a) shows the MMF3 positional offset from AMI, normalised by rescaled total error . The solid histogram shows the clear detections only, and the red outline shows clear and moderate detections together. A Rayleigh distribution is plotted in red for comparison. b) shows the ratio between the absolute offsets (Δ) between AMI and MMF3 and AMI and PwS as a function of S/N; as shown in Fig. 16, PwS does better at high S/N.