Time-frequency distributions in spectroscopic Fourier-domain optical coherence tomography

Current analysis for spectroscopic optical coherence tomography (SOCT) signals is limited by an uncertainty relationship between time (depth) and frequency (wavelength). Various joint time-frequency distributions (TFDs) can meliorate the limits to obtain the best information. Synthesized signals which correspond to three typical SOCT signals in the Fourier-domain under different SOCT imaging schemes, were generated and validate several different TFDs, including short time Fourier transform (STFT), continuous wavelet transform (CWT), Wigner-Villy distribution (WVD), and smoothed pseudo WVD (SPWVD). We found that different SOCT imaging scheme requires different optimal TFDs. STFT offers the most reliable and fast time-frequency (TF) analysis, which is appreciate for retrieving the absorption spectra from a homogeneously absorbing media; WT offers the best spatial resolution or the best spectral resolution locally; WVD generate the most compact TF analysis, but suffers from the artifacts due to the cross terms. SPWVD is applied to yields high spectral and spatial resolution and be free from the artifacts and limitations commonly observed with WVD.