Ultrasonic TOFD image registration algorithm of sub-pixel accuracy based on DFT

This article is based on the correlation of FFT(Fast Fourier Transform) to study the ultrasonic TOFD(Time Of Flight Diffraction) image registration algorithm and according to the principle of template matching algorithm, the process is simple and the registration locations are accurate, so that the detected images are clear and defected features are obvious. The subsequent sub-pixel image registration algorithm of TOFD will improve registration accuracy to sub-pixel level, to further perfect the TOFD image registration algorithms, more conducive to subsequent image processing.