SPARS 2011

And so it begins! A whole week of nothing but sparsity in various forms and guises. My summer has officially started!

The proceedings collect all the accepted one-page submissions, which I find provide very tantalizing details. And for a cool down, I am reading Michael Elad’s excellent book Sparse and Redundant Representations: From Theory to Applications in Signal and Image Processing. It does for sparse signal processing what Hamming’s book does for digital filters: completely accessible, drawing together numerous disciplines, and giving a good big picture perspective.

Today began with a bang, featuring Yi Ma.
Just as Andrew Ng’s Google Talk, Ma amazed me (and I am sure many others) with his examples of the incredible power of Robust PCA for everything from face and text alignment, to extracting the geometry of buildings from 2D pictures without any use of edge or corner detection.
All one needs are the pixels, and the rest is done by the assumption that the image can be decomposed into a low rank texture matrix, and a sparse matrix with non-textural items, like a person moving in front of a background.
One of my favorite examples was where he took 30 images of Bill Gate’s face.
Robust PCA aligned them all, corrected for transformations like shearing, and produced a mean image of Bill Gates.
Now, I wonder, can we do the same for a piece of classical music, where we create a mean version of a particular Bach Partita from a dozen Glenn Gould recordings?

There were many other fantastic talks and conversations to be had.
Because my internet access at this expensive hotel is free only for 30 minutes every 24 hours at a severely limited bandwidth, I must limit my description to that.
Tomorrow will be another exciting day in “Sparseland”, as Elad calls it.


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