Gephex 0.4.3 updated for Ubuntu 8.10

Since there hasn't been a better version of Gephex since 0.4.3 (though I haven't tried compiling the repository recently, last time was not successful), I've downloaded the source and hacked it until it built on Ubuntu 8.10 updated to today:


I haven't tested it all the way, especially the video input modules, but it probably works.

Most of the changes have to do with updates to gcc, where it treats classname::method in cpp files as errors, and some files needed to include stdlib.h or string.h that didn't before. Also some structure definition in libavcodec had to be messed with- the static declaration removed.

nasm, qt3 in the form libqt3-headers, and libxv-dev had to be installed (and other non-standard things for 8.10 that I already had installed for other purposes). For qt3, flags for the include, bin, and lib dir needed to be passed to configure.

I had to run configure in the ffmpeg library and disable mmx with the --disable-mmx flag, putting that flag in the top-level makefile didn't work. My configuration specific makefiles are in the tarball so you would definitely have to rerun configure to override them.

Next I'll be creating a new custom gephex module for my ARToolkit multimarker UI project.



I've tested this build more extensively, and have discovered that the Ubuntu visual effects that are on by default cause the gephex output window to flicker. To disable them go to System | Preferences | Appearance | Visual Effects and select none. It's possible I need to build gephex with OpenGL support and these options will co-exist better.

Also, my screencap frei0r module I've depended on extensively in the past updates extremely slowly on the laptop I'm using currently, it may be an ATI thing (I originally developed it on an Nvidia system).


Marker Tracking as Visualization Interface

My idea is that I would be able to do an ARToolkit based visualization performance by using a clear table with markers I can slide, rotate, add and remove, and all those movement could correspond to events on screen. Unlike other AR videos the source video wouldn't be incorporated into the output necessarily, the markers provide an almost infinitely expressive set of UI knobs and sliders.

So far I have this:

AR User Interface from binarymillenium on Vimeo.

The lighting is difficult, the markers need to be white and black pixels but the plexiglass tends to produce reflections. Also if the light source itself is visible a marker will not be able to be right on top of it. I need a completely black backdrop under the plexiglass so there are no reflections that will obscure the markers, and also more numerous and softer diffuse lights.

One way to solve the reflection problem is to have the camera looking down at a table, though it's a little harder to get the camera up high enough, and I didn't want my hands or body to obscure the markers- the clear table idea is more elegant and self-contained.

The frame rate isn't very high, I need to work on making it all more real-time and responsive. It may have to be that one computer is capturing video and finding marker positions and sending them to another computer completely free to visualize it. Also more interpolation and position prediction could smooth things out, and cover up gaps if a marker isn't recognized in a frame, but that could produce more lag.