基于谱域光学多普勒层析技术的绝对速度测量

Absolute Velocity Measurement by Spectral Domain Optical Doppler Tomography

谱域光学多普勒层析(ODT)技术相对于传统的时域ODT技术,具有更快的成像速度和更大的测速动态范围。发展了基于谱域ODT技术的绝对速度测量方法,该方法综合运用多普勒频移和多普勒展宽信息实现多普勒夹角的确定,进而实现流体绝对速度的测量。给出了谱域ODT中计算多普勒频移和多普勒展宽的理论分析,并对毛细玻璃管内聚苯乙烯小球水溶液的流速进行了实际测量,实验结果和期望值能很好吻合。最后展示了该方法在老鼠脑部血管流速测量中的应用。

Spectral domain optical Doppler tomography （ODT） can achieve much higher imaging speed and velocity dynamic range than the time domain technology. A method to measure the absolute velocity is developed in a spectral domain ODT system,where Doppler angle is determined by combined information on the measured Doppler shift and Doppler bandwidth,and then the flow velocity is determined from Doppler angle and Doppler shift. Theoretical development relevant to Doppler measurement and absolute velocity determination is given. Measurement on flow velocity of aqueous solution of polystyrene beads in a capillary tube is done,in good agreement with the expected one. Finally,the developed method is applied to the study of rat’s cerebral arteries.