Journal of Broadcast Engineering (방송공학회논문지)

The Korean Institute of Broadcast and Media Engineers (한국방송∙미디어공학회)
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Bandpass Filter Based Focus Measure for Extended Depth of Field

피사계심도 확장을 위한 대역통과 필터 기반 초점 정량화 기법

  • Cha, Su-Ram (Dept. of Electronics Engineering, Ewha Womans University) ;
  • Kim, Jeong-Tae (Dept. of Electronics Engineering, Ewha Womans University)
  • 차수람 (이화여자대학교 전자공학과) ;
  • 김정태 (이화여자대학교 전자공학과)
  • Received : 2011.08.17
  • Accepted : 2011.09.19
  • Published : 2011.09.30
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Abstract

In this paper, we propose a novel focus measure that determines in-focus and out-of-focus region in an image. In addition, we achieved extended depth of field by blending the acquired image and Wiener filtered image using a decision map based on the designed focus measure. Since conventional focus measures are based on the amount of high frequency components in an acquired image, the measures may not be accurate if there exist high frequency components in out-of-focused region. To overcome the problem, we designed the novel focus measure based on effective band pass filtering. In simulations and experiments, the proposed method showed better performance than existing methods.

본 논문에서는, 피사계심도가 낮은 카메라로 획득한 영상에서 초점이 맞는 부분과 그렇지 않은 부분을 나누는 새로운 초점 정량화를 설계하고 초점 정량화에 기반한 decision map을 이용하여 획득한 영상과 위너필터링으로 복원한 영상의 정합을 통해 영상의 피사계심도를 확장하였다. 기존의 초점 정량화 방법은 고주파 성분의 크기에 따라서 초점 정량화를 수행하므로 초점이 맞지 않은 부분에 고주파 성분이 있는 경우 성능이 저하된다는 단점이 있다. 본 논문에서는 이를 극복하기 위하여 효과적인 대역필터를 설계하였으며 제안하는 방법이 기존에 방법에 비해서 성능이 우수함을 시뮬레이션 및 실험을 통해 입증하였다.

Keywords

References

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