US Patent 7856139 Signal correcting method

A signal correcting method includes: obtaining multiple types of signals at each of a plurality of points; extracting a point with signal values corresponding to the multiple types of signals, which have a predetermined relationship to signal values of the multiple types of signals at a target point; and correcting the multiple types of signals at the target point based upon the signal values corresponding to the multiple types of signals at the target point and the signal values corresponding to the multiple types of signals at the extracted point.