US Patent 10322804 Device that controls flight altitude of unmanned aerial vehicle

A device controls a movement direction of an unmanned aerial vehicle having mounted thereon an imaging device that captures an image. The device includes one or more memories and a processor which, in operation, recognizes, as a plurality of markers, a plurality of objects from the image captured by the imaging device, each of the plurality of markers attached to one of the plurality of objects. The processor further calculates an area of a polygon formed by the plurality of markers, and controls the movement direction of the unmanned aerial vehicle such that the area of the polygon is maximized.