Model of Light Field Imaging and its Application in Refocus and All-Focus

Abstract:

In this paper, the light field is modeled from four fundamental factors and the spatial multiplexing of light field is analyzed. The relationship between the light field and the pixel in raw image is described for one typical light field camera. Then, the light field data is adopted in refocus and all-focus imaging. In the aspect of refocus, the hill-climbing algorithm is designed to found the highest value of the image clarity, which is evaluated with the second order gradient square function. On all-focus, the divide and conquer algorithm is adopted to find the optimal path in a gird. The experiment results confirm that the light field model is valid. The proposed refocus method is robust in comparisons with other four clarity measures. Our all-focus method can greatly eliminate the block artifact.

• Periodical: Advanced Materials Research (Volume 1039)
• Pages: 266-273
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1039.266
• Online since: October 2014
• Authors: Xu Zhang*, Chen Li
• Keywords: All-Focus, Clarity Evaluation Function, Hill-Climbing, Light Field Imaging, Refocus

References

[1] S. Gortler, R. Grzeszczuk, R. Szeliski, and M. Cohen, The lumigraph. In ACM SIGGRAPH, 1996. 1.

[2] L . McMillan, G. Bishop, Plenoptic modeling: An image-based rendering sistem. Proceedings of the 22nd annual conference on Computer graphics and interactive techniques. ACM, 1995: 39-46.

DOI: 10.1145/218380.218398

[3] E. H. Adelson, J. R. Bergen, The Plenoptic Function and the Elements of Early Vision, Computational Models of Visual Processing, 1991, 3-20.

[4] M. Levoy, P. Hanrahan, Light Field Rendering. ACM Trans. Graph. (SIGGRAPH), 1996, 31-42.

[5] S. Gortler, R. Grzeszczuk, R. Szelinski, M. Cohen, The Lumigraph. ACM Trans. Graph. (SIGGRAPH), 1996, 43-54.

[6] I. Ihrke, G. Wetzstein, W. Heidrich, A theory of plenoptic multiplexing, IEEE Conference on Computer Vision and Pattern Recognition, 2010, 483-490.

DOI: 10.1109/cvpr.2010.5540174

[7] C. Zhou, S.K. Nayar, Computational Cameras Convergence of Optics and Processing, IEEE Transactions on Image Processing, 20(12), 3322-3340, (2011).

DOI: 10.1109/tip.2011.2171700

[8] R. Ng, Fourier slice photography, ACM Transactions on Graphics (TOG), 2005, 24(3), 735-744.

DOI: 10.1145/1073204.1073256

[9] T. Georgiev, C. Zheng, B. Curless, D. Salesin, S. Nayar, C. Intwala, Spatio-angular resolution tradeoffs in integral photography. Eurographics Symposium on Rendering, 2006, 263-272.

[10] K. Ueda, T. Koike, K. Takahashi, T. Naemura, Adaptive integral photography imaging with variable-focus lens array. Proc SPIE: Stereoscopic Displays and Applications XIX, 2008, 6803, 68031A.

DOI: 10.1117/12.767208

[11] A. Lumsdaine, T. Georgiev, The focused plenoptic camera, IEEE International Conference on Computational Photography, 2009, 1-8.

DOI: 10.1109/iccphot.2009.5559008

[12] M. Levoy, B. Chen, V. Vaish, M. Horowitz, I. McDowall, M. Bolas, Synthetic Aperture Confocal Imaging. ACM Transactions on Graphics (TOG), 2004, 23(3), 825-834.

DOI: 10.1145/1015706.1015806

[13] Y. Taguchi, A. Agrawal, A. Veeraraghavan, S. Ramalingam, R. Raskar, Axial-Cones: Modeling Spherical Catadioptric Cameras for Wide-Angle Light Field Rendering, ACM Transactions on Graphics (TOG), 2010, 29(6), 172, 1-172: 8.

DOI: 10.1145/1882261.1866194

[14] Lytro. The lytro camera. https: /www. lytro. com.

[15] D. G. Dansereau, O. Pizarro, S. B. Williams, Decoding, calibration and rectification for lenselet-based plenoptic cameras. In IEEE CVPR, 2013. 1, 2, 4.

DOI: 10.1109/cvpr.2013.137

[16] D. Cho, M.L.S. Kim, Y.W. Tai, Modeling the calibration pipeline of the Lytro camera for high quality light-field image reconstruction[C]. ICCV, (2013).

DOI: 10.1109/iccv.2013.407

[17] C. Micheloni, G. L. Foresti , Active tuning of intrinsic camera parameters[J]. Automation Science and Engineering, IEEE Transactions on, 2009, 6(4), 577-587.

DOI: 10.1109/tase.2009.2017735

[18] M. Shuxiao, J. Wei, An improved algorithm For RGB colored images auto-focusing, Communication Technology (ICCT), 2011 IEEE 13th International Conference on. IEEE, 2011, 377-380.

DOI: 10.1109/icct.2011.6157900

[19] M. Mitchell, J.H. Holland, S. Forrest, When will a genetic algorithm outperform hill climbing?, NIPS. 1993, 51-58.

[20] E.G. Talbi, T. Muntean, Hill-climbing, simulated annealing and genetic algorithms: a comparative study and application to the mapping problem, System Sciences, 1993, Proceeding of the Twenty-Sixth Hawaii International Conference on. IEEE, 1993, 2, 565-573.

DOI: 10.1109/hicss.1993.284069

[21] Q. Miao, C. Shi, P. Xu, et al. Multi-focus image fusion algorithm based on shearlets[J], Chinese Optics Letters, 2011, 9(4), 041001.

DOI: 10.3788/col201109.041001

[22] W. Huang, Z. Jing. Evaluation of focus measures in multi-focus image fusion[J]. Pattern Recognition Letters, 2007, 28(4), 493-500.

DOI: 10.1016/j.patrec.2006.09.005