Effects of the modulation frequency, duty cycle and image restoration (labeled on top of each column) on the SIC level in Stokes Q images. The Stokes I (upper row) and the normalized Stokes Q (bottom row) are shown for the data sets with 100 and 11.1 Hz modulation frequency presented in Fig. 6. Both a plain average, covering 1.16 min wall time a), b), e), and f), and the corresponding MOMFBD-restored versions c), d), g), and h) are presented. The original plate scale of the images is 0.08 arcsec/pixel in both directions. However they have been binned using a 2 × 2 pixel² window. The figures in parentheses in the right border of each image denote its grayscale range (upper panels) and standard deviation, or rms contrast for Stokes I, computed across the images (lower panels).