Contrast improvement for swept source optical coherence tomography image of sub-surface tissue

摘要

Swept source optical coherence tomography (SSOCT) is an attractive biological imaging technology due to its advantages of simple setup and high imaging speed. As the light intensity attenuated rapidly in high scattering biological tissues, the contrast of OCT image will drop with depth. In this paper a new method was introduced to compensate the attenuation of imaging contrast in SSOCT. The interference signal was divided into two channels of analog to digital converter (ADC) with a splitting ratio of 1:5. The higher level signal in one channel was used to reconstruct deeper structure of tissue and the lower level signal in the other channel was used to reconstruct surface structure of tissue. Low-frequency signals in one channel were filtered by a high pass filter and then combined with the signal in the other channel to obtain a high contrast image in both surface and deep area of tissue. Human finger and porcine airway imaging obtained with the system show that the contrast of SSOCT images can be improved in deeper region of tissue.