Abstract
A spectral calibration technique, a data processing method and the importance of calibration and re-sampling methods for the spectral domain optical coherence tomography system were numerically studied, targeted to optical coherence tomography (OCT) signal processing implementation under graphics processing unit (GPU) architecture. Accurately, assigning the wavelength to each pixel of the detector is of paramount importance to obtain high quality images and increase signal to noise ratio (SNR). High quality imaging can be achieved by proper calibration methods, here performed by phase calibration and interpolation. SNR was assessed employing two approaches, single spectrum moving window averaging and consecutive spectra data averaging, to investigate the optimized method and factor for background noise reduction. It was demonstrated that the consecutive spectra averaging had better SNR performance.
Highlights
Optical coherence tomography (OCT) is a noninvasive, contact-free and cost-effective imaging modality providing high resolution cross-sectional images of the probed sample [1, 2]
The moving window averaging can be applied to the single spectrum, but might compromise the resolution associated to the point spread function of the SD-optical coherence tomography (OCT) system, since the averaging will smooth out sharp signal variations
The results showed that the consecutive spectra averaging method provides a higher signal to noise ratio (SNR) than the moving window one
Summary
Optical coherence tomography (OCT) is a noninvasive, contact-free and cost-effective imaging modality providing high resolution cross-sectional images of the probed sample [1, 2]. In spectral domain optical coherence tomography (SD-OCT), the detected light intensity is a function of the wavelength, I(λ), and the sample’s reflectivity depth profile, or A-line, is obtained by applying a Fourier transform over the corresponding modulated optical spectrum. The detection arm was modified by using a customized prism placed directly after the diffraction grating to evenly disperse the spectrum in the optical frequency or optical wavenumber These proposed hardware approaches eliminate the need for numerical re-sampling, reducing computing time. Another approach uses an external k-trigger electronic board for swept source OCT to acquire the data uniformly sampled in k-space [6]. The two considered approaches were moving the window over spectrum averaging and consecutive spectra data averaging
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