像素平移法提高频域光学相干层析成像深度

Interpixel Shift Technique for Increasing Imaging Depth of Frequency Domain Optical Coherence Tomography

增大频域光学相干层析术(FDOCT)成像深度是扩大FDOCT应用范围的一个关键。主要研究了基于像素平移法提高频域OCT成像深度的问题。讨论了像素平移法的基本原理,阐述了频域OCT理论最大成像深度与电荷耦合元件(CCD)像素数的关系。通过点扩散函数实验、5层盖玻片成像实验以及手指皮肤的活体成像实验验证了像素平移法对于提高频域OCT成像深度的作用。手指皮肤的成像实验表明256个像素点的CCD和512个像素点的CCD采用像素平移法后实际成像深度分别增加到了原来的1.98倍和1.12倍。Matlab软件模拟验证方法为频域OCT系统中CCD的像素数选择提供了参考。

Increasing the imaging depth of frequency domain optical coherence tomography（FDOCT） is a key to expand its applications. The method of increasing the imaging depth of FDOCT which is based on the interpixel shift technique is investigated. The principle of the interpixel shift technique is discussed, and the relationship between theoretical maximum imaging depth of FDOCT and the pixel number of charge coupled device（CCD） is elucidated.Then the point spread function（PSF）, imaging experiments of five-layer cover glass as well as the vivo imaging experiments of fingers are carried out to demonstrate the effect of interpixel shift technique on the enhancement of imaging depth. The imaging experiments of fingers show that the actual imaging depth increases to 1.98 and 1.12 times after using pixel shift technique in an OCT system with a 256-pixel CCD or a 512-pixel CCD, respectively. The Matlab software simulation validation method provides reference for the FDOCT system on the choice of the pixels of CCD.