Now showing items 21-40 of 508

    • 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 ...
    • Simultaneous Speckle Reduction and Data Compression using Best Wavelet Packet Bases with Applications to SAR based ATD/R 

      Wei, Dong; Guo, Haitao; Odegard, Jan E.; Lang, Markus; Burrus, C. Sidney (1995-04-20)
      We propose a novel method for simultaneous speckle reduction and data compression based on shrinking, quantizing and coding the wavelet packet coefficients of the logarithmically transformed image. A fast algorithm is used ...
    • A Wavelet-Based Statistical Model for Image Restoration 

      Wan, Yi; Nowak, Robert David (2001-10-20)
      In this paper we develop a wavelet-based statistical method for solving the image restoration problem. In this approach, a signal prior is set up by modeling the image wavelet coefficients as independent Gaussian mixture ...
    • A Multiscale Bayesian Framework for Linear Inverse Problems and Its Application to Image Restoration 

      Wan, Yi; Nowak, Robert David (2001-01-20)
      In this paper we develop a wavelet-based statistical method for solving linear inverse problems. The Bayesian framework developed here is general enough to treat a wide class of linear inverse problems involving (white ...
    • New Bayesian Model Averaging Framework for Wavelet-Based Signal Processing 

      Wan, Yi; Nowak, Robert David (2000-06-20)
      This paper develops a new signal modeling framework using Bayesian model averaging formulation and the redundant or translation-invariant wavelet transform. The aim of this framework is to provide a paradigm general enough ...
    • Quasi-Circular Rotation Invariance in Image Denoising 

      Wan, Yi; Nowak, Robert David (1999-10-20)
      This paper studies a new method for wavelet-based image denoising which is translation invariant (TI) <b>and</b> rotation invariant (RI). These invariances are crucial in image denoising and, more generally, may play ...
    • A Bayesian Multiscale Approach to Joint Image Restoration and Edge Detection 

      Wan, Yi; Nowak, Robert David (1999-07-20)
      This paper presents a novel wavelet-based method for simultaneous image restoration and edge detection. The Bayesian framework developed here is general enough to treat a wide class of linear inverse problems involving ...
    • Wavelet-Domain Approximation and Compression of Piecewise Smooth Images 

      Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2006-05-01)
      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 piecewise smooth ...
    • Random Projections of Signal Manifolds 

      Wakin, Michael; Baraniuk, Richard G. (2006-05-01)
      Random projections have recently found a surprising niche in signal processing. The key revelation is that the relevant structure in a signal can be preserved when that signal is projected onto a small number of random ...
    • 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> ...
    • The Multiscale Structure of Non-Differentiable Image Manifolds 

      Wakin, Michael; Donoho, David; Choi, Hyeokho; Baraniuk, Richard G. (2005-08-01)
      In this paper, we study families of images generated by varying a parameter that controls the appearance of the object/scene in each image. Each image is viewed as a point in high-dimensional space; the family of images ...
    • A Markov Chain Analysis of Blackjack Strategy 

      Wakin, Michael; Rozell, Chris (2004-07-01)
      Blackjack receives considerable attention from mathematicians and entrepreneurs alike, due to its simple rules, its inherent random nature, and the abundance of "prior" information available to an observant player. Many ...
    • Wavelet-domain Approximation and Compression of Piecewise Smooth Images 

      Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2006)
      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 ...
    • Phase and Magnitude Perceptual Sensitivities in Nonredundant Complex Wavelet Representations 

      Wakin, Michael; Orchard, Michael; Baraniuk, Richard G.; Chandrasekaran, Venkat (2003-11-01)
      The recent development of a nonredundant complex wavelet transform allows a novel framework for image analysis. Work on this representation has recognized that the phase and magnitude of complex coefficients can be related ...
    • 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 ...
    • Rate-Distortion Optimized Image Compression using Wedgelets 

      Wakin, Michael; Romberg, Justin; Choi, Hyeokho; Baraniuk, Richard G. (2002-06-01)
      Most wavelet-based image coders fail to model the joint coherent behavior of wavelet coefficients near edges. Wedgelets offer a convenient parameterization for the edges in an image, but they have yet to yield a viable ...
    • 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 ...
    • 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 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 ...
    • 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 ...