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Signal Processing and Communications (SPCOM), 2012 International Conference on

Date 22-25 July 2012

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Displaying Results 1 - 25 of 102
  • [Front cover]

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  • Message from the general co-chairs

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    Freely Available from IEEE
  • Message from the TPC co-chairs

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    Freely Available from IEEE
  • Fractional Calculus based analysis of Phase Locked Loop

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (267 KB) |  | HTML iconHTML  

    Analysis of Phase Locked Loop in Fractional domain is the main objective of the paper. Initially basics of Fractional Calculus and Phase Locked Loop is revisited. A fractional order Phase Locked Loop(FOPLL) is obtained by replacing conventional Low Pass filter and Voltage Controlled Oscillator with their fractional order counterparts. Calculations such as error phase, output phase, steady state errors, stability conditions are carried out. From the results it is observed that phase offset is independent of the fractional order. It has been observed that lower fractional order PLL's will produce higher bandwidth as compared to their integer counterparts. It has also been observed that the Locking range and Capture range can be improved by using lower values of fractional orders. View full abstract»

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  • Classification of normal and pathological voices using TEO phase and Mel cepstral features

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (369 KB) |  | HTML iconHTML  

    In this paper, a new feature-set, viz., Teager Energy Operator (TEO) phase has been proposed for automatic classification of normal vs. pathological voices. Development of TEO phase has been motivated from recently proposed linear prediction (LP) residual phase for speaker recognition. Classification was performed using a discriminatively-trained 2nd order polynomial classifier on a subset of the Massachusetts Ear and Eye Infirmary (MEEI) database. Score-level fusion of TEO phase and state-of-the-art Mel frequency cepstral coefficients (MFCC) gave reduction in equal error rate (EER) by 1.86 % than EER of MFCC alone. Proposed TEO phase feature set is also evaluated under degraded conditions using the NOISEX-92 database for the case of additive car noise. View full abstract»

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  • Direct-MUSIC on sparse arrays

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (876 KB) |  | HTML iconHTML  

    Nested and coprime arrays are sparse arrays which can identify O(m2) sources using only m sensors. Systematic algorithms have recently been developed for such identification. These algorithms are traditionally implemented by performing MUSIC or a similar algorithm in the difference-coarray domain. This paper considers the use of nested and coprime arrays for the case where the number of sources is less than m. It will be demonstrated that there are some important advantages even in this case. With the number of sources limited like this, it is possible to use MUSIC directly on the nested or coprime array rather than in the coarray domain. But owing to array sparsity, the unambiguous identifiability property has to be revisited. This paper first mentions two results for such identifiability. Second, the improvement in the Cramer-Rao bound (over uniform linear arrays or ULAs) is analyzed. One conclusion is that the CRB improvements of nested and coprime arrays are comparable to those of other known sparse arrays such as MRAs. It is also observed that nested and coprime arrays have higher resolvability than the ULA, for a fixed number of sensors. View full abstract»

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  • On comparing multivariate complex random signals

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (233 KB) |  | HTML iconHTML  

    We consider the problem of comparing two complex multivariate random signal realizations to ascertain whether they have identical power spectral densities. A binary hypothesis testing approach is formulated and a generalized likelihood ratio test (GLRT) is derived. An asymptotic analytical solution for calculating the test threshold is provided. The results are illustrated via computer simulations. Past work on this problem is limited to either scalar signals or real-valued multivariate signals. The proposed test has potential applications in diverse areas including user authentication in wireless networks with multiantenna receivers and spectrum sensing in cognitive radio networks with multiantenna receivers. View full abstract»

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  • A novel generalized time-frequency transform inspired by the Fractional Fourier Transform for higher order chirps

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB) |  | HTML iconHTML  

    In this manuscript, we propose a class of linear integral transforms that extends the capabilities of the Fractional Fourier Transform (FrFT), while preserving some key properties of the FrFT. The FrFT has diverse applications in literature, including the parameter estimation of linear chirp signals. Here, we also illustrate ways to employ the proposed new transforms to estimate higher order chirps, such as quadratic chirp signals. View full abstract»

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  • Epoch extraction from emotional speech

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (347 KB) |  | HTML iconHTML  

    This work proposes a modified zero frequency filtering (ZFF) method for epoch extraction from emotional speech. Epochs refers the instants of maximum excitation of the vocal tract. In the conventional ZFF method, the epochs are estimated by trend removing the output of the zero frequency resonator (ZFR) using the window length equal to the average pitch period of the utterance. Use of this fixed window length for the epoch estimation causes spurious or missed estimation from the speech signals having rapid pitch variations like in emotional speech. This work therefore proposes a refined ZFF method for epoch estimation by trend removing the output of ZFR using the variable windows obtained by finding the average pitch periods for every fixed blocks of speech and low pass filtering the resulting trend removed signal segments using the estimated pitch as the cutoff frequency. The epoch estimation performance is evaluated for five different emotions in the German emotional speech corpus having simultaneous electro-glotto graph (EGG) recordings. The improved epoch estimation performance indicates the robustness of the proposed method against rapid pitch variations in emotional speech signals. The effectiveness of the proposed method is also confirmed by the improved epoch estimation performance on the Hindi emotional speech database. View full abstract»

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  • Design of 3-D FCO filter bank using Eigenfilter based kernel for transformation of variables

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2617 KB) |  | HTML iconHTML  

    In this paper, a method for designing two-channel zero-phase 3-D Face Centered Orthorhombic (FCO) filter bank is illustrated. We present Eigenfilter based method for designing symmetric transformation kernels which can be used in generalized McClellan transformation method for designing 3-D FCO filter banks. Design examples are provided to demonstrate the effectiveness of the design method and it has been shown that good 3-D FCO filter banks can be obtained using 3-D symmetric transformation kernels designed with Eigenfilter approach. View full abstract»

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  • Design of data width requirement for fixed-point turbo decoders based on modified MAP algorithm

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (318 KB) |  | HTML iconHTML  

    Turbo codes are the most exciting and potentially important development in the coding theory and it has already entered the field of practical application. The most important and foremost design issue prior to the implementation of soft decoder for such turbo code is the estimation of bits required to represent the quantized soft log-likelihood ratio (LLR), internal metrics and extrinsic information. This paper presents the systematic approach to estimate the number of bits and the precision required for these factors, such that the performance of decoder is similar to the ideal bit error rate (BER) performance with an infinite precision. Specifically, we have presented this methodology for turbo decoders based on modified MAP algorithm using Maclaurin series. This paper also presents the mathematical analysis which shows the dependency of precision on the BER performance for such modified MAP algorithm. View full abstract»

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  • Characterization of ECG signals using multiscale approach

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (541 KB) |  | HTML iconHTML  

    Electrocardiogram signals are examined for accurately diagnosing the heart abnormalities. Different signal processing techniques have been applied on these signals to interpret and detect the heart diseases. Considering the inherent self similar pattern of ECG signals as a signature for normal behaviour, the present work explores the usefulness of the associated Hurst exponent as a means for characterizing the ECG signals for their normal, anomalous behaviours. The paper applies on ECG data sets various methods that detect Hurst exponent with and without wavelet transform. Our experimental observations present the ranges of Hurst exponents that signify the presence of anomalous behaviour in ECG data. View full abstract»

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  • Synthesis of waveforms from zero-lag cross-correlation matrix with specified constraints and power levels

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (203 KB) |  | HTML iconHTML  

    In MIMO radar applications, zero-lag cross-correlation matrix of the transmitted waveforms is designed for a desired transmit beampattern and spatial ambiguity function. The transmitted waveforms are to be synthesized from this matrix subject to certain constraints. Recently, Jian Li et al. [1] formulated the synthesis problem as a multi-step optimization and outlined an iterative algorithm, named as cyclic algorithm, for implementing the optimization. Development of a MATLAB code for implementing the multi-step optimization is non-trivial and it calls for a significant effort. In this paper, we present the steps of the iterative algorithm in some detail and illustrate the results obtained from our code with some examples. Though the synthesis problem is motivated from MIMO radar applications, the algorithm can be considered as generic. View full abstract»

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  • A novel offline PLI-RWA, regenerator placement and wavelength converter placement algorithm for translucent optical WDM networks

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (330 KB) |  | HTML iconHTML  

    The emergence of translucency in WDM networks as a trade-off between the low cost of full transparency and high signal quality provided by full opacity has led to immense interest in translucent network design by the research community in recent years. Efficient translucent network design necessitates the judicious choice of regeneration sites and number of regenerators in order to maintain a predefined quality of transmission and to reduce the overall network cost. In this paper, we explicate a framework that corroborates the offline version of Physical Layer Impairment Aware Routing and Wavelength Assignment (PLI-RWA) problem in translucent networks. The originality of the proposed PLI-Signal Quality Aware RWA (PLI-SQARWA) algorithm lies in finding the routes which use fewest amounts of regenerators and constituting an efficient Regenerator Placement (RP) algorithm to place regenerators before wavelengths are assigned leading to maximal use of regenerators as wavelength converters. Subsequently, in the WA phase, for any further wavelength contention resolutions; we resort to optical wavelength converters. A relevant difference between existing studies and the proposed algorithm is that PLI-SQARWA provisions both, regeneration and wavelength conversion which guarantees zero signal and wavelength blocking. We proceed to the performance comparison of PLI-SQARWA with a heuristic for RWA and RP called COR2P (Cross-Optimization for RWA and RP) and the comparison results reveal that PLI-SQARWA outperforms COR2P in terms of number of network regenerators and time delay while demonstrating similar blocking performance to COR2P at various traffic loads. The results also suggest that to minimize time delay due to Optical-Electrical-Optical (OEO) conversions, using optical wavelength converters for only wavelength contention resolution is a judicious choice rather than resorting to regenerators. Finally, it can be inferred from the study that there exists a trade-off between- the overall network cost and the maximum tolerable delay. View full abstract»

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  • Fast template matching based on multilevel successive elimination algorithm

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1580 KB) |  | HTML iconHTML  

    This paper proposes a fast template matching method based on multilevel successive elimination algorithm (MSEA) and yields exactly the same result as the exhaustive search algorithm. The algorithm uses two stage searching method to effectively determine the peak point of correlation accurately and robustly. In the first stage, the pixel positions are sampled to form a rectangular or hexagonal grid structure of pixels. The SEA or MSEA is performed on the sampled grid positions. The output of the first stage method is the coordinate at which we get the minimum SAD value. In the second stage, centering on this position, we perform the normalized cross correlation (NCC) with box filtering operation on each pixel position in a window size of 16×16 pixels. The best matching point is obtained at the peak point of NCC value. The method has broad applications in the fields of real time moving object tracking, pattern recognition, machine vision etc. Experimental results are presented here to verify substantial computational savings of the proposed algorithm in comparison with the SEA/MSEA. View full abstract»

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  • A novel control strategy to simulate solar panels

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (474 KB) |  | HTML iconHTML  

    This paper proposes the need for accurate and fast solar panel simulators for the purpose of accurately modeling the behavior of Smart Grids. A comprehensive strategy for accurate simulation of solar panels under different conditions and various kinds of loads is developed using adaptive control, based only on data from the solar panel datasheet. A novel method for more accurate solar panel simulation is proposed using a controller-based strategy. We demonstrate that with a set of adaptive controllers accurate tracking of any general load connected to the simulator is achievable. Simulations validate the efficacy of the proposed method for solar panel simulation. View full abstract»

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  • Game theory based dynamic bit-rate adaptation for H.264 scalable video transmission in 4G wireless systems

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (217 KB) |  | HTML iconHTML  

    In this paper, we propose a game theoretic framework for decentralized H.264 scalable video bit-rate adaptation in 4G wireless networks. The framework presented employs a pricing based utility function towards video streaming quality optimization. An algorithm is presented for iterative strategy update of the competing scalable coded video streaming end users towards an equilibrium allocation. In this context we demonstrate the existence of a Nash equilibrium for the proposed video bit-rate adaptation game based on the quasi-concavity of the net video utility function. Existence of Nash equilibrium ensures efficient usage of the 3G/4G bandwidth resources towards video quality and revenue maximization. We present simulation results to comprehensively illustrate the performance of the above game theoretic video quality adaptation scheme. We also discuss the behavior of the parameters of the net video utility function, their impact on video bit-rate allocation and overall bandwidth utilization of the wireless network. View full abstract»

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  • Construction of 4-band linear-phase orthogonal perfect-reconstruction filter banks using iterative eigenfilter method

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (587 KB) |  | HTML iconHTML  

    This paper presents an eigenfilter based method for the design of 4-band perfect reconstruction (PR) filter banks. All the filters of the filter bank exhibit linear phase and orthogonality property. The eigenfilter method has been used so far to impose linear constraints on the filter, however, in this paper, we discuss how to impose nonlinear constraints on the filter using the eigenfilter method. The analysis lowpass filter impulse response is obtained using an iterative approach in the eigenfilter method to minimize the error as given by the alias cancellation equations in the PR filter bank. Once the analysis lowpass filter impulse response h0[n] is obtained, the other filters are obtained using shuffling matrices. We present two design examples of a 4-channel perfect reconstruction filter bank. We also report a minor modification in the eigenfilter method for imposing non-homogeneous linear constraints on the filter. View full abstract»

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  • A trajectory-based ball detection and tracking system with applications to shot-type identification in volleyball videos

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (847 KB) |  | HTML iconHTML  

    This paper presents a trajectory-based ball detection and tracking algorithm for volleyball videos to classify the different types of shots in the game. In case of volleyball games, the task of ball detection and tracking become more complex due to the presence of too many number of players in a rather small space. The direct detection methods often fail due to the high rate of occlusion of the ball image with players. The distortion of the ball image due to the effect of ball and camera motion leads to a number of wrong detection. In this paper, the trajectory information of a volleyball for different shot sequences is studied and used to estimate the ball locations. The ball candidates are generated using the shape and size features. A Kalman filter-based approach is used to generate a set of candidate trajectories. The actual ball trajectory is extracted by analysing the physical characteristics of the ball motion. The trajectory informations are then used to classify the different shot sequences in the volleyball game for better representation and analysis. View full abstract»

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  • Robust features for accurate spatio-temporal registration of video copies

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (257 KB) |  | HTML iconHTML  

    Pirate copies of movies are proliferating on the Internet and causing huge piracy issues. Any anti-piracy strategy requires not only copy detection but also precise frame alignment of pirate video with master content, prior to the estimation of geometric distortions and capture location in a theater. Most studies in pirate video registration focus on the alignment of watermarked sequences, while few efforts are made to align non-watermarked videos using content-based features. In this paper, we propose a spatio-temporal scheme for aligning pirate and master contents using visual features, which consists of three stages: First, a video sequence is compactly represented using 1-D SURF (Speeded-Up Robust Features) signatures; Second, temporal frame alignments are computed using sliding window based dynamic programming method; Third, robust SURF descriptors are employed to generate spatial frame alignments. The results demonstrate the improved registration accuracy of the proposed method against various transformations. View full abstract»

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  • Self-interference cancellation models for full-duplex wireless communications

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    In this paper, we study two models for self or loopback interference cancellation in full-duplex wireless communications. Both models are based on an underlying Z-channel with side information. We obtain achievable rate regions with suitable coding schemes under both models. Under model 1, where the self-interference channel gain is random, we employ training to estimate the unknown gain, and optimize the required training time. Under model 2, where the self-interference gain is exactly known, we show that the capacity of an ideal full-duplex node can be realized even when the side information is low rate and quantized. Our results show that loopback interference, rather than being treated as noise, can be effectively dealt with by suitable coding. View full abstract»

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  • Spatio temporal key-point detection and video representation in 3D complex wavelet domain

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (522 KB) |  | HTML iconHTML  

    Technology advances in information technology has been evolving for a long time. With this, the need for effective retrieval of video data has increased manifold. In this paper, we propose spatio temporal key-point based approach for content based video retrieval (CBVR). The proposed framework characterizes videos based on spatio temporal key-points. Most of the existing approaches extract key-points from static video frames, while little work has been done on spatio-temporal key-points. We present a new spatio temporal key-point detector and descriptor using 3D complex wavelet transform. Detected key-points are converted to spatio temporal features to represent videos. Results of empirical analysis are provided to substantiate the retrieving capability of the proposed framework. View full abstract»

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  • Power-law transformation for enhanced recognition of born-digital word images

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    In this paper, we discuss the issues related to word recognition in born-digital word images. We introduce a novel method of power-law transformation on the word image for binarization. We show the improvement in image binarization and the consequent increase in the recognition performance of OCR engine on the word image. The optimal value of gamma for a word image is automatically chosen by our algorithm with fixed stroke width threshold. We have exhaustively experimented our algorithm by varying the gamma and stroke width threshold value. By varying the gamma value, we found that our algorithm performed better than the results reported in the literature. On the ICDAR Robust Reading Systems Challenge-1: Word Recognition Task on born digital dataset, as compared to the recognition rate of 61.5% achieved by TH-OCR after suitable pre-processing by Yang et. al. and 63.4% by ABBYY Fine Reader (used as baseline by the competition organizers without any preprocessing), we achieved 82.9% using Omnipage OCR applied on the images after being processed by our algorithm. View full abstract»

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  • Set-partitioning based forward/backward soft decision algorithms for MIMO detection

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (230 KB) |  | HTML iconHTML  

    A near maximum a posteriori (MAP)-optimal soft detector that outputs a posteriori probabilities (APP's) for multiple-input multiple-output (MIMO) systems in flat fading channels is proposed. This is referred to as `reduced state maximum a posteriori (RSMAP)' algorithm. This detection algorithm is based on BCJR algorithm and also uses ideas from reduced state sequence estimation (RSSE) and set partitioning. This algorithm is shown to be near optimal and the computational complexity to implement it is estimated. Finally we also show that applying the well known max-log approximation on this algorithm results in nearly same performance at much lower complexity. View full abstract»

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  • Scalable video coding using Symmetric Residue Pyramid and rate-distortion optimization

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (559 KB) |  | HTML iconHTML  

    Videos are often required to be transmitted over different media. Scalability is an important aspect of video transmission. In case of challenged network, graceful reconstruction from a truncated bitstream becomes an issue. In order to leverage capabilities of standard video codecs, we suggest our scalable coding through a wrapper on top of any Commercial Off-the-Shelf (COTS) codecs. A single video is encoded as a set of smaller subvideos. The wrapper performs splitting and composingof subvideos. A Rate-Distortion (RD) analysis has been done to allocate optimal rates to individual subvideos. This optimal allocation minimizes overall distortion. In this paper, a hybrid scalable format which uses Symmetric Residue Pyramid for reconstruction is proposed. Superior PSNR values and visual quality have been achieved in comparison to the techniques involving other up-sampling methods. View full abstract»

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