基于特征谱线与约束拟合相位的绝对波数标定方法  

An absolute wavenumber calibration method based on characteristic spectral line and constrained fitting phase

作　　者：王迪[1] 韩涛[1] 钱黄河 刘智毅 丁志华[1] Wang Di;Han Tao;Qian Huang-He;Liu Zhi-Yi;Ding Zhi-Hua(State Key Laboratory of Modern Optical Instrumentation,College of Optical Science and Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学光电科学与工程学院,现代光学仪器国家重点实验室,杭州310027

出　　处：《物理学报》2022年第21期139-147,共9页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2017YFA0700501);国家自然科学基金(批准号:62035011,11974310,31927801,61905214);浙江省自然科学基金(批准号:LR20F050001)资助的课题。

摘　　要：谱域光学相干层析成像(spectral-domain optical coherence tomography,SD-OCT)系统中普遍存在波数域的非线性采样问题.为实现常规快速傅里叶变换算法下离散界面的精确定位与OCT图像的高质量重建,需要解决光谱仪中离散采样点绝对波数的精确标定问题.本文提出了一种基于精确光程差下特征谱线与约束拟合相位的绝对波数标定方法,在谱域OCT系统的样品臂中,使用具有精确厚度差异的金属量规,获得特征谱线对应的绝对相位值,进一步精确求解出特征谱线对应的相位包裹次数,克服了常规干涉光谱相位方法中普遍存在的2π歧义,结合窗口约束条件下高信噪比区域的拟合相位,实现光谱仪采样点绝对波数的精确标定.通过全面比较本文方法与传统插值重采样方法在离散界面定位、轴向分辨率以及图像重建质量等方面的差异,验证了本方法的显著优势.Spectral-domain optical coherence tomography(SD-OCT)systems generally have nonlinear sampling problems in wavenumber domain.In order to realize the precise positioning of the discrete interfaces and the high-quality reconstruction of OCT images under conventional fast Fourier transform,it is necessary to solve the precise calibration problem of the absolute wavenumber of the discrete sampling points in the spectrometer.In this work,an absolute wavenumber calibration method is proposed based on the absolute phase of the characteristic spectral line and the constraint polynomial fitting phase under precise optical path difference.In the sample arm of the SD-OCT system,the metal gauges with precise thickness difference are used to obtain the absolute phase value of the characteristic spectral line,and the phase wrapping times corresponding to the characteristic spectral line are further accurately solved.Thus,this method overcomes the 2πambiguity of spectral phase in conventional interferometric phase methods.At the same time,combined with the polynomial fitting phase of the high signal-to-noise ratio region under window constraint,the accurate calibration of the absolute wavenumber of each sampling point is realized.Finally,comprehensive comparison between the proposed method and the traditional resampling method in terms of discrete interface positioning,axial resolution and image reconstruction quality verifies the significant advantages of this method.

关 键 词：谱域光学相干层析成像 光谱相位 绝对波数标定 窗约束拟合 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] O439[自动化与计算机技术—计算机科学与技术]