Single-scale masks of filaments (Sect. 2.4). The images of spatial scales from Fig. 7 are shown here at their base level as the normalized filament masks ℳ_λj after the removal of relatively small clusters of pixels of non-filamentary nature (including noise, background, and sources) with . In the five images displayed, structures with less than 1.31 × 10³, 8.15 × 10⁴, 6.85 × 10⁵, 5.76 × 10⁶, and 5.65 × 10⁷ pixels have been removed (cf. Fig. 7).