Model images of debris disc in polarized light (top row) and comparison of the 4 × 4 binned Q_φ image (panel d) with the one-belt model (panel c) and the two-belts model (panel e) in the bottom row. The insets in the top row show the radial SB profiles of the one-belt model (panel a) and the two-belts model (panel b). All models are convolved with the instrumental PSF. Colour bar shows flux in counts per binned pixel.