DOI QR코드

DOI QR Code

Accelerated compression of sub-images by use of effective motion estimation and difference image methods in integral imaging

집적영상에서 효율적인 물체움직임 추정 및 차 영상 기법을 이용한 서브영상의 고속 압축

  • 이형우 (광운대학교 전자공학과) ;
  • 김은수 (광운대학교 전자공학과, 홀로디지로그 휴먼미디어 연구센터)
  • Received : 2012.10.09
  • Accepted : 2012.11.18
  • Published : 2012.12.31

Abstract

In this paper, we propose a novel approach to effectively compress the sub-images transformed from the picked-up elemental images in integral imaging, in which motion vectors of the object in each sub-image are fast and accurately estimated and compensated by combined use of MSE(mean square error)-based TSS(tree-step search) and FS(full search) schemes. This is, the possible object areas in each sub-image are searched by using the fast TSS algorithm in advance, then the these selected object areas are fully searched with the accurate FS algorithm. Furthermore, the sub-images in which all object's motion vectors are compensated, are transformed into the residual images by using the difference image method and finally compressed with the MPEG-4 algorithm. Experimental results reveal that the proposed method shows 214% improvement in the compression time per each image frame compared to that of the conventional method while keeping the same compression ratio with the conventional method. These successful results confirm the feasibility of the proposed method in the practical application.

본 논문에서는 서브영상(sub-image)에 MSE(mean square error)기반의 블록정합 알고리즘인 TSS (three-step search)와 FS (full search)를 복합적으로 적용함으로써 물체움직임을 고속, 정밀하게 추정 보상하고, 차 영상 기법을 통해 공간적 중복데이터를 제거한 잔여영상(residual image)을 고속 압축할 수 있는 새로운 기법을 제시하였다. 즉, 제안된 기법에서는 픽업된 영상 간의 유사성을 향상시키기 위하여 픽업된 요소영상으로부터 서브영상을 재합성한 뒤, TSS 기반의 MSE 알고리즘을 사용하여 전 물체영역을 대상으로 가능한 물체영역 만을 고속으로 찾은 다음, 그 가능한 물체영역에 정밀한 FS 탐색 알고리즘을 적용하여 물체영상의 정확한 움직임 벡터를 추정하여 보상하게 된다. 또한, 움직임이 보상된 물체영상에 차 영상(difference image) 기법을 적용하여 서브영상 간의 공간적 중복 데이터를 제거한 잔여영상을 얻게 되고 이는 MPEG-4 알고리즘을 통해 최종적으로 압축되게 된다. 실험결과, 제안된 기법은 기존방식에 비해 영상 압축률은 그대로 유지하면서 프레임 당 압축시간이 214% 향상됨을 보임으로써 제안된 기법의 실제 응용 가능성을 제시하였다.

Keywords

References

  1. G.. Lippmann, "La photographie integrale," Comptes- Rendus Academie des Sciences 146, 446-451, 1908.
  2. H. Liao, M. Iwahara, N. Hata, and T. Dohi, "High-quality integral videography using a multiprojector," Opt, Express 12, 1067-1076, 2004. https://doi.org/10.1364/OPEX.12.001067
  3. J. -S. Park, D. -C. Hwang, D. -H. Shin, and E. -S. Kim, "Resolution-enhanced Computational Integral Imaging Reconstruction using Intermediate -view Reconstruction Technique," Opt, Eng. Vol. 45, No. 11, 117004, 2006. https://doi.org/10.1117/1.2393235
  4. Martinez-Cuenca, G. Saavedra, M. Martinez -Corral, and B. Javidi, "Enhanced depth of field integral imaging with sensor resolution constraints," Opt, Express 12, 5237-5242, 2004. https://doi.org/10.1364/OPEX.12.005237
  5. M. Forman and A. Aggoun "Quantization strategies for 3D-DCT based comopression of full parallax 3D images," in Proceedings of IEE 6th International conference on image Processing and Applications, IPA97, No. 443, 32-35, 1997.
  6. S. Yeom, A. Stern, and B. Javidi, "Compression of 3D color integral images," Opt, Express 12, 1632-1642, 2004. https://doi.org/10.1364/OPEX.12.001632
  7. J. -S. Jang, S. Yeom, and B. Javidi, "Compression of ray information in three -dimensional integral imaging," Opt, Eng. 44, 127001, 2005. https://doi.org/10.1117/1.2148947
  8. H. -H. Kang, D. -H. Shin, and E. -S Kim, "Compression scheme of sub-images using Karhunen-Loeve transform in three -dimensional integral imaging," Opt, Comm. 281, 3640-3647, 2008. https://doi.org/10.1016/j.optcom.2008.03.051
  9. H. -H. Kang, D. -H Shin, and E. -S Kim, "Efficient compression of motion-compensated sub-images with Karhunen-Loeve transform in three-dimensional integral imaging," Opt, Comm. 283, 920-928, 2010. https://doi.org/10.1016/j.optcom.2009.11.033
  10. C. -H. Yoo, H. -H. Kang, and E. -S. Kim, "Enhanced compression of integral images by combined use of residual images and MPEG-4 algorithm in three-dimensional integral imaging," Opt, Comm. 284, 4884-4893, 2011. https://doi.org/10.1016/j.optcom.2011.06.020
  11. H. -H. Kang, J. -H. Lee, E. -S. Kim, "Enhanced compression rate of integral images by using motion-compensated residual images in three-dimensional integral-imaging," Opt, Express 20, 5440-5459, 2012. https://doi.org/10.1364/OE.20.005440
  12. D. -C. Hwang, J. -S. Park, S. -C. Kim, D. -H. Shin, E. -S. Kim, "Magnification of 3D reconstructed images in integral imaging using an intermediate-view reconstruction technique," Appl. Opt. 45, 4631-4637, 2006. https://doi.org/10.1364/AO.45.004631
  13. H. Arimoto, B. Javidi, "Integral three -dimensional imaging with digital reconstruction," Opt. Lett. Vol. 26, 157-159, 2001. https://doi.org/10.1364/OL.26.000157
  14. D. S. Taubman and M. W. Marcellin, [JPEG2000- image Compression Fundamentals, Standards and Practice], Kluwer Academic Publishers, 6, 2002.