Perceiving 3D in the absence of measurable stereo-acuity

Abstract

Aim: Increasingly, those who are considered ‘stereoblind’ by clinical testing, report that a 3D effect is perceived when watching stereoscopic films at the cinema. We report here the findings of a pilot study investigating the perception of 3D of stereoscopic video clips and games consoles, in observers who have no measurable stereo-acuity. Methods: Seven subjects were assessed for stereoacuity using standard clinical tests. They were then asked to perform an object depth ordering task on an autostereoscopic screen (Nintendo 3DS) and a 3D video rating task, to determine recognition of depth in entertainment media. Results: No subject had measurable stereo-acuity or simultaneous perception. Only 2 subjects achieved 41% and 55% correct depth identification on the 3DS task; the other 5 subjects performed poorly. When viewing stereoscopic 3D video clips, even subjects who demonstrate zero ability to identify depth on the 3DS task rated the ‘pop-out’ 3D effect very highly, giving a median (interquartile range) score of 8 (5) out of 10. Comparatively, 2D control videos were given a rating of 3 (8) out of 10. Conclusion: Subjects with no clinically measurable stereo-acuity report compelling ‘pop-out’ depth effects when viewing 3D stereoscopic video. There are many mechanisms for determining depth from a scene, with the presence of motion potentially allowing the appreciation of stereoscopic depth. The nature of the technological method of stereoscopic 3D delivery may also aid recognition of, or give other significant cues to, depth through artefacts or presentation method.