Abstract: A desired search area is efficiently monitored. A surveillance device that is installed in a flying aircraft in the sky and that monitors the situation at the sea surface from the sky, including 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 at an object at the sea surface, and a processor 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.

Abstract: A needless irradiation region in an image-acquisition apparatus is reduced. Provided is a light-transmitting portion that radiates light and a light-receiving portion that receives reflected light, which is the light emitted from the light-transmitting portion being reflected upon reaching a target, and that converts the obtained reflected light to an image signal and outputs the image signal. The light-transmitting portion includes an irradiation scanning section that makes an irradiation region for a field of view smaller than the size of the entire field of view and that irradiates the entire field of view with light by scanning the irradiation region for the field of view.

Abstract: A desired search area is efficiently monitored. A surveillance device that is installed in a flying aircraft in the sky and that monitors the situation at the sea surface from the sky, including 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 at an object at the sea surface, and a processor 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.