I'd like to create a simple 2D map of a room by getting pictures (ceiling) of all directions (360° - e.g. movie frames), recognize the walls by edge detection, delete other unwanted objects, concat the images at the right position (cf. walls, panorama) and finally create the approximate 2D map (looking on it from above). Getting the scale would be another parameter, which might be useful.

I have some own ideas at the moment, by using e.g. the Sobel algorithm, but it would be interesting if somebody out there knows some project or software (GPL,freeware prefered) doing this already, as I'm still looking for some examples, which might help me.

Thanks.