Simulated DH images (3–9 λ/D) for the five HLC mask solutions (a), (b), (c), (d), and (e) as described in the text and displayed in Fig. 3. They all share the colorbar indicated at the bottom of the figure. The mean, μ, and standard deviation, σ, of monochromatic contrast inside the DH are given in the table below each image. The imaging system was assumed aberration-free and no optimization of the DM shapes was applied as we modified the mask design.