Method and apparatus for aligning signals

Abstract

This invention relates to alignment of signals, particularly for use in a quality assessment system. The invention provides a method and apparatus for aligning a first signal comprising a sequence of frames with a second signal comprising a sequence of frames, the method comprising the steps of: determining a similarity measure between each of a plurality of frames of the first signal and each of a plurality of frames of the second signal; assigning a matching value to each frame of the first signal wherein the matching value indicates a relative position of a matching frame in the second signal, by repeating the sub-steps of: generating a relative delay histogram the histogram comprising a set of values corresponding to each of a set of relative delays by: selecting a subset of frames of the first signal and for each frame of said subset identifying the frame of the second signal having the greatest similarity with said frame; determining the relative delay between the identified frame of the second signal and said frame of the first signal; and incrementing the value of the histogram corresponding to said relative delay; identifying one or more peaks in the relative delay histogram; and assigning the matching value to each frame contributing to a peak in dependence upon said identified peaks.