pix_to_vel.m

function velocity = pix_to_vel(pix)
    % pix= envelope that's extracted from images
    pix = squeeze(squeeze(pix));
    crop_height = 784;
    prf = 3000;
    orig_im_height = 784;
    crop_resize = 784;
    limits = linspace(-prf/2, prf/2, prf+1);
    freq_per_pix = length(limits)/orig_im_height;
    freq = limits(floor(pix /crop_resize*crop_height / crop_height*orig_im_height * freq_per_pix)+1);
    velocity = -1*(3*10^8*freq/2/(77*10^9));