The Spectral Calibration of Swept-Source Optical Coherence Tomography Systems Using Unscented Kalman Filter

The ever-increasing demand for acquiring images at a faster rate and consequently of deeper layers of tissue in swept-source optical coherence tomography (SS-OCT), has motivated researchers to investigate techniques capable of performing fast acquisition without compromising sensitivity. Non-linear spectral sweeps, phase instability, and increased noise levels of swept lasers can cause the image quality to deteriorate, especially if a lower quality light source is used. This work leverages the unscented Kalman filter aiming to alleviate these shortcomings. Using this filter, both the non-idealities of the non-linear sweep and the increased noise levels are accounted for. Simulations show promising performance results in terms of extracting the non-linear spectral sweep as a function of time. The UKF also shows better metrics compared to other versions of the Kalman filter when it comes to tracking non-linearities and hardware implementation complexity giving the method significant advantages in real-time applications of hand-held, portable optical coherence tomography devices.