Measuring vibrato rate of a sung note I'm doing a project where I need to measure the rate of vibrato cycles in a sung note under various conditions. The stimulus will be a several-second-long audio sample of a held a capella note with vibrato; the output should be the rate of the vibrato repetition (e.g. 4Hz, 10.5Hz, etc). The audio will be captured specifically for this study; I won't be sampling existing audio, and don't need to deal with interfering signals. The underlying pitch of the note can be whatever is needed, although precision probably won't be possible.

Here's an example sonogram:



Ideally, this would be done with a Linux command line chain or shell script, but if I need to write some Python that would be fine, too.
This publication may be of interest for you:

Jonathan Driedger, Stefan Balke, Sebastian Ewert, and Meinard Müller: Template-Based Vibrato Analysis of Music Signals, in: Proceedings of the International Conference on Music Information Retrieval, New York, USA, 2016, pp. 239–245. [PDF]

Furthermore, there is an accompanying website for this paper.