Wednesday, May 20, 2009

In other newz, ...

I have finally finished a paper I am excited about, which we have submitted to the Tenth International Society for Music Information Retrieval Conference in Kobe JAPAN in October. In this work we extend a previously presented approach for image similarity search to work with databases of sound compressed and described using sparse approximation.

The graphic above, from our paper, shows one of the neatest results I have seen. In the background is the waveform of a bunch of sound data: six people saying "Cottage cheese is best with chives", one short segment of music, and another short segment of noise. We take one of the instances of "cheese" and ask our algorithm to find all portions of the signal that are similar to it --- but within the sparse approximation domain. Using only one atom pair (M=1) for each subsequence, we find a sharp spike exactly where the original "cheese" came from. When M=10, we are considering 55 atom pairs for each subsequence, and we see two additional humps. These correspond to "cheese", but said by other people, including one of the opposite sex! Now, if we take our "cheese" query, and nearly cover it up with noise (to the tune of -10 dB SNR!), then decompose it and look for similar portions of the signal, the results are hardly affected! As I have always said, sparse approximation can be incredibly robust to noise.

Finally, the part everyone has been waiting for, the story everyone is talking about. On Monday evening we had our inaugural meeting of the Puteaux Run Club. Though the first rule of the Puteaux Run Club is to not talk about the Puteaux Run Club on a blog such as this, we will make this one exception because of "various factors." These factors include the incredible diversity of wildlife one sees while running through Bois de Boulogne (map to left). This incredibly scenic "woods" is right outside of Paris, just below Puteaux --- which is why, and only why, we went running through here. Among the lakes are strewn fishermen; and on some lawns are picnickers. There are a few hippodromes for equestrian activities, and lots of rabbits that just sort of hop around. But most special of all, while running through a particular section, if you are lucky you can see, sometimes hiding in the bushes, sometimes lazing on the path, but always among a variety of lovely flora, well-dressed or un-dressed prostitutes of every stripe.

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