低播放速率需求的360度立體光場投影顯示系統與其影像之分析

Abstract

在360度立體光場顯示器(Light-Field Display)的系統中，為了要實現360度的環狀多視角(Multi-View)，無可避免地要透過各種設計滿足非常多視角畫面的影像需求。在光場顯示器的設計中，主要有透過架設一台非常高速率的投影機與架設許多台小型微投影機兩種方式來滿足此訴求，而這不同設計方式反映著成本考量之問題。 在本論文中，我們主要是透過光學模擬軟體分析光場顯示器的各種系統主題。首先是光場顯示器的兩種不同架設方式的系統架構與成像原理。透過不同系統架構的設計，影響著最後成像的影像品質好壞。接著，我們透過改良螢幕的幾何結構，降低了播放速率的需求。由於在影像投影的時候會有影像因為斜向投影等導致的影像失真變形的問題，本論文中針對該系統提供演算法對影像進行修正達到最後成像與原待重建之物體最接近的優化後結果。 透過光學模擬軟體的優勢，本文針對光場顯示器中的子畫面(Sub-Image)與觀賞範圍做進一步分析。在調變螢幕的散光結構(Diffuser)可以修正影像模糊以及明暗不均的問題。以及透過設定接收器的距離，可以得到量化影像失真的結果。在本論文的實驗中，我們建立了一個量化的分析依據，用來當做子畫面相銜接的好壞的評斷標準，以及其他與影像品質相關之趨勢。 在未來的研究中，可以試著透過增加光學元件等方式，達到再降低對高播放速率的要求、以及可以透過跟不同領域結合，例如穿戴式的偵測裝置，透過先前得到量化影像失真的數據，達到對影像做即時性修正的結果。

A 3D light field display system requires several design modifications to achieve the multi-view characteristic of a 360˚ 3D image. While certain light field display utilized a high frame rate projector¬¬ or many micro projectors to achieve the modifications, they also drastically increased the cost of the system. This thesis discusses the use of an optical simulation software to analyze different parameters in a light field display. First, different system configurations can affect the displayed image quality. Improving the geometric structure of the reflective screen can also decrease the frame rate requirement of the system. Since images projected and reflected from a tilted screen can result in image distortion, this thesis focuses on the analyses of different parameters to correct the distortion while maintaining the original dimensions of the 3D image. Optical simulation software further allows studies of sub-images within a light field display and the viewing angle of the system. Varying the diffusion angles of the reflective screen can correct blurred image and non-uniform brightness within the image. In addition, the receiver distance can help to quantify the amount of image distortion. This research formulates a quantitative method that can be used as an indicator for determining the quality of sub-image realignment and other image properties. Future studies can incorporate optical components into the system to further decrease the need for high frame rate projector. Multi-disciplinary cooperation, such as utilizing a tracking device to achieve real-time image correction by using previous image distortion data.