A fuel injection method is provided for correcting the fuel injection amount accurately by eliminating offset components when detecting a current flowing through a solenoid for fuel injection. An image acquisition and processing tool can place the camera in a low-sensitivity mode and a high-sensitivity mode. The pulling element, in a region directly adjacent to the buckle casing is at least partly enclosed by a cover. There are further provided systems comprising a computer readable storage medium containing program instructions for execution by a processor to design a mask; and a processor for executing the program instructions stored on the computer readable storage medium for performing such methods. A page number conversion unit converts the page numbers for searching into the corresponding electronic document page numbers, based on a result of comparison by the page number comparator.