Quantification of ciliary beat frequency:
Basic Concept
Ciliary beat frequency can be determined from the variation in the light intensity of the microscope image  that results from ciliary movement.  This variation in light intensity is frequently detected from a few cilia with a photomultiplier to generate an analog wave form that represents the repetitive beat cycles.   

Semi-Automation
Beat frequency is obtained by counting the peaks per second.   To accelerate this analysis and overcome poor signal to noise ratios, the waveforms are often processed (on-line) using a spectrum analyzer that relies on functions such as fast Fourier Transforms. While this approach provides frequency data, the time resolution of the data is reduced to the duration of the sampling window (1 - 2 s). This approach is inadequate for the analysis of rapid changes in beat frequency induced by Ca2+
High-Speed Video
Because ciliary beat frequency can approach rates of 40 Hz, accurate quantification of the waveform signal requires a minimum sampling rate of 80 Hz. If the various phases of the beat cycle are to be measured, faster sampling rates are required.  A high-speed video system using conventional video has been designed to record ciliary activity at 240 frames per second (fps). The advantages of using video images is that multiple groups of cilia can be measured simultaneously.

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