A method and apparatus for generating an elemental image by an integral image technique are provided. A recessed section is located within the circular surface and extends below the circular surface for contacting the surface of a turntable platter. The disk drive further comprises switching circuitry operable to connect the voice coil to the capacitor while accelerating the VCM, and to disconnect the voice coil from the capacitor and connect the voice coil to the BEMF voltage while decelerating the VCM. An implantable medical device can then be navigated relative to the mapping data. An air-fuel mixture in the combustion chamber, which is obtained by mixing together fuel and air evenly to the stoichiometric air-fuel ratio or a richerleaner air-fuel ratio than the stoichiometric air-fuel ratio, is ignited using both the central spark gap and the plurality of peripheral spark gaps.