Now showing items 1-20 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