Left panel: fractions of “true” detections (solid color lines) and “spurious” detections (dotted color lines) in tests of filament extractions as a function of the robustness threshold RT used with DisPerSE (in units of on the bottom x-axis and 10²¹cm⁻² on the top x-axis), for four values of the persistence threshold PT (0.5 rms_min, rms_min, 2 rms_min, 4 rms_min, color coded as shown at the top right of the plot). The synthetic filaments used in these tests all had Gaussian profiles with FWHM = 0.1 pc, an AR = 10, a column density contrast C⁰ = 1 over the background, and were distributed in the map shown in Fig. A.1a. The statistics shown in the plot are based on a total of 1000 such synthetic filaments for each set of the two DisPerSE parameters RT and PT. The two horizontal black lines indicate completeness levels of 70% and 90%, respectively. Right panel: as in left panel but for synthetic filaments with intrinsic column density contrast C⁰ = 2 over the background.