Multiple-focal-planes 3D displays: A practical solution to the vergence-accommodation conflict?

The vergence-accommodation conflict in conventional stereo displays causes poor stereoscopic performance and observer discomfort. We examined the effectiveness of multiple-focal-plane displays in overcoming these issues. Specifically, we examined a technique referred to as ‘depth filtering’, in which continuous variations in focal distance are approximated by distributing image intensity across several image planes [1]. A key potential advantage of this technique is that focal distance can be sampled adequately with relatively few, widely spaced focal planes. We examined this by measuring (i) stereoacuity, and (ii) the time needed for stereoscopic fusion, as a function of image-plane separation. Stereo fusion time for depth-filtered and real targets was similar. Stereoacuity for depth-filtered stimuli with image-plane separations <0.7 diopters (D) was only slightly poorer than for real targets, but deteriorated more rapidly at larger plane separations. The results are encouraging for multi-plane displays, suggesting that a display with just five image planes, 0.6 D apart, could cover the range 42 cm to infinity.