Spectral Domain OCT System

Optical Coherence Tomography(OCT) is a new imaging technology based on thecoherence between tissue backscattering light and reference light. Combined with scanimaging mode, it can realize the biological tomography of three-dimensional structure.With advantages of low-invasive, high detection sensitivity and imaging speed,especiallymicrometer resolution and millimeter penetration depth, there are broadapplicationin clinical medicine.In this thesis, based on the principle of spectral domain OCT, we designed and built aspectral domain OCT system. Using a2×2fiber coupler to achieve Michelson structure,the imaging spectrometer was designed to select the1200l/mmgrating and the125mmlens.The incident angle(relative to the grating) was selected as53degrees, and the output angleof the center wavelength1310nm was selected as45degrees.System is based on Graphics processing unit (GPU) acceleration, and the imagingvelocity (including image acquisition, reconstruction, and display) reached~20frames persecond(each frame size is1000×512pixels). Key performance parameters of the systeminclude: lateral resolution~14mm, vertical resolution~14mm, horizontal imaging range~5mm, longitudinal imaging range of~2mm, the dynamic range~50dB, and thesensitivity~90dB at equal optical path point.Because the data collected isreal signal, we proposed a non-uniform discrete Hartleytransform(NDHT) to achieve a new image reconstruction method. Through the mirrorimaging and human skin imaging, it is validated that NDHT imaging accuracy equals theinterpolated discrete Fourier transform, which is superior to the result of direct discreteFourier transform.In order to bringthis technique into skin imaging, we combined the anatomical modelof skin with the spectral domain OCT model of dermatology.We get the imaging of normal human skin and normal rat skin, andanalyzed the results. To image the wound healingprocess, a wound model was designed. Also a frozen model was designed to observe thefrozen functions in tissue.