Fig. 3.

Procedure of fitting to retrieve the attenuation coefficient. One A-scan in (b) is extracted from an intravascular OCT image in (a) along the red line, speckle smoothed and fitted in subsequent windows. The retrieved ${\mu }_{\mathrm{OCT}}$ is plotted as an overlay on the grayscale image in (c). Colormap: 0 to $12{\mathrm{mm}}^{-1}$.