Dual-mode Skin Imaging System Research Based On OCT And Hyperspectgral Imaging

Optical Coherence Tomography(OCT)and Hyperspectral Imaging(HSI)are two new types of biomedical optical imaging technologies which can achieve non-destructive imaging of in vivo biological tissues with high sensitivity and high resolution rate,non-invasive and no radiation.OCT is based on coherent detection to realize three-dimensional imaging of sample tissue structure,while HSI is mainly based on the light absorption characteristics of the sample to achieve imaging of the sample surface,these two have certain complementarities.Therefore,this thesis designed and developed a dual-mode imaging system combining OCT and HSI,and studied its application on the skin.The main contents of this article are as follows:1.This thesis designed and developed a set of dual-mode optical imaging system based on OCT and HSI.The OCT subsystem is designed based on a 1060 nm swept light source.The A-scan speed reaches 100 kHz,the imaging depth is 5 mm(in air),the axial and lateral resolutions are 8 μm and 70.3 μm,respectively.The HSI subsystem is designed based on a push-broom imaging spectrometer.,the imaging spectrum range of the system is 465-630nm,and the spectral resolution and spatial resolution are resolved to 2.1nm and 31.3μm.2.Software design and development of dual-mode system was based on mixed programming of Labview and Matlab,including timing control of two subsystems,data acquisition,image reconstruction,real-time image display and image preprocessing.The thesis set the parameters during data acquisition on the front panel of Labview,at the same time,the B-scan image and the original interference spectrum of the OCT part and the spectral image of the hyperspectral part are displayed in real time.The main pre-processing includes OCT subsystem spectral shaping,Fourier transform,fixed mode noise removal,etc,and wavelength calibration for the hyperspectral subsystem.3.The application of dual-mode imaging system in the detection of skin pigmented moles,the specific research content includes:(1)The registration of OCT and HSI images realizes the fusion of bimodal imaging data.(2)Clustering hyperspectral data by K-means algorithm,GMM algorithm and HAC algorithm,so as to realize the segmentation and detection of skin pigmented mole areas.The three algorithms have reached an accuracy rate of more than 90%and a high Dice coefficient,of which the highest accuracy rate is 92.61%,and the corresponding Dice coefficient is 94.53%.(3)Based on OCT to realize the three-dimensional imaging and depth analysis of pigmented moles,obtain the subcutaneous contour and depth structure,and quantitatively analyze the differences by measuring the attenuation coefficient and fractal dimension of the pigmented moles area and normal tissues.In summary,the innovation of this thesis is the successful design of the OCT and HSI dual-mode imaging system,the combination of OCT and HSI technology on the hardware,and the rapid imaging of skin tissue.Combined with the method of pattern recognition,it proves its feasibility in skin tissue detection and has good clinical application potential.