虚拟双光束ODT系统探索与研制

Exploration and Development of Virtual Du-al-Beam ODT System

摘要: 通常在使用ODT (Optical Doppler Tomography)系统获取组织内部速度信息时必须已知振镜扫描光束与速度方向的夹角，限制了ODT系统应用场景。若振镜的扫描速度远大于流速，则可近似认为相邻的两次扫描是对同一点的流速进行测量。本文利用MEMS (Micro Electromechanical System)实现可控的快速扫描。采用虚拟双光束测量法通过将多普勒角转化为双光束之间的夹角成功解决了ODT系统采集速度信息时必须已知扫描光束与速度方向夹角的问题。采用基于最小二乘的高斯–塞德尔迭代算法提高了系统的实时性。搭建系统后对手背皮肤进行扫描，得到了皮肤浅表层的三维结构并构建了血流信号的三维模型，验证了本系统在体测量的可行性。

Abstract: Usually when using ODT (Optical Doppler Tomography) system to obtain internal speed information in the organization, the angle between the galvanometer scanning beam and the speed direction must be known, which limits the application scenarios of ODT system. If the scanning velocity of the galvanometer is much greater than the flow rate, it can be approximately assumed that two adja-cent scans are measuring the flow velocity at the same point. This paper uses MEMS (Micro Elec-tromechanical System) to achieve controllable fast scanning. By using the virtual dual beam meas-urement method, the Doppler angle is converted into the angle between the two beams, which suc-cessfully solves the problem that the angle between the scanning beam and the velocity direction must be known when the ODT system collects velocity information. The Gaussian-Seidel iterative algorithm based on least squares is used to improve the real-time performance of the system. After building the system, the skin on the back of the hand was scanned, the three-dimen- sional struc-ture of the superficial layer of the skin was obtained, and a three-dimensional model of the blood flow signal was constructed, which verified the feasibility of in vivo measurement of the system.