The Effect of Interocular Contrast Differences on the Appearance of Augmented Reality Imagery

Augmented reality (AR) devices seek to create compelling visual experiences that merge virtual imagery with the natural world. These devices often rely on wearable near-eye display systems that can optically overlay digital images to the left and right eyes of the user separately. Ideally, the two eyes should be shown images with minimal radiometric differences (e.g., the same overall luminance, contrast, and color in both eyes), but achieving this binocular equality can be challenging in wearable systems with stringent demands on weight and size. Basic vision research has shown that a spectrum of potentially detrimental perceptual effects can be elicited by imagery with radiometric differences between the eyes, but it is not clear whether and how these findings apply to the experience of modern AR devices. In this work, we first develop a testing paradigm for assessing multiple aspects of visual appearance at once, and characterize five key perceptual factors when participants viewed stimuli with interocular contrast differences. In a second experiment, we simulate optical see-through AR imagery using conventional desktop LCD monitors and use the same paradigm to evaluate the multi-faceted perceptual implications when the AR display luminance differs between the two eyes. We also include simulations of monocular AR systems (i.e., systems in which only one eye sees the displayed image). Our results suggest that interocular contrast differences can drive several potentially detrimental perceptual effects in binocular AR systems, such as binocular luster, rivalry, and spurious depth differences. In addition, monocular AR displays tend to have more artifacts than binocular displays with a large contrast difference in the two eyes. A better understanding of the range and likelihood of these perceptual phenomena can help inform design choices that support high-quality user experiences in AR.