Now showing items 1-35 of 35

  • 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 ...
  • 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 ...
  • 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 ...
  • 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. ...
  • 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 ...
  • 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 ...
  • 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 ...
  • Improved Wavelet Denoising via Empirical Wiener Filtering 

    Ghael, Sadeep; Sayeed, Akbar M.; Baraniuk, Richard G. (1997-07-01)
    Wavelet shrinkage is a signal estimation technique that exploits the remarkable abilities of the wavelet transform for signal compression. Wavelet shrinkage using thresholding is asymptotically optimal in a minimax ...
  • Multiscale Density Estimation 

    Willett, Rebecca; Nowak, Robert David (2003-08-20)
    The nonparametric density estimation method proposed in this paper is computationally fast, capable of detecting density discontinuities and singularities at a very high resolution, spatially adaptive, and offers near ...
  • 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, ...
  • Multiscale Queuing Analysis 

    Ribeiro, Vinay Joseph; Riedi, Rudolf H.; Baraniuk, Richard G. (2006-10-01)
    This paper introduces a new multiscale framework for estimating the tail probability of a queue fed by an arbitrary traffic process. Using traffic statistics at a small number of time scales, our analysis extends the ...
  • Multiscale Queuing Analysis 

    Ribeiro, Vinay Joseph; Riedi, Rudolf H.; Baraniuk, Richard G. (2004-09-01)
    We develop a new approach to queuing analysis for an infinite-length queue with constant service rate fed by an arbitrary traffic process. Our approach is particularly relevant to queues fed with long-range-dependent (LRD) ...
  • Multiscale Queuing Analysis of Long-Range-Dependent Network Traffic 

    Ribeiro, Vinay Joseph; Riedi, Rudolf H.; Crouse, Matthew; Baraniuk, Richard G. (2001-02-20)
    This paper develops a novel approach to queuing analysis tailor-made for multiscale long-range-dependent (LRD) traffic models. We review two such traffic models, the wavelet-domain independent Gaussian model (WIG) and the ...
  • Network Traffic Modeling using a Multifractal Wavelet Model 

    Riedi, Rudolf H.; Crouse, Matthew; Ribeiro, Vinay Joseph; Baraniuk, Richard G. (1999-02-01)
    In this paper, we describe a new multiscale model for characterizing positive-valued and long-range dependent data. The model uses the Haar wavelet transform and puts a constraint on the wavelet coefficients to guarantee ...
  • New class of wavelets for signal approximation 

    Odegard, Jan E.; Burrus, C. Sidney (1996-05-20)
    This paper develops a new class of wavelets for which the classical Daubechies zero moment property has been relaxed. The advantages of relaxing higher order wavelet moment constraints is that within the framework of ...
  • On the Correlation Structure of Multiplicity M Scaling Functions and Wavelets 

    Gopinath, Ramesh A.; Odegard, Jan E.; Burrus, C. Sidney (1992-05-20)
    None
  • On the Correlation Structure of Multiplicity M Scaling Functions and Wavelets 

    Gopinath, Ramesh A.; Odegard, Jan E.; Burrus, C. Sidney (1992-01-15)
    In this paper we study the auto-correlation and cross-correlation structure of the scaling and wavelet functions associated with compactly supported orthonormal wavelet basis. These correlation structures play an important ...
  • On the Moments of the Scaling Function psi_0 

    Gopinath, Ramesh A.; Burrus, C. Sidney (1992-01-15)
    This paper derives relationships between the moments of the scaling function psi_0(t) associated with multiplicity M, K-regular, compactly supported, orthonormal wavelet bases [6, 5] that are extensions of the multiplicity ...
  • Optimal wavelets for signal decomposition and the existence of scale limited signals 

    Odegard, Jan E.; Gopinath, Ramesh A.; Burrus, C. Sidney (1992-01-15)
    Wavelet methods give a flexible alternative to Fourier methods in non-stationary signal analysis. The concept of <i>band-limitedness</i> plays a fundamental role in Fourier analysis. Since wavelet theory replaces ...
  • 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 ...
  • Representation and Compression of Multi-Dimensional Piecewise Functions Using Surflets 

    Chandrasekaran, Venkat; Wakin, Michael; Baron, Dror; Baraniuk, Richard G. (2006-03-01)
    We study the representation, approximation, and compression of functions in M dimensions that consist of constant or smooth regions separated by smooth (M-1)-dimensional discontinuities. Examples include images containing ...
  • Simulation of Non-Gaussian Long-Range-Dependent Traffic using Wavelets 

    Ribeiro, Vinay Joseph; Riedi, Rudolf H.; Crouse, Matthew; Baraniuk, Richard G. (1999-05-01)
    In this paper, we develop a simple and powerful multiscale model for the synthesis of non-Gaussian, long-range dependent (LRD) network traffic. Although wavelets effectively decorrelate LRD data, wavelet-based models have ...
  • 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 ...
  • 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 ...
  • Unsupervised SAR Image Segmentation using Recursive Partitioning 

    Baraniuk, Richard G. (2000-04-01)
    We present a new approach to SAR image segmentation based on a Poisson approximation to the SAR amplitude image. It has been established that SAR amplitude images are well approximated using Rayleigh distributions. We show ...
  • 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 queuing analysis of Gaussian and non-Gaussian long-range-dependent network traffic 

    Ribeiro, Vinay Joseph (1999-05-20)
    In this thesis, we develop a simple and powerful multiscale model for the synthesis of nonGaussian, long-range-dependent (LRD) network traffic. The wavelet transform effectively doecorrelates LRD signals and hence is ...
  • 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 ...
  • 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 ...
  • 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 ...