提出了一种基于固定光程差干涉信号的光谱标定方法。在频域光学相干层析成像(OCT)系统中引入一个光程差为固定值的干涉信号,则每次采集的信号同时包含该固定光程差的干涉信号和样品的干涉信号,通过滤波的方式将该固定光程差的信号分离出来,再利用其相位实现对系统样品干涉信号的光谱标定。理论分析了该方法的可行性。在100 kHz扫频光源OCT系统中,用反射镜作为样品在不同深度位置进行了光谱标定实验,获得了不同深度位置的点扩展函数和轴向分辨率,与利用光源clock触发采集的波数等间隔干涉信号处理结果对比,该方法具有更好的有效性。

A spectral calibration method for optical coherence tomography (OCT) is proposed. The method is implemented by introducing an interference signal with a fixed optical path difference (OPD) in the Fourier domain OCT system. The sample interference signal and the fixed OPD signal are acquired simultaneously. Then the fixed OPD signal is obtained from the mixed signals through a filter step, and its phases are calculated to calibrate the interference signal of the sample in the system. We theoretically analyze the feasibility of the proposed method. In a 100 kHz swept source OCT system, the spectral calibration experiments with a mirror as the sample are performed at different depth positions. The point spread functions and the axial resolutions are obtained. Compared with the results using the light source clock, the proposed method has a better effectiveness.