Correlation-based image registration for applications using pressure-sensitive paint

Abstract

A new algorithm, named correlation-based image registration, was developed to improve the resolution of image registration for applications using pressure-sensitive paint. The local displacement vectors were obtained by finding the displacement that maximized the cross correlation between two interrogation windows obtained under wind-off and wind-on conditions. A layer of speckle was sprayed to apply the cross-correlation method in a small interrogation window, without requiring identification of control points as used in the conventional method. Recursive multigrid processing was employed to increase the nonlinear spatial resolution. Several interpolation methods for the image transformation procedure were evaluated: windowed-sinc interpolation was the most accurate, and 4 x 4 cubic interpolation was the most efficient.