November 6, 2012

SEG 2012: From Las Vegas with notes

Back in 2002 ICASSP, i thought Orlando had a little something... artificial. Fake trees, weird hotels. Ten years later in 2012 SEG (Society of Explorations Geophysicists) annual meeting in Las Vegas, well the fake fragrance mixes even more with air conditioned, and the weather is really cool. No need to keep twitting on the event because Matt Hall at Agile* does it already. The papers i'll have to study a little deeper are the following:
I'm keeping a last word for Generalized windowed transforms for seismic processing and imaging (Charles C. Mosher). Having worked with wavelets in geophysics for decades, Chuck comes up with a 20 years' work on developing a slighly redundant windowed transform, based on finite support filters in the frequency domain associated with fractional subsampling, to reduce the aliasing, and moving artifacts to some form of blending. This ends up in a non tight frame, mostly implemented in the Fourier transformed domain. 

This transform is meant to be used in blended acquistion, or even compressing sensing, two of the current trends in geophysical meetings. No wonder, the cost of data acquisition is so high in seismic exploration that one may expect huge savings if they succeed in reducing the acquisition rate by just a factor of two. What puzzles me, still, is that the same petroleum industry which could not loose 1-bit out of 24-integer or 32-bit float data in lossy compression, now looked at blended acquisition (followed by source separation) or compressive sensing has potential data deluge saviors. I even have the feeling that a few people cannot yet tell the difference between those two.

2 comments:

  1. I was very happy to find your blog — lots of good things to read. And even happier to see this post about SEG!

    I felt bad not mentioning Chuck in my own posts, because his method seemed highly cunning, but he left me in his mathematical dust :) Now I can just point to you.

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  2. You are quite right. I have been lucky enough to catch Chuck in the aisles. I knew his work on seismic data compression, which has been my topic for a while. He has been kind enough to spend 15 minutes more to explain his 20-year achievement to me. Now i kinda got half-a-point. It looks like an almost-stationnary M-channel decomposition. With limited support in the frequency domain, allowing some rational subsampling, hence a reduction in the redundancy. A lot of mysteries remain, he should release it in his JavaSeis suite, but maybe i'll take a test before. Thank you for your feedback!

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