I. Introduction
Replicating the visual world in the most faithful and immersive way has always been the target of visual representation technology, notably cameras/sensors, codecs and displays. For decades, a digital picture has always been a 2D array of pixels where each pixel accumulates the light incident from all directions on a specific sensor position. However, this is a limited representation model as highlighted by the so-called plenoptic function [1] [2], which models the light in the 3D space with a 7D function of five spatial coordinates, notably three position coordinates and two directional coordinates, thus expressing the fact that light rays have a direction.