Visual perception of distance in 3D-augmented reality head-up displays

A head-up display (HUD) is conveniently used to provide information on the display without changing the user's gaze. 3D HUDs, capable of projecting three-dimensional information beyond the 2D HUDs, enable the projection of augmented reality (AR) objects into the real world. Research on the perception of 3D AR HUDs is crucial for their efficient utilization and secure commercialization. In this study, we examined whether a 3D HUD is more comfortable than a 2D HUD in the context of viewing real-world environments and augmented reality objects together. Additionally, we analyzed participants' perception of distance and fatigue for AR objects at varying distances from the 3D HUD. The study found that using a 3D HUD in an AR environment resulted in less fatigue than using a 2D HUD, as determined by a Mann–Whitney statistical analysis. Participants were able to match the depth of AR objects in a 3D HUD within a range of 3 to 50 m, with similar diopter and parallax angular distance errors, regardless of the distance of the AR object. Visual fatigue increases with increasing distance from the virtual-image plane and can be modeled as a quadratic function in the domain of diopter and parallax angles.