Comparison of different filter functions, U (left) and Q (right), for AM map reconstruction. The figure shows in blue (dotted lines) the AM filter functions defined by Schneider (1996, S96) with R = 9′; in red (dash-dotted lines) the AM filter functions defined in Schirmer (2004, TANH) with R = 7′; in purple (dash-dotted lines) the AM filter functions defined in Jarvis et al. (2004, J04) with σ = 4′; and in green (dashed lines) the AM filter functions defined by Miyazaki et al. (2018, M18). The filter U_M18 is also a compensated filter thanks to the U₀ term, but due to the high truncation radius we used, this is not distinctly visible. Finally, the AM filter functions corresponding to the wavelet filter functions at scale i = 4 are displayed in orange (solid lines). All the filters are normalised to have a maximum amplitude of 1.