Algorithm 1 Extrinsic parameter calibration.

Find SIFT features in original poster image

for frame = 0 to frame = n do

for cam = 0 to cam = 5 do

Find SIFT features in the image

Poster found?

end for

if Poster found in more than two cameras then

Solve PnP problem for one of the cameras

Find initial estimation of poster position in global coordinates

Add to the list of frames and features to be used in the optimization

end if

end for

Optimize parameters to minimize re-projection error sum