Natural-surveillance analyses street-view images to measure how visible streets are from nearby buildings, indicating safety and observation levels. Purpose of Tool: Natural-surveillance is an open-source Python methodology for estimating “natural surveillance” (i.e., the passive “eyes on the street” effect) at scale by analysing street-level imagery with computer vision techniques. It detects building openings (e.g., windows, doors) in street-view imagery, localizes them in