Fabbri's Blog

Google Image Swirl

2009-11-18T15:38:00.001-08:00

http://googleblog.blogspot.com/2009/11/explore-images-with-google-image-swirl.html

Fixing EPS bounding box automatically

2009-11-17T11:53:00.001-08:00

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.

vxl vgui compilation workaround (and others)

2006-12-15T14:02:00.000-08:00

In this post and the comments section below are various issues encountered while compiling VXL under Linux, and how I solved them.

To solve the following errors, put a blank "opengl_xmesa_include" in cmake. I have NVIDIA drivers and everything works fine after this.

make[1]: *** [core/vgui/tests/CMakeFiles/vgui_test_events.dir/all] Error 2 Linking CXX executable vgui_test_front_back /home/rfabbri/cprg/vxlprg/vxl-bin/lib/libvgui.a(vgui_accelerate_x11.o): In function `vgui_accelerate_x11::vgui_copy_back_to_aux()': /home/rfabbri/cprg/vxlprg/vxl/core/vgui/internals/vgui_accelerate_x11.cxx:426: undefined reference to `XMesaGetCurrentBuffer' /home/rfabbri/cprg/vxlprg/vxl/core/vgui/internals/vgui_accelerate_x11.cxx:435: undefined reference to `XMesaGetBackBuffer' /home/rfabbri/cprg/vxlprg/vxl-bin/lib/libvgui.a(vgui_accelerate_x11.o): In function `vgui_accelerate_x11::vgui_copy_aux_to_back()': /home/rfabbri/cprg/vxlprg/vxl/core/vgui/internals/vgui_accelerate_x11.cxx:458: undefined reference to `XMesaGetCurrentBuffer' /home/rfabbri/cprg/vxlprg/vxl/core/vgui/internals/vgui_accelerate_x11.cxx:467: undefined reference to `XMesaGetBackBuffer'

Oympics and World cup in Brazil

2009-10-02T18:20:00.000-07:00

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

Website back up

2009-08-13T10:10:00.000-07:00

My website is back after I took my server out of the lab.
www.lems.brown.edu/~rfabbri
or, during daytime, you can check:
cortex.homelinux.org

Applets - the geometry of 2 and 3 views

2009-05-29T08:56:00.001-07:00

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

http://www.ai.sri.com/~luong/research/Meta3DViewer/EpipolarGeo.html

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

More action in twitter

2009-05-14T21:36:00.001-07:00

http://twitter.com/rfabbri
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.

RISD GRADUATE THESIS EXHIBITION 2009

2009-05-14T11:04:00.000-07:00

2 colors are enough

2009-05-12T21:59:00.000-07:00

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.

Google Similar Image Search

2009-04-20T13:41:00.001-07:00

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?

http://similar-images.googlelabs.com/

Hispanic Immigration & Graphic Design

2009-03-13T18:47:00.001-07:00

Here's my wife's newly designed thesis website: www.from-both-sides.org/home

I passed prelims!

2009-03-05T13:28:00.001-08:00

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

Video screen shots in Linux

2009-02-11T12:20:00.001-08:00

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:

http://recordmydesktop.sourceforge.net

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.

Ignoring Mortality We Worship Mediocrity

2009-01-23T10:13:00.000-08:00

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.

International Computer Vision Summer School

2009-01-17T09:08:00.001-08:00

... In Italy.
http://svg.dmi.unict.it/icvss2009/index.html

Happy 2009

2009-01-13T21:54:00.001-08:00

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.

Google indexes magazines and newspapers on Book Search

2008-12-10T12:10:00.001-08:00

http://googleblog.blogspot.com/2008/12/search-and-find-magazines-on-google.html

Optimal 3D Triangulation Code

2008-12-09T20:20:00.001-08:00

The source code (in C) for a recently published optimal 3D triangulation / reconstruction algorithm can be found at:

http://www.iim.ics.tut.ac.jp/~sugaya/public-e.html

The method supposedly does not have the singularities of the widely-used Hartley-Sturm algorithm, and was developed by K. Kanatani, Y. Sugaya, and H. Niitsuma.

Tangorian Giraffes

2008-12-04T18:32:00.001-08:00

VxL code browsing in ViM

2008-12-01T14:16:00.001-08:00

When working with a huge codebase, its nice to be able to browse
through the code lying in different directories.
Most other sites about ctags only deal with files in the same
directory, though.
I use vxl.sf.net, which consists of a huge source tree of C++
libraries, headers, and templates.
Here is my solution:

I installed exuberant-ctags (make sure this is the one in your system),

then I issued the following command:

ctags -R vxl lemsvxlsrc

from the directory containing the vxl source tree 'vxl' and the
internal Brown 'lemsvxlsrc' tree.
This generates a tags file. Now, tell VIM to always use that by
setting a tags search path:

" Set the tag file search order
set tags=./tags,tags,~/tags,/home/rfabbri/cprg/vxlprg/tags

You can add the above line to your ~/.vimrc or, even better, to a file
in ~/.vim/ftplugins/cpp_xxx.vim, where xxx is a custom extension you
choose.

Brazilian Cheese Bread Recipe

2008-01-22T07:43:00.001-08:00

Here is my mom's cheese bread recipe:

Ingredients 2 Cups of milk 3/4 cup of corn oil (or any light tasting oil) 1 table spoon of salt 1-3 cups of cheese, either parmesan or romano (you can try other hard cheeses) 2 big eggs or 3 small ones 1 package of "povilho doce" flour, Yoki brand (or any other brand)

Instructions Mix milk, oil, and salt into a pan and bring to a boil, mixing the bottom once in a while. Be careful as the milk will suddenly boil and you don't want it to spill. Now empty the flour into a deep bowl. Pour the milk mixture over the flour, while mixing well avoiding the formation of clumps. Leave the dough sitting until it cools down (about 15 min, but they say the longer, the better). Now alternate between adding the eggs and the cheese, while working the dough with your hands in order to mix everything together as well as possible. The longer you squeeze the dough, the better. You can now wash your hands, then butter-up a cookie sheet or similar container, then add a little bit of oil to your hands, spreading it out. Make little balls of the desired size, adding oil to your hands whenever the dough starts getting sticky. Pre-heat the oven to 356F, and bake your Brazilian cheese bread.

The cheese bread takes around 15min to bake, sometimes longer. After those 15min, if the cheese bread is not light-gold, then continue baking and monitor the oven every 5min to see if it has reached the desired coloration. Usually you don't want it to get too brown, but tastes vary.

Windows partition deleted.

2008-10-28T12:27:00.001-07:00

Never used it, never needed it, never respected it. Now let me pump up my Linux environment with the Windows carcass left in my harddrive :-)

Pós-doc e Pós-grad na USP

2008-10-28T09:29:00.001-07:00

Altamente recomendado!
Sem duvida o melhor grupo cientifico em que ja estive :)

==========================
OPORTUNIDADES PARA PÓS-GRADUÇÃO E PÓS-DOUTORADO
GRUPO DE COMPUTAÇÃO INTERDISCIPLINAR, IFSC-USP
Outubro de 2008 a Maio de 2009

Comunicamos diversas possibilidades para pesquisa, a nível de
pós-graduação e pós-doutorado, no Grupo de Computação Interdisciplinar (GCI)
do IFSC-USP. As principais áreas de pesquisa incluem mas não se limitam a:
1. VISÃO E IMAGENS
2. INTELIGÊNCIA ARTIFICIAL
3. REDES COMPLEXAS
3. BIOINFORMÁTICA E BIOLOGIA DE SISTEMAS
4. COMPUTAÇÃO DE ALTO DESEMPENHO
5. SISTEMAS DISTRIBUÍDOS E GRIDS
6. REDES DE COMPUTADORES
Os candidatos poderão ter formação anterior em computação, informática,
física, matemática, engenharia, estatística, química ou bioinformática.
Os trabalhos de pesquisa serão desenvolvidos nas respectivas áreas de formação
dos candidatos. As possibilidades de pós-graduação incluem o IFSC (nível 7
CAPES) e Bioinformática da USP (nível 5 CAPES).

PARA INFORMAÇÕES ADICIONAIS, visite a página
http://cyvision.if.sc.usp.br/~francisco/comp_inter/index.html

John Maeda talk at Brown

2008-10-16T19:48:00.001-07:00

The new RISD president, and former MIT Media-Labber John Maeda spoke
today at Brown.

It was an interesting experience, more of a light sequence of simple
facts that did the job of kepping people entertained; I feel nobody
was profoundly illuminated.
But maybe that's exactly the message - life simple facts and tidbits
can be more important than they seem. But at the same time it does
bring a sense of unfulfilment and apathy towards getting
anything explained, nailed down, or thoroughly illuminated. I had a
simple mild positive reaction to it. Simplicity and mediocrity
inevitably must have something in common. Its much like short Tao
wisdom.

One of his little ideas that really shook me was the fact that
technology is kind of saturating in the 21st century, and that what we
really need is more human reality, sensibility, and creativity into
our lives.
That's pretty much true. As a computer vision scientist, I think we
already threw hardware at problems a lot, and although it does bring
insights and immediate results, what we really feel the need for is
some human spark, human care, and human design to actually get
algorithms to be smarter, faster, and solve the innumerous problems
that fundamentally weren't solved before. Yes, like the vision
problem.

A Modern Shiny Execution of 3D Computer Vision

2008-08-29T16:09:00.001-07:00

Using Photographs to Enhance Videos of a Static Scene from pro on Vimeo.