Evolution of the instantaneous Strehl ratio and the average dark-hole contrast with a 5% broad band imaging. The AO is driven to maximize focal-plane contrast. NCPAs are estimated every 200 ms (indicated by the vertical, dashed, gray lines) using the technique described in Sect. 3. The dashed blue and red lines indicate the average Strehl ratio and contrast, respectively, for the case when there are no NCPAs.