Now showing items 1-37 of 37

  • The 2nu-SVM: A Cost-Sensitive Extension of the nu-SVM 

    Davenport, Mark A. (2005-12-01)
    Standard classification algorithms aim to minimize the probability of making an incorrect classification. In many important applications, however, some kinds of errors are more important than others. In this report we ...
  • Adaptive Representation of JPEG 2000 Images Using Header-based Processing 

    Neelamani, Ramesh; Berkner, Kathrin (2002-09-20)
    To bridge the mismatch between the sizes of images and display devices, we present an efficient and automatic algorithm to create an adaptive image representation called SmartNail. Given a digital image and rectangular ...
  • 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 ...
  • 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 ...
  • Coding Theoretic Approach to Image Segmentation 

    Ndili, Unoma; Nowak, Robert David; Figueiredo, Mario (2001-10-20)
    In this paper, using a coding theoretic approach, we implement Rissanen's concept of minimum description length (MDL) for segmenting an image into piecewise homogeneous regions. Our image model is a Gaussian random field ...
  • Coding Theoretic Approach to Image Segmentation 

    Ndili, Unoma (2001-05-20)
    Using a coding theoretic approach, we achieve unsupervised image segmentation by implementing Rissanen's concept of Minimum Description Length for estimating piecewise homogeneous regions in images. MDL offers a mathematical ...
  • 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 ...
  • Compression Color Space Estimation of JPEG Images using Lattice Basis Reduction 

    Neelamani, Ramesh; Baraniuk, Richard G.; de Queiroz, Ricardo (2001-10-01)
    Given a color image that was previously JPEG-compressed in some hidden color space, we aim to estimate this unknown compression color space from the image. This knowledge is potentially useful for color image enhancement ...
  • Controlling False Alarms with Support Vector Machines 

    Davenport, Mark A.; Baraniuk, Richard G.; Scott, Clayton D. (2006-05-01)
    We study the problem of designing support vector classifiers with respect to a Neyman-Pearson criterion. Specifically, given a user-specified level alpha, 0 < alpha < 1, how can we ensure a false alarm rate no greater than ...
  • Distributed Image Compression for Sensor Networks using Correspondence Analysis and Super-Resolution 

    Wagner, Raymond; Nowak, Robert David; Baraniuk, Richard G. (2003-09-01)
    We outline a distributed coding technique for images captured from sensors with overlapping fields of view in a sensor network. First, images from correlated views are roughly registered (relative to a sensor of primary ...
  • 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 ...
  • 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 ...
  • 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 ...
  • Image Restoration Using the EM Algorithm and Wavelet-Based Complexity Regularization 

    Figueiredo, Mario; Nowak, Robert David (2002-05-20)
    This paper introduces an <i>expectation-maximization</i> (EM) algorithm for image restoration (deconvolution) based on a penalized likelihood formulated in the wavelet domain. Regularization is achieved by promoting a ...
  • Image Super-Resolution for Improved Automatic Target Recognition 

    Wagner, Raymond; Waagen, Donald; Cassabaum, Mary (2004-04-01)
    Infrared imagers used to acquire data for automatic target recognition are inherently limited by the physical properties of their components. Fortunately, image super-resolution techniques can be applied to overcome the ...
  • JPEG Compression History Estimation for Color Images 

    Neelamani, Ramesh; de Queiroz, Ricardo; Fan, Zhigang; Dash, Sanjeeb; Baraniuk, Richard G. (2005-07-01)
    We routinely encounter digital color images that were previously JPEG-compressed. En route to the image's current representation, the previous JPEG compression's various settings&mdash;termed its JPEG compression history ...
  • Model-based Inverse Halftoning with Wavelet-Vaguelette Deconvolution 

    Neelamani, Ramesh; Nowak, Robert David; Baraniuk, Richard G. (2000-09-01)
    In this paper, we demonstrate based on the linear model of Kite that inverse halftoning is equivalent to the well-studied problem of deconvolution in the presence of colored noise. We propose the use of the simple and ...
  • Multiscale Analysis for Intensity and Density Estimation 

    Willett, Rebecca (2002-04-20)
    The nonparametric multiscale polynomial and platelet algorithms presented in this thesis are powerful new tools for signal and image denoising and reconstruction. Unlike traditional wavelet-based multiscale methods, these ...
  • Multiscale Approximation of Piecewise Smooth Two-Dimensional Function using Normal Triangulated Meshes 

    Jansen, Maarten; Baraniuk, Richard G.; Lavu, Sridhar (2005-07-01)
    Multiresolution triangulation meshes are widely used in computer graphics for representing three-dimensional(3-d) shapes. We propose to use these tools to represent 2-d piecewise smooth functions such as grayscale ...
  • Multiscale Image Segmentation Using Joint Texture and Shape Analysis 

    Neelamani, Ramesh; Romberg, Justin; Riedi, Rudolf H.; Choi, Hyeokho; Baraniuk, Richard G. (2000-07-01)
    We develop a general framework to simultaneously exploit texture and shape characterization in multiscale image segmentation. By posing multiscale segmentation as a model selection problem, we invoke the powerful framework ...
  • Multiscale Likelihood Analysis and Image Reconstruction 

    Willett, Rebecca; Nowak, Robert David (2003-08-20)
    The nonparametric multiscale polynomial and platelet methods presented here are powerful new tools for signal and image denoising and reconstruction. Unlike traditional wavelet-based multiscale methods, these methods are ...
  • Multiscale modeling and estimation of Poisson processes with application to photon-limited imaging 

    Timmerman, Klaus; Nowak, Robert David (1999-04-20)
    Many important problems in engineering and science are well-modeled by Poisson processes. In many applications it is of great interest to accurately estimate the intensities underlying observed Poisson data. In particular, ...
  • On Nearly Orthogonal Lattice Bases 

    Neelamani, Ramesh; Dash, Sanjeeb; Baraniuk, Richard G. (2005-07-01)
    We study "nearly orthogonal" lattice bases, or bases where the angle between any basis vector and the linear subspace spanned by the other basis vectors is greater than 60&deg;. We show that a nearly orthogonal lattice ...
  • On The Problem of Simultaneous Encoding of Magnitude and Location Information 

    Castro, Rui; Wakin, Michael; Orchard, Michael (2002-11-20)
    Modern image coders balance bitrate used for encoding the location of signicant transform coefficients, and bitrate used for coding their values. The importance of balancing location and value information in practical ...
  • Platelets for Multiscale Analysis in Medical Imaging 

    Willett, Rebecca; Nowak, Robert David (2002-04-20)
    This paper describes the development and use of multiscale, platelet-based image reconstruction algorithms in medical imaging. Such algorithms are effective because platelets approximate images in certain (piecewise) ...
  • Platelets for Multiscale Analysis in Photon-Limited Imaging 

    Willett, Rebecca; Nowak, Robert David (2002-09-20)
    This paper proposes a new multiscale image decomposition based on platelets. Platelets are localized functions at various scales, locations, and orientations that produce piecewise linear image approximations. For smoothness ...
  • Platelets: A Multiscale Approach for Recovering Edges and Surfaces in Photon-Limited Medical Imaging 

    Willett, Rebecca; Nowak, Robert David (2001-10-20)
    This paper proposes a new multiscale image decomposition based on platelets. Platelets are localized functions at various scales, locations, and orientations that produce piecewise linear image approximations. Platelets ...
  • TEMPLAR: A Wavelet-Based Framework for Pattern Learning and Analysis 

    Scott, Clayton; Nowak, Robert David (2001-04-20)
    Despite the success of wavelet decompositions in other areas of statistical signal and image processing, current wavelet-based image models are inadequate for modeling patterns in images, due to the presence of unknown ...
  • Template Learning from Atomic Representations: A Wavelet-Based Approach to Pattern Analysis 

    Scott, Clayton; Nowak, Robert David (2001-04-20)
    Despite the success of wavelet decompositions in other areas of statistical signal and image processing, current wavelet-based image models are inadequate for modeling patterns in images, due to the presence of unknown ...
  • Wavelet-based deconvolution for ill-Conditioned systems 

    Neelamani, Ramesh (2000-05-20)
    This thesis proposes a new approach to wavelet-based image deconvolution that comprises Fourier-domain system inversion followed by wavelet-domain noise suppression. In contrast to other wavelet-based deconvolution approaches, ...
  • Wavelet-based deconvolution for ill-conditioned systems 

    Neelamani, Ramesh; Choi, Hyeokho; Baraniuk, Richard G. (2000-02-01)
    We propose a hybrid approach to wavelet-based deconvolution that comprises Fourier-domain system inversion followed by wavelet-domain noise suppression. In contrast to other wavelet-based deconvolution approaches, the ...
  • Wavelet-based Deconvolution for Ill-conditioned Systems 

    Neelamani, Ramesh; Choi, Hyeokho; Baraniuk, Richard G. (1999-03-01)
    In this paper, we propose a new approach to wavelet-based deconvolution. Roughly speaking, the algorithm comprises Fourier-domain system inversion followed by wavelet-domain noise suppression. Our approach subsumes a number ...
  • Wavelet-Based Deconvolution Using Optimally Regularized Inversion for Ill-Conditioned Systems 

    Neelamani, Ramesh; Choi, Hyeokho; Baraniuk, Richard G. (1999-07-20)
    We propose a hybrid approach to wavelet-based deconvolution that comprises Fourier-domain system inversion followed by wavelet-domain noise suppression. In contrast to conventional wavelet-based deconvolution approaches, ...
  • Wavelet-based Rician noise removal for magnetic resonance imaging 

    Nowak, Robert David (1999-10-20)
    It is well-known that the noise in magnetic resonance magnitude images obeys a Rician distribution. Unlike additive Gaussian noise, Rician noise is signal-dependent and consequently spearating signal from noise is a ...
  • Wavelet-Domain Regularized Deconvolution for Ill-Conditioned Systems 

    Neelamani, Ramesh; Choi, Hyeokho; Baraniuk, Richard G. (1999-10-01)
    We propose a hybrid approach to wavelet-based image deconvolution that comprises Fourier-domain system inversion followed by wavelet-domain noise suppression. In contrast to conventional wavelet-based deconvolution approaches, ...
  • WInHD: Wavelet-based Inverse Halftoning via Deconvolution 

    Neelamani, Ramesh; Nowak, Robert David; Baraniuk, Richard G. (2002-10-20)
    We propose the <i>Wavelet-based Inverse Halftoning via Deconvolution</i> (WInHD) algorithm to perform inverse halftoning of error-diffused halftones. WInHD is motivated by our realization that inverse halftoning can be ...