運用同軸數位全像術克服薄散射介質之光資訊畸變復原之研究

Studies on sending optical information through a thin turbid medium without distortion by using in-line digital holographic technique

陳子凡(Zi-Fan Chen)

指導教授 ： 林烜輝 ； 薇 娜

國立交通大學/理學院/電子物理系所/碩士(2018年)

摘要

本論文主要探討如何克服光資訊經薄散射介質後所產生之畸變，而將資訊完整地從輸入端送到輸出平面上。其關鍵在於如何找出薄散射介質之穿透函數與如何將散射介質之影響移除，我們的方法是利用數位全像術。
首先，建立相位移式(phase-shifting)同軸數位全像取像與重建之技術。其次，以此為根本，先取得薄散射介質之穿透函數。然後，再以此系統取得經薄散射介質之物體光資訊(強度與相位)，並透過角頻譜法則找出在薄散射介質的平面上，物體光波的分佈，我們就可利用全像共軛法移除散射介質之影響，復原經薄散射介質造成影像之畸變，重建出清晰之影像，達到將光資訊送過薄散射介質的目的。而本文最後也展示數位全像技術的動態處理的優點，藉由將輸入器件換成空間光學調制器顯示動態影像，可展示數位同軸全像克服薄散射介質對動態影像之畸變的能力。

關鍵字

全像 ； 數位全像 ； 同軸數位全像 ； 散射介質

並列摘要

Sending optical information through a scattering or diffusive medium is a difficult challenge and still attracts extensive attention from the scientific community because of its potential applications. In fact, information of an optical field through a diffusive medium is not lost, but instead is coded by the complex transmission function of the medium. Thus, with the knowledge of the diffuser, the information pass through thin scattering media without distortion can be possible. Holographic technologies have long been used for recording and reconstructing the complexing amplitude of light field. As technology advances, the rapid development of 2D sensors, such as CCD and CMOS has provided low-cost and high-performance digital recording tools for holography. Digital holography provides not only many capabilities of conventional holography but also novel inventions of holographic applications.
In this thesis, we present our investigations on sending optical information through a thin turbid medium using in-line digital holographic technique. In our method, the recovery of the optical field is done using digital in-line holography and numerical phase conjugation. The complex field of the diffuser is first measured and analyzed by using phase-shifting in-line digital holographic technique. When the distorted light field of an object placed behind this diffuser is captured, the measured complex field of the diffusor can be used to numerically remove scattering effect and reconstruct the object. The working principle and optical experiments will be described and demonstrated in this thesis.

並列關鍵字

holography ； digital holography ； in-line digital holography ； scattering media

參考文獻

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