Fig. 1. Principle of compact light field photography.

a A conventional light field camera captures the scene from different views with a lens array and records all sub-aperture images. In contrast, CLIP records (operator ${\mathbf{A}}_k$) only a few nonlocal measurements (${\mathbf{f}}_k$ to f_n) from each sub-aperture image and exploits the depth-dependent disparity (modeled by B_k) to relate the sub-aperture images for gathering enough information to reconstruct the scene computationally. Refocusing is achieved by varying the depth-dependent disparity model B_k. b Seeing through severe occlusions by CLIP as a camera array, with each camera only recording partial nonlocal information of the scene. A obscured object (from the camera with black rays) remains partially visible to some other views (with green rays), whose nonlocal and complementary information enables compressive retrieval of the object. c Illustration of instantaneous compressibility of the time-of-flight measurements for a 3D scene in a flash LiDAR setup, where a transient illumination and measurement slice the crowded 3D scene along the depth (time) direction into a sequence of simpler instantaneous 2D images. d–f CLIP embodiments that directly perform nonlocal image acquisitions with a single-pixel, a linear array, and 2D area detectors, respectively. A single pixel utilizes a defocused spherical lens to integrate a coded image, with u and v behind the lnes being the angular dimension. A cylindrical lens yields along its invariant axis a radon transformation of the en-face image onto a 1D sensor. The complex-valued mask such as a random lens produces a random, wide-field PSF that varies with object depth to allow light field imaging. PSF point spread function, CLIP compact light field photography, LiDAR light detection and ranging, 1D, 2D, 3D one, two, and three-dimensional.