Now showing items 1-20 of 245

    • An Adaptive Optimal-Kernel Time-Frequency Representation 

      Jones, Douglas L.; Baraniuk, Richard G. (1995-10-01)
      Time-frequency representations with fixed windows or kernels figure prominently in many applications, but perform well only for limited classes of signals. Representations with signal- dependent kernels can overcome this ...
    • Adaptive Wavelet Transforms for Image Coding 

      Claypoole, Roger L.; Davis, Geoffrey; Sweldens, Wim; Baraniuk, Richard G. (1997-11-01)
      We introduce a new adaptive transform for wavelet-based image coding. The lifting framework for wavelet construction motivates our analysis and provides new insight into the problem. Since the adaptive transform is non-linear, ...
    • Adaptive Wavelet Transforms for Image Coding 

      Claypoole, Roger L.; Davis, Geoffrey; Sweldens, Wim; Baraniuk, Richard G. (1997-11-01)
      We introduce a new adaptive transform for wavelet-based image coding. The lifting framework for wavelet construction motivates our analysis and provides new insight into the problem. Since the adaptive transform is non-linear, ...
    • Adaptive Wavelet Transforms for Image Coding using Lifting 

      Claypoole, Roger L.; Davis, Geoffrey; Sweldens, Wim; Baraniuk, Richard G. (1998-03-01)
      Summary form only given. Image compression relies on efficient representations of images, and within smooth image regions, the wavelet transform provides such a representation. However, near edges, wavelet coefficients ...
    • Adaptive Wavelet Transforms via Lifting 

      Claypoole, Roger L.; Baraniuk, Richard G.; Nowak, Robert David (1998)
      This paper develops new algorithms for adapted multiscale analysis and signal adaptive wavelet transforms. We construct our adaptive transforms with the <i>lifting scheme</i>, which decomposes the wavelet transform into ...
    • Adaptive Wavelet Transforms via Lifting 

      Claypoole, Roger L.; Baraniuk, Richard G.; Nowak, Robert David (1999-01-15)
      This paper develops new algorithms for adapted multiscale analysis and signal adaptive wavelet transforms. We construct our adaptive transforms with the <i>lifting scheme</i>, which decomposes the wavelet transform into ...
    • Adaptive Wavelet Transforms via Lifting 

      Claypoole, Roger L.; Baraniuk, Richard G.; Nowak, Robert David (1998-05-01)
      This paper develops two new adaptive wavelet transforms based on the lifting scheme. The lifting construction exploits a spatial-domain, prediction-error interpretation of the wavelet transform and provides a powerful ...
    • Adaptive Weighted Highpass Filters Using Multiscale Analysis 

      Nowak, Robert David; Baraniuk, Richard G. (1998-07-01)
      In this paper, we propose a general framework for studying a class of weighted highpass filters. Our framework, based on a multiscale signal decomposition, allows us to study a wide class of filters and to assess the ...
    • Additive and Multiplicative Mixture Trees for Network Traffic Modeling 

      Sarvotham, Shriram; Wang, Xuguang; Riedi, Rudolf H.; Baraniuk, Richard G. (2002-05-01)
      Network traffic exhibits drastically different statistics, ranging from nearly Gaussian marginals and long range dependence at very large time scales to highly non-Gaussian marginals and multifractal scaling on small scales. ...
    • Analysis of Multiscale Texture Segmentation using Wavelet-Domain Hidden Markov Trees 

      Choi, Hyeokho; Hendricks, Brent; Baraniuk, Richard G. (1999-10-01)
      This paper describes a technique for estimating the Kullback-Leibler (KL) distance between two Hidden Markov Models (HMMs), and for measuring the quality of the estimator. It also provides some results based on applying ...
    • Analysis of the DCS one-stage Greedy Algorothm for Common Sparse Supports 

      Baron, Dror; Duarte, Marco F.; Wakin, Michael; Sarvotham, Shriram; Baraniuk, Richard G. (2005-11-01)
      Analysis of the DCS one-stage Greedy Algorothm for Common Sparse Supports
    • Analysis of Wavelet domain Wiener Filters 

      Choi, Hyeokho; Baraniuk, Richard G. (1998-10-01)
      We investigate Wiener filtering of wavelet coefficients for signal denoising. Empirically designed wavelet-domain Wiener filters outperform many other denoising algorithms based on wavelet thresholding. However, up to now, ...
    • Applications of Adaptive Time Frequency Representations to Underwater Acoustic Signal Processing 

      Baraniuk, Richard G.; Jones, Douglas L.; Tom, Brotherton; Larry, Marple (1991-11-01)
      The authors describe the application of an adaptive optimal kernel (AOK) time-frequency representation to the processing of underwater acoustic data. The optimal kernel is a signal-dependent radially Gaussian function. ...
    • Applications of Terahertz Imaging 

      Mittleman, Daniel M.; Neelamani, Ramesh; Baraniuk, Richard G.; Nuss, Martin C. (1998-08-01)
      The recent advances involving imaging with sub-picosecond terahertz pulses have opened up a wide range of possibilities in the applications of far-infrared technology. For the first time, a commercially viable terahertz ...
    • Approximation and Compression of Piecewise Smooth Images Using a Wavelet/Wedgelet Geometric Model 

      Romberg, Justin; Wakin, Michael; Baraniuk, Richard G. (2003-09-01)
      Inherent to photograph-like images are two types of structures: large smooth regions and geometrically smooth edge contours separating those regions. Over the past years, efficient representations and algorithms have been ...
    • An Architecture for Distributed Wavelet Analysis and Processing in Sensor Networks 

      Wagner, Raymond; Baraniuk, Richard G.; Du, Shu; Johnson, David B.; Cohen, Albert (2006-04-01)
      Distributed wavelet processing within sensor networks holds promise for reducing communication energy and wireless bandwidth usage at sensor nodes. Local collaboration among nodes de-correlates measurements, yielding a ...
    • Asymptotic Performance of Transmit Diversity via OFDM for Multipath Channels 

      Ahmed, Nadeem; Baraniuk, Richard G. (2002-11-01)
      Many wireless systems exploit transmit diversity for more reliable detection of signals at the receiver. To accomplish this, coding is spread across multiple transmit antennas. An example of this is the well known "Alamouti ...
    • Bayesian Tree-Structured Image Modeling 

      Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2000-04-01)
      Wavelet-domain hidden Markov models have proven to be useful tools for statistical signal and image processing. The hidden Markov tree (HMT) model captures the key features of the joint statistics of the wavelet coefficients ...
    • Bayesian Tree-Structured Image Modeling using Wavelet-domain Hidden Markov Models 

      Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (1999-07-20)
      Wavelet-domain hidden Markov models have proven to be useful tools for statistical signal and image processing. The hidden Markov tree (HMT) model captures the key features of the joint probability density of the wavelet ...
    • Bayesian Tree-Structured Image Modeling using Wavelet-domain Hidden Markov Models 

      Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2001-07-01)
      Wavelet-domain hidden Markov models have proven to be useful tools for statistical signal and image processing. The hidden Markov tree (HMT) model captures the key features of the joint probability density of the wavelet ...