Detection of phrase boundaries in Japanese by low-pass filtering of fundamental frequency contours

Major syntactic boundaries are often accompanied by a rise in the phrase component of the fundamental frequency (F0) contour. Detecting such rises, therefore, can be signi cantly helpful to the speech recognition process. We developed a method to detect syntactic boundaries with phrasecomponent rise (henceforth, phrase boundaries), based on the compression of the accent component of the F0 contour (in logarithmic scale), using a low-pass lter. In this method, F0 contours are viewed as signals in the time domain, which can be roughly separated into phrase and accent components due to their di erent frequency contents. Phrase boundaries are detected whenever a signi cant rise occurs in the derivative of the ltered F0 contour. (The concepts of phrase and accent components can be found in [1]). The method managed to detect about 77% of manually detectable phrase boundaries, though with a relatively high insertion rate. The insertion rate can be reduced by using the partial AbS method, proposed by the authors [7].