信号处理方法的选择是光学相干层析(Optical Coherence Tomography,OCT)系统研制的重要环节,直接决定着OCT系统的硬件构建和实现。应用硬件实现OCT信号处理的方法虽然速度快,但存在硬件开销大,系统配置可调节性差等缺点。进而采用了基于数字希尔伯特变换的软件方法来处理OCT信号。该数字处理方法对探测得到的离散干涉实信号进行解析拓展,得到同时具有振幅信息和相位信息的复信号,其中的振幅信息被用于OCT的图像重建。介绍了研制的光纤OCT系统和各驱动单元的同步时序控制,最后给出了人体皮肤和洋葱的OCT高清晰层析图。
Signal processing method is critical for the development of optical coherence tomography (OCT) system, which decides the OCT system hardware designment. Hardware implementation of signal processing is fast but costs more and is less adjustable for different system configurations. Hence the method based on digital Hilbert transformation performed in software is adopted. The post-detection digital approach obtains the analytic signal from the real discrete interference signal, and the amplitude information fetched from the complex signal containing both amplitude and phase is used to reconstruct the structural OCT image. The developed fiber-based system and synchronizing time sequence for actuating units in the system are described, and structural OCT images of skin from human volunteer and fresh onion are presented.