By Topic

Reciprocal Focus Profile

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Dong-Chen Tsai ; Grad. Inst. of Commun. Eng., Nat. Taiwan Univ., Taipei, Taiwan ; Chen, H.H.

A focus profile having a steeper peak is more resistant to image noise in the autofocus (AF) process of a digital camera. However, a focus profile of such shape normally has a flatter out-of-focus region on either side of the profile, resulting in a slow AF process due to the lack of clue about where the lens should move when the lens is in such regions. To address the problem, we provide a statistical analysis of the focus profile and show that a strictly monotonic transformation of the focus profile preserves the accuracy of the AF. On the basis of this analysis, we propose a new focus profile representation that transforms the focus profile to the reciprocal domain in which the reciprocal focus profile is modeled by a polynomial function. This transformation makes the AF mathematically tractable and boosts the search speed. Experimental results are shown to demonstrate the advantage of the proposed representation .

Published in:

Image Processing, IEEE Transactions on  (Volume:21 ,  Issue: 2 )