A New Geometrical Interpretation of Trilinear Constraints
We give a new geometrical interpretation of the 
well-known algebraic trilinear constraints used in motion 
analysis from three views observation. We show 
that those algebraic equations correspond to depth errors 
appropriately weighted by a function of the relative 
reliability of the corresponding measurements. 
Therefore directly minimizing the algebraic trilinear 
equations, in the least squares sense, is a strategy that 
works well for estimating motion. In addition, we 
propose a new scheme for recovering the scale factor 
for motion estimation that is very insensitive to input 
noise. All our theoretical statements are supported by 
experimental results.