多邊形取樣的Kinoform電腦全像片之研究

Abstract

配合電腦圖學技術的精進發展，本篇論文選用和其基礎概念相同之多邊形法來計算記錄於電腦全像片上之物波光場。沿用L. Ahrenberg教授於2008年所提出的多邊形處理法解析模型，希望透過此法減少快速傅立葉(FFT)轉換的使用，加速運算流程以減少運算所需時間。我們以Misfit Model 3D軟體從外部繪製好目標三維物件後，再以Matlab讀取並執行多邊行處理法解析模形的計算，更進一步的探討光源位置所造成的陰影等更深層的問題。而為了能以單片的Holoeye公司出產的LC-R2500液晶光學調制器顯示全像片。我們將運算所得之物波光場編碼成Kinoform形式的純相位電腦全像片。 為了改善Kinoform相位電腦全像片的邊緣加強效應，我們加入了亂數相位以模擬光擴散板，使得資訊分布的更加均勻。然而此種解析模型加入亂數相位後，將會失去大部分的景深資訊，無法達成我們希望重現三維立體視覺的目的。對此，本文提出了一個適用解析模型的三角形分割法，此方法能夠克服景深資訊遺失的問題。我們以上述之原理對二維及三維物件進行記錄後編碼成相位電腦全像片，再以數位方式重建。 最後，我們以LC-R2500來顯示二維物件記錄後編碼成的全像片，並以4F系統將重建之像呈現在影像記錄器上以便觀察。重建結果既符合我們原物件記錄時的資訊，也和數位重建結果互相符合。因此，我們以實驗結果驗證了本論文所提出之方法所產生的相位電腦全像片，能夠將物體的三維深度資訊記錄並且能夠正確的重建。

We present a method to create a computer-generated hologram (CGH) which is made from the 3D computer graphic models composed of 2D polygons. As the developing of technique of computer graphic, this promising approach of making CGH is getting popular. We follow the analytical model proposed by Professor L. Ahrenberg in 2008 with some modification. The analytical model is used to avoid complicated FFT computation to reduce time consuming. We use Misfit Model 3D as the 3D object creating program. Then load the object and process the calculation by MATLAB. To display the CGH on the optical modulation display LC-R2500 which produced by Holoeye, we encode our CGH in the Kinofrom approach. In order to improve the image quality of Kinofrom CGH, we add random phase as diffuser to make the light more uniform. However, this step will lost most depth information. Here, we proposed a divided method on this kind analytical model to solve the edge enhancement and improve the quality of the Kinoform CGH. Finally, we use both numerical and optical experiment to reconstruct our computer generated hologram. We prove that the method proposed in this paper can reconstruct the object correctly.