Spatial distortions in swept source optical coherence tomography due to lateral scanning

The paper presents errors in axial distance measurements and deviations of contours in swept source (SS) optical coherence tomography (OCT) cross sections due to lateral scanning. The study shows how these errors and deviations depend on the adjustments of the interface optics between a lateral scanner device and the target imaged. A theoretical model and experiments demonstrate that these errors and deviations are given by the Doppler shift frequency imprinted by the lateral scanning. The smaller the number of sweeps per lateral scanning interval, the larger these errors and deviations. The study also shows that the sign of error and deviation of contours can be put in correspondence with the spectral sweeping direction. Even more, it is shown that such effects can be used to predict the tuning direction of the swept source without an optical spectrum analyzer.