A Monophonic Pitch-Tracking Algorithm Based on Waveform Periodicity Determinations Using Landmark Points
David E. Cooper, Kia Ng · Computer Music Journal · 1996
In many musical situations, currently available MIDI controllers prove inflexible or artificial to musicians unfamiliar with their ergonomic eccentricities. While the range of such devices has been extended beyond the piano-style keyboard to ones modeled on wind, string, and percussion instruments, they can still be frustrating to use because of their generalized nature. Our aim is to provide a means whereby conventional instruments can be used to control musical processes in a way that is transparent to the performer. Such a system must have a fast response time, be non-computationally intensive, and operate effectively on a lowspecification hardware platform. In this article, we propose an approach to monophonic pitch tracking that uses the pattern and shape of digitized sound waves to isolate the fundamental frequency, rather than the more common frequencyand time-domain methods. We discuss the strategy of segmentation of the sampled sound wave and a procedure for finding the shortest distance between two shape-similar repeating segments. A new composition that makes use of the algorithm, Philip Wilby's Dance Before the Lord for brass band and electronics, is presented as an illustration of the practical application of the algorithm.