Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Hybrid Algorithm for Interpolation Based on Macro-block Gray Value Gradient under H.264

H.264하에서 마크로 블록 그레이 값의 미분을 사용한 인터폴레이션

  • Wang, Shi (Division of Electronics and Information Eng., Graduate School, Chonbuk National University) ;
  • Chen, Hongxin (Division of Electronics and Information Eng., Graduate School, Chonbuk National University) ;
  • Yoo, Hyeon-Joong (Dept. of Information and Telecommunication Eng., Sangmyung University) ;
  • Kim, Hyong-Suk (Division of Electronics and Information Eng., Graduate School, Chonbuk National University)
  • Published : 2009.02.28
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Abstract

H.264 suggests applying a 2-D 6-tap wiener filter to realize the interpolation for half-pixel positions, followed by a bilinear interpolation to get the data of quarter-pixels precision. This method is comparatively simpler; however, it only considers the affection of 4-connection neighborhood ignoring the influence that comes from the changing rate between respective neighborhoods. As a result, it has the characteristics of a Low-pass filter under the risk of losing high-frequency weights. The Cubic interpolation uses the gray-values within the larger regions of points to be sampled for interpolation. Nevertheless, the cubic interpolation is more complicated and computational. We give a deep analysis on the features while applying both bilinear and cubic interpolation in H.264 presenting a proper selection of interpolation algorithm with respect to specific distribution of gray-value in a certain grand block. The experiments point out that load far motion searching and interpolation are reduced when promoting the precision of interpolation simultaneously.

H.264에서는 2-D 6-tap wiener filter가 1/2 화소의 위치로부터 1/4 화소 위치를 보간해 내는데 사용되고 있다. 이 방법은 비교적 간단하지만 이웃 화소들의 변화율을 무시하고, 4 방향의 이웃 화소들의 영향만 고려하게 되므로, 결과적으로 저역 필터의 특성을 갖게 된다. 그런데, 큐빅 보간 법을 사용하면 보다 넓은 영역의 화소 값을 고려하여 보간하는 장점은 있지만 계산이 복잡하다는 단점이 있다. 이 연구에서는 H.264에서 bilinear와 cubic 보간 법을 사용할 경우의 특성들을 해석하여, 임의의 큰 블록에 보다 적합한 보간 방법을 자동 선택할 수 있도록 하였다. 실험에서 물체영상의 움직임 탐색과 보간에 요구되는 계산량을 보간의 정밀화를 통하여 대폭 감소시킬 수 있음을 보였다.

Keywords

References

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