Journal of Broadcast Engineering (방송공학회논문지)

The Korean Institute of Broadcast and Media Engineers (한국방송∙미디어공학회)
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A Deblocking Algorithm Using Anisotropic Diffusion for Block DCT-based Compressed Images

이방성 확산을 이용한 블록 DCT 기반 압축 영상의 블록효과 제거

  • Choi, Euncheol (EOSystem Co. Ltd, Dept. of Electrical and Electronic Engineering, Yonsei University) ;
  • Han, Youngseok (Dept. of Electrical and Electronic Engineering, Yonsei University) ;
  • Park, Min Kyu (Dept. of Electrical and Electronic Engineering, Yonsei University) ;
  • Kang, Moon Gi (Dept. of Electrical and Electronic Engineering, Yonsei University)
  • 최은철 ((주)이오시스템 광기술연구소, 연세대학교 전기전자공학과) ;
  • 한영석 (연세대학교 전기전자공학과) ;
  • 박민규 (연세대학교 전기전자공학과) ;
  • 강문기 (연세대학교 전기전자공학과)
  • Published : 2005.09.01
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Abstract

In this paper, a new anisotropic diffusion based on Alvarez, Lions, and Morel (ALM) diffusion model is proposed for the suppression of blocking artifact caused by discrete cosine transform (DCT) based image compression. The proposed diffusion model, which incorporates a 'rate control parameter' (RCP), makes it possible to reduce blocking artifacts while to preserve the edge. The RCP controls the rate between isotropic and anisotropic diffusion. Isotropic diffusion is encouraged to eliminate the blocking artifacts in a block boundary of a smooth region, while anisotropic diffusion is encouraged to keep the edge or texture sharp in edge and a block boundary within an edge region. Additionally, to avoid oversmoothness of the texture region, a 'speed control parameter' (SCP), which makes diffusion process slow in the texture region, is employed.

본 논문은 블록DCT(Discrete Cosine Transform) 기반의 영상 압축 과정에서 발생하는 블록효과(block artifact)를 제거하기 위해 ALM(Alvarez, Lions, and Morel) 확산 모델에 기반을 둔 새로운 이방성 확산(anisotropic diffusion)을 제안한다. 등방성 확산은 평탄 영역에 나타나는 블록 경계를 제거하는 역할을 하는 반면, 이방성 확산은 윤곽선 영역이나 텍스쳐 영역을 보존하는 역할을 하기 때문에, 제안된 확산 모델은 블록 효과를 제거하면서 윤곽선(edge)을 보존하기 위해 등방성 확산(isotropic diffusion)과 이방성 확산의 비율을 제어하는 확산비율 조절 매개 변수(RCP : rate control parameter)가 제안 되었다. 또한, 텍스쳐 영역의 과도한 평탄화를 막기 위해 속도 매개 변수(SAP : speed control parameter)를 고안하였으며, 이는 텍스쳐 영역의 확산 속도를 감소시기는 역할을 한다.

Keywords

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