Archive

Archive for February, 2008

Use that Sweet Spot

February 18th, 2008 1 comment

With the easy availability of scientific papers through the internet, it is easy to quickly get your hands on tons of pdfs. Then what? I look through the pile very quickly and pick out the one or two papers that look the most relevant. This quick pass consists of glancing at the abstract and the figures.

Knowing that this quick and dirty scan is probably becoming the norm, I’ve started including a telling graphic right in the Sweet Spot. This is a term my colleagues and I have come up with for the top of the right column on the first page. Check it out:

sweet spot papers

Including the Sweet Spot graphic may get your paper read more, it may get your paper read less. Either way, it helps the reader make a snap decision about whether or not your paper is of interest to them. I feel like it makes the paper visually more attractive and inviting, too.

Any other Sweet-Spotters out there?

Categories: Academic, Featured Tags: , ,

Beamer and Latex With Keynote Theme

February 15th, 2008 27 comments

LaTeX is a typsetting system that allows you to make great-looking documents, and is well-used to make academic papers. I even use it for homeworks and other documents. There are also packages that allow it to make fantastic posters and slide presentations as well. I spent the last few days getting caught up on this, and want to share what I’ve figured out:

  • A sexy Beamer theme that looks like Keynote
  • How to format the footer
  • How to make slide numbers
  • How to remove the navigation symbols
  • How to make movies show up in presentations
  • The best references

I’ll talk about each of these briefly and give links to download a demo presentation and the .tex and .sty files that made it. Here’s a sneak peek of what it looks like!

keynote beamer presentation

   Click to continue →

Categories: LaTeX Tags: , ,

Posting to WordPress from emacs

February 12th, 2008 No comments

Most things I do on the computer, I do within emacs. I use it for email, writing programs, compiling programs, running programs, typeseting papers, running shell commands, etc.

So how did I make this post from within emacs? Google led me to this post detailing how to set up weblogger. Here’s the quick and dirty setup:

bash$ cd ~/.emacs.d/
bash$ cvs -z3 -d:pserver:anonymous@cvs.savannah.nongnu.org:
/sources/emacsweblogs \co -d weblogger weblogger/lisp

Put this in your .emacs and execute it (highlight and C-x C-e):
(add-to-list 'load-path "~/.emacs.d/weblogger")
(require 'weblogger)

You’re now ready to start a session: M-x weblogger-setup-weblog. It will prompt you for your XML-RPC server/path. For example, I log into http://www.shawnlankton.com/wp-admin to post, so my XML-RPC path is http://www.shawnlankton.com/xmlrpc.xml.

One final touch is to turn off auto-fill when in weblogger-mode because carriage returns get interpreted literally as <br>. A quick fix:
(add-hook 'weblogger-entry-mode-hook
'(lambda () (auto-fill-mode nil)))

Categories: Tips Tags:

Roasted Rosemary Veggies

February 11th, 2008 No comments

I’m just discovering roasting as a means to cook vegetables. Its a very hands-off method that results in a nice flavor. This dish feels very autumn-y to me, but I’ve been enjoying throughout the winter. This particular time I made an especially wild addition… purple cauliflower!

Ingredients

   Click to continue →

Categories: Recipe Tags: ,

West Coast Trip

February 10th, 2008 3 comments

The beginning of February found me making my way up the West Coast on the coastal Highway 101. My friends Jimi and Rome and I flew out west to present some recent research at a conference. Jimi and I decided to take the long way home and drive up the coast all the way to Seattle. Along the way we met old and new friends, saw some amazing things, and had loads of fun. Check out some of the pictures we took:

Even though we spent a week on Pacific time, I realize that I need to spend a lot more to see even a fraction of what there is to do out there! I might try to spend a month out that way this summer. I left some of my heart in San Francisco, I was inspired and entranced by the beautiful landscape, and Seattle is nothing but great!

Categories: Photos, Travel Tags: ,

Quick and simple derivatives in Matlab

February 8th, 2008 1 comment

Ever try to compute the directional derivatives on a matrix? Google turn up menacing formulas for Taylor expansions, grid spacing, and boundary conditions?

A quick and simple way of computing derivatives is to perform arithmetic on shifted versions of the matrix, and vectorized indexing help Matlab speed things up. For example, use the following for the (central) x-derivative:

dx = (M(:,[2:end end]) - M(:,[1 1:end-1]))/2

You can even define inline functions to perform the shift and derivative operations. Below are definitions for the shift operations and first and second order derivatives.

% shift operations
shiftD = @(M) M([1 1:end-1],:);
shiftL = @(M) M(:,[2:end end]);
shiftR = @(M) M(:,[1 1:end-1]);
shiftU = @(M) M([2:end end],:);

% derivatives
Dx = @(M) (shiftL(M) - shiftR(M))/2;
Dy = @(M) (shiftU(M) - shiftD(M))/2;
Dxx = @(M) (shiftL(M) - 2*M + shiftR(M));
Dyy = @(M) (shiftU(M) - 2*M + shiftD(M));
Dxy = @(M) (shiftU(M) - shiftD(M) + shiftL(M) - shiftR(M))/4;

And use them like this:
>> Ax = Dx(A)
Ax =
-7.0000 -6.5000 5.5000 5.0000
3.0000 2.5000 -1.5000 -1.0000
-1.0000 -1.5000 2.5000 3.0000
5.0000 5.5000 -6.5000 -7.0000

>> Ayy = Dyy(A)
Ayy =
-11 9 7 -5
15 -13 -11 9
-9 11 13 -15
5 -7 -9 11

Categories: Matlab Tags:

PIL in OSX, The Easy Way

February 5th, 2008 3 comments

After spending about an hour fighting with PIL (Python Imaging Library) and trying to get it to install properly with all of its dependencies I discovered that some wonderful person posted a ready-made pil installer for osx. This worked like a charm. First try. No problems.

God I love it when people do stuff like this. Now, hang on as I learn to do image processing with Python on my mac.

Decoupling Camera and Target Motion

February 1st, 2008 No comments

Video tracking is widely used for surveillance, security, and defense purposes. In cases where the camera is not fixed due to pans and tilts, or due to being fixed on a moving platform, tracking can become more difficult. Camera motion must be taken into account, and objects that come and go from the field of view should be continuously and uniquely tracked. We propose a tracking system that can meet these needs by using a frame registration technique to estimate camera motion. This estimate is then used as the input control signal to a Kalman filter which estimates the target’s motion model based on measurements from a mean-shift localization scheme. Thus we decouple the camera and object motion and recast the problem in terms of a principled control theory solution.

Our experiments show that using a system built on these principles we are able to track videos with multiple objects in sequences with moving cameras. Furthermore, the techniques are computationally efficient and allow us to accomplish these results in real-time. Of specific importance is that when objects are lost off-frame they can still be uniquely identified and reacquired when they return to the field of view.

This work was published in the Proceedings of the SPIE on Electronic Imaging in this paper: Improved Tracking by Decoupling Camera and Target Motion.

See this paper and more on the publications page.