Contributed Session III: Global Luminance and Local Contrast Modulate Interocular Delay in Virtual Reality

Abstract

Virtual reality (VR) systems take advantage of depth cues to create immersive environments that simulate a three-dimensional world. Most often these cues provide consistent information about depth, but on occasion, such cues conflict with each other to create compelling phenomena that illustrate the function of underlying mechanisms. Here we examine the interaction of depth produced by local contrast, global luminance, and interocular luminance differences (i.e., a Pulfrich effect). We measure depth perception with two adjustment tasks. 1: Two moving streams of balls, one upwards (the standard) and the other sideways; the observer adjusts the depth of the sideways stream to lie in the same plane as the upward stream. 2: Balls move sinusoidally back and forth in the frontal plane; if depth is perceived, the pattern appears as a rotating helix. The observer adjusts the helical path until the balls appear to move in a single depth plane. We report that at low luminance levels dark balls are more effective at creating depth than bright balls; at higher luminance levels the effectiveness of dark balls decreases but the effectiveness of bright balls remains constant. Based on these data, we demonstrate how changes in the luminance of the background (or balls) can lead to shifts in the apparent depth order and the apparent direction of helical rotation. The results suggest a method for investigating potentially conflicting contributions of contrast and Pulfrich depth information.