Speckle noise suppression for quantitative analysis of tissue optical properties with OCT

Measurement of tissue optical properties can be used for noninvasive monitoring of analytes and tissue characterization. Noninvasive measurement of tissue optical properties (attenuation, scattering coefficient, optical thickness, etc.) can be performed with optical coherence tomography (OCT) technique. However, speckle noise substantially deteriorates the accuracy of the measurements with this technique. In this paper, we studied suppression of speckle noise for accurate measurement of backscattering signal with the OCT technique. The backscattering signal variance resulted from speckle noise was experimentally determined for a scattering standard and human skin. The dependence of speckle and electronic noise on the range of spatial and temporal averaging of OCT signals was studied. Our results demonstrated that the accuracy of measurement of backscattering signals with OCT technique from skin can be 0.65% and may reach 0.1-0.2% if optimum averaging parameters are used.