 The spectral domain fringe signal, formula_7 is given by

The corresponding time domain signal, formula_9, is given by

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.Time domain Doppler OCT uses the spectrogram method to create the image.When the spectrum changes with time, it is defined as Spectrogram.