Geometric information of scenes available with four-dimensional (4-D) light fields (LFs) paves the way for post-capture refocusing. Light field refocusing methods proposed so far have been limited to a single planar or a volumetric region of a scene. In this letter, we demonstrate simultaneous refocusing of multiple volumetric regions in LFs. To this end, we employ a 4-D sparse finite-extent impulse response (FIR) filter consisting of multiple hyperfan-shaped passbands. We design the 4-D sparse FIR filter as an optimal filter in the least-squares sense. Experimental results confirm that the proposed filter provides 63% average reduction in computational complexity with negligible degradation in the fidelity of multi-volumetric refocused LFs compared to a 4-D nonsparse FIR filter.

中文翻译：

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光场的多体积重聚焦

具有四维 (4-D) 光场 (LF) 的场景的几何信息为捕获后重新聚焦铺平了道路。迄今为止提出的光场重聚焦方法仅限于场景的单个平面或体积区域。在这封信中，我们展示了 LF 中多个体积区域的同时重新聚焦。为此，我们采用了由多个超扇形通带组成的 4-D 稀疏有限范围脉冲响应 (FIR) 滤波器。我们将 4-D 稀疏 FIR 滤波器设计为最小二乘意义上的最佳滤波器。实验结果证实，与 4-D 非稀疏 FIR 滤波器相比，所提出的滤波器平均降低了 63% 的计算复杂度，而多体积重聚焦 LF 的保真度下降可忽略不计。