Hierarchical blur identification

A hierarchical blur identification method which is able to identify severe blurs having a relatively large support size is proposed. The method is based on the expectation-maximization algorithm and begins by identifying a low-pass version of the point-spread function (PSF) from a reduced-resolution version of the blurred image. The result is used to initialize the identification of the PSF from a higher-resolution image. By repeating this process, the support size and resolution of the identified PSF are gradually increased, achieving an efficient identification of large PSFs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>