Design And Experimental Research Of Swept Source Optical Coherence Doppler Tomography Imaging System

Swept Source Optical Coherence Doppler Tomograghy(SSODT)is a threedimensional optical imaging technique with non-invasive,high-resolution,and realtime imaging features.Therefore,it has important applications in medical fields such as blood flow imaging and blood flow velocity measurement in epidermal tissue and ophthalmology.This dissertation systematically analyzed the imaging principles of SSODT technology,elucidated the influence of single components on the imaging performance of the system,designed and built a high-resolution,high-speed,large depth-of-filed SSODT imaging system.The work is focused on numerical simulations and experimental research.First,this dissertation introduces the key parameters to evaluate the performance of the imaging system,such as resolution,imaging speed,field of view,signal-to-noise ratio,etc.,based on the imaging principle of SSODT,and analyzes the influence of the device parameters of the SSODT system on the performance indexes in detail.Through device parameter optimization,optical path optimization,and algorithm optimization of motion and data acquisition,a high-performance SSODT imaging system with a central band of 1310 nm is realized.Then,based on the SSODT imaging system,the experimental study of the imaging performance of the system was carried out.The structural parameters of the devices such as reflector,glass slide,coin,microlens array were measured,which were in good agreement with the theoretical simulation results and achieved the expected imaging effect.According to the imaging results,the performance indexes of the SSODT system were analyzed,and the achievable axial resolution was 15.5 ?m,the imaging depth was 5.84 mm,and the signal-to-noise ratio reached more than 60 d B,which met the design requirements of the SSODT system.Next,theoretical simulations of the detectable flow velocity range of SSODT system,including the minimum flow velocity,the threshold flow velocity and the maximum flow velocity,were performed based on the system parameters,which verified the rationality of the phase-resolved method for imaging single-layer and multilayer tissue structures.An experimental device was built to simulate blood flow motion on the surface of the reflector to realize the functional extension of blood flow velocimetry using the SSODT system,and processed the data at different flow rates through the phase-resolved method.The experimental results were in basic agreement with the theoretical calculation values.Finally,3D imaging of the fisheye,with an imaging depth of 5 mm,can clearly see the cornea and crystalline lens in the structure of the fisheye,which has certain application value.