Dual-beam angular compounding for speckle reduction in Optical Coherence Tomography

Optical coherence tomography (OCT), as a low-coherence interferometric imaging technique, inevitably suffers from speckle noise, which can reduce image quality and signal-to-noise (SNR). In this paper, we present a dual-beam angular compounding method to reduce speckle noise and improve SNR of OCT image. Two separated parallel light beams are created on the sample arm using a 1x2 optical fiber coupler and are focused into samples at different angles. The epi-detection scheme creates three different light path combinations of these two light beams above. The three combinations produce three images in single B-scan, which are completely separated in depth. The three images show uncorrelated speckle patterns and therefore can be averaged to create a new image with reduced speckle noise. Compared to those reported angular and spatial compounding methods, our method retains their advantages, and moreover has a faster imaging speed and keep the transverse resolution. This method was evaluated on human fingertips in vivo. The results demonstrated a good improvement in speckle contrast.