Accelerated Generation of a Pinhole-Type Holographic Stereogram Based on Human Eye Characteristics in Near-Eye Displays

Xu Zhang,Zi Wang,Tao Chen,Kefeng Tu,Yujian Pang,Qibin Feng,Piao Dai,Guoqiang Lv

doi:10.3390/photonics9020095

Abstract

In near-eye displays (NEDs), issues such as weight, heat, and power consumption mean that the rendering and computing power is usually insufficient. Due to this limitation, algorithms need to be further improved for the rapid generation of holograms. In this paper, we propose two methods based on the characteristics of the human eye in NEDs to accelerate the generation of the pinhole-type holographic stereogram (HS). In the first method, we consider the relatively fixed position of the human eye in NEDs. The number of visible pixels from each elemental image is very small due to the limited pupil size of an observing eye, and the calculated amount can be dramatically reduced. In the second method, the foveated region rendering method is adopted to further enhance the calculation speed. When the two methods are adopted at the same time, the calculation speed can be increased dozens of times. Simulations demonstrate that the proposed method can obviously enhance the generation speed of a pinhole-type HS.

Highlights

Near-eye displays have attracted a great deal of interest since they are essential devices giving immersive and interactive experiences in virtual reality (VR) and augmented reality (AR) applications [1,2]
Most commercial near-eye displays (NEDs) are based on binocular disparities by presenting a pair of stereoscopic images, which causes a mismatch between the accommodation distance and the convergence distance of human eyes
We propose two methods based on the characteristics of the human eye in NEDs to accelerate the generation of the pinhole-type holographic stereogram (HS)

Summary

Introduction

Near-eye displays have attracted a great deal of interest since they are essential devices giving immersive and interactive experiences in virtual reality (VR) and augmented reality (AR) applications [1,2]. Wave-optics-based algorithms mainly contain the point-sourcebased methods [9], polygon-based methods [10] and layer-based methods [11] In these methods, complicated physical phenomena, such as occlusion, shading, reflection, refraction, glossiness, and transparency, are hard to encode into the CGH [12]. The observer’s eye can sample light rays from the virtual pinholes This means that the spatial resolution of the reconstructed object is determined by the number of pinholes or EIs. In order to improve the display quality, it is usually possible to increase the number of pinholes while keeping each EI’s resolution unchanged, but this will bring additional rendering costs and computational costs [22]. We propose two methods based on the characteristics of the human eye in NEDs to accelerate the generation of the pinhole-type HS. Simulations demonstrate that the proposed methods can obviously enhance the generation speed of pinhole-type HSs

Pinhole Type HS

Proposed Methods

Calculation Acceleration Based on Visible Pixels

The Method