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Showing posts from May, 2014

Sparse template-based adaptive filtering

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The phenomenon arises in several real-life signal processing contexts: acoustic echo-cancellation (AEC) in sound and speech,  non-destructive testing where transmitted waves may rebound at material interfaces (e.g. ultrasounds), or pattern matching in images. Here in seismic reflection or seismology. Weak signals (of interest) are buried under both strong random and structured noise. Provided appropriate templates are obtained, we propose a structured-pattern filtering algorithm (called Ricochet) through constrained adaptive filtering in a  transformed domain. Its generic methodology impose sparsity: in different wavelet frames (Haar, Daubechies, Symmlets) coefficients, using the L-1 or Manhattan norm, as well as on adaptive filter coefficients using concentration measures (for sparser filters in the time domain): L-1, the Frobenius norm squared, and the mixed L-1,2 norms). Regularity properties are constrained as well, for instance slow variation on the adaptive filter coefficien…

Postdoc position: Very large data management in Geosciences

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[UPDATE: 2014/09/21 Position filled]

So we (IFPEN) have a postdoc position on "Very large data management in Geosciences" (gestion des très gros volumes de données en géosciences), with details at:  http://www.laurent-duval.eu/siva-2014-postdoc-large-data-geosciences.htmlhttp://www.gdr-isis.fr/news/2392/121/Postdoc-position-Very-large-data-management-in-Geosciences.html
Abstract: The main purpose of the post-doctoral work is to propose new data compression techniques for volumetric meshes able to manage seismic data values attached to geometry elements (nodes or cells) with adaptive decompression for post-processing functionalities (visualization). Compression algorithms adapted to "big data" will enable our current software scalability, for instance, geoscience fluid-flow simulation or transport combustion simulation on very large meshes. Obtained results are intended to contribute to IFPEN scientific lock about very large data management with a target of being a…

Computational Harmonic Analysis: Winter School

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This message was communicated to me by Caroline Chaux, to share:
Computational Harmonic Analysis: Winter School, Marseille, October 2014
We are pleased to announce the winter school on Computational Harmonic Analysis - with Applications to Signal and Image Processing, that will be held in October 2014 (20-24), in Marseille, France (at CIRM).

The topics will be: Mathematical and numerical aspects of frame theoryTime-frequency frames and applications to audio analysisWavelets, shearlets and geometric frames (and others *-lets or directional wavelets)Inverse problems and optimization This winter school will bring together PhD-students and young PostDocs (as well as a few experts) in the field of computational harmonic analysis, in order to explain the background and the efficiency as well as the range of application of a number of numerical algorithms which are based on the Fourier-, the wavelet and the Short-Time Fourier Transform (Time-Frequency and Gabor Analysis), as well as other atom…
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ICASSP 2014 in Florence has just ended. The slogan was "The art of signal processing". In Florence, Art is indeed everywhere, and science, signal processing included, is not very far apart.
Take for instance this example of an analysis/synthetis three-band, apparently linear, and complex gutter-bank. I do suspect a certain redundancy i cannot yet understand. Is it related to other diffusion-based filter-banks?

Signal processing for chemical sensing (OGST Special issue)

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OGST (Oil & Gas Science and Technology) has just published a special issue on "Advances in signal processing and image analysis for physicochemical, analytical chemistry and chemical sensing", vol. 69, number 2 (March-April 2014). It somehow parallels the ICASSP 2013 Special session on  Signal Processing for Chemical Sensing. Moreover, a contributed book in planned on the topic.

The editorial (F. Rocca and L. Duval) deals with informational content of data, sensory principles and, of source, the law of parcimony (beautifully illustrated in "The name of the rose"), Ockham's razor, in other words, sparsity, a common aspect in recent signal processing techniques. So why is the topic interesting for chemical engineers and scientists?

With the advent of more affordable, higher resolution or innovative data acquisition techniques (for instance hyphenated instrumentation such as two-dimensional chromatography), the need for advanced signal and image processing too…

ICASSP 2014: Tutorials "sive" Florence monuments

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Starting tomorrow, the International Conference on Acoustics, Speech and Signal Processing hosts 15 tutorials on solid topics, ranging from convex optimization to big data and signal processing on graphs. 
If you are wealthy enough to have registred, you may download the tutorial support pdf files from the given links, and uncompress them with the password provided with your registration. If not, sive, well, we are in the magnificient Florence, at least 12 key places are worth paying a visit, namely: palazzovecchio, fortezzadabasso, pontevecchio, santamariadelfiore, palazzopitti, santamarianovella, giardinodiboboli, santacroce, piazzalemichelangelo, campaniledigiotto, sanlorenzo, corridoiovasariano. If you know three other hidden places, fell free to tell.

T1 - Statistical Signal Processing for Graphs
Subject Area: Fundamentals
Speakers: Nadya T. Bliss (Arizona State University), Alfred O. Hero (University of Michigan, Ann Arbor), Benjamin A. Miller (MIT Lincoln Laboratory)

T2 - Monoto…