1. An optical coherence tomography (“OCT”) application apparatus which performs an OCT application on an object, which OCT application apparatus comprises: an OCT scanning apparatus which outputs a scanning beam of OCT scanning radiation; and an active tracking system that generates and scans a tracking beam of tracking radiation in a predetermined pattern over a region; wherein the active tracking system comprises an analysis system that: when the object is at a calibration position, scans the tracking beam about an irregular reference tracking feature in the region, and detects a calibration retro-reflected tracking beam to form calibration information; after the calibration information is formed, scans the tracking beam over the region, detects a displacement retro-reflected tracking beam, and analyzes the detected displacement retro-reflected tracking beam together with the calibration information to detect movement of the object; generates tracking signals; and applies the tracking signals to a tracking mechanism system to cause the tracking beam and the scanning beam to follow movement of the object.