  Depth perception of objects can greatly affect a user's experience of an
augmented reality (AR) application. Many AR applications require depth matching
of real and virtual objects and have the possibility to be influenced by depth
cues. Color and luminance are depth cues that have been traditionally studied
in two-dimensional (2D) objects. However, there is little research
investigating how the properties of three-dimensional (3D) virtual objects
interact with color and luminance to affect depth perception, despite the
substantial use of 3D objects in visual applications. In this paper, we present
the results of a paired comparison experiment that investigates the effects of
object shape, fidelity, color, and luminance on depth perception of 3D objects
in handheld mobile AR. The results of our study indicate that bright colors are
perceived as nearer than dark colors for a high-fidelity, simple 3D object,
regardless of hue. Additionally, bright red is perceived as nearer than any
other color. These effects were not observed for a low-fidelity version of the
simple object or for a more-complex 3D object. High-fidelity objects had more
perceptual differences than low-fidelity objects, indicating that fidelity
interacts with color and luminance to affect depth perception. These findings
reveal how the properties of 3D models influence the effects of color and
luminance on depth perception in handheld mobile AR and can help developers
select colors for their applications.
