warper.cs class from johnny lee's wiimote whiteboard application

[jeromeguarin]

i developed an application entitled, Interactive whiteboard through laser detection technology. it is inspired by the wiimote whiteboar app.it uses the laser pointer as a mouse pointer.it can perform left click,in turn performing double clicks for opening .exe, drag for moving/copying files, and several mouse operations.right click isn't necessary.

the problem is the calibration method.

the warper class in the wiimoteWhiteboard application developed by johnny lee, helps with the camera calibration process.coordinates are used (coordinates from the camera and from the projected screen or from the pc used) to form a matrix right?

but how does it become a 4x4 matrix? when there are only 8 entries that came from the four points?
why should it be a 4x4?

here is the same code:

http://code.google.com/p/wiituio/source/browse/trunk/WiiTUIO/WiiProvider/Warper.cs?spec=svn4&r=2

thanks.