Now showing items 1-8 of 8

  • 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 ...
  • Compressing Piecewise Smooth Multidimensional Functions Using Surflets: Rate-Distortion Analysis 

    Chandrasekaran, Venkat; Wakin, Michael; Baron, Dror; Baraniuk, Richard G. (2004-03-01)
    Discontinuities in data often represent the key information of interest. Efficient representations for such discontinuities are important for many signal processing applications, including compression, but standard Fourier ...
  • Compression of Higher Dimensional Functions Containing Smooth Discontinuities 

    Chandrasekaran, Venkat; Wakin, Michael; Baron, Dror; Baraniuk, Richard G. (2004-03-01)
    Discontinuities in data often represent the key information of interest. Efficient representations for such discontinuities are important for many signal processing applications, including compression, but standard Fourier ...
  • Edge Characteristics in Wavelet-Based Image Coding 

    Wakin, Michael (2001-04-20)
    Accurate prediction of wavelet coefficients relies on an understanding of the phase effects of edge alignment. This research examines techniques for uncovering edge information based on the available coefficients. These ...
  • 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 ...
  • Surflets: A Sparse Representation for Multidimensional Functions Containing Smooth Discontinuities 

    Chandrasekaran, Venkat; Wakin, Michael; Baron, Dror; Baraniuk, Richard G. (2004-07-01)
    Discontinuities in data often provide vital information, and representing these discontinuities sparsely is an important goal for approximation and compression algorithms. Little work has been done on efficient representations ...
  • Wavelet-domain Approximation and Compression of Piecewise Smooth Images 

    Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2005-01-15)
    The wavelet transform provides a sparse representation for smooth images, enabling efficient approximation and compression using techniques such as zerotrees. Unfortunately, this sparsity does not extend to <i>piecewise ...