The Oct Three-dimensional Reconstruction And Doppler Imaging Study

Optical coherence tomography (OCT) is a noninvasive biomedical imaging method with micron scales resolution which could provide three-dimensional structural information of tissue in vivo without the need for excision or preparing sections. Visualization of the three-dimensional OCT information can effectively help researchers have a better understanding of the data. There are many methods of OCT three-dimensional reconstruction, providing different means of expression to show the internal information in samples, including: multi-planar reconstruction, projection, surface rendering, volume rendering, etc.The images reconstructed from OCT signals form the sources of the three-dimensional reconstruction. The images include no only the structural images of sample, but also the Doppler images with important information such as internal blood flow. In order to providing a high quality image data, it is necessary to do signal preconditioning and choose a suitable image reconstruction algorithm. For example, the Doppler reconstruction needs to choose the short time Fourier transformation or the Hilbert transformation, depending on the different requirement in the experiment.The various methods of three-dimensional reconstruction are introduced in this thesis. Software is designed using Visual C++, to provide three-dimensional scanning and get the data necessary for three-dimensional reconstruction. The three-dimensional structural reconstruction is demonstrated using MATLAB. And some algorithms of Doppler reconstruction are realized to evaluate the different effect in Doppler images. An experiment on mouse is demonstrated to test the algorithms.Five chapters are included in this thesis. In the first chapter, the principle of OCT and the current situation of three-dimensional reconstruction is introduced. It is presented the choosing of software development tools used in the project. In the second chapter, the three-dimensional signal acquisition in OCT is described. Thesignal processing in both analog and digital is introduced. In the third chapter, various methods of three-dimensional reconstruction as well as the preprocessing of OCT images are presented. The three-dimensional reconstruction and the related animation are demonstrated using the data from three-dimensional . scanning experiment. In the fourth chapter, two algorithms of Doppler reconstruction are introduced. An experiment is demonstrated to compare the difference in the two algorithms. Finally, a conclusion of our work and the direction of further improvements are presented in the fifth chapter.