Journal of the Institute of Electronics Engineers of Korea SP (대한전자공학회논문지SP)

The Institute of Electronics and Information Engineers (대한전자공학회)
권호 표지

Weighted Edge Adaptive POCS Demosaicking Algorithm

Edge 가중치를 이용한 적응적인 POCS Demosaicking 알고리즘

  • 박종수 (광운대학교 컴퓨터공학과) ;
  • 이성원 (광운대학교 컴퓨터공학과)
  • Published : 2008.05.25
Download PDF
⟨ Previous Next ⟩

Abstract

Most commercial CCD/CMOS image sensors have CFA(Color Filter Array) where each pixel gathers light of a selective color to reduce the sensor size and cost. There are many algorithms proposed to reconstruct the original clolr image by adopting pettern recognition of regularization methods to name a few. However the resulting image still suffer from errors such as flase color, zipper effect. In this paper we propose an adaptive edge weight demosaicking algorithm that is based on POCS(Projection Onto Convex Sets) not only to improve the entire image's PSNR but also to reduce the edge region's errors that affect subjective image quality. As a result, the proposed algorithm reconstruct better quality images especially at the edge region.

최근 대부분의 보급형 CCD/CMOS 영상 센서는 크기와 비용을 줄이기 위해 한 가지 색상만 선택적으로 통과시키는 CFA(Color Filter Array)를 사용한다. 따라서 원래의 컬러 영상을 복원하기 위하여 패턴인식이나, 정규화 등을 이용한 많은 알고리즘이 제안되었으나, 지엽적인 색상오류, zipper 효과 등의 오류를 충분히 제거하지 못하고 있다. 본 논문에서는 전체 영상의 PSNR 뿐 아니라 주관적인 화질에 영향을 주는 에지 부분에서의 오류를 줄이기 위하여, 기존에 제시되었던 방법인 POCS(Projection Onto Convex Sets) 알고리즘을 기반으로 에지 가중치를 적응적으로 적용하였다. 그 결과 강한 에지 부분에서 보다 효율적인 컬러복원을 할 수 있었다.

Keywords

References

  1. B. E. Bayer, "Color imaging array," U.S. Patent 3, 971,065, July 1976
  2. K.T. Mullen, "The contrast sensitivity of human color vision to red-green and blue-yellow chromatic grating," Journal of Physiology, 359, 1995, pp. 381-400
  3. T. W. Freeman, "Median Filter for Reconstructing Missing Color Samples, " U.S. Patent 4 724 395, 1988
  4. J.Hamilton and J.Adams, "Adaptive Color Plane Interpolation in Single Sensor Color Electronic Camera," U.S. Patent 5 629 734, 1997
  5. W. Lu, and Y.Tan, "Color filter array demosaicing: New method and performance measure," IEEE Trans. Image Processing, vol. 12, no. 10, pp. 1194-1210, Oct. 2003 https://doi.org/10.1109/TIP.2003.816004
  6. D.Cok, "Signal Processing Method and Apparatus for Sampled Image Signals, " U.S Patent 4 630 307, 1986
  7. X. Li "Demosaicing by Successive Approximation, IEEE Transactions on Image Processing, vol. 14, no.3, March 2005
  8. B. K. Gunturk, Y. Altunbasak and R. M. Mersereau, "Color plane interpolation using alternating projections," IEEE Transactions on Image Processing, vol.11, no.9, 2002
  9. R.Kimmel, "Demosaicing: image reconstruction from color CCD samples," IEEE Trans. Image Processing, vol. 7, no. 3, pp. 1221-1228, 1999
  10. X. Wang, W. Lin, P, P. Xue, "Demosaicing with Improved Edge Direction Detection", IEEE Cnf. Circuits and Systems, 2005. ISCAS 2005. IEEE international Symposium on 23-26 May 2005 Page(s): 2048 - 2051 Vol.3
  11. Kodak Lossless True Color Image Suite (http://r0k.us/graphics/kodak/kodak/)