The classic template matching directly uses images as templates and correlation coefficients as the measure of matching degree. A novel template matching method for eye localization based on projection coefficient templates and nonlinear correlation is proposed. Unlike classic template matching, the projection coefficients on the basis function of the Karhunen-Loeve transform are used as templates, and the nonlinear correlation is proposed to measure the matching degree. The reduction of computation costs is achieved by taking advantage of the eye symmetry.
"Eye localization in face image based on a novel template matching method," Optical Engineering 51(2), 027203 (5 March 2012). https://doi.org/10.1117/1.OE.51.2.027203