雷射投影光場立體顯示器之影像品質評估

Abstract

這幾年來裸眼立體顯示器這塊研究領域越來越炙手可熱，不管在展示場或者是商家店面都漸漸有類似的應用。而光場立體顯示器(light field 3D display)又是其中很熱門的一種，透過設計非常多的視角畫面來滿足人眼所感受到的視深感受。 在本論文中，我們結合了雷射微投影機和光場顯示系統去架出了雷射光場顯示器(laser projection light field 3D display)，其系統的優點除了包含雷射投影的優點之外，還有著可擴張，節省成本，觀看視角廣等優點。我們的系統主要分成兩個，以變換不同的散射螢幕跟相對應的系統參數作為兩種不同的系統。而我們還以光學模擬軟體來模擬系統結果並與真實的系統情況做比較，並改變一些系統參數看出散射角對影像的影響。而後我們又以量測找出關於此種立體顯示器的詭影值(crosstalk)的分布，並與其它立體顯示器比較後有較好的效果。我們還以主觀性實驗去量化人眼對於影像的感知深度(perceptual depth)，並用量測實驗找出在兩種不同系統中不同的主觀性實驗結果中影響看到影像的視深因子，也估計出散射螢幕角要小到多少程度才會讓人眼視覺看到的立體影像跟真實狀況的物體接近。 在未來的研究上，可以將平面的螢幕改為曲面的螢幕，並觀察影像在這樣曲面的結構下會有一些較好的影像呈現效果。或者可以在雷射顯示器會有的特殊現象上雷射光斑(laser speckle)做研究。而利用演算法去解決光場顯示器中影像扭曲也是個研究方向。

Recently, auto-stereoscopic displays are the popular topics. There are many fields which use the auto-stereoscopic display technique. Light field displays are the most important topic in the auto-stereoscopic displays, and the systems require several design modifications to achieve the multi view characteristic of stereoscopic image. In the Master Thesis, we design a laser projection light field 3D display combined with the MEMS laser projectors and light field 3D display. The low cost and scalable system include the advantages of the laser projector and wide view angle. We use the two different diffuser screen and corresponding parameters to build two different systems. We also use the software to simulate two systems and compare the image results with the image results of our real system, and observe how the diffusion angle of the screen affect the image results. The crosstalk value of our system are measured and we compare the results with the other auto-stereoscopic display, and our systems have the better image quality of the crosstalk. We use the subjectivity experiment to define the perceptual depth of human, and we compared the two results with the real condition. The image people saw in the system with smaller are closer to the real object, and we design the experiment to find out how two system offer motion parallax by the number of sub-image. And we estimate how the image close to the full motion parallax when we promote the diffusion angle of screen. In the future research, we can displace the planar diffuser with the curved diffuser and there would be some advantages for curved screen. Or the laser speckle is another research in the laser display field. Fatigue is one of the research topics in the stereoscopic display.