Now showing items 1-25 of 25

  • 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 ...
  • Applications of Terahertz Imaging 

    Mittleman, Daniel M.; Neelamani, Ramesh; Baraniuk, Richard G.; Nuss, Martin C. (1998-08-01)
    The recent advances involving imaging with sub-picosecond terahertz pulses have opened up a wide range of possibilities in the applications of far-infrared technology. For the first time, a commercially viable terahertz ...
  • 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 ...
  • The Embedded Triangles Algorithm for Distributed Estimation in Sensor Networks 

    Delouille, Veronique; Neelamani, Ramesh; Chandrasekaran, Venkat; Baraniuk, Richard G. (2003-09-01)
    We propose a new iterative distributed estimation algorithm for Gaussian hidden Markov graphical models with loops. We decompose a loopy graph into a number of linked <i>embedded triangles</i> and then apply a parallel ...
  • 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 ...
  • Gas Sensing using Terahertz Time-Domain Spectroscopy 

    Mittleman, Daniel M.; Jacobsen, R. H.; Neelamani, Ramesh; Baraniuk, Richard G.; Nuss, Martin C. (1998-01-15)
    A method for detection and identification of polar gases and gas mixtures based on the technique of terahertz time-domain spectroscopy is presented. This relatively new technology promises to be the first portable far-infared ...
  • Inverse problems in image processing 

    Neelamani, Ramesh (2004)
    Inverse problems involve estimating parameters or data from inadequate observations; the observations are often noisy and contain incomplete information about the target parameter or data due to physical limitations of the ...
  • JPEG Compression History Estimation for Color Images 

    Neelamani, Ramesh; de Queiroz, Ricardo; Fan, Zhigang; Baraniuk, Richard G. (2006-06-01)
    We routinely encounter digital color images that were previously compressed using the Joint Photographic Experts Group (JPEG) standard. En route to the image's current representation, the previous JPEG compression's various ...
  • JPEG Compression History Estimation for Color Images 

    Neelamani, Ramesh; de Queiroz, Ricardo; Fan, Zhigang; Baraniuk, Richard G. (2003-09-01)
    We routinely encounter digital color images that were previously JPEG-compressed. We aim to retrieve the various settings - termed JPEG compression history (CH) - employed during previous JPEG operations. This information ...
  • 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 ...
  • Lattice Algorithms for Compression Color Space Estimation in JPEG Images 

    Neelamani, Ramesh; de Queiroz, Ricardo; Baraniuk, Richard G. (2001-08-01)
    JPEG (Joint Photographic Experts Group) is an international standard to compress and store digital color images [5]. Given a color image that was previously JPEG-compressed in some hidden color space, we aim to estimate ...
  • 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 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 ...
  • 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 ...
  • Recent advances in Imaging and Spectroscopy with T-rays 

    Mittleman, Daniel M.; Neelamani, Ramesh; Gupta, Maya; Baraniuk, Richard G.; Nuss, Martin C. (1998-12-01)
    Recent work in terahertz "T-Ray" imaging is reported. With the ongoing development of commercially viable THz-TDS imaging system, opitmail signal processing strategies for the THz waveforms must be developed. Algorithms ...
  • Recent Advances in Terahertz Imaging 

    Koch, Martin; Rudd, J. Van; Neelamani, Ramesh; Gupta, Maya; Baraniuk, Richard G.; Mittleman, Daniel M. (1999-06-01)
    We review recent progress in the field of terahertz "T-ray" imaging. This relatively new imaging technique, based on terahertz time-domain spectroscopy, has the potential to be the first portable far-infared imagin ...
  • Robust Distributed Estimation in Sensor Networks using the Embedded Polygons Algorithm 

    Delouille, Veronique; Neelamani, Ramesh; Baraniuk, Richard G. (2004-04-01)
    We propose a new iterative distributed algorithm for linear minimum mean-squared-error (LMMSE) estimation in sensor networks whose measurements follow a Gaussian hidden Markov graphical model with cycles. The <i>embedded ...
  • Robust Distributed Estimation Using the Embedded Subgraphs Algorithm 

    Delouille, Veronique; Neelamani, Ramesh; Baraniuk, Richard G. (2006-08-01)
    We propose a new iterative, distributed approach for linear minimum mean-square-error (LMMSE) estimation in graphical models with cycles. The embedded subgraphs algorithm (ESA) decomposes a loopy graphical model into a ...
  • 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. (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 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 (1999)
    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 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-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 ...