Now showing items 1-20 of 508

    • 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 review cost-sensitive extensions of standard support vector machines (SVMs). In particular, we describe cost-sensitive extensions of ...
    • 3-D Local Radon Power Spectra for Seismic Attribute Extraction 

      Steeghs, Philippe; Fokkema, Jacob T; Diephuis, Gerhard (1998-01-15)
      In this paper we discuss a method for volume attribute extraction that is based on a new type of local Radon power spectrum. The new algorithm results in robust and geologically meaningful volume attributes, such as volume dip and azimuth. Seismic volume attribute analysis greatly facilitates the interpretation of large 3-D seismic data volumes. ...
    • 3D Geometry Coding using Mixture Models and the Estimation Quantization Algorithm 

      Lavu, Sridhar (2002-09-01)
      3D surfaces are used in applications such as animations, 3D object modeling and visualization. The geometries of such surfaces are often approximated using polygonal meshes. This thesis aims to compress 3D geometry meshes by using an algorithm based on normal meshes and the Estimation-Quantization (EQ) algorithm. Normal meshes are multilevel ...
    • A HIGH RESOLUTION DATA-ADAPTIVE TIME-FREQUENCY REPRESENTATION 

      JONES, DOUGLAS LLEWELLYN (1987)
      The short-time Fourier transform and the Wigner distribution are the time-frequency representations that have received the most attention. The Wigner distribution has a number of desirable properties, but it introduces nonlinearities called cross-terms that make it difficult to interpret when applied to real multi-component signals. The short-time ...
    • A NOVEL FRAMEWORK FOR SURFACE RECONSTRUCTION FROM 3-DIMENSIONAL CONTOURS 

      KEHTARNAVAZ, NASSER (1986)
      In many applications, such as computer vision, medical imaging, scene forming, and motion animation, surface data is available in the form of two-dimensional (2D) or three-dimensional (3D) contours. Reconstruction of the surface integrates this information into a three-dimensional format. A good surface reconstruction framework must be able to include ...
    • Adaptive Iterative Reqeighted Least Squares Design of LP FIR Filters 

      Vargas, Ricardo; Burrus, C. Sidney (1999-03-01)
      This paper presents an efficient adaptive algorithm for designing FIR digital filters that are efficient according to an Lp error criteria. The algorithm is an extension of Burrus' iterative reweighted least-squares (IRLS) method for approximating Lp filters. Such algorithm will converge for most significant cases in a few iterations. In some cases ...
    • ADAPTIVE NONLINEAR IMAGE RESTORATION BY A MODIFIED KALMAN FILTERING APPROACH 

      RAJALA, SARAH ANN (1980)
      An adaptive nonlinear Kalman-type filter is presented in this dissertation for the restoration of two-dimensional images degraded by general image formation system degradations and additive white noise. A vector difference equation model is used to model the degradation process. The object plane distribution function is partitioned into disjoint ...
    • An Adaptive Optimal-Kernel Time-Frequency Representation 

      Jones, Douglas L.; Baraniuk, Richard G. (1995-10-01)
      Time-frequency representations with fixed windows or kernels figure prominently in many applications, but perform well only for limited classes of signals. Representations with signal- dependent kernels can overcome this limitation. However, while they often perform well, most existing schemes are block-oriented techniques unsuitable for on-line ...
    • 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 display frame smaller than the image, we define the SmartNail as an appropriately cropped part of a suitably scaled-down image. We ...
    • Adaptive Wavelet Transforms for Image Coding 

      Claypoole, Roger L.; Davis, Geoffrey; Sweldens, Wim; Baraniuk, Richard G. (1997-11-01)
      We introduce a new adaptive transform for wavelet-based image coding. The lifting framework for wavelet construction motivates our analysis and provides new insight into the problem. Since the adaptive transform is non-linear, we examine the central issues of invertibility, stability, and artifacts in its construction. We describe a new type of ...
    • Adaptive Wavelet Transforms for Image Coding 

      Claypoole, Roger L.; Davis, Geoffrey; Sweldens, Wim; Baraniuk, Richard G. (1997-11-01)
      We introduce a new adaptive transform for wavelet-based image coding. The lifting framework for wavelet construction motivates our analysis and provides new insight into the problem. Since the adaptive transform is non-linear, we examine the central issues of invertibility, stability, and artifacts in its construction. We describe a new type of ...
    • Adaptive Wavelet Transforms for Image Coding using Lifting 

      Claypoole, Roger L.; Davis, Geoffrey; Sweldens, Wim; Baraniuk, Richard G. (1998-03-01)
      Summary form only given. Image compression relies on efficient representations of images, and within smooth image regions, the wavelet transform provides such a representation. However, near edges, wavelet coefficients decay slowly and are expensive to code. We focus on improving the transform by incorporating adaptivity. Construction of nonlinear ...
    • Adaptive Wavelet Transforms via Lifting 

      Claypoole, Roger L.; Baraniuk, Richard G.; Nowak, Robert David (1998)
      This paper develops new algorithms for adapted multiscale analysis and signal adaptive wavelet transforms. We construct our adaptive transforms with the <i>lifting scheme</i>, which decomposes the wavelet transform into prediction and update stages. We adapt the prediction stage to the signal structure and design the update stage to preserve the ...
    • Adaptive Wavelet Transforms via Lifting 

      Claypoole, Roger L.; Baraniuk, Richard G.; Nowak, Robert David (1999-01-15)
      This paper develops new algorithms for adapted multiscale analysis and signal adaptive wavelet transforms. We construct our adaptive transforms with the <i>lifting scheme</i>, which decomposes the wavelet transform into prediction and update stages. We adapt the prediction stage to the signal structure and design the update stage to preserve the ...
    • Adaptive Wavelet Transforms via Lifting 

      Claypoole, Roger L.; Baraniuk, Richard G.; Nowak, Robert David (1998-05-01)
      This paper develops two new adaptive wavelet transforms based on the lifting scheme. The lifting construction exploits a spatial-domain, prediction-error interpretation of the wavelet transform and provides a powerful framework for designing customized transforms. We use the lifting construction to adaptively tune a wavelet transform to a desired ...
    • Adaptive Weighted Highpass Filters Using Multiscale Analysis 

      Nowak, Robert David; Baraniuk, Richard G. (1998-07-01)
      In this paper, we propose a general framework for studying a class of weighted highpass filters. Our framework, based on a multiscale signal decomposition, allows us to study a wide class of filters and to assess the merits of each. We derive an automatic procedure to tune a filter to the local structure of the image under consideration. The entire ...
    • Adding Linguistic Constraints to Document Image Decoding: Comparing the Iterated Complete Path and Stack Algorithms 

      Popat, Kris; Greene, Dan; Romberg, Justin; Bloomberg, Dan (2001-01-20)
      Beginning with an observed document image and a model of how the image has been degraded, Document Image Decoding recognizes printed text by attempting to find a most probable path through a hypothesized Markov source. The incorporation of linguistic constraints, which are expressed by a sequential predictive probabilistic language model, can improve ...
    • Additive and Multiplicative Mixture Trees for Network Traffic Modeling 

      Sarvotham, Shriram; Wang, Xuguang; Riedi, Rudolf H.; Baraniuk, Richard G. (2002-05-01)
      Network traffic exhibits drastically different statistics, ranging from nearly Gaussian marginals and long range dependence at very large time scales to highly non-Gaussian marginals and multifractal scaling on small scales. This behavior can be explained by forming two components of the traffic according to the speed of connections, one component ...