Isotropic Blur Identification for Fully Digital Auto-focusing

Abstract

In this paper, we propose a blur identification for fully digital auto-focusing (FDAF) techniques under the assumption of isotropic point spread function (PSF). The proposed blur identification starts with the estimation of one-dimensional (1D) step response, and estimate the two-dimensional (2D) PSF using the fundamental relationship between the step and the impulse responses. For more accurate blur identification, we present the PSF interpolation method that fills out the PSF element off the concentric circle. We also propose least squares 2D PSF solutions that robustly estimates the strength of the concentric circles under noisy, incomplete observation environment. Experimental results prove that the proposed blur identification method outperforms the existing ones in the sense of both accuracy and efficiency.

This work was supported by Korean Ministry of Science and Technology under the National Research Laboratory Project, by Korean Ministry of Information and Communication under the Chung-Ang University HNRC-ITRC program, and by the Korea Research Foundation Grant funded by Korean Government (MOEHRD)(R08-2004-000-10626-0).