Single-scale source detection (Sect. 2.5). The field of Fig. 2 is shown as the initial footprint image ℱ_D after the source detection (upper left). The same set of spatial scales is displayed in the single-scale segmentation images ℐ_Dj   S (left to right, top to bottom) showing the source segmentation masks determined from ℐ_Dj   C (Fig. 7). The masks were obtained and analyzed by the detection procedure described in Sect. 2.5. The scale sizes S_j are visualized by the yellow-black circles and annotated at the bottom of the panels. The color coding is a function of the square root of the source number (which makes up the actual pixel values in these segmentation images).