Computational Multi-Layer Light Field Display- Systematic Analysis, Evaluation and Optimization Method
(2015 Feb - 2020 June) OSC
A computational multilayer light field (MLLF) 3D display, which recreates multiple directional views of a reference light field by a stack of spatial light modulators, is one of the promising approaches that could potentially solve the vergence-accommodation cue conflict problem plaguing conventional stereoscopic 3D display systems. Those multiple angular samples of light rays enter the eye pupil simultaneously to drive the eye to accommodate at the rendered depth rather than the depth of the display surface.
Even though several pioneer works have been conducted to analyze the MLLF 3D display performance and different types of the MLLF 3D display prototypes have been built, there still lacks a systemic analysis method for the MLLF display, which takes the display factors, ocular factors as well as diffraction into consideration. Meanwhile, the conventional evaluation method based on the pixel-to-pixel remapping relationship is inadequate for the MLLF 3D display. Therefore a new evaluation metric which takes the multiple view integration into account is required for the MLLF 3D display evaluation. Furthermore, there lacks the optimization method for the engineering parameters of the MLLF displays system to improve display performance.
To overcome those problems mentioned above, in this work, an analytical eye model, a systematic analysis method, an evaluation method, as well as a method for display parameter optimization are proposed. The analytical eye model describes a generalized framework to form the perceived retinal image for various 3D displays, which can model the display aberration, eye aberration, accommodation, as well as the eye refractive errors. Apply this analytical model into the MLLF 3D display system to develop the systematic analysis method, which can model the effects of the display factors, the view dependency of the reference LF, the diffraction effect to characterize the perceived retinal image and investigate the accommodative response for a MLLF 3D display system. Furthermore, the new evaluation metrics which use the slope difference of the reconstruction light field as the objective criteria to represent contrast drop (MTF), shape deformation (SN), and phase shift (PS) are proposed. Then an experiment based on a dual-layer LCoS reflection setup is implemented to validate the evaluation method. Moreover, to develop the optimization method for the system parameters, the pixel pitch p, and the layer separation are investigated for its impacts on the reconstruction and diffraction (only for pixel pitch). Then the experiment with downsampled pixels and the experiment with the larger layer separation are implemented to validate the optimization method.
 Mohan Xu and Hong Hua, "Systematic method for modeling and characterizing multilayer light field displays," Opt. Express 28, 1014-1036 (2020)
 Mohan Xu and Hong Hua "Method for evaluating 3D display systems based on perceived retinal image", Proc. SPIE 11310, Optical Architectures for Displays and Sensing in Augmented, Virtual, and Mixed Reality (AR, VR, MR), 113100A (19 February 2020)
 M. Xu and H. Hua, "Systematic Analysis Method for Multilayer Light Field Display," in Imaging and Applied Optics 2018 ,OSA Technical Digest (Optical Society of America, 2018), paper 3W3G.3.
 Mohan Xu and Hong Hua, ”Analytical eye model for 3D display systems”. (Drafted)
 Mohan Xu and Hong Hua, "Evaluation method for the reconstruction LF intensity of the multilayer light field displays” (Work in progress)
(More papers will be published soon, due to confidentiality agreement, more details can be released after then.)