IEEE Trans Pattern Anal Mach Intell. 2022 Sep;44(9):5430-5444. doi: 10.1109/TPAMI.2021.3073739. Epub 2022 Aug 4.
The light field (LF) reconstruction is mainly confronted with two challenges, large disparity and the non-Lambertian effect. Typical approaches either address the large disparity challenge using depth estimation followed by view synthesis or eschew explicit depth information to enable non-Lambertian rendering, but rarely solve both challenges in a unified framework. In this paper, we revisit the classic LF rendering framework to address both challenges by incorporating it with advanced deep learning techniques. First, we analytically show that the essential issue behind the large disparity and non-Lambertian challenges is the aliasing problem. Classic LF rendering approaches typically mitigate the aliasing with a reconstruction filter in the Fourier domain, which is, however, intractable to implement within a deep learning pipeline. Instead, we introduce an alternative framework to perform anti-aliasing reconstruction in the image domain and analytically show comparable efficacy on the aliasing issue. To explore the full potential, we then embed the anti-aliasing framework into a deep neural network through the design of an integrated architecture and trainable parameters. The network is trained through end-to-end optimization using a peculiar training set, including regular LFs and unstructured LFs. The proposed deep learning pipeline shows a substantial superiority in solving both the large disparity and the non-Lambertian challenges compared with other state-of-the-art approaches. In addition to the view interpolation for an LF, we also show that the proposed pipeline also benefits light field view extrapolation.
光场(LF)重建主要面临两个挑战,大视差和非朗伯效应。典型的方法要么使用深度估计来解决大视差挑战,然后进行视图合成,要么回避显式深度信息以实现非朗伯渲染,但很少在统一的框架中解决这两个挑战。在本文中,我们通过将先进的深度学习技术与经典 LF 渲染框架相结合,重新审视了经典 LF 渲染框架,以解决这两个挑战。首先,我们从理论上证明了大视差和非朗伯挑战背后的根本问题是混叠问题。经典的 LF 渲染方法通常通过在傅里叶域中使用重建滤波器来减轻混叠,但这在深度学习管道中难以实现。相反,我们引入了一种替代框架,在图像域中进行抗混叠重建,并从理论上证明了在混叠问题上具有相当的效果。为了充分发挥潜力,我们通过设计集成架构和可训练参数,将抗混叠框架嵌入到深度神经网络中。该网络通过使用特殊训练集(包括规则 LF 和非结构化 LF)进行端到端优化进行训练。与其他最先进的方法相比,所提出的深度学习管道在解决大视差和非朗伯挑战方面具有显著的优势。除了 LF 的视图插值,我们还表明,所提出的流水线也有利于光场视图外推。