Vanishing point calculation as a statistical inference on the unit sphere

An examination is made of vanishing point calculation as a statistical estimation problem. It is assumed that image line segments have been previously clustered into groups of convergent lines. For each group, the vanishing point location is estimated as the polar axis of an equatorial distribution on the unit sphere, and the statistical error of the estimate is determined. The sensitivity of the estimates to the number of lines in a convergent cluster is studied.>