Target Acquisition vs. Expressive Motion: Dynamic Pitch Warping for Intonation Correction

This article concerns techniques for the dynamic correction of pitch during production of continuous sounds on digital musical instruments, driven by stylus input on a tablet in this particular case.

While at first blush this might sound very far from the issues typically of concern for input devices, the authors do an excellent job of relating this problem to issues typically encountered when pointing in graphical user interfaces, relating it to techniques such as Expanding Widgets (in visual space) and Sticky Icons (in the motor space), for example.

Through a series of algorithm explorations and studies, this contribution illustrates how a dynamic corrections influence both the accurate production of notes, which is one concern, as well as free-form expressivity (such as vibrato, ligato, and glissandro) in the manner in which the notes are produced, which is a second—and often competing—concern in musical performance (if not for input devices in general).

The results are convincing, and intriguing—such as the authors’ suggestion that their dynamic correction could be applied to the beautification of ink strokes, a thought that indeed had occurred to me, as well, as I read this article (perhaps unsurprisingly so, given my longstanding interesting in pen computing).

The authors also note that the technique is available under a freeware license, and has been implemented in the Cantor Digitalis—which won first place in a recent musical instrument competition.