What is the Patient Looking at? Robust Gaze-Scene Intersection under free-viewing conditions

Locating the user?s gaze in the scene, also known as Point of Regard (PoR), following gaze regression is important for many downstream tasks in a multitude of environments. Previous techniques suffered from high computational costs associated with pre-processing the scene information to a manner that is suitable for PoR estimation. We propose a geometrically inspired algorithm that, despite its simplicity, provides high accuracy and performance under a variety of challenging situations including sparse depth maps, high noise, and high dynamic parallax between the user and the scene camera. We demonstrate the utility of the proposed algorithm in regressing the PoR from scenes captured in the Intensive Care Unit (ICU) at Chelsea Westminster Hospital NHS Foundation Trust.