Spatially low-pass filtered images of the 51 Eri image shown in Fig. 11 right (top, logarithmic scale) and difference between the image and its low-pass filtered version (bottom, linear scale). The images are masked to show only the AO-corrected area and hide the DM artifacts and the coronagraphic signature. From left to right with a filtering fraction (percentage of low frequencies kept in the image) of 5%, 10%, 15%, 20%, and 25%.