News & Events

65 News items, Awards, Events or Talks found.


  •  TALK    Sparse projections onto convex sets
    Date: Tuesday, July 3, 2012
    Speaker: Prof. Volkan Cevher, EPFL
    MERL Host: Petros T. Boufounos
    Abstract
    • Many natural and man-made signals exhibit a few degrees of freedom relative to their dimension due to natural parameterizations or constraints. The inherent low-dimensional structure of such signals are mathematically modeled via combinatorial and geometric concepts, such as sparsity, unions-of-subspaces, or spectral sets, and are now revolutionizing the way we address linear inverse problems from incomplete data.

      In this talk, we describe a set of structured sparse models for constrained linear inverse problems that feature exact and epsilon-approximate projections in polynomial time. We pay particular attention to the sparsity models based on matroids, multi-knapsack, and clustering as well as spectrally constrained models. We then study sparse projections onto convex sets, such as the (general) simplex, and ell-1,2,inf balls. Finally, we describe a hybrid optimization framework which explicitly leverages these non-convex models along with additional convex constraints to obtain better recovery performance in compressive sensing, learn interpretable sparse densities from finite samples, and improved sparse Markowitzs portfolios with better return/cost performance.
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  •  NEWS    ICASSP 2012: 8 publications by Petros T. Boufounos, Dehong Liu, John R. Hershey, Jonathan Le Roux and Zafer Sahinoglu
    Date: March 25, 2012
    Where: IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
    MERL Contacts: Dehong Liu; Jonathan Le Roux; Petros T. Boufounos
    Brief
    • The papers "Dictionary Learning Based Pan-Sharpening" by Liu, D. and Boufounos, P.T., "Multiple Dictionary Learning for Blocking Artifacts Reduction" by Wang, Y. and Porikli, F., "A Compressive Phase-Locked Loop" by Schnelle, S.R., Slavinsky, J.P., Boufounos, P.T., Davenport, M.A. and Baraniuk, R.G., "Indirect Model-based Speech Enhancement" by Le Roux, J. and Hershey, J.R., "A Clustering Approach to Optimize Online Dictionary Learning" by Rao, N. and Porikli, F., "Parametric Multichannel Adaptive Signal Detection: Exploiting Persymmetric Structure" by Wang, P., Sahinoglu, Z., Pun, M.-O. and Li, H., "Additive Noise Removal by Sparse Reconstruction on Image Affinity Nets" by Sundaresan, R. and Porikli, F. and "Depth Sensing Using Active Coherent Illumination" by Boufounos, P.T. were presented at the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP).
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  •  NEWS    IEEE Transactions on Information Theory: publication by Petros T. Boufounos
    Date: February 27, 2012
    Where: IEEE Transactions on Information Theory
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The article "Universal Rate-Efficient Scalar Quantization" by Boufounos, P.T. was published in IEEE Transactions on Information Theory.
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  •  NEWS    WIFS 2011: publication by Petros T. Boufounos and Shantanu D. Rane
    Date: November 29, 2011
    Where: IEEE International Workshop on Information Forensics and Security (WIFS)
    MERL Contact: Petros T. Boufounos
    Research Area: Information Security
    Brief
    • The paper "Secure Binary Embeddings for Privacy Preserving Nearest Neighbors" by Boufounos, P. and Rane, S. was presented at the IEEE International Workshop on Information Forensics and Security (WIFS).
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  •  NEWS    ACSSC 2011: publication by Petros T. Boufounos and others
    Date: November 6, 2011
    Where: Asilomar Conference on Signals, Systems and Computers (ACSSC)
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The paper "Greedy Sparsity-Constrained Optimization" by Bahmani, S., Boufounos, P. and Raj, B. was presented at the Asilomar Conference on Signals, Systems and Computers (ACSSC).
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  •  NEWS    Applied and Computational Harmonic Analysis: publication by Petros T. Boufounos and others
    Date: November 1, 2011
    Where: Applied and Computational Harmonic Analysis
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The article "Democracy in Action: Quantization, Saturation and Compressive Sensing" by Laska, J.N., Boufounos, P.T., Davenport, M.A. and Baraniuk, R.G. was published in Applied and Computational Harmonic Analysis.
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  •  NEWS    ICIP 2011: 4 publications by Matthew E. Brand, Petros T. Boufounos, Shantanu D. Rane, Anthony Vetro and Dong Tian
    Date: September 11, 2011
    Where: IEEE International Conference on Image Processing (ICIP)
    MERL Contacts: Matthew Brand; Anthony Vetro; Petros T. Boufounos
    Brief
    • The papers "Distributed Compression of Zerotrees of Wavelet Coefficients" by Wang, Y., Rane, S., Boufounos, P. and Vetro, A., "A Trellis-based Approach for Robust View Synthesis" by Tian, D., Vetro, A. and Brand, M., "Concentric Ring Signature Descriptor for 3D Objects" by Nguyen, H.V. and Porikli, F. and "Parallel Quadratic Programming for Image Processing" by Brand, M. and Chen, D. were presented at the IEEE International Conference on Image Processing (ICIP).
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  •  NEWS    IGARSS 2011: publication by Petros T. Boufounos and Dehong Liu
    Date: July 24, 2011
    Where: IEEE International Geoscience and Remote Sensing Symposium (IGARSS)
    MERL Contacts: Dehong Liu; Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The paper "High Resolution SAR Imaging Using Random Pulse Timing" by Liu, D. and Boufounos, P.T. was presented at the IEEE International Geoscience and Remote Sensing Symposium (IGARSS).
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  •  TALK    Gigapixel Binary Sensing: Image Acquisition Using Oversampled One-Bit Poisson Statistics
    Date & Time: Wednesday, June 15, 2011; 12:00 PM
    Speaker: Dr. Yue M. Lu, Harvard School of Engineering and Applied Sciences
    MERL Host: Petros T. Boufounos
    Abstract
    • Before the advent of digital image sensors, photography, for the most part of its history, used film to record light information. In this talk, I will present a new digital image sensor that is reminiscent of photographic film. Each pixel in the sensor has a binary response, giving only a one-bit quantized measurement of the local light intensity.

      To analyze its performance, we formulate the binary sensing scheme as a parameter estimation problem based on quantized Poisson statistics. We show that, with a single-photon quantization threshold and large oversampling factors, the Cramer-Rao lower bound of the estimation variance approaches that of an ideal unquantized sensor, that is, as if there were no quantization in the sensor measurements. Furthermore, this theoretical performance bound is shown to be asymptotically achievable by practical image reconstruction algorithms based on maximum likelihood estimators.

      Numerical results on both synthetic data and images taken by a prototype sensor verify the theoretical analysis and the effectiveness of the proposed image reconstruction algorithm. They also demonstrate the benefit of using the new binary sensor in applications involving high dynamic range imaging.

      Joint work with Feng Yang, Luciano Sbaiz and Martin Vetterli.
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  •  TALK    Recursive Sparse Recovery and Applications in Dynamic Imaging
    Date & Time: Friday, June 3, 2011; 11:00 AM
    Speaker: Prof. Namrata Vaswani, Iowa State University
    MERL Host: Petros T. Boufounos
    Abstract
    • In this talk, I will discuss our recent work on Recursive Sparse Recovery (RecSparsRec) and show how it provides novel solutions to two very different problems in dynamic imaging. RecSparsRec refers to recursive approaches to causally recover a time sequence of signals/images from a greatly reduced number of measurements (compared to existing approaches), by utilizing their sparsity.

      The motivating application for RecSparsRec is fast recursive dynamic magnetic resonance imaging (MRI) for real-time applications like MRI-guided surgery. MRI is a technique for cross-sectional imaging that acquires Fourier projections of the cross-section to be reconstructed, one-at-a-time. Thus, the ability to accurately reconstruct using fewer measurements directly translates into reduced scan times. This, along with online (causal) and fast (recursive) reconstruction algorithms, can enable real-time imaging of fast changing physiological phenomena, and thus make real-time MRI feasible. Cross-sectional images of the brain, heart, or other organs are known to be wavelet sparse. Our recent work was the first to observe that, in a time sequence, their sparsity pattern changes quite slowly. Using this fact, we were able to reformulate the RecSparsRec problem as one of sparse reconstruction with partially known support. We introduced a simple, but very powerful, approach called!
      Modified-CS that achieves provably exact reconstruction (in the noise-free case) and whose error is provably stable over time (in the noisy case), with using much fewer measurements than existing work. Our preliminary experiments indicate that Modified-CS needs roughly 5-times fewer measurements than existing MR scanner technology and 1.5-times fewer than existing research literature.

      I will briefly also discuss our ongoing work on the difficult video analysis problem of separating foreground moving objects from a background scene that is itself is changing and dong this in real-time. This can be posed as a recursive robust principal components analysis (PCA) problem in the presence of correlated sparse outliers or equivalently, as a problem of recursive sparse recovery in the presence of very large, but ``low rank" noise (noise with a low rank covariance matrix).
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  •  NEWS    IEEE Transactions on Information Theory: publication by Petros T. Boufounos and others
    Date: May 23, 2011
    Where: IEEE Transactions on Information Theory
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The article "Sparse Recovery from Combined Fusion Frame Measurements" by Boufounos, P.T., Kutyniok, G. and Rauhut, H. was published in IEEE Transactions on Information Theory.
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  •  NEWS    ICASSP 2011: 4 publications by Petros T. Boufounos, Zafer Sahinoglu and Shantanu D. Rane
    Date: May 22, 2011
    Where: IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
    MERL Contact: Petros T. Boufounos
    Brief
    • The papers "Compressive Sensing for Over-the-Air Ultrasound" by Boufounos, P.T., "Privacy Preserving Probabilistic Inference with Hidden Markov Models" by Pathak, M., Rane, S., Sun, W. and Raj, B., "Saturation-robust SAR Image Formation" by Wei, D. and Boufounos, P.T. and "Scale-Invariant GLRT in Stochastic Partially Homogeneous Environments" by Wang, P., Sahinoglu, Z., Pun, M.-O., Li, H. and Himed, B. were presented at the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP).
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  •  NEWS    International Conference on Sampling Theory and Applications (SampTA) 2011: publication by Petros T. Boufounos
    Date: May 2, 2011
    Where: International Conference on Sampling Theory and Applications (SampTA)
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The paper "Hierarchical Distributed Scalar Quantization" by Boufounos, P.T. was presented at the International Conference on Sampling Theory and Applications (SampTA).
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  •  NEWS    SPIE Defense, Security and Sensing, Algorithms for Synthetic Aperture Radar Imagery 2011: publication by Petros T. Boufounos, Shantanu D. Rane, Anthony Vetro and others
    Date: April 27, 2011
    Where: SPIE Defense, Security and Sensing, Algorithms for Synthetic Aperture Radar Imagery
    MERL Contacts: Anthony Vetro; Petros T. Boufounos
    Research Area: Digital Video
    Brief
    • The paper "Low-Complexity Efficient Raw SAR Data Compression" by Rane, S., Boufounos, P., Vetro, A. and Okada, Y. was presented at SPIE Defense, Security and Sensing, Algorithms for Synthetic Aperture Radar Imagery.
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  •  NEWS    PCS 2010: publication by Petros T. Boufounos, Shantanu D. Rane, Anthony Vetro and others
    Date: December 7, 2010
    Where: Picture Coding Symposium (PCS)
    MERL Contacts: Anthony Vetro; Petros T. Boufounos
    Research Area: Digital Video
    Brief
    • The paper "Wyner-Ziv Coding of Multispectral Images for Space and Airborne Platforms" by Rane, S., Wang, Y., Boufounos, P. and Vetro, A. was presented at the Picture Coding Symposium (PCS).
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  •  NEWS    MILCOM 2010: 2 publications by Petros T. Boufounos and Jinyun Zhang
    Date: October 31, 2010
    Where: IEEE Military Communications Conference (MILCOM)
    MERL Contacts: Jinyun Zhang; Petros T. Boufounos
    Brief
    • The papers "Level Crossing Rates and Average Outage Durations of SINR with Multiple Co-Channel Interferers" by Annavajjala, R. and Zhang, J. and "Compressive Sensing for Streaming Signals using the Streaming Greedy Pursuit" by Boufounos, P.T. and Asif, M.S. were presented at the IEEE Military Communications Conference (MILCOM).
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  •  NEWS    ICIP 2010: 4 publications by Robert A Cohen, Petros T. Boufounos, Anthony Vetro and Huifang Sun
    Date: September 26, 2010
    Where: IEEE International Conference on Image Processing (ICIP)
    MERL Contacts: Petros T. Boufounos; Anthony Vetro; Huifang Sun
    Brief
    • The papers "Direction-Adaptive Transforms for Coding Prediction Residuals" by Cohen, R.A., Klomp, S., Vetro, A. and Sun, H., "Streaming Compressive Sensing for High-Speed Periodic Videos" by Asif, M.S., Reddy, D., Boufounos, P.T. and Veeraraghavan, A., "Frame Compatible Formats for 3D Video Distribution" by Vetro, A. and "Occlusion Handling Based on Support and Decision" by Min, D., Yea, S. and Vetro, A. were presented at the IEEE International Conference on Image Processing (ICIP).
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  •  NEWS    CISS 2010: 2 publications by Petros T. Boufounos and others
    Date: March 17, 2010
    Where: Annual Conference on Information Sciences and Systems (CISS)
    MERL Contact: Petros T. Boufounos
    Brief
    • The papers "Average Case Analysis of Sparse Recovery from Combined Fusion Frame Measurements" by Boufounos, P.T., Kutyniok, G. and Rauhut, H. and "Compressive Sampling for Streaming Signals with Sparse Frequency Content" by Boufounos, P.T. and Asif, M.S. were presented at the Annual Conference on Information Sciences and Systems (CISS).
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  •  NEWS    ICASSP 2010: 9 publications by Anthony Vetro, Shantanu D. Rane and Petros T. Boufounos
    Date: March 14, 2010
    Where: IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
    MERL Contacts: Anthony Vetro; Petros T. Boufounos
    Brief
    • The papers "Privacy and Security of Features Extracted from Minutiae Aggregates" by Nagar, A., Rane, S.D. and Vetro, A., "Hiding Information Inside Structured Shapes" by Das, S., Rane, S.D. and Vetro, A., "Ultrasonic Sensing for Robust Speech Recognition" by Srinivasan, S., Raj, B. and Ezzat, T., "Reconstruction of Sparse Signals from Distorted Randomized Measurements" by Boufounos, P.T., "Disparity Search Range Estimation: Enforcing Temporal Consistency" by Min, D., Yea, S., Arican, Z. and Vetro, A., "Synthesizing Speech from Doppler Signals" by Toth, A.R., Raj, B., Kalgaonkar, K. and Ezzat, T., "Spectrogram Dimensionality Reduction with Independence Constraints" by Wilson, K.W. and Raj, B., "Robust Regression using Sparse Learning for High Dimensional Parameter Estimation Problems" by Mitra, K., Veeraraghavan, A.N. and Chellappa, R. and "Subword Unit Approaches for Retrieval by Voice" by Gouvea, E., Ezzat, T. and Raj, B. were presented at the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP).
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  •  NEWS    Rice University ECE Department Technical Report: publication by Petros T. Boufounos and others
    Date: November 1, 2009
    Where: Rice University ECE Department Technical Report
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
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  •  NEWS    ACSSC 2009: 3 publications by Philip V. Orlik, Jinyun Zhang and Petros T. Boufounos
    Date: November 1, 2009
    Where: Asilomar Conference on Signals, Systems and Computers (ACSSC)
    MERL Contacts: Jinyun Zhang; Philip V. Orlik; Petros T. Boufounos
    Brief
    • The papers "Parametric Compression of Rank-1 Analog Feedback in MIMO-OFDM" by Porat, R. and Orlik, P.V., "Codebook-based Quantized MIMO Feedback for Closed-loop Transmit Precoding" by Pun, M.-O., Porat, R., Orlik, P.V., Zhang, J. and Kuze, T. and "Greedy Sparse Signal Reconstruction from Sign Measurements" by Boufounos, P.T. were presented at the Asilomar Conference on Signals, Systems and Computers (ACSSC).
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  •  NEWS    The Wavelets XIII: publication by Petros T. Boufounos and others
    Date: September 4, 2009
    Where: The Wavelets XIII
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The paper "Compressed Sensing for Fusion Frames" by Boufounos, P.T., Kutyniok, G. and Rauhut, H. was presented at The Wavelets XIII.
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  •  NEWS    IPSN 2009: publication by Petros Boufounos and others
    Date: April 13, 2009
    Where: International Conference on Information Processing in Sensor Networks (IPSN)
    MERL Contact: Petros T. Boufounos
    Research Area: Computational Sensing
    Brief
    • The paper "Near-Optimal Bayesian Localization via Incoherence and Sparsity" by Cevher, V., Boufounos, P., Baraniuk, R.G., Gilbert, A.C. and Strauss, M.J. was presented at the International Conference on Information Processing in Sensor Networks (IPSN).
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  •  NEWS    IEEE Transactions on Audio, Speech and Language Processing: 2 publications by Petros T. Boufounos and others
    Date: January 15, 2007
    Where: IEEE Transactions on Audio, Speech and Language Processing
    MERL Contact: Petros T. Boufounos
    Brief
    • The articles "Position and Trajectory Learning for Microphone Arrays" by Smaragdis, P. and Boufounos, P. and "Convolutive Speech Bases and their Application to Supervised Speech Separation" by Smaragdis, P. were published in IEEE Transactions on Audio, Speech and Language Processing.
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  •  NEWS    WASPAA 2005: 3 publications by Petros T. Boufounos, Ajay Divakaran and Paris Smaragdis
    Date: October 16, 2005
    Where: IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA)
    MERL Contact: Petros T. Boufounos
    Brief
    • The papers "Latent Variable Decomposition of Spectrograms for Single Channel Speaker Separation" by Raj, B. and Smaragdis, P., "Learning Source Trajectories Using Wrapped-Phase Hidden Markov Models" by Smaragdis, P. and Boufounos, P. and "Audio Analysis for Surveillance Applications" by Radhakrishnan, R., Divakaran, A. and Smaragdis, P. were presented at the IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA).
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