Now showing items 164-183 of 508

  • Handset Detector Architectures for DS-CDMA Wireless Systems 

    Livingston, Frank; Chandrasekhar, Vikram; Vaya, Mani; Cavallaro, Joseph R. (2002-05-20)
    This paper investigates detector architectures for wireless handsets employing DS-CDMA. The code-matched filter (MF) and minimum output energy (MOE) detectors are analyzed with respect to fixed-point arithmetic behavior. ...
  • Hidden Markov Models for Wavelet-based Signal Processing 

    Crouse, Matthew; Baraniuk, Richard G.; Nowak, Robert David (1996-11-01)
    Current wavelet-based statistical signal and image processing techniques such as shrinkage and filtering treat the wavelet coefficients as though they were statistically independent. This assumption is unrealistic; considering ...
  • Hidden Markov Tree Modeling of Complex Wavelet Transforms 

    Choi, Hyeokho; Romberg, Justin; Baraniuk, Richard G.; Kingsbury, Nicholas G. (2000-06-01)
    Multiresolution signal and image models such as the hidden Markov tree aim to capture the statistical structure of smooth and singular (edgy) regions. Unfortunately, models based on the orthogonal wavelet transform suffer ...
  • Hidden Markov Tree Models for Complex Wavelet Transforms 

    Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G.; Kingsbury, Nicholas G. (2002-05-01)
    Multiresolution models such as the hidden Markov tree (HMT) aim to capture the statistical structure of signals and images by leveraging two key wavelet transform properties: wavelet coefficients representing smooth/singular ...
  • A Hierarchical and Multiscale Analysis of E-Business Workloads 

    Menascé, Daniel; Almeida, Virgilio; Riedi, Rudolf H. (2002-01-15)
    Understanding the nature and characteristics of E-business workloads is a crucial step to improve the quality of service offered to customers in electronic business environments. Using a multi-layer hierarchical model, ...
  • A Hierarchical Wavelet-Based Framework for Pattern Analysis and Synthesis 

    Scott, Clayton (2000-04-20)
    Despite their success in other areas of statsitical signal processing, current wavelet-based image models are inadequate for modeling patterns in images, due to the presence of unknown transformations inherent in most ...
  • Hierarchical Wavelet-Based Image Model for Pattern Analysis and Synthesis 

    Scott, Clayton; Nowak, Robert David (2000-07-20)
    Despite their success in other areas of statistical signal processing, current wavelet-based image models are inadequate for modeling patterns in images, due to the presence of unknown transformations (e.g., translation, ...
  • High-Resolution Navigation on Non-Differentiable Image Manifolds 

    Wakin, Michael; Donoho, David; Choi, Hyeokho; Baraniuk, Richard G. (2005-03-01)
    The images generated by varying the underlying articulation parameters of an object (pose, attitude, light source position, and so on) can be viewed as points on a low-dimensional <i>image parameter articulation manifold</i> ...
  • How Quickly Can We Approach Channel Capacity? 

    Baron, Dror; Khojastepour, Mohammad; Baraniuk, Richard G. (2004-11-01)
    Recent progress in code design has made it crucial to understand how quickly communication systems can approach their limits. To address this issue for the channel capacity C, we define the nonasymptotic capacity C/sub ...
  • Hybrid Linear / Bilinear Time-Scale Analysis 

    Pasquier, Martin; Goncalves, Paulo; Baraniuk, Richard G. (1999-01-01)
    We introduce a new method for the time-scale analysis of non-stationary signals. Our work leverages the success of the "time-frequency distribution series / cross-term deleted representations" into the time-scale domain ...
  • Hybrid Linear/Bilinear Time-Scale Analysis 

    Pasquier, Martin; Goncalves, Paulo; Baraniuk, Richard G. (1996-06-01)
    We introduce a new method for the time-scale analysis of nonstationary signals. Our work leverages the success of the â time-frequency distribution series/cross-term deleted representationsâ into the time-scale domain ...
  • Hybrid Linear/Quadratic Time-Frequency Attributes 

    Baraniuk, Richard G.; Coates, Mark J.; Steeghs, Philippe (2000-06-01)
    We present an efficient method for robustly calculating time-frequency attributes of a signal, including instantaneous mean frequency, bandwidth, and kurtosis. Most current approaches involve a costly intermediate step of ...
  • Hybrid Linear/Quadratic Time-Frequency Attributes 

    Baraniuk, Richard G.; Coates, Mark J.; Steeghs, Philippe (2001-04-01)
    We present an efficient method for robustly calculating time-frequency attributes of a signal, including instantaneous mean frequency, bandwidth, kurtosis, and other moments. Most current attribute estimation techniques ...
  • Image Compression using an Efficient Edge Cartoon + Texture Model 

    Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (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 ...