Now showing items 177-196 of 508

  • Image Compression using an Efficient Edge Cartoon + Texture Model 

    Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (IEEE Computer Society, 2002-04-01)
    Wavelet-based image coders optimally represent smooth regions and isolated point singularities. However, wavelet coders are less adept at representing perceptually important edge singularities, and coding performance ...
  • Image Compression using Multiscale Geometric Edge Models 

    Wakin, Michael (2002-05-20)
    Edges are of particular interest for image compression, as they communicate important information, contribute large amounts of high-frequency energy, and can generally be described with few parameters. Many of today's most ...
  • Image Data Compression 

    Wei, Dong (1995-05-01)
    Wavelet-based multi-resolution representation has become a cutting-edge technology in the area of image data compression. Though the discrete wavelet transform is closely related to the perfect-reconstruction octave-band ...
  • IMAGE DATA COMPRESSION AND RECONSTRUCTION BASED ON FREQUENCY DOMAIN CONSIDERATIONS AND PARTIAL DIFFERENTIAL EQUATION MODELS 

    CHEN, TING-CHUNG CHARLES (1981)
    The image data compression and reconstruction problems are investigated in this dissertation, and new techniques for their solution are presented. Conventional image transform coding techniques are given a spatial domain ...
  • Image enhancement by nonlinear wavelet processing 

    Odegard, Jan E. (1994-10-20)
    In this paper we describe how the theory of wavelet thresholding introduced by Donoho and Johnstone can successfully be applied to two distinct problems in image processing where traditional linear filtering techniques are ...
  • Image Restoration Using the EM Algorithm and Wavelet-Based Complexity Regularization 

    Figueiredo, Mario; Nowak, Robert David (2002-05-20)
    This paper introduces an <i>expectation-maximization</i> (EM) algorithm for image restoration (deconvolution) based on a penalized likelihood formulated in the wavelet domain. Regularization is achieved by promoting a ...
  • Image Super-Resolution for Improved Automatic Target Recognition 

    Wagner, Raymond; Waagen, Donald; Cassabaum, Mary (2004-04-01)
    Infrared imagers used to acquire data for automatic target recognition are inherently limited by the physical properties of their components. Fortunately, image super-resolution techniques can be applied to overcome the ...
  • Imaging with Terahertz Pulses 

    Dorney, Timothy D.; Johnson, Jon L.; Mittleman, Daniel M.; Baraniuk, Richard G. (2000-07-01)
    Recently, a real-time imaging system based on terahertz (THz) time-domain spectroscopy has been developed. This technique offers a range of unique imaging modalities due to the broad bandwidth, sub-picosecond duration, and ...
  • Imaging with THz Pulses 

    Dorney, Timothy D.; Johnson, Jon L.; Mittleman, Daniel M.; Baraniuk, Richard G. (2000-09-01)
    A real-time imaging system based on terahertz (THz) time-domain spectroscopy has been demonstrated. This technique offers a range of unique imaging modalities due to the broad bandwidth, sub-picosecond duration, and ...
  • Implementation of Channel Estimation and Multiuser Detection Algorithms for W-CDMA on Digital Signal Processors 

    Rajagopal, Sridhar; Xu, Gang; Cavallaro, Joseph R. (1999-08-20)
    Proposed algorithms for Third Generation W-CDMA communication systems have extremely high performance requirements. In this paper, we study the implementation issues involved for one of the proposed multiuser channel ...
  • An Improved Multifractal Formalism and Self Affine Measures 

    Riedi, Rudolf H. (1993-01-20)
    This document is a six page summary of my Ph.D. thesis in which multifractal formalism based on counting on coarse levels (as opposed to a dimensional approach) is developed. This formalism is then applied to self-affine ...
  • An Improved Multifractal Formalism and Self Similar Measures 

    Riedi, Rudolf H. (1995-01-01)
    To characterize the geometry of a measure, its so-called generalized dimensions D(<i>q</i>) have been introduced recently. The mathematically precise definition given by Falconer turns out to be unsatisfactory for reasons ...
  • Improved Time-Frequency Filtering of Signal-Averaged Electrocardiograms 

    Sayeed, Akbar M.; Jones, Douglas L. (1995-01-15)
    A recently proposed time-frequency filtering technique has shown promising results for the enhancement of signal-averaged electrocardiograms. This method weights the short-time Fourier transform (STFT) of the ensemble-averaged ...
  • Improved Type-Based Detection of Analog Signals 

    Goncalves, Paulo; Baraniuk, Richard G. (1997-04-01)
    When applied to continuous-time observations, type-based detection strategies are limited by the necessity to crudely quantize each sample. To alleviate this problem, we smooth the types for both the training and observation ...
  • Improved Wavelet Denoising via Empirical Wiener Filtering 

    Ghael, Sadeep; Sayeed, Akbar M.; Baraniuk, Richard G. (1997-07-01)
    Wavelet shrinkage is a signal estimation technique that exploits the remarkable abilities of the wavelet transform for signal compression. Wavelet shrinkage using thresholding is asymptotically optimal in a minimax ...
  • Improving the Resolution of Bearing in Passive Sonar Arrays by Eigenvalue Analysis 

    Johnson, Don; DeGraaf, Stuart (1981-08-01)
    A method of improving the bearing-resolving capabilities of a passive array is discussed. This method is an adaptive beamforming method, having many similarities to the minimum energy approach. The evaluation of energy ...
  • An Information processing approach to distributed detection 

    Lexa, Michael; Johnson, Don (2003-09-20)
    We apply the recent theory of information processing to a hybrid distributed detection architecture that combines the traditional parallel and tandem architectures. Central to this theory is the Kullback-Leibler discrimination ...
  • Information processing during transient responses in the crayfish visual system 

    Rozell, Chris; Johnson, Don; Glantz, Raymon (2003-06-01)
    We analyzed sustaining fiber responses in the crayfish visual system to light pulses using information processing techniques. The light pulse stimuli elicited a transient and a steady-state component in the EPSP input and ...
  • Information processing of linear block decoders 

    Lexa, Michael; Johnson, Don (2002-10-20)
    This paper develops a systematic method of studying the benefits of soft decoding for linear block codes by applying the concepts of information processing. We show that soft decoding uniformly improves decoder performance ...
  • Instantaneous Frequency Estimation using the Reassignment method 

    Odegard, Jan E.; Baraniuk, Richard G.; Oehler, Kurt L (1998-01-15)
    This paper explores the method of reassignment for extracting instantaneous frequency attributes from seismic data. The reassignment method was first applied to the spectrogram by Kodera, Gendrin and de Villedary and later ...