Which imaging domain in OCT uses a Fourier transform to reconstruct depth information?

Which imaging domain in OCT uses a Fourier transform to reconstruct depth information?

• A. Time Domain
• B. Spectral (Fourier) Domain
• C. Phase Domain
• D. Spatial Domain

Answer: (B)

In OCT, depth information is recovered by transforming how the interference signal varies with wavelength into a depth profile. In spectral-domain OCT you measure the interference spectrum across wavelengths, and the depth structure modulates that spectrum. Applying a Fourier transform to the measured spectrum converts those spectral components into a depth-resolved reflectivity profile, giving the A-scan. This Fourier relationship is the reason this domain is described as Fourier-domain or spectral-domain OCT. Time-domain OCT achieves depth by scanning the reference arm delay, not by a spectral Fourier transform. Phase domain uses phase information for motion or phase-sensitive effects rather than reconstructing depth from a spectrum, and spatial domain refers to lateral rather than depth information.

In OCT, depth information is recovered by transforming how the interference signal varies with wavelength into a depth profile. In spectral-domain OCT you measure the interference spectrum across wavelengths, and the depth structure modulates that spectrum. Applying a Fourier transform to the measured spectrum converts those spectral components into a depth-resolved reflectivity profile, giving the A-scan. This Fourier relationship is the reason this domain is described as Fourier-domain or spectral-domain OCT. Time-domain OCT achieves depth by scanning the reference arm delay, not by a spectral Fourier transform. Phase domain uses phase information for motion or phase-sensitive effects rather than reconstructing depth from a spectrum, and spatial domain refers to lateral rather than depth information.