gistfile1.matlab

function [aline1] = getPhaseComplexDFT(nScans, nAlines, fringe, new_index, dispersion)
    % window function
    window = hann(length(new_index));

    % generate bg by averaging fringes
    bgm_1 = mean(fringe(:, 1:4:nAlines), 2);
    bgm_2 = mean(fringe(:, 2:4:nAlines), 2);
    bgm_3 = mean(fringe(:, 3:4:nAlines), 2);
    bgm_4 = mean(fringe(:, 4:4:nAlines), 2);
    bg = repmat([bgm_1 bgm_2 bgm_3 bgm_4], 1, nAlines/4);

    % background subtraction
    data_signal = fringe - bg;

    % FFT real data
    dft_signal = fft(data_signal);
    
    % copy to extended vector, zero padding
    % length(new_index) = nScans/2 (oph. system) or nScans/4 (doppler system)
    dft_signal = [dft_signal(1:length(new_index), :); zeros(length(new_index), nAlines)];
    
    % circular shift -1/4 to remove frequency shift effect
    dft_signal = circshift(dft_signal, -size(dft_signal, 1)/4);

    % IFFT to get complex fringes
    scan_signal_zoom1 = ifft(dft_signal);

    % calibration
    dft_complex1 = interp1(scan_signal_zoom1, new_index);
    
    % numerical dispersion compensation & apply window function
    dft_complex1 = dft_complex1 .* repmat(dispersion .* window, 1, nAlines);
    
    % FFT for imaging
    dft_complex_zoom1 = fft(dft_complex1);

    % circular shift -1/2 to remove frequency shift effect
    aline1 = circshift(dft_complex_zoom1, -size(dft_complex_zoom1, 1)/2);
    
    % flip upside down
    aline1 = flipud(aline1);
end