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An Image Enhancement Algorithm based on Color Constancy and Histogram Equalization using Edge Region

색채 항상성 방법과 경계 영역 기반 히스토그램 평활화 방법을 이용한 영상의 화질 향상 방법

  • Cho, Dong-Chan (Hanyang University, Department of Electronics Computer Engineering) ;
  • Kang, Hyung-Sub (Hanyang University, Department of Electronics Computer Engineering) ;
  • Kim, Whoi-Yul (Hanyang University, Department of Electronics Computer Engineering)
  • 조동찬 (한양대학교 전자컴퓨터통신공학과) ;
  • 강형섭 (한양대학교 전자컴퓨터통신공학과) ;
  • 김회율 (한양대학교 전자컴퓨터통신공학과)
  • Received : 2009.12.28
  • Accepted : 2010.05.10
  • Published : 2010.05.30

Abstract

A unified image enhancement method is proposed for high-resolution image which based on color constancy and histogram equalization using edge region. To speed up the method, smaller image is used when parameters of color constancy and histogram equalization are determined. In the color constancy process, nth-derivative of gaussian is applied to x and y axis separately in order to estimate the color of the illumination rapidly. In the histogram equalization process, the histogram obtained from near-edge region is used for the histogram equalization. In the experiments, high-resolution images taken by digital camcorder are used for verifying the performance of the proposed method.

고선명 영상에 대한 수요가 증가하면서 다양한 방면에서 좀 더 선명하고 큰 영상을 보고 촬영하려는 요구가 늘어나고 있다. 특히 디스플레이 장치의 크기가 커지고 이에 따라 영상의 해상도가 커지면서 영상에서 나타나는 잡음이나 화질 저하가 이전에 비하여 더욱 더 눈에 띄게 나타나게 되었다. 본 논문에서 고선명 영상과 같이 해상도가 큰 영상의 색상과 명암 대비를 효과적이고 빠르게 개선하기 위한 방법을 제안한다. 고해상도 영상에서 처리 속도를 높이면서 효과적으로 화질 향상 방법을 적용하기 위해 고해상도 영상을 축소시킨 영상에서 화질 향상 방법에 필요한 변수를 추출해낸다. 영상의 색상을 향상시키기 위해 기존의 색채 항상성 방법을 개선시킨 방법을 적용하였고 명암 대비를 향상시키기 위해 경계 영역을 활용한 변형 히스토그램 평활화 방법을 적용하였다. 마지막으로 고해상도 영상을 촬영할 수 있는 디지털 캠코더를 이용하여 촬영한 실험 영상으로 제안하는 방법의 성능을 분석하였다.

Keywords

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