Research On Near-infrared Polarized Depth Imaging System

The depth imaging of biological tissues can visually and non-destructively observe the morphology and structure of organs or tissues.It plays an important role in medical diagnosis,treatment and biometric identification,and is a crucial method for biomedical research.Near-infrared(NIR)light owns the properties of strong tissue penetrating and weak tissue scattering,which has a great advantage in depth imaging of biological tissues.However,due to the low imaging contrast and resolution,the practical application of NIR optical imaging is limited.Research on improving the imaging contrast and resolution of NIR optical depth imaging has a great significance.In this research,polarization imaging method was introduced,and an active NIR polarization imaging method was proposed and realized.Based on the theoretical research of NIR polarization imaging of biological tissues,NIR polarization imaging systems with large field of view and the microscopic imaging system were built and optimized through hardware and software design.The systems were used to image the agar-carbon fiber phantom,the human palm veins and the human nailfold microcirculation.Images of samples under different polarization status were obtained.The preprocessing of original images was performed,like image position matching and feature selection,according to the image features.Then,a series of polarization parametric images including!",_#,_$,_%,_&,sin and can be obtained through the established theoretical model.The comparisons of imaging contrast and spatial resolution between the original image and polarization parametric images show that the NIR polarization imaging can be used for the depth imaging of biological tissues.And polarization parametric images contain more detailed information of sample with improved imaging clarity,contrast and resolution,compared with the ordinary intensity images.Moreover,results show that different samples exhibit different sensitivity to different polarization parameters.For example,the_#image of agar-carbon fiber,_$image of human palm veins,and_%,images of human nailfold microcirculation have better imaging effect.NIR polarization imaging method can provide a non-destructive optical detection way with improved imaging contrast and resolution for the depth imaging detection of human subcutaneous veins and nailfold microcirculation.