用于扫频光源光学相干层析术的色散补偿法

Dispersion compensation algorithm for swept-source optical coherence tomography

在扫频光源光学相干层析术中,系统和样品中的色散会影响大深度范围内成像分辨率的保持。本文提出一种深度相关的色散补偿算法,用于精确补偿样品不同深度处的色散失配。其主要思想是在干涉光谱的频域中对样品图像按照不同深度进行分段,随后用基于抛物线法的迭代补偿法在每个深度处对样品进行色散补偿。该算法不需要对样品材料信息有预先了解,可在扫频光源光学相干层析系统得到的光谱中原位应用。通过在探测深度范围为5.720 mm的扫频光源光学相干层析系统中对盖玻片堆、损伤KDP晶体等不同样品进行的实验,证明该算法在全探测深度范围内都能有效提升纵向分辨率并使其接近理论值,且对于不同种类的样品都有较好的适应性。

In swept source optical coherence tomography,the maintenance of imagi ng resolution in a wide range of depth is affected by the dispersion which is brought by the system and the samples.In this manuscript,a depth dependent compensation algorithm is reported,which is used to accurately compensate the dispersion mismatch at different depths of the sample.The main i dea of this algorithm is that segments the sample image according to different depths in the frequency domain of interference spectrum,and then uses the iterative compensation method based on parabola to c ompensate the dispersion at all depths of the sample.The algorithm is independent of the prio r knowledge about samples and,as such,can be directly applied to the spectrum obtained by swept source optical coherence tomography.Through the experiments on different samples such as cover glass heaps and damaged KDP crystal in a swept source optical coherence tomography system with t he detected depth of 5.720mm,it is proved that the depth dependent algorithm is able to effectiv ely improve the axial resolution within the full depth of detection and make it close to the theoretic al value,at the same time,it has good adaptability for different types of samples.