Patent ID: 8296131

Claim:
A method of providing a quality measure for an output voice signal generated to reproduce an input voice signal, the method comprising: partitioning the input voice signal and the output voice signal into frames; for each frame in the input voice signal, determining frame disturbance for a plurality of frames of the input voice signal which correspond to an utterance in the input voice signal, relative to a corresponding utterance in the output voice signal; performing a dynamic time warp by (a) temporally aligning frames in corresponding utterances of the input voice signal and the output voice signal based on calculated frame disturbances, (b) determining which frame disturbances are to be used as a subset for calculating a MOS quality measure for the output voice signal; wherein determining which frame disturbances are to be used, comprises: calculating a grid having (A) a first axis representing frames of an original utterance of the input voice signal, (B) a second, perpendicular, axis representing frames of a corresponding reproduced utterance of the output voice signal, and (C) intersecting nodes in said grid representing magnitude of frame disturbance at each node; calculating a path on said grid which provides an improved time alignment; for at least one node of said intersecting nodes, replacing one or more frames in the input voice signal and the output voice signal with one or more new frames that generate a plurality of new nodes in a vicinity of said one node that have smaller pitch than nodes generated by original frames, wherein replacement frames have greater overlap than the original frames; performing a dynamic time warp on each one of said plurality of new nodes; and based on the determination of which frame disturbances are to be used, calculating the MOS quality measure for the output voice signal.