Cilia beating frequency conversion into beat/sec

Hi All,

I take avi file for cilia beating frequency data analysis.
When I convert the cine (original format) to avi, I set the fps to 15fps and save in avi.

Then, I drop the avi files in ImageJ/Fiji with macro for beating frequency in the unit of beats/sec.
For this steps, I get make graph in excel using the results from ImageJ/Fiji then count the peaks. For example, peak1:200, peak2:300, peak3:450
calculation I do is:

  1. 450-300=150, 300-200=100
  2. 150+100/2= 125 frames/beat
  3. Convert it to beats/sec: 200frames/secX1beat/125 frames=1.6 beats/sec

My concerning part is that step 3) converting, multiplying 200 frames/sec to get beats/sec unit.
Does it have to be 15fps that this is the f/s I chose when I converted the cine file to avi at the beginning?
Help will be appreciated a lot.

Hi @nok308

To my mind, if you have 125 frames per beat, you need to calculate how many seconds this represents. If indeed your movie is 15 fps then you would do 125/15 to give you 8.33 seconds per beat. Take the inverse of this (1/8.33) to give you 0.12 beats per second.

All of this predicates on the original frame rate being correct. This will depend on whether you’re resampling to 15 fps (IE dropping unused frames) or setting the frame rate to 15 fps (IE playing all of the frames but doing so at 15 per second). Easy way to check is whether your cine and your AVI have the same duration (which would indicate resampling).

Hope that helps.

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Thank you so much dnmason!
It is very helpful!

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