1. A method for determining signal similarity between a query signal and a reference signal via composition, the method comprising: searching said reference signal to detect at least one matching region to a region of said query signal, the shape and size of said matching region being determined as a function of a local evidence score for said region, wherein said local evidence score is a function at least of a quality of the match of said region and of its statistical significance; and composing at least part of said query signal from at least one said matching region which provides at least one of: local evidence scores and a global evidence score for said query signal; wherein said global evidence score defines the extent of a global similarity of said query signal to said reference signal.