Simulation of the gain in contrast achieved by offsetting the pinhole of MATISSE on β Pic b, separated here by 534 mas from its host star. The upper and lower plots depict the stellar and planetary contribution to the coherent flux (the fringe envelope) as seen through the circular MATISSE pinhole (white area, hence the Airy-like shape of the output flux) centred on the star and on the planet, respectively. They are simulated at a wavelength of 3.5 μm and normalized to the maximal intensity of the star-centred stellar PSF. When the pinhole is centred on the planet, the speckle flux is reduced to the same level as the planetary flux. In each simulation, the asymmetric shape of the PSF of the offset object (relative to the pinhole) is due to imperfect spatial filtering of the Airy rings falling in the pinhole.