Surveillance device and surveillance method

A surveillance device that is installed in a flying aircraft in the sky and that monitors the situation at a sea surface from the sky, the device comprising:

• a light-transmitting portion that is provided with a light source and that radiates a plurality of slit-like beams from the sky toward a search area at the sea surface;
• a light-receiving portion that receives a plurality of reflected beams that have been reflected by an object at the sea surface;
• a decision unit that determines whether or not the object at the sea surface that has reflected the beams is a target object from information about the reflected beams obtained by the light-receiving portion;
• and
• an input device for inputting a wave period and traveling velocity of the flying aircraft,
• wherein the distance between the slit-like beams or the traveling velocity of the aircraft is adjusted so that a value obtained by dividing the distance between the slit-like beams by the traveling velocity of the flying aircraft does not coincide with the wave period.

A surveillance method that is implemented in a flying aircraft in the sky, for monitoring the situation at a sea surface from the sky, the method comprising:

• radiating a plurality of slit-like beams at predetermined intervals from the sky toward a search area at the sea surface;
• receiving a plurality of reflected beams that have been reflected by an object at the sea surface;
• and
• determining whether or not the object at the sea surface that has reflected the beams is a target object from information about the reflected beams.