Correlation-Based Image Registration for Applications Using Pressure-Sensitive Paint
Sang-Hyun Park, Hyung Jin Sung · AIAA Journal · 2005
A new algorithm, named correlation-based image registration, was developed to improve the resolution of im-age 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. Recur-sive 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 × 4 cubic interpolation was the most efficient. Nomenclature A, B, C = Stern–Volmer constant h = interpolation kernel I = luminescent intensityQ1 N = interpolation kernel size P = pressure R = cross-correlation function w = window function in sinc kernel δ = displacement ε = relative error Subscripts ref = reference condition reg = registered condition I.