Machines that have been developed to determine the topography of a region from stereo-pair photographs are subject to correlation errors resulting in incorrect elevation calculations. In this paper, the determination of the location of the peak of the correlation function of two similar arrays of picture elements is modeled as a parameter estimation problem. The Cramer-Rao lower bound and various measures of contrast are considered as possible features in recognition schemes for predicting the magnitude of correlation errors. Preliminary simulation results are included.