Fourier plane and optical processing for sub-pixel image registration

Accurate registration of image pairs is critical to a number of image processing tasks, including image splicing, change detection, image co-addition, and super-resolution processing. We have applied digital Fourier plane correlation and optical joint-transform correlation to image registration. We demonstrated RMS registration accuracy of 0.09 pixels for a digital system and 0.1 pixels for an optical system. The experimental system uses an electrically addressed spatial light modulator (SLM) at the input plane of a joint transform correlator and an optically addressed SLM at the Fourier plane. We operate our optical system in burst mode at the rate of 50 correlations per second. The paper describes digital and experimental implementations of the image registration system. We discuss preprocessing algorithms used to prepare inputs for correlation, post-processing algorithms to interpolate the output, and the effect of these processing variations on system performance.