Swept Source Optical Coherence Tomography System Based On LabVIEW

Optical coherence tomography technology was born in the1990s, which is based on lowcoherence interferemetry and heterodyne detection technology combining with confocal scanningmicroscopy, and it is a new tomography which has the capability of observing biological tissue.When compared with other traditional biomedical imaging techniques, OCT has many significantadvantages of high resolution, non-radiation, non-invasive, high imaging speed, and high detectionsensitivity, which is known as “optical biopsy”. Therefore, OCT has wide applications inbiomedical imaging, crafts detection and so on, thus, it has good prospects for development.Swept Source OCT is one kind of FD-OCT, combining tunable laser and point detectiontechnology, which is able to generate interference patterns as quickly as the spectral domain OCT.SS-OCT has the advantages of high speed imaging as spectral domain OCT and point detection astime domain OCT. Now, swept source OCT has become a hot topic of OCT imaging research.This dissertation analyzes the current status of OCT research and applications at home andabroad, and focuses on the imaging method and system technology of SS-OCT. The main worksand innovations are listed as below:1. The basic theory of OCT is reviewed, and the imaging principles, the development statusand prospects for different kinds of OCT are introduced. Then the key technical parameters, themain factors influencing performance, and the method for performance optimization for SS-OCTare proposed and studied.2. A Swept Source OCT system is developed based on LabVIEW, which consists of fourmodules of swept laser source, interferometer, sample scanning, data acquisition. The swept lasersource has a sweep rate of50K Hz, with the center wavelength of1310nm, the wavelength rangefrom1266.6to1369.2nm, and the average power of22mW. The SSOCT system realizes opticalcoherence tomographic imaging at axial scanning speed of50KHz with axial resolution of8.9μm,lateral resolution of12.4μm and depth range of5mm in air. We get some high speed opticalcoherence tomography images of human skin tissue, fruit peel, and crafts using the SS-OCT systemsuccessfully.3. A set of imaging software based on LabVIEW for the SS-OCT system is developed, whichis mainly comprised of system sequence control, data acquisition, data processing and imagereconstruction. The software system is designed by modularization, which is based on theLabVIEW combining with MATLAB. The software based on LabVIEW combing with MATLAB has a much shorter development period for SS-OCT than the software based on traditional codes,and also improve the operability, reliability, stability, thus can be easily updated and maintained.4. The spectral calibration method based on the SS-OCT system is proposed andexperimentally tested. The system utilized an external clock uniform in K-space as triggerssynchronously generating by the swept source, a K-trigger mode for data acquisition so that auniform data sampling in K-space is enabled without other linear wavenumber re-calibracation.The method based on hardware is very suited for high speed real-time spectral calibration inSS-OCT.