Friday, January 27, 2012

drawing sexy graphs in matlab

Everybody who loves computer sciences loves graphs.  But the fat 'n juicy graphs, the ones with complex structure you just gotta visualize.  To enjoy these beautiful data structures, the hackers at AT&T gave us, the world, Graphviz as a powerful tool for visualizing complex graphs in two dimensions.  I do a lot of stuff in Matlab, so I've put my simple graphviz matlab wrappers up on Github so everybody can enjoy them. I do a lot of stuff with graphs...

My repository, which I'm already using as a submodule in many of my projects, can be found here:

Here is a matlab script (included as a Github gist), which should be ran in an empty directory, and it will download a nice mat file plus clone my repo and show the following nice graph.  I perform two graphviz passes where the first one is used to read the graphviz coordinates (from the sfdp embedding) and use Matlab's jet colormap to color the edges based on distances in this space.  In other words, nearby nodes which are connected will be connected by red (hot) edges and faraway nodes will be connected by blue (cold) edges.

The matrix visualized comes from an electromagnetic model, the details can be found here:

The original picture generated by Yifan Hu is here for comparison:


Tuesday, January 10, 2012

100,000+ page views on my computer vision blog

I like high-risk / high-reward activity.  While some say that this is my temperament (perhaps a vestige of youth?) I simply say: "that's how I roll."  Maybe I was too young when I read Kuhn's Structure of Scientific Revolutions, or maybe I was born with iconoclastic ideals, but I earnestly believe that life is too short to always do what you've been told.  One of my favorite maxims is the following: "The only limits we have are the ones we impose upon ourselves."

I took a gamble when I started this blog, blurring the line between all things related to computer vision, philosophy, artificial intelligence, machine learning, and other fun things which constitute my intellectual life.  During my PhD I was even discouraged from blogging, because "my superiors" incessantly reminded me that "you get famous by writing CVPR papers" and not by wasting time maintaining a "cute" blog.  Today I'd like to argue that my adventure in blogging has not been a failure at all!

I had multiple reasons for wanting to blog, several of which I list below:
  • I wanted to practice my writing, and what better way to practice writing than by writing!
  • I wanted an outlet to discuss certain ideas which I find invaluable in my pursuit of building intelligence, but which aren't necessarily publishable.  On my blog I am the sole contributor, the sole editor.  If you don't like what I have to say, start your own blog.  I don't need anonymous reviews, the CVPR submission process stresses me out enough for one lifetime.
  • I wanted a medium to advertise my own work as well other works which I find important for graduate students in Computer Vision to know about.
  • I wanted to expose the field of Computer Vision to a broader audience and hopefully get others excited about this amazing research field.

Today I'm glad to announce that according to statcounter, my computer vision blog has reached over 100,000 views.  In an absolute sense, this really is nothing to be excited about.  By since my CMU homepage has approximately 30,000 views, this means that my blog is 3x as popular as my academic homepage!  Next goal: 1,000,000 page views!

I actually meet more people that know me through my blog than through my research papers, even though I put in 100x the effort in doing the research behind those papers.  I don't plan on taking up blogging full time anytime soon, but it feels good to know that my blogging adventure has paid off.

Here are some of the top keywords which have been used to find my blog:

Here are some of my most popular blog posts of all time:

I encourage anybody who reads my blog to shoot me a quick "yo what's up!" at a local conference or where ever else our paths might cross.  I also encourage everybody to suggest the types of things they would like to read about on my blog.