Image registration, averaging, and compounding for high speed extended depth optical coherence tomography

Abstract

An optical coherence tomography (OCT) system including a source of broadband optical radiation and a beamsplitter coupled to the source is provided. The beamsplitter divides the source radiation into a reference path and a sample path. The reference path includes an optical switch to switch the reference path between a first path having a first reference reflector at a first reference optical path length and a second path having a second reference reflector at a second reference optical path length, different from the first reference optical path length. The system further includes a beam combiner that mixes source radiation reflected from a subject in the sample path with source radiation returned from the first reference reflector during a first time interval and the second reference reflector during a second time interval. A detection system detects a first wavelength dependent interferogram during the first time interval and a second wavelength dependent interferogram during the second time interval. A processor preconditions the first and second wavelength dependent interferograms; multiples the first preconditioned wavelength dependent interferogram and the second preconditioned wavelength dependent interferogram; and computes a first A-scan from the first wavelength dependent interferogram; a second A-scan from the second wavelength dependent interferogram; a spatial offset between the first and second A-scans derived from the multiplicative product of the preconditioned first and second wavelength dependent interferograms; and a combined A-scan from the first and second A-scans.