Study On Weak Signal Detection Techniques Of Optical Coherence Tomography

Optical Coherence Tomography (OCT) is a new technique, which was proposed in 1990s. OCT is based on the use of the short coherence length of broadband light source to yield to high axial resolution optical sectioning images. Because of its advantages of noninvasiveness, high detecting sensitivity and high axial resolution, OCT can produce the images of the micro-structures of tissues in vivo. It may have wide applications in biomedicine.In this paper, first the basic theory of OCT is introduced. Then, the typical OCT system is disassembled to several parts, and their theories are studied deeply. Several ways of beam scanning are discussed importantly. Based on their characteristics, the special methods of signal processing are derived from the general method, and their advantages and disadvantages are discussed. Besides, in order to evaluate the performance of the OCT system, the relationship between signal noise ratio and image capture rate is studied deeply. Finally, based on these theories, the whole OCT imaging system, including mechanism, optics, electrics and computer software, is designed, and the experiments have been made with it. The results of the experiments demonstrate feasibility and validity of the system, and may be helpful for further research.