- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- Date: November 1, 2009
Where: Rice University ECE Department Technical Report
MERL Contact: Petros T. Boufounos
Research Area: Computational Sensing
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- 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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- 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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- 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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- 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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- 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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