Effects of Depth Layer Switching between an Optical See-Through Head-Mounted Display and a Body-Proximate Display

TL;DR

This study investigates how switching between an optical see-through head-mounted display and a nearby display affects user performance, revealing significant increases in task time and errors during visual search tasks across different depth layers.

Contribution

It provides empirical evidence quantifying the performance costs of depth layer switching in joint OST HMD and body-proximate display systems.

Findings

Task completion time increased by ~50%.

Error rate doubled during cross-layer visual search.

Depth switching imposes a significant performance trade-off.

Abstract

Optical see-through head-mounted displays (OST HMDs) typically display virtual content at a fixed focal distance while users need to integrate this information with real-world information at different depth layers. This problem is pronounced in body-proximate multi-display systems, such as when an OST HMD is combined with a smartphone or smartwatch. While such joint systems open up a new design space, they also reduce users' ability to integrate visual information. We quantify this cost by presenting the results of an experiment (n=24) that evaluates human performance in a visual search task across an OST HMD and a body-proximate display at 30 cm. The results reveal that task completion time increases significantly by approximately 50 % and the error rate increases significantly by approximately 100 % compared to visual search on a single depth layer. These results highlight a design trade-off when designing joint OST HMD-body proximate display systems.