An optimized depth-resolved dispersion compensation method in optical coherent tomography signal processing

Abstract

An optimized depth-resolved dispersion compensation method for achieving better dispersion compensation effect is presented in optical coherence tomography signal processing. When performing depth-resolved dispersion compensation, it is necessary to use a rectangular window function to intercept the interference signals at different depths of the sample from the A-line signal before FFT. Windowed FFT will cause errors in phase extraction, which will lead to inaccurate dispersion coefficient. Herein, the rectangular window function needs to be optimized. The phase is extracted after FFT of the interference signal obtained by the primary rectangular window. According to the functional relationship between the phase and the wave number in the presence of dispersion, the obtained phase is fitted to the quadratic polynomial by the least square method, and the standard error of the fitted quadratic polynomial is used as the criterion. Constantly changed the width and center position of the rectangular window to obtain the smallest standard error. The smallest standard error corresponds to the optimized rectangular window, which is used to intercept the signal and perform FFT to obtain a phase close to the true value. Therefore, the dispersion compensation coefficients of the OCT system at different depths are accurately extracted. It is verified by simulation and experiment that this method can achieve better dispersion compensation effect.