使用正交極化光於全域式頻率域光學同調斷層掃描之研究與實驗驗證

Experimental Investigation of Full Range High Speed FD-OCT Based on Orthogonally Polarized Light

許明軒(Ming-Shiuan Shiu)

指導教授 ： 鄭旭志

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2011年)

https://doi.org/10.6827/NFU.2011.00113

摘要

在科技越來越進步的同時，醫療科技也是朝著越來越精細、快速，不傷及身體的方向前進著，早前科技有著超音波，現今科技有著使用光學來進行檢查的方法，利用光學的打入體內反射出的訊號做解調，由於介質的不同，光行經不同介質時會產生不同速度，所以我在這篇論文主要研究著光學同調斷層掃描的系統(Optical Coherence Tomography; OCT)，OCT主要分為時域(Time-Domain OCT)與頻域(Frequency-Domain OCT)，差別在於TDOCT是使用移動平台將參考端與待測物各層接面的光成差相差為0時產生的訊號判斷樣品的資訊，FDOCT只需將經過系統後反射的光解調後並經由程式轉換即可得到樣品資訊，本篇論文將對FDOCT對研究，目的在於將此系統的性能增強。
本論文研究利用正交極化光演算法的相位演算法去改進FDOCT系統的速度，相較於TDOCT系統，利用正交極化光演算法的頻域光學同調斷層掃描系統擁有快速、穩定、一次性、簡單，且沒有移動平台在移動上的振動誤差，我們在傳統的FDOCT系統中加入一極化片和一個四分之ㄧ波片並將其旋轉至適當的角度，在光經過了兩個波片進入系統出來的兩道光的相位相差了π/2，將這兩道光分別反傅立葉轉換並運算後可以得知待測物的訊息，一般反傅立葉轉換都會因Hermitian的關係使得測量範圍只有一半，本論文中將會在演算法中進行修改使得測量範圍達到全域，換句話說系統是個可以藉由一次的量測全域的FDOCT系統。

關鍵字

光學同調斷層掃描 ； 正交極化光 ； 相移演算法 ； 全域掃瞄 ； 消除DC項

並列摘要

Now the technology is more advanced as well as Medical technology. The Medical technology is also more meticulous, fast and is an untouchable way for body. It has ultrasonic in the past and nowadays it uses optics to check body. Insert the light into body and it reflects the signal to demodulate. Due to the difference of medium, the light has different speed in different medium. So I will mainly research OCT(Optical Coherence Tomography) in the research paper. OCT is divided into TDOCT (Time-Domain OCT) and FDOCT (Frequency-Domain OCT). TDOCT is used auto stage and the signal it produced which Optical path difference is zero differ from Reference and each sample’s surface to judge the sample’s information. FDOCT just demodulate reflected light which is through the system and converse by computer to get the sample’s information. This research paper will be researched for FDOCT and strengthen its function.
The research paper showed phase-shift algorithm of orthogonal polarization to improve the speed of frequency domain optical coherence tomography. Compared with time domain optical coherence tomography system, frequency domain optical coherence tomography system of orthogonal polarization algorithm is high speed, stable, disposable and simple to use and no movable stage has vibrational errors. We added a polarization film and a quarter of wave plate and whirl them to appropriate angle in the frequency domain optical coherence tomography. Through both lights’ phases of this experiment differed π/2[1] and separate them with in so that we could know the sample after we did. Due to Hermitian, inverse fourier transform would be half in the measured range normally. The research paper will show how to achieve full of measured range. In other words, the system will be one shot to measurement full-range of frequency optical coherence tomography.

並列關鍵字

OCT ； Orthogonal Polarized Light ； Phase-shift algorithm ； full-domain ； move DC term

參考文獻

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