Carl’s notes

On Ubuntu Linux, Eclipse expects to find plugins in the /usr/local/lib/eclipse/ folder.

Running Matlab R2008a on Linux I got a bunch of error messages in the console.

Locking assertion failure. Backtrace:
#0 /usr/lib/libxcb-xlib.so.0 [0xb55257c7]
#1 /usr/lib/libxcb-xlib.so.0(xcb_xlib_unlock+0x31) [0xb5525891]
#2 /usr/lib/libX11.so.6(_XReply+0x254) [0xb57ef494]
#3 /usr/local/matlab/sys/java/jre/glnx86/jre1.6.0/lib/i386/xawt/libmawt.so [0xaec302be]
#4 /usr/local/matlab/sys/java/jre/glnx86/jre1.6.0/lib/i386/xawt/libmawt.so [0xaec0eed7]
#5 /usr/local/matlab/sys/java/jre/glnx86/jre1.6.0/lib/i386/xawt/libmawt.so [0xaec0f188]
#6 /usr/local/matlab/sys/java/jre/glnx86/jre1.6.0/lib/i386/xawt/libmawt.so(Java_sun_awt_X11GraphicsEnvironment_initDisplay+0x2f) [0xaec0f48f]
#7 [0xafb5c68e]

The solution is to run export MATLAB_JAVA=/usr/lib/jvm/java-6-sun/jre/ before running Matlab. A permanent solution is to add that line to /etc/profile.

See MatlabCentral for more details.

ReacTIVision can process image data recorded as PGM files.

First acquire some video from the webcam with mencoder.

mencoder tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0 -nosound -ovc lavc -o myvideo.avi

This was taken from an article on linux.com. I’ve found that v4l2 works but v4l doesn’t. Replace video0 with your video device.

To convert the avi to a series of PGM files use mplayer.

mplayer -vo pnm:pgm myvideo.avi

This error undefined reference to `__gxx_personality_v0' might appear when you try to link C++ object files with the C linker (cc or gcc) instead of the C++ linker (g++). Maybe the Makefile is using some default values for the compiler.