Abstract: There is provided a method of identifying a region of interest in sample. The method comprises obtaining one or more optical coherence tomography (OCT) axial scans at one or more locations over the sample surface; for each axial scan, determining an integrated total of OCT intensity over the depth of the scan, and determining an attenuation depth into the sample at which a predetermined fraction of the integrated total is reached; and determining the from the one or more attenuation depths a region of interest in the sample. Generally, the method does not rely the accuracy (or inaccuracy) of any particular scientific model of scattering and attenuation. It is therefore robust and can be employed across a wide variety of samples, including non-biological ones.