Estimation of PSF using logarithmic amplitude spectrum and restoration of blurred image
Yuka Nagashima, S. Ōmatu, Michifumi Yoshioka · Electronics and Communications in Japan · 2013
Abstract In this research, it is assumed that the degraded images, which are represented as a convolution of the original images with PSFs (point spread functions), are defocused images by the lens system or the limit of resolution. It has been proposed to estimate both the PSF and the original image by a Bayesian‐based iterative method. In the Bayesian‐based iterative method of image restoration, we need to set suitably an initial value of the PSF and the original image. The initial value of the original image is a blurred image, since there is only a slight difference between blurred and original images. On the other hand, since there is insufficient information on the PSFs, it is too difficult to set the initial values of the PSFs. If blurred images are represented as convolutions of the original images with the PSFs, the band limit of the blurred image will approach the band limit of the PSF. Therefore, we determine the initial value of the PSF by estimating the band limit of the PSF from the logarithmic amplitude spectrum of the blurred image. Finally, we confirm the effectiveness of the proposed method by simulations and experiments with out‐of‐focus pictures. © 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 96(3): 31–37, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11447