Airborne, remote sensing system that uses reflected polarized skylight to detect the presence of oil discharges into water

Noting that oil and water have respectively unique properties for surface reflection of polarized skylight, an experimental device consisting of a TV camera with a special filter arrangement was constructed to use this principal to provide a remote means to discriminate for the presence of oil. Water, and other possibly present water soluable substances capable of giving false oil-tar-get images, can be observed in both polar planes. However, polarized light reflected from oil can only be observed in the horizontal plane. A light filtering system permitting a series of successive, rapid changes between the vertical and horizontal polar plane views causes the presence of oil to be observed as a flashing image against a relatively static background. This system has been flight tested, and shows some promise as a simplex, remote sensing instrument with an "on-line" capability for airborne surveillance for oil pollution.