US Patent 11662417 Active marker device and method of design thereof

An active marker device, and method of design thereof, for use in a motion tracking system are provided. In one arrangement, the device comprises a mounting body comprising a mounting surface. A plurality of light emitting units are mounted on respective mounting portions of the mounting surface. A control system controls the plurality of light emitting units such that light is emitted simultaneously from a selected subset of light emitting units. A plurality of optical elements are mounted on the mounting surface. Each optical element covers a different one of the light emitting units and is configured so that an inner surface of the optical element is separated from an outer surface of the light emitting unit. Each optical element redirects a portion of light emitted by the light emitting unit covered by the optical element to be more parallel to the mounting portion of the light emitting unit.