Out-of-focus blur estimation and restoration for digital auto-focusing system

Author

Kim, Sang Ku ; Paik, Joon Ki

Author_Institution

Dept. of Electron. Eng, Chung-Ang Univ., Seoul, South Korea

Volume

34

Issue

12

fYear

1998

fDate

6/11/1998 12:00:00 AM

Firstpage

1217

Lastpage

1219

Abstract

A fully digital auto-focusing system based on point-spread function (PSF) estimation is proposed. To increase accuracy in estimating the PSF of the defocused image, the input image is subdivided, and the step responses of edge-containing subimages are averaged. The PSF, which results from out-of-focus blur, is estimated by differentiating the averaged step response along the appropriately estimated edge direction under the assumption that an image usually contains a piece-wise linear boundary between an object and background. By using the estimated PSF, the corresponding image restoration filter is realised, based on the constrained least squares approach

Keywords

estimation theory; focusing; image restoration; least squares approximations; piecewise-linear techniques; step response; PWL boundary; blur restoration; constrained least squares approach; defocused image; digital auto-focusing system; edge-containing subimages; image restoration filter; out-of-focus blur estimation; piece-wise linear boundary; point-spread function estimation; step responses;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el:19980762

Filename

702382