Polyphase back-projection filtering for image resolution
enhancement
Boaz Cohen and Its’hak Dinstein
Electrical and Computer Eng. Dept.,
Ben Gurion Univ. of the Negev,
Beer-Sheva 84105, Israel.
E-mail: boazc@ee.bgu.ac.il, dinstein@bguee.bgu.ac.il
Abstract
The method for reconstruction and restoration of super-resolution
images from sequences of low-resolution images presented here is an extension
of the algorithm proposed by Irani and Peleg ('Improving resolution by
image registration', CVGIP: Graphical Models and Image Processing, 1991,
53, (3), pp. 231-239). After estimating the projective transformation parameters
between the image sequence frames, the observed data is rearranged into
a sequence with only quantized sub-pixel translations. The super-resolution
reconstruction is an iterative process, in which a high-resolution image
is initialized and iteratively improved. The improvement is achieved by
back-projecting the errors between the translated low-resolution images
and the respective images obtained by simulating the imaging system. The
imaging system's point-spread function (PSF) and the back-projection function
are first estimated with a resolution higher than that of the super-resolution
image. The two functions are then decimated so that two banks of polyphase
filters are obtained. The use of the polyphase filters allows exploitation
of the input data without any smoothing and/or interpolation operations.
The presented experimental results show that the resolution improvement
is better than the results obtained with Irani and Peleg’s algorithm.
Back to my Homepage