Fast Fourier Transform Technique and Affine Transform Estimation-Based High Precision Image Registration Method

New techniques are developed for determining spatial or geometric distortion between two images of the same scene. First, the properties of the Fourier transform of a two dimensional function under the affine transformation are given. The relations between the spatial and spectral frequency domains are shown. As a result, techniques for the estimation of the coefficients of the distortion model using the spectral frequency information are developed. Image registration can be achieved by applying the fast Fourier transform (FFT) technique for cross correlation of mis-registered imagery to determine spatial distance. The correlation results may be rather broad, making detection of the peak difficult, what can be suppressed by enhanced cross-correlation technique. Yield greatly improves the delectability and high precision of image misregistration.