Electrical and Electronics Engineers, Inc.

关键词： Speech predictive encoding Telephony Phase change materials Degradation Time division multiplexing Statistics Switches Error correction Communication system traffic

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predictive encoding using coset codes

Predictive encoding using coset codes

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IEEE International Conference on Image Processing

作者： A. Jagmohan A. Sehgal N. Ahuja University of Illinois Urbana-Champaign USA

predictive encoding with respect to multiple possible predictors is a common scenario encountered in many digital set-top box applications, such as redundant storage of video/audio data, real-time robust communication with peripherals and Internet video/audio telephony. A key problem associated with this scenario is that of predictive mismatch or drift. In the present paper, we pose the problem of predictive encoding with multiple possible predictors as a variant of the well-known Wyner-Ziv side-information problem. We propose an approach based on the use of coset codes for predictive encoding, for mitigating the effect of drift without overly sacrificing compression efficiency. The proposed approach can be used to improve coding performance in a wide range of practical applications such as multiple description coding, scalable coding and redundant storage of video/audio streams. We illustrate the efficacy of the proposed approach through a simple example based on the application of low-delay Internet telephony. Our results indicate that the proposed approach significantly outperforms conventional predictive encoding for communication over lossy channels.

关键词： predictive encoding Decoding Streaming media Robustness Internet telephony predictive coding Wavelet transforms Source coding Video compression Audio compression

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Reverse water-filling in predictive encoding of speech

Reverse water-filling in predictive encoding of speech

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IEEE Workshop on Speech Coding Proceedings

作者： S.V. Andersen W.B. Kleijn Department of Speech Music and Hearing KTH Royal Institute of Technology Stockholm Sweden

Reverse water-filling suggests that, at low bit rates, the synthesis filter for predictive encoding should differ from the model filter of the signal to be encoded. However, reverse water-filling follows from optimum encoding and stationary Gaussian assumptions. By means of simple experiments, we show that reverse water-filling applies to predictive encoding of speech. For a vector analysis-by-synthesis encoding based on a first order autoregressive signal model, the use of a synthesis filter derived from reverse water-filling resulted in consistently improved segmental SNR measures.

关键词： predictive encoding Speech synthesis Filters Signal synthesis Decoding Distortion measurement Bit rate Vectors Filling Gaussian processes

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A drift-free motion-compensated predictive encoding technique for multiple description coding

A drift-free motion-compensated predictive encoding techniqu...

引用

IEEE International Conference on Multimedia and Expo (ICME)

作者： Yen-Chi Lee Y. Altunbasak R.M. Mersereau Center for Signal and Image Processing Georgia Institute of Technology Atlanta GA USA

Multiple description coding (MDC) is a source coding technique that exploits path diversity to increase the robustness of transmitting a compressed signal over error-prone channels. However, the applicant of MDC to video coding is still problematic because a prediction mismatch problem, called drift, may occur at the decoder when one description is lost. In this paper, we propose a drift free motion-compensated predictive coding method for multiple description scalar quantizers. The proposed method maintains two more prediction loops at the encoder side to produce all possible predictions. Then, the two descriptions are generated from these two additional prediction loops in such a way that the drift can be prevented when only one description is received. By receiving both descriptions, the decoder can still combine these two descriptions in the central prediction loop to improve the video quality. Experimental results show that the proposed method can effectively prevent drift and improve the quality of single-description reconstruction by 0.2-0.8 dB as compared to the method in [A. Reibman et al., 1999].

关键词： predictive encoding Decoding Image coding Image reconstruction Source coding Robustness Video coding Signal processing Image processing predictive coding

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Photic drive response in people with epilepsy: Exploring the interaction with background alpha rhythm

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VISION RESEARCH 2025年 228卷 108548页

作者： Ali, Eman N. Lueck, Christian J. Martin, Kate L. Borbelj, Angela Maddess, Ted Australian Natl Univ Eccles Inst Neurosci John Curtin Sch Med Res 131 Garran Rd Acton ACT 2601 Australia King Fahad Specialist Hosp Dept Neurosci Dammam Saudi Arabia Australian Natl Univ Sch Med & Psychol Acton ACT Australia Canberra Hosp Dept Neurol Canberra ACT Australia

Photic drive responses (PDRs) are used to explore cortical hyperexcitability. We quantified PDRs and interactions with the alpha rhythm in people with epilepsy (PwE). Fifteen PwE (mean age +/- SD 47.3 +/- 4.6 years;8 males), and 15 control subjects (mean age 52.7 +/- 4.6 years;9 males) underwent EEG with modified intermittent photic stimulation (IPS). The modification allowed so-called alpha-band gain to be measured. None of the PwE had demonstrated photosensitivity. The modified IPS method alternated eyes-open and eyes-closed conditions with and without IPS. The alpha-band gain appeared as N-fold changes in PDR when IPS (or its harmonics) and the alpha-bands overlapped. An epileptic attack within 1 month of testing significantly increased alpha-band gain by 1.36x. Generalised epilepsy (but not focal epilepsy) significantly decreased alpha-band gain y 0.79x. Each decade of age beyond the mean age significantly increased alpha-band gain by 1.09x. Similar significant interactions were seen between alpha and the second harmonic of IPS driving frequencies that matched alpha frequencies, i.e. for recent attack and, generalized epilepsy. The interactions thus appeared to be occurring between cortical IPS outputs and the alpha generator. These changes were most evident at electrodes O1 and O2. Investigating alpha-band gain using modified IPS offers a way to quantify cortical hyperexcitability in epilepsy and other diseases. It also provides new information about alpha and so too predictive coding, which appears to be at least partly governed by alpha.

关键词： Epilepsy Photic drive response Cortical excitability Alpha rhythm generator predictive encoding

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A practical course in digital video communications based on MATLAB

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IEEE TRANSACTIONS ON EDUCATION 1996年第2期39卷 127-136页

作者： Arnold, JF Cavenor, MC School of Electrical Engineering Defence Force Academy University슠of New South Wales Canberra ACT Australia

The outline of new course in video coding is presented in which the basic concepts are reinforced by way of a series of graded MATLAB exercises. Following a brief overview of the motion-compensated discrete cosine transform (DCT) encoder, a number of exercises are described in which the student obtains an understanding of image correlations and entropy and the concepts involved in predictive encoding. The data compaction properties of the discrete cosine transform are then illustrated together with interframe motion-estimation and motion-compensated prediction. All aspects of the evolving video encoder are then integrated by way of a simplified encoder syntax that is based upon the standard Moving Picture Experts Group (MPEG) syntax. This allows students to exchange digital bit-streams and decode image sequences that have been encoded by fellow students. Advanced topics such as fast motion estimation techniques, error resilience, and other coding approaches are briefly discussed.

关键词： MATLAB Discrete cosine transforms Video coding Entropy predictive encoding Compaction MPEG standards Decoding Image sequences Fellows

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predictively encoded graph convolutional network for noise-robust skeleton-based action recognition

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APPLIED INTELLIGENCE 2022年第3期52卷 2317-2331页

作者： Yoon, Yongsang Yu, Jongmin Jeon, Moongu Gwangju Inst Sci & Technol GIST Sch Elect Engn & Comp Sci Gwangju 61005 South Korea Curtin Univ Sch Elect Engn Comp & Math Sci Perth WA 610 Australia

In skeleton-based action recognition, graph convolutional networks (GCNs), which model human body skeletons using graphical components such as nodes and connections, have recently achieved remarkable performance. While the current state-of-the-art methods for skeleton-based action recognition usually assume that completely observed skeletons will be provided, it is problematic to realize this assumption in real-world scenarios since the captured skeletons may be incomplete or noisy. In this work, we propose a skeleton-based action recognition method that is robust to noise interference for the given skeleton features. The key insight of our approach is to train a model by maximizing the mutual information between normal and noisy skeletons using predictive coding in the latent space. We conducted comprehensive skeleton-based action recognition experiments with defective skeletons using the NTU-RGB+D and Kinetics-Skeleton datasets. The experimental results demonstrate that when the skeleton samples are noisy, our approach achieves outstanding performances compared with the existing state-of-the-art methods.

关键词： predictive encoding Graph convolutional network Noise-robust Skeleton-based action recognition

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Enhancing the compression performance in medical images using a novel hex-directional chain code (Hex DCC) representation

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SOFT COMPUTING 2021年第7期25卷 5807-5830页

作者： Brinda, T. Dharma, Dejey Anna Univ Reg Campus Tirunelveli Dept Comp Sci & Engn Tirunelveli India

This paper is about a novel representation based on lossless encoding for medical images. It relies on directional codes for efficient storage and transmission. Image compression is a recent research, where removal or elimination of redundant information is carried out in an image. In this paper, for medical image compression, an edge- and texture-based entropy coding is presented. The proposed work is partitioned into two stages. In the first stage, a novel lossless hex-directional chain code or chain code 16 (C16) boundary representation approach is applied for edge encoding. In this C16 method, a set of pixels are connected along the edge of an image based on the direction code. Eliminating redundant information and retaining the topological information is the basic idea of chain code. It concerns the shape and the structure of the object which helps in preserving the quality of an image. In the second stage, predictor-based entropy coding is applied for adopting texture feature as a basic primitive. Finally, the outcome of the two stages is provided to the entropy coder for attaining compression. The proposed method is tested with standard benchmark chain code dataset and medical image datasets for various modalities of different sizes. Performance metrics such as compression ratio (%), encoding time and mean square error are used to evaluate the proposed technique. From the results attained, it is evident that the proposed technique results in better compression performance when compared to the existing methods.

关键词： Medical image compression Hex-directional chain code (Hex DCC) Lossless compression Compression ratio predictive encoding Entropy encoding

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Affine-structure-based facial image encoding

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IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 1999年第4期146卷 211-221页

作者： Chatterjee, S Banerjee, S Biswas, KK Indian Inst Technol Dept Comp Sci & Engn New Delhi 110016 India

A real-time algorithm for affine-structure-based video compression for facial images is presented. The face undergoing motion is segmented and triangulated to yield a set of control points. The set of control points generated by triangulation are tracked across a few frames using an intensity-based correlation technique. For accurate motion and structure estimation a Kalman-filter-based algorithm is used to track features on the facial image. The structure information of the control points is transmitted only during the bootstrapping stage. After that only the motion information is transmitted to the decoder. This reduces the number of motion parameters associated with control points in each frame. The local motion of the eyes and lips is captured using local 2-D affine transformations. For real time implementation a quad-tree based search technique is adopted to solve local correlation. Any remaining reconstruction error is accounted for using predictive encoding. Results on real image sequences demonstrate the applicability of the method.

关键词： video coding Combinatorial mathematics motion parameters data compression correlation methods image motion analysis image segmentation video compression face segmentation bootstrapping facial images Filtering methods in signal processing affine-structure-based facial image encoding Video signal processing Kalman filters quadtrees motion information reconstruction error real-time algorithm intensity-based correlation technique face triangulation tracking Image and video coding filtering theory feature tracking quad-tree based search technique image reconstruction local correlation Kalman-filter-based algorithm image sequences low-bit rate video real image sequences local 2D affine transformations predictive encoding

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