利用液晶空間光調變器實現新穎架構之光學邏輯閘及其應用

A Novel Structure and Application of Optical Logic Gate with Liquid Crystal Spatial Light Modulators

李正文(Cheng-Wen Li)

指導教授 ： 陳祖龍

元智大學/電機通訊學院/電機工程學系/碩士(2007年)

https://doi.org/10.6838/YZU.2007.00024

摘要

本論文中，我們提出了利用液晶空間光調變器來做為新穎架構之光學邏輯閘，並應用光學互斥或邏輯閘進行影像之加密與解密。傳統之光學互斥或邏輯閘，在進行液晶空間光調變器之像素對位時，因為使用光透鏡進行點對點之調校，易造成光學系統之架構龐雜且敏感。當進行實作時，需耗費較長時間的儀器架設與調準，我們提出了將兩片液晶光調變器進行重疊對位與膠著固定之架構，使得架設光學系統的複雜度與所需空間降低，而且在進行實驗時，亦可減少光學平台的環境震動對實驗結果所造成之影響。
本系統使用瓊斯矩陣進行二元影像加密與解密之推演，於影像加密部分以隨機產生之二元圖像進行編碼；解碼方式為輸入加密後影像與編碼時使用之隨機圖像進行耦合而得到解碼之影像。最後，我們運用均方差與影像訊號雜訊比來測試評估本系統於不同解碼圖像下所得之解密影像。我們系統的成效可經由實驗與模擬呈現之結果驗證出。

關鍵字

液晶空間光調變器 ； 光學邏輯閘

並列摘要

In this thesis, optical logic gate is proposed by a novel structure and its application. Two liquid crystal spatial light modulators (LCSLMs) are used to construct the optical logic gate system. This optical logic gate with XOR operation is used to achieve both image encoding and decoding operations. This system is composed of two sets of LCSLMs, which is aligned by microscope and stuck with adhesive. It will take us less time to set up the system and to perform strict alignment in experiment. On the other hand, it can reduce the influence of vibration in optical experiment.
We investigate the binary image encryption and decryption with Jones matrix in this system. In image encryption, we obtained the random binary image after encoding process. Furthermore, the decoded image is obtained by coupling of the encrypted image and random key. Finally, we utilize MSE and PSNR to evaluate the decrypted image under different random key. The simulation and experimental results are presented to investigate the performance of our system.

並列關鍵字

Liquid Crystal Spatial Light Modulators ； Optical Logic Gate

參考文獻

[1]F. T. S. Yu, “Legacy of optical information

television as a programmable spatial light modulator,”

Opt. Eng., Vol. 35, pp. 15-19, 1996.

[4]P. Yeh and C. Gu, Optics of Liquid Crystal Displays,

John Wiley & Sons, Reading, New York, 1999.