基于光学相干层析散斑的流速测量方法

Flow Velocity Measurement Based on Speckle in Optical Coherence Tomography

发展了一种基于光学相干层析(OCT)散斑的流速测量方法。与传统激光散斑信号相似,样品中某一点处OCT信号随时间的波动与该处散射颗粒的平均速度有一定的依赖关系。通过对OCT信号的滤波和解调,得到OCT散斑波动信号,再对该信号进行傅里叶变换,得到散斑信号的频谱分布,然后依据频谱分布中高低频分量比值(HLR)与流速间的定量关系,就能确定样品中的流速分布。基于OCT散斑强度信号而非相位信息的流速测量方法,实验研究了HLR与流速间的关系,并给出了毛细玻璃管模型的流速分布图像。

Flow velocity measurement based on speckle in optical coherence tomography （OCT） images is developed. Similar to traditional laser speckle signal, time-varying fluctuations in OCT speckle intensity is related to the average velocity of scattering particles within the sampling volume. Fluctuated signal of the speckle intensity is obtained from the detected OCT signal by filtering and demodulation. Then the spectrum of the speckle is deduced through Fourier transform of the fluctuated signal, and quantitative measurement of flow velocity can be conducted according to the calculated ratio of high to low （HLR） spectrum. The method of flow measurement based on speckle intensity in OCT instead of phase information is introduced. Investigation on the relationship of the calculated HLRs with the flow velocities is experimentally conducted. Flowing particles in a tube in mimic of capillary is visualized by the proposed method.