Upper and lower row panels: filament in SDO/AIA 193 Å and 171 Å, respectively. Panels a and d: context of the filament we are considering. Central panels b and e: closer view of the studied filament and the region considered in this study (black box). Panels c and f: filament in AIA 193 Å and 171 Å in the field of view chosen by the rectangular box in (b) and (e). The artificial slits are overplotted on the filament. The slits are labelled by the corresponding numbers.