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Ocular OCT retinal thickness map, right eye Time-domain OCT of the macular area of a retina at 800 nm, axial resolution 3 μm Spectral-domain OCT macula cross-section scan. Optical coherence tomography (OCT) is a technique for obtaining sub-surface images of translucent or opaque materials at a resolution equivalent to a low-power microscope.
Fourier Transform relations between the time domain signals and spectral domain signals are shown in the equations above, which correspond to the two types of OCT. As a result, the time domain method and the Fourier domain method can both achieve high-resolutions.
One approach to decreasing the influence of movement on signal detection is to shorten the scanning time. A short scan time prevents too much patient movement during signal acquisition. With the development of Fourier-domain OCT, spectral-domain OCT, and swept source signal acquisition time was greatly improved making OCTA possible. [40]
SV-OCT can be done with spectral domain OCT (SD-OCT) and swept source OCT (SS-OCT). [5] SD-OCT and SS-OCT are both methods of Fourier domain OCT (FD-OCT), which has significantly faster image acquisition speed compared to time domain OCT. In general, OCT measures the echo time delay and intensity of reflected and backscattered light.
Following regulatory clearances in the major geographies between 2009 and 2012 of fast acquisition Fourier domain OCT, the use of intracoronary OCT rapidly increased. It is used to help coronary disease diagnosis, planning of the intervention, assess procedural results, and prevent complications.
Both the spatial domain and spectral domain descriptions of the collected OCT signal, can be related by Fourier transformation: = | {()} | where is the Fourier transform. However, due to the wavelength dependence with depth for both scattering and absorption in tissue, direct Fourier transform cannot be applied to obtain localized spectroscopic ...
OCT Biomicroscopy is the use of optical coherence tomography (OCT) in place of slit lamp biomicroscopy to examine the transparent axial tissues of the eye. [1] Traditionally, ophthalmic biomicroscopy has been completed with a slit lamp biomicroscope that uses slit beam illumination and an optical microscope to enable stereoscopic, magnified, cross-sectional views of transparent tissues in the ...
While the Fourier transform can simply be interpreted as switching the time domain and the frequency domain, with the inverse Fourier transform switching them back, more geometrically it can be interpreted as a rotation by 90° in the time–frequency domain (considering time as the x-axis and frequency as the y-axis), and the Fourier transform ...