Abstract
Monocular depth cues can provide a vivid sense of depth through image structure (such as perspective and occlusion) or through differential changes with movement (such as motion parallax). The persistence of monocular depth perception in the low-resolution limit has implications for the utility of retinal prostheses that are implanted within only one eye. An image depth-rating task previously demonstrated a significant difference in depth perceived from pixellated and post-blurred as compared to pixellated static images with false depth cues (N=11). In this study, the degree to which image representation affects the performance of functional tasks is investigated. Furthermore, the potential role of foveation in improving the performance of such tasks at low-resolution with restricted field-of-view is also studied. Foveation may be critical to improving the functionality of retinal prostheses that currently use a head-mounted camera without eye-tracking capability.
A functional reaching task with a head-mounted display (HMD) was used to determine monocular depth perception capabilities at low resolution with different image representations. Images were acquired from a head-mounted wide-field-of-view camera, processed to low resolution (pixellation and blur or pixellation alone), and then displayed in real time in front of the subject’s eyes. In the eye-pointed mode, the subject’s gaze directed the subregion of the wide-field-of-view image displayed to the user; head position alone determined the subregion of the image displayed in the head-pointed mode.
Subjects (N=3) were able to reach and grasp a bottle while avoiding obstacles faster with pixellated and blurred than pixellated representations. The task was completed faster when foveation was used to position the camera view.
Experimental results demonstrate that monocular depth perception at low resolutions is useful in functional tasks. Results also show that appropriate presentation of images, as well as the implementation of foveation in retinal prostheses, will improve the efficiency of depth task performance.
Meeting abstract presented at VSS 2013