A systematic method for designing depth-fused multi-focal plane three-dimensional displays

Lack of accurate focus cues in conventional stereoscopic displays has potentially significant effects on depth perception accuracy and visual fatigue. Recently several multi-focal plane display prototypes have been demonstrated with the promise of improving the accuracy of focus cue rendering in stereoscopic displays. In this paper, we present a systematic method to address two fundamental issues in designing a multi-focal plane display: (1) the appropriate dioptric spacing between adjacent focal planes; and (2) the depth-weighted fusing function to render a continuous three-dimensional (3-D) volume using a sparse number of focal planes placed in the space. By taking account of both ocular factors of the human visual system (HVS) and display factors of a multi-focal plane system, we determine that an appropriate spacing between two adjacent focal planes should be ~0.6 diopter (D) while a smaller spacing may be necessary for further improving retinal image quality. We further develop a set of nonlinear depth-weighted fusing function with the promise of balancing perceptual continuity of a 3-D scene and retinal image quality. Our method was based on quantitative evaluation of the modulation transfer functions (MTF) of depth-fused images formed on retina.