Thursday, May 27, 2010

Around the blogs in 80 hours

Yesterday, I mentioned the NPR piece and its supporting website showing some examples of Compressive Sensing in Audio. Well, Bob Sturm read it and wrote about it in "Compressed Sensing" and Undersampled Audio Reconstruction. Go read it, I'll wait....It should always be remembered that the concept of incoherent sampling is a central one in compressed sensing (beyond RIP and so forth..). This is why I wrote this example in Compressed Sensing: How to wow your friends back in 2007 that features an example with delta and sines. Let us note that in Compressive Sensing Audio, for the delta/sines assumption to hold, you really need have to sample enough within time-localized phenomena. In other words, Compressed Sensing is not a license to make appear something you did not catch with the sampling process. This needs to be said often, as in MRI or steady-state audio, the signal is being sampled with diracs in their appropriate phase spaces (Fourier for MRI and time for Audio) that will get you a result directly applicable by a compressive sensing approach. In other fields like imagery however, you do not sample directly in a good phase space and you need new types of exotic hardware to perform these new types of incoherent measurements.

Other entries of interest and relevant to CS included:

Of interest is the following page: Noise, Dynamic Range and Bit Depth in Digital SLRs


Credit photo: Thierry Legault, via the Bad Astronomy blog. The ISS and Atlantis in transit with the Sun.

2 comments:

The Vlad said...

Igor,

Is it just me or does this picture of the sun give rise to a strong illusion of shrinking motion?

T.

Igor said...

Tony,

Define "shrinking motion".

Igor.

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