Sea ice,as an important indicator of climate change,is a primary threat to ships navigating the polar oceans.Continuous monitor of sea ice is necessary for safe navigation.Satellite data could not provide continuous data between images;on-site observation can be performed at notably few places.As supplemental equipment,ship-mounted cameras have been widely used in recent years to monitor ships surroundings.An algorithm was designed to extract sea ice concentration automatically from a ship-mounted camera.To what extent can local small-scale observation represent larger background sea ice condition?Video stream data acquired during the ${26^{{