Influence of Object Height, Shadow and Adapting Luminance on Outdoor Depth Perception in Augmented Reality

Augmented reality (AR) technology has great potential in the applications of training, exhibition, and visual guidance, all of which demand precise virtual-real registration in perceived depth. Many AR applications such as navigation and tourism guidance are usually implemented in outdoor environments. However, prior research on depth perception in AR predominantly focused on the indoor environment, characterized by a lower illumination level and more confined space compared to outdoor settings. To address this gap, this paper presented a systematic investigation into the depth perception in outdoor environments. Two experiments were conducted in this study: the first one aimed to explore how to eliminate the bias induced by the floating object and how the knowledge of object height influences the perceived depth. The second experiment examined how ambient luminance affects depth estimation in AR. Our findings revealed an overestimation of perceived depth when participants were unaware of the actual height of the floating object, but an underestimation when they were informed of this information prior to the experiment. Additionally, shadows effectively reduced depth errors regardless of whether participants were informed of the object's height. The second experiment further indicated that, in outdoor environments, reducing ambient luminance significantly improves the accuracy of depth perception in AR.