Now showing items 159-178 of 508

    • A Geometric Hidden Markov Tree Wavelet Model 

      Romberg, Justin; Wakin, Michael; Choi, Hyeokho; Baraniuk, Richard G. (2003-08-01)
      In the last few years, it has become apparent that traditional wavelet-based image processing algorithms and models have significant shortcomings in their treatment of edge contours. The standard modeling paradigm exploits ...
    • Geometric Methods for Wavelet-Based Image Compression 

      Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2003-08-01)
      Natural images can be viewed as combinations of smooth regions, textures, and geometry. Wavelet-based image coders, such as the space-frequency quantization (SFQ) algorithm, provide reasonably efficient representations for ...
    • Geometric Tools for Image Compression 

      Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2002-11-01)
      Images typically contain strong geometric features, such as edges, that impose a structure on pixel values and wavelet coefficients. Modeling the joint coherent behavior of wavelet coefficients is difficult, and standard ...
    • Geometry Compression of Normal Meshes using Rate-Distortion Algorithms 

      Lavu, Sridhar; Choi, Hyeokho; Baraniuk, Richard G. (2003-06-01)
      We propose a new rate-distortion based algorithm for compressing 3D surface geometry represented using triangular normal meshes. We apply the Estimation-Quantization (EQ) algorithm to compress normal mesh wavelet coefficients. ...
    • GEOMETRY OF PARTIAL SUMS 

      READ, RANDOL ROBERT (1971)
    • 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 (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 ...
    • 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 ...
    • 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 ...