1. A method of acquiring an image set using optical coherence tomography (OCT), comprising: scanning a first portion of a defined volume at a low-density sampling rate to obtain a plurality of low-density frames; scanning a second portion of the defined volume at a high-density sampling rate, higher than the low-density sampling rate, to obtain at least one high-density frame; and combining the low-density frames and the at least one high-density frame to provide a complete mixed-density image set.