A detection device detects an obstacle within a target region by setting the target region, setting a scan trajectory, and setting a pattern of an irradiation position of a laser beam within the target region based on a signal related to a moving state of the detection device or a moving object on which the detection device is mounted. Each tooth extends outwardly and upwardly from the circular blade portion. A second film layer is formed and a portion of the second film layer is removed to form openings and to form a second alignment mark pattern. A central communications station could be used to maintain secure, shared private key encrypted communications with each premises system, using a redirector arrangement or relay to allow each premises system to communicate securely with a central monitoring station and with other systems. The region of overlap Yo is processed with a reverse transform to create an overlap region Z in an original feature space.