Improved method for amplitude estimation of time domain optical coherence tomography

This paper presents a technique for estimation of amplitude information from an interferometric time-domain optical coherence tomography (OCT) signal. The conventional estimation scheme is based on the in-phase and quadrate (IQ) demodulation concept. A disadvantage of this method is that the IQ components include a ripple whose frequency is the double of the interferometric signal frequency. The improved method of demodulation, presented in this paper, yields a more precise estimation of the amplitude information by fundamentally removing the ripple. Theoretical and experimental OCT signals are applied to both demodulation systems and the amplitude is computed. The detected signals from both demodulation systems are compared. Results show that the proposed method of demodulation produces a significant improvement in the estimation of amplitude information in destructive conditions due to noise and misalignment in the OCT system.