Image Registration in Range Using a Constrained Piecewise Linear Model: Analysis and New Results

An analysis of the conditions under which range registration was previously performed using a piecewise linear approximation to a comparametric function is presented. Stricter constraints are introduced which result in a better estimation of the exposure difference between two images of the same scene. Specifically, a positive slope constraint is imposed on each linear segment. Also, the knot locations defining each segment are now based on evenly distributing the comparagram data among a preselected number of segments. Finally, to better unbias the estimate of the exposure parameter using the piecewise approximation, a weighting is included that essentially modifies the Simpson’s rule approximation used in the original procedure for estimating the exposure difference.