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Volumetric Focus

Light field cameras, both array and lenslet-based, gather more light for a given depth of field than conventional cameras. The extra light manifests itself as redundancy in the light field, which must be processed in order to be exploited. Conventional approaches attempt depth estimation directly from the noisy data, or focus on a plane in the scene to reduce noise, trading off depth of field.

We introduce volumetric focus, a linear noise-rejecting filter that maintains focus over a controllable range of depths, rather than focusing on a single plane. It rejects noise even when keeping the whole scene in focus.

  • We derive the 4D hyperfan-shaped frequency-domain region of support of the light field, a subset of a 4D hypercone
  • We design linear hyperfan filters and show them outperforming competing methods including planar focus, 2D fan filters, and a range of nonlinear image and video denoising techniques
  • We include results in low light and through murky water and particulate matter
  • We demonstrate the inclusion of aliased components for high-quality rendering

Publications

•  D. G. Dansereau, O. Pizarro, and S. B. Williams, “Linear volumetric focus for light field cameras,” ACM Transactions on Graphics (TOG), Presented at SIGGRAPH 2015, vol. 34, no. 2, p. 15, Feb. 2015. Available here.

•  D. G. Dansereau, D. L. Bongiorno, O. Pizarro, and S. B. Williams, “Light field image denoising using a linear 4D frequency-hyperfan all-in-focus filter,” in Proceedings SPIE Computational Imaging XI, 2013, p. 86570P. Available here.

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