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

Abstract

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.

Lightweight spatial-multiplexed dual focal-plane head-mounted display using two freeform prisms

“…The conclusion is identical to those obtained by the systematic and theoretical analysis of the depth-filtering multiple focal-plane display in Ref. [13]. MacKenzie et al presented a detailed analysis of retinal-image formation as a function of image-plane separation, and measured accommodation responses to these depth-filtered stimuli [10] .…”

“…Thus, the FOV of the tiled HMD in the direction perpendicular to the tiling surface is expanded. Rather than forming a large FOV by tiling the fields, the FOVs of two display channels in this letter are completely overlapped, and the virtual screens have a depth difference of 0.6 D according to previous works [9,10,13] . In the current work, we propose four design schemes by considering the structure, design complexity, light efficiency, and stray light issues of the dual focal-plane optical system, as shown in Fig.…”

Systematic characterization and optimization of 3D light field displays

“…The conventional S3D displays fail to render correct retinal blur effects and stimulate natural eye accommodation response, which causes several cue conflicts and is considered as one of the key contributing factors to various visual artifacts associated with viewing S3D displays, such as distorted depth perception [3] and visual discomfort [4]. In recent years, several display methods that are potentially capable of resolving the VAC problem have been demonstrated, including holographic displays [5], volumetric displays [6,7], multi-focal plane displays [8][9][10] and light field displays [11][12][13][14][15][16][17][18][19][20]. Among these different methods, the light field display method is considered as one of the most promising 3D display techniques.…”

High-performance integral-imaging-based light field augmented reality display using freeform optics

“…By driving the display in a dualdepth mode, the system achieves high-resolution displays of targets with a large depth separation of nearly 3 diopters while rendering focus cues comparable to their real counterparts. The vari-depth and multi-depth modes of the InI-based light field rendering method share some similarity to the conventional vari-focal [24] and multi-focal plane HMD works [6][7][8][9] in the sense that the depth of the CDP is either adaptively varied according to the depth of interest in the vari-depth mode or is rapidly switched among several discrete depths in the multi-depth mode. However, their visual effects and implications on focus cues are noticeably different.…”

“…These displays thus force an unnatural decoupling of the accommodation and convergence cues and induce a fundamental problem sometimes referred to as vergence-accommodation conflict (VAC), which might lead to various visual artifacts such as distorted depth perception and visual fatigue [1,2]. In recent years, several display methods that are potentially capable of resolving the VAC problem have been demonstrated, including holographic displays [3], volumetric displays [4,5], multi-focal plane displays [6][7][8][9], and light field displays [10][11][12][13][14][15][16][17][18]. Among these methods, integral-imagingbased (InI-based) light field display allows the reconstruction of the full parallax of a 3D scene seen from a predesigned viewing window and have been conventionally demonstrated for its use in direct-view 3D display systems [10,11].…”