Patent ID: 7446861

Claim:
An apparatus comprising: a pointing device including a reflecting portion for reflecting an electromagnetic wave; and a sensing portion including a generating portion for generating the electromagnetic wave, a detecting portion for detecting the electromagnetic wave reflected from the reflecting portion, a delay portion for delaying either one of a time for the detecting portion to detect the electromagnetic wave and a time to mix a signal from the detecting portion and a signal from the generating portion, and a memory portion for storing information as to the electromagnetic wave to be reflected at the reflecting portion in advance, wherein the sensing portion acquires information as to a time wave form of the electromagnetic wave reflected from the reflecting portion obtained by using the delay portion, separates information as to the electromagnetic wave reflected from the reflecting portion from the information as to the time wave form using the information stored in the memory portion, and acquires a relative position between the sensing portion and the pointing device from a time period between generation, at the generating portion, of the electromagnetic wave reflected from the reflecting portion and detection thereof at the detecting portion.