Research On Synchronous Phase-shifting Micro-interference Technology Of Microangiography

Blockage and lesion of micrangium are the aura of many diseases.Microangiography requires high imaging resolution.Optical imaging is an effective means of microangiography.Optical coherence tomography(OCT)is widely used in microangiography.However,OCT is indirect imaging,which requires response period and is not easy to get real-time image.The blood flow velocity is detected by the Doppler effect.There is a technical bottleneck in slow blood flow detection limited by the angle of incidence.This paper combined microscopy with simultaneous phase-shifting interferometry.The simultaneous phase-shifting microscopic interferometry was applied to microangiography.The imaging mechanisms,related processing models and algorithms were studied in this paper.The principle of morphological detection and blood flow velocity detection of red blood cells in microvessels were analyzed.The optical path of simultaneous phase-shifting microscopic interferometer was proposed in this paper.A simultaneous phase-shifting microscopic interferometer was built to obtain the phase information of bovine blood red cell smear at 5 ?m level and ?100 ?m microvascular sample(Glass capillary)containing bovine blood red cell solution.The quantitative measurement of the morphology of bovine red cell at 5 ?m level was realized by extracting the phase of red blood cell in microvessel prototype from the residual error which was obtained from zernike polynomial fitting.The simultaneous phase-shifting microscopic interferometry was proposed to measure the phase of red blood cells in real time,to leverage the characteristics of slow blood flow and small number of red blood cells in microvessels.A characteristic volume model of red blood cell was established to match the characteristic red blood cells from multi-frame phase maps and the ?100 ?m simulated microvascular sample with flow velocity of 0.1-1.0 mm/s and inner was tested.The measurement error of blood flow velocity was less than 11.2%.The feasibility of the proposed detection method was validated,which provided theoretical basis and experimental basis for the popularization and application of simultaneous phase-shifting microscopic interferometry in fundus microangiography.