Raster scanning and averaging for reducing the influence of speckles in optical coherence tomography

The application of small-angle raster scanning and averaging in the sample arm of the Michelson interferometer in optical coherence tomography (OCT) is described. Raster averaging is used to increase the signal-to-noise ratio and to reduce the speckle noise of the 2D OCT image in diagnostics of surface layers of human skin and subcutaneous blood vessels in vivo. The method allows using low-coherence source of low-power radiation and increasing the depth of human skin coherent probing up to 1.5 – 1.8 mm. The reduction of speckle noise in the obtained OCT image for the first time allowed visualisation of subcutaneous blood vessels at the entire depth of their localisation.