Transparent visual presentation: image information and ambiguity
F H Oosterhoff, Huib de Ridder · 2000
Presenting images in transparent overlay probably introduces ambiguity in figure-ground perception. We are interested in the factors that influence this ambiguity. A monocular see-through Head Mounted Display (HMD) presenting fixed focus images is used to create extended reality. We have investigated image visibility in relation to four virtual focus distances between 33 cm and infinite. The HMD presented transparent virtual images overlaying background images. Background images were presented with a 17-inch monitor at 1 m distance. The two images were perceived as one. An effective stimulus comprised one ‘landolt-c ’ within a circular configuration of seven hoops. A checkerboard was used as an affective stimulus. Stimuli were gaussian blurred. A trial consisted of a fixation cross, the combined stimuli and random noise subsequently. Correlating fixation either to effective or affective stimulus disbanded attention and task. Stimulus and presentation characteristics were randomised. Subjects ’ score correct on ‘landolt-c ’ orientation was obtained by means of a 2AFC paradigm. Spatial frequency was the visual component both stimuli had in common. Results showed that paradigm and stimuli were functional for visibility testing. The virtual image showed ambiguity by proximity of the background. Fixation at a different depth decreased visibility, although presentation behind the background yielded mostly constant results. We suggest investigating visual priorities and context for use of visual information, to avoid unnecessary ambiguity. Keywords: ambiguity, extended reality, head mounted display, psychophysics, transparency, ubiquitous communication.