Hybrid opto-digital joint transform correlator (HODJTC) is effective for image motion measurement, but it is different from the traditional joint transform correlator because it only has one optical transform and the joint power spectrum is directly input into a digital processing unit to compute the image shift. The local cross-correlation image can be directly obtained by adopting a local Fourier transform operator. After the pixel-level location of cross-correlation peak is initially obtained, the up-sampling technique is introduced to relocate the peak in even higher accuracy. With signal-to-noise ratio ? 20 dB, up-sampling factor k ? 10 and the maximum image shift ? 60 pixels, the root-mean-square error of motion measurement accuracy can be controlled below 0.05 pixels.
© 2010 Chinese Optics LettersPDF Article