US Patent 7251597 Method for tracking a pitch signal

A method for tracking pitch signal, including receiving a detected pitch signal that consists of a succession of pitch values, and for each current pitch value in the detected signal perform the following steps: constructing sub-sequences of consistent pitch values from neighboring pitch values. Next, calculating significance of the sub-sequences, and selecting a sub-sequence or a collection of consistent subsequences with highest significance. If the current pitch value is not consistent with the sub-sequence with highest significance, smoothing the current pitch value by diving it or multiplying it by an integer value>1, so as to render it consistent with the sub-sequence with highest significance.