1. A signal processing method executed by a processor controlled system for comparing a plurality of input signals and determining a level of similarity between the plurality of signals, the method comprising: dividing at least one of the plurality of signals into plural small areas; comparing the small areas and integrating a similarity at a plurality of a time difference values and/or expansion values, wherein a conversion parameter that is an expansion rate and/or a magnitude of shift where a maximum correlation is determined and is used for making a similarity determination; and further determining similarity between the plurality of signals on the basis of an integrated similarity and thereafter identifying at least two of the plurality of input signal as being the same based on the integrated similarity and wherein a voting unit votes on an acquired similarity for a time difference and expansion rate and the similarity is integrated at specific positions in order to determine similarity.