26 March 2012

A Viral Video about Imaging

Ok I'm not sure if this video has gone truly viral yet, but at least two of my scientist friends posted it :)

About a week ago Nature.com posted this video about new research on imaging objects that are not in line-of-sight by using scattered light and an ultrafast camera. The researchers are from MIT, Harvard, and Rice University. So now if we can image hidden objects, what happens to the invisibility cloak?? :)

I watched the video yesterday and was excited to get into school and have access to the actual paper! It's fascinating what they've been able to do. Here are the parts of their "discussion" section which I find most interesting:

"Our reconstruction method assumes that light is only reflected once by a discrete surface on the hidden object without inter-reflections within the object and without subsurface scattering. We further assume that light travels in a straight line between reflections. Light that does not follow these assumptions will appear as time-delayed background in our heatmap and will complicate, but not necessarily prevent reconstruction."

The problem of reconstructing the hidden object using the scattered light is one example of what people in my field call an inverse problem. There are a lot of parameters involved-- the reflection surfaces, the textures of those surfaces, other cluttering objects. If you don't know the values of those parameters, then the problem becomes harder. Some of these problems have been looked at from a different perspective in the area of radar imaging.

One of the neatest things I have learned about recently is coded aperture photography. What that means is a type of filter is put on the aperture of your camera-- the filter is "coded" meaning that light from parts of the scene will be blacked out and parts will be allowed to pass (see this image for illustration). Coded aperture has been successful in improving imaging in many fields, including astronomical imaging and depth field imaging. In the Nature paper the authors also mention this as something that could be included, along with many other neat theoretical directions that are related to my work.

"A promising theoretical direction is in inference and inversion techniques that exploit scene priors, sparsity, rank, meaningful transforms and achieve bounded approximations. Adaptive sampling can decide the next-best laser direction based on a current estimate of the 3D shape. Further analysis will include coded sampling using compressive techniques and noise models for SNR and effective bandwidth. Our current demonstration assumes friendly reflectance and planarity of the diffuse wall."

13 March 2012

UW Artist in Residence

Lynda Barry is this semester's artist in residence at the University of Wisconsin. I learned about Barry from a facebook post by my friend Leah. Leah is taking Barry's class "What It Is", and they had a special guest of Matt Groening last week!

Barry recently wrote a book and she elaborates on some of the ideas in this NPR discussion from talk of the nation.

She encourages us to create-- "Adults would never consider [drawing] on a piece of paper and then just throwing it away afterwards." I do that a lot with math, and with pictures when I'm with my nieces and nephew, but rarely otherwise. My friend Sheila is inspiring when it comes to creativity in action-- she's always making cards for friends, painting a wall in her house, making digital art.

Another quote from the Barry interview: "I think that creative work-- which becomes an elective after 7th grade-- has a lot to do with mental health. The way that I explain that is: One thing that seems to be universally understood-- all around the world-- is that if you had a kid, ...little Timmy, and I say Timmy I'm going to give you everything you ever want in your whole life except you will not be allowed to play until you are 18 years old. What do you know about that kid? Almost everyone around the world can tell you that kid will be crazy. ... Then what if I said Timmy you can't play, but I'm going to show you a video of a kid playing. Or I'm going to take you to watch this lego master-- you can watch him live, you can be right up front and watch him. That doesn't help either. I feel like as adults, that's kind of where we are. ...Mainly we feel like [creativity] is something best left to professionals-- like Jessica Simpson or something."

These ideas inspired me so much on Saturday that I went to Target and bought a watercolor set and some play dough. I already made a lovely painting (ask my roommate, she's going to frame it!) My favorite way to spend free time is to try something new-- right now I'm taking a martial arts class-- but maybe next I'll get back to writing stories, doing cross-stitch, or start something new like painting or collage. You know I still have my ee lab kit from sophomore year... it has proved impossible for me to throw it away, but I got a great suggestion recently that I should make a collage from it! Hmm... before I get carried away with ideas of what I could achieve, better to focus on Lynda's advice by doing something I wouldn't mind throwing away. Maybe tomorrow I'll open that play dough.

10 March 2012

Traveling Salesman

After reading Jordan's review of William J. Cook's "In Pursuit of the Traveling Salesman," I'm excited to check the book out myself! I wanted to put a favorite quote from the review here, but I was getting ready to copy the whole thing, so just go read it.