Polyphase back-projection filtering for resolution enhancement of image sequences

A method for resolution enhancement of image sequences by polyphase back-projection filtering is presented. The first super-resolution image is initialized by interpolation of the first low-resolution image. The imaging system is simulated for every super-resolution image at a time, and the error between the simulated image and the corresponding low-resolution image is calculated. The resolution enhancement is achieved by back-projecting this error to the corresponding super-resolution image. The imaging system's PSF and the back-projection filter are estimated with a resolution higher than that of the super-resolution images, and the filtering is done by polyphase versions of these filters. The polyphase filters have embedded sub-pixel displacements corresponding to the translation parameters between the super-resolution image and the low-resolution one. The use of the polyphase filters allows exploitation of the observed data without any smoothing and/or interpolation operations. Also, no modeling of the PSF by an analytical function is necessary. Presented experimental results show encouraging resolution enhancements.