Now showing items 1-20 of 52

    • 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 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, ...
    • 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 ...
    • Bayesian Wavelet Domain Image Modeling using Hidden Markov Trees 

      Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (1999-10-01)
      Wavelet-domain hidden Markov models have proven to be useful tools for statiscal signal and image processing. The hidden Markov tree (HMT) model captures the key features o teh join statistics of the wavelet coefficients ...
    • Coherent Image Processing using Quaternion Wavelets 

      Chan, Wai Lam; Choi, Hyeokho; Baraniuk, Richard G. (2005-08-01)
      We develop a quaternion wavelet transform (QWT) as a new multiscale analysis tool for geometric image features. The QWT is a near shift-invariant, tight frame representation whose coefficients sport a magnitude and three ...
    • Coherent Multiscale Image Processing using Quaternion Wavelets 

      Chan, Wai Lam; Choi, Hyeokho; Baraniuk, Richard G. (2006-10-01)
      The quaternion wavelet transform (QWT) is a new multiscale analysis tool for geometric image features. The QWT is a near shift-invariant tight frame representation whose coefficients sport a magnitude and three phases: ...
    • Community Driven Digital Signal Processing Laboratories in Connexions 

      Baraniuk, Richard G.; Choi, Hyeokho; Jones, Douglas L.; Potter, Lee (2004-06-01)
      The conventional textbook is largely inadequate for digital signal processing (DSP) laboratory education due to inherent factors such as a small and fragmented market and rapid hardware obsolescence. Freely available ...
    • Directional Hypercomplex Wavelets for Multidimensional Signal Analysis and Processing 

      Chan, Wai Lam; Choi, Hyeokho; Baraniuk, Richard G. (2004-05-01)
      We extend the wavelet transform to handle multidimensional signals that are smooth save for singularities along lower-dimensional manifolds. We first generalize the complex wavelet transform to higher dimensions using a ...
    • Distributed Camera Network Localization 

      Mantzel, William; Choi, Hyeokho; Baraniuk, Richard G. (2004-11-01)
      Localization, estimating the positions and orientations of a set of cameras, is a critical first step in camera-based sensor network applications such as geometric estimation, scene reconstruction, and motion tracking. We ...
    • Distributed Multiscale Data Analysis and Processing for Sensor Networks 

      Wagner, Raymond; Sarvotham, Shriram; Choi, Hyeokho; Baraniuk, Richard G. (2005-02-01)
      While multiresolution data analysis, processing, and compression hold considerable promise for sensor network applications, progress has been confounded by two factors. First, typical sensor data are irregularly spaced, ...
    • Distributed Wavelet Transform for Irregular Sensor Network Grids 

      Wagner, Raymond; Choi, Hyeokho; Baraniuk, Richard G.; Delouille, Veronique (2005-07-01)
      Wavelet-based distributed data processing holds much promise for sensor networks; however, irregular sensor node placement precludes the direct application of standard wavelet techniques. In this paper, we develop a new ...
    • DSP Education At Rice University 

      Frantz, Patrick; Choi, Hyeokho; Baraniuk, Richard G. (2003-09-01)
      Rice University has a decades-long tradition of both digital signal processing (DSP) research and education, beginning in 1968. Since that time, Rice University has become a world leader and continued to be a pioneer in ...
    • Edge Localized Image Sharpening via Reassignment with Application to Computed Tomography 

      Dorney, Timothy D.; Bhashyam, Srikrishna; Doran, Andrew; Choi, Hyeokho; Flandrin, Patrick; Baraniuk, Richard G. (2000-07-01)
      Traditional filtering methods operate on the entire signal or image. In some applications, however, errors are concentrated in specific regions or features. A prime example is images generated using computed tomography. ...
    • Estimation-Quantization Geometry Coding Using Normal Meshes 

      Lavu, Sridhar; Choi, Hyeokho; Baraniuk, Richard G. (2003-03-01)
      We propose a new algorithm for compressing three-dimensional triangular mesh data used for representing surfaces. We apply the Estimation-Quantization (EQ) algorithm originally designed for still image compression to the ...
    • ForWaRD: Fourier-Wavelet Regularized Deconvolution for Ill-Conditioned Systems 

      Neelamani, Ramesh; Choi, Hyeokho; Baraniuk, Richard G. (2004-02-01)
      We propose an efficient, hybrid <i>Fourier-Wavelet Regularized Deconvolution</i> (ForWaRD) algorithm that performs noise regularization via scalar shrinkage in both the Fourier and wavelet domains. The Fourier shrinkage ...
    • An FPGA-based Daughtercard for TIs C6000 family of DSKs 

      Gadhiok, Manik; Hardy, Ricky; Murphy, Patrick; Frantz, Patrick; Choi, Hyeokho; Cavallaro, Joseph R. (2005-06-01)
      In this paper we present an FPGA-based daughtercard designed for TIs C6000 family of DSP Starter Kits (DSKs). The hardware, initially designed for a course project, provides a platform for studying heterogeneous systems ...
    • 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 ...