Single-scale removal of noise and background (Sect. 2.3). The field of Fig. 2 is shown as the full clean image ℐ_λD   C at 350 μm (upper left) that accumulates clean images over all scales. The same set of spatial scales is displayed in the single-scale images ℐ_λDj   C (left to right, top to bottom), cleaned of noise and background with an iterative procedure described in Sect. 2.3. All intensity peaks visible in the scales belong to the sources; most of the noise and background fluctuations (visible in Fig. 2) have been removed. The scale sizes S_j are visualized by the yellow-black circles and annotated at the bottom of the panels. For better visibility, the values displayed in the panels are somewhat limited in range; the color coding is a function of the square root of intensity in MJy/sr.