Depth Compensated Spectral Domain Optical Coherence Tomography via Digital Compensation

Abstract: Spectral Domain Optical Coherence Tomography (SD-OCT) is a well-known imaging modality which allows for \textit{in-vivo} visualization of the morphology of different biological tissues at cellular level resolutions. The overall SD-OCT imaging quality in terms of axial resolution and Signal-to-Noise Ratio (SNR) degrades with imaging depth, while the lateral resolution degrades with distance from the focal plane. This image quality degradation is due both to the design of the SD-OCT imaging system and the optical properties of the imaged object. Here, we present a novel Depth Compensated SD-OCT (DC-OCT) system that integrates a Depth Compensating Digital Signal Processing (DC-DSP) module to improve the overall imaging quality via digital compensation. The designed DC-DSP module can be integrated to any SD-OCT system and is able to simultaneously compensate for the depth-dependent loss of axial and lateral resolutions, depth-varying SNR, as well as sidelobe artifact for improved imaging quality. The integrated DC-DSP module is based on a unified Maximum a Posteriori (MAP) framework which incorporates a Stochastically Fully-connected Conditional Random Field (SF-CRF) model to produce tomograms with reduced speckle noise and artifact, as well as higher spatial resolution. The performance of our proposed DC-OCT system was tested on a USAF resolution target as well as different biological tissue samples, and the results demonstrate the potential of the proposed DC-OCT system for improving spatial resolution, contrast, and SNR.