Resolution enhancement by polyphase back-projection filtering

The method for reconstruction and restoration of super resolution images from low resolution sequences presented here is an extension of Irani and Peleg's algorithm ("Improving Resolution by Image Registration", CVGIP: Graphical Models and Image Processing, Vol. 53, No. 3, pp. 231-239, 1991). The input is a set of low resolution images that have been registered to a pixel translation accuracy. A high resolution image is initialized and iteratively improved by back-projecting the errors between the low resolution images and the respective images obtained by simulating the imaging system. The sub-pixel translations between the low resolution images are quantized. The imaging system's PSF and back projection function are estimated with a resolution higher than that of the super resolution image and decimated so that two banks of polyphase filters are obtained. The use of the polyphase filters allows exploitation of all the input images without any smoothing or interpolation operations.