In case of a fire in urban large structures such as super high-rise buildings, evacuation guidance must
be provided to the occupants in order to minimize human deaths and injuries. Therefore, it is essential to
provide emergency evacuation guidance when a major fire occurs. In order to effectively support evacuation
guidance, it is important to identify major items such as fire location, occupant position, escape route, etc.
Also, it is important to quickly identify evacuation areas where residents can safely evacuate from a fire. In this paper, we analyze the CCTV video and propose a method of measuring visibility of the evacuation
zone from the smoke caused by the fire in order to determine the safety of evacuation area. To do this,
we first extract the background video from the smoke video to measure the visibility of the specific area
due to smoke. After generating an edge-extracted image for the extracted background video, the degree of
visibility is measured by calculating the change in the edge strength due to smoke.