Wednesday, December 30, 2009

Google's definition of 'Open'

Interesting article at google about the meaning of Open here.

Wednesday, November 18, 2009

Google Image Swirl

Tuesday, November 17, 2009

Fixing EPS bounding box automatically

Writing a paper. Time to put Matlab or Scilab plots in. You go file->
save as EPS to include into Latex.
Surprise: Matlab has an awful bounding box space around the figure.
You want to autocrop it but its a vector graphics format,
so you can't use mogrify -trim +repage <filename> as you would normally
do with an image.

Solution: epstool. It does an autocrop for the EPS file:

epstool --copy --bbox input.eps output.eps

and your final plot will still look crisp.

Another option: save as PDF in matlab. Then use ImageMagick's convert to convert it to eps:

convert file.pdf file.eps

this will keep the vector graphics intact (at least in recent versions of ImageMagick).

Of course, you can always use pdflatex instead and avoid EPS altogether.

Friday, October 02, 2009

Oympics and World cup in Brazil

The 2016 olympic games will be at Rio! Also, the 2014 world cup will be in Curitiba, Brazil:

Thursday, August 13, 2009

Website back up

My website is back after I took my server out of the lab.
or, during daytime, you can check:

Friday, May 29, 2009

Applets - the geometry of 2 and 3 views

These are insightful applets to introduce the concept of epipolar
geometry of two and three views.

When you press any key, you can drag the 3D point around and sense how
the geometry changes.

Thursday, May 14, 2009

More action in twitter
Because the iphone interfaces to twitter rock. And "twittering" to blogger using gmail — like I'm doing right now — just doesn't sound as cool.


Tuesday, May 12, 2009

2 colors are enough

I posted another video like this a while ago, but I always get amazed at them. I can't help but think how shape and boundaries are enough for vision. I'd like to write up what's the role of the contrast sign in producing these effects. For one, the shadows being black helps a lot. The black traces the robots leave on the street make it look like it is covered in snow. Here is a simple inversion of the video (no sound so you can play them together without interference): Shadows become highlights, and the ground seems to be covered in water instead of snow. It would be cool to have another version of the vid with only the boundaries between the black & white regions.

Monday, April 20, 2009

Google Similar Image Search

This new cool feature allow you to search for images similar to a given image. Let's say you want to search for "apple" - how to search only for the Apple, Inc, not the fruit?

Friday, March 13, 2009

Thursday, March 05, 2009

I passed prelims!

...and I am now officially back to answering emails.

Wednesday, February 11, 2009

Video screen shots in Linux

I recently had to do a video of a rotating 3D reconstruction.

The simplest thing that worked out of the box was a utility called recordMyDesktop:

Easy to install & use, at least in Gentoo. The way I used it was simple:

recordmydesktop -x X_pos -y Y_pos -width WIDTH -height HEIGHT -o foo.ogv

play it with

mplayer foo.ogv

Mplayer/Mencoder can also be used to convert it to any other video format if you want, e.g. to AVI:

mencoder -idx input.ogv -ovc lavc -lavcopts vcodec=mjpeg -oac mp3lame -o output.avi

I also need to generate an animated GIF. Here's how:

mplayer input.ogv -vo gif89a:output=output.gif:fps=5 -vf crop=850:562:17:99 -frames 999

If you use the input from the OGV file (not AVI), the quality will likely be better.

You can nonlinearly edit the video by opening the GIF in GIMP and deleting the frames you don't want as layers, then saving it. If you want to alter the speed, make sure you set this during the export and make sure you check the box that tells GIMP to override the default frame delays. You can also use GIMP to crop your video further.

To play your GIF animation, just open it in firefox or any browser.

Friday, January 23, 2009

Ignoring Mortality We Worship Mediocrity

This video is a good inspiration for us to gain courage to be innovative and bold I'm trying to build up the courage to grow a mohawk -:^) Only then I will feel like I'm truly living up to my ideals.

Tuesday, January 13, 2009

Happy 2009

Got married in December! I am now a man with responsibilities, another reason I've been studying for my prelims now. Need to finish my PhD! Among the subjects, I've picked differential geometry and complex analysis as a minor. Reviewing math after some motivation from research feels really productive. And, man, times have changed - during my PhD years I've witnessed the rise of core information technologies such as Youtube & Wikipedia (sounds already like grandpa talk!). What great tools to study math with. Check out this video on mobius transformations (related to homographies in projective geometry): Which goes back to support an old point of mine: computer technologies have an explosive (exponential) effect in improving society.