Design Of Full-range Swept Source OCT System

Swept source optical coherence tomography(SSOCT) is a noninvasive, contactless, in vivo optical imaging technique which is based on the theory of partially coherent light and uses the back-scattering light of biological tissue, provides cross-sectional images of transparent highly-scattering samples. Swept source OCT has the advantage of an improved signal to noise ratio and high imaging-speed. It is not limited by the spectrometer. But SSOCT has the disadvantage of limited image range which limits the application in the clinical medicine. Aim at the image feature of SSOCT, this paper propose the full-range SSOCT system.In this paper, based on the study and analysis of the FD-OCT theory, the swept source OCT system is designed. The SSOCT system includes high-speed swept source, full-fiber Mach-Zehnder interferometer, high-speed data acquisition board, signal processing processing and image displaying software platform.The main work is finished by this paper as follows:1? Based on the Fourier diffraction theorem and the interference theory, driving the theoretical formula of the FDOCT; Analyzing the advantage and disadvantage of FDOCT, Proposing a specific design scheme of full-range swept source OCT system. 2? Analyzing the multi-factors which effect the longitudinal resolution and the image range in FDOCT; Summarizing the present OCT techniques; Discussing the dispersion match algorithm based on the dispersion theory in OCT system and proposing an iterative dispersion encoded sparce signal reconstruction algorithm combining the compress sensing therom; Simulating the DEFR algorithm using the matlab language and proving the feasibility of algorithm; 3? Designing the experimental platform of SSOCT, including :designing the Michelson interference light path, configuring the high-speed data acquisition board, resolving the delay between the OCT interference signal and the calibration signal and resolving the problem of impedance matching during the signal transmission?programming the image displaying software platform and realizing the displaying of the cross-sectional images of the tested samples. 4? Obtaining the cross-sectional images of cover slips and biological tissues;Comparing with the traditional single dispersion match OCT algorithm,the DEFR algorithm effectively suppress the complex conjugate mirror terms and the auto-correlation terms and thereby generate full range tomograms; The experiment result is consistent with the simulation result,thereby verifying the correctness of the DEFR algorithm...