Perceptual Sensitivity to Stereo Geometry Errors in Head-Mounted Displays

TL;DR

This paper develops a geometric model to predict how inaccuracies in stereo rendering and viewing geometry in head-mounted displays affect perceived distance, and demonstrates real-time feedback can correct these perceptual errors.

Contribution

It introduces a geometric framework for predicting stereo geometry errors in HMDs and validates it through experiments with a Quest 3 headset, showing how feedback can recalibrate perception.

Findings

Stereo geometry errors cause under- and over-estimation of distance.

Real-time visual feedback can recalibrate perceived distance.

The geometric model accurately predicts perceptual distortions.

Abstract

Stereoscopic head-mounted displays (HMDs) render and present binocular images to create an egocentric, 3D percept to the HMD user. Within this render and presentation pipeline there are potential rendering camera and viewing position errors that can induce deviations in the depth and distance that a user perceives compared to the underlying intended geometry. For example, rendering errors can arise when HMD render cameras are incorrectly positioned relative to the assumed centers of projections of the HMD displays and viewing errors can arise when users view stereo geometry from the incorrect location in the HMD eyebox. In this work we present a geometric framework that predicts errors in distance perception arising from inaccurate HMD perspective geometry and build an HMD platform to reliably simulate render and viewing error in a Quest 3 HMD with eye tracking to experimentally test these predictions. We present a series of five experiments to explore the efficacy of this geometric framework and show that errors in perspective geometry can induce both under- and over-estimations in perceived distance. We further demonstrate how real-time visual feedback can be used to dynamically recalibrate visuomotor mapping so that an accurate reach distance is achieved even if the perceived visual distance is negatively impacted by geometric error.