1

I have a hardware device with a LED that fades between bright and dark once about every 2.4 seconds. I want to figure out what function is used to create its pattern.

I have taken a video of the LED pulsing and then use linux tools ffmpeg and imagemagick to extract brightness values and plot them on a graph. (Raw data for anyone curious).

enter image description here

At this point I'm at a loss of how to further identify this function. I've tried plotting popular functions from this incredible article into wolfram alpha.

I suspect it may be a gaussian function like: e^sin(x) wolfram alpha.

I am researching Fourier Transforms on youtube, but my inexperience is preventing me from seeing how to apply that to this wave form.

I am very inexperienced and I graciously would like advice from anyone with ideas. What tools and techniques could I use to more precisely identify this function?

enter image description here

Additional resources

daw
  • 49,113
  • 2
  • 38
  • 76
spuder
  • 131
  • It's probably not actually any particular simple mathematical function. – Suzu Hirose Aug 16 '22 at 08:13
  • It looks quite a lot like the triangular one ... Or maybe there is a slight deceleration at each peak, so maybe slightly sinusoid. If one analyzes the actual data captured, we might be able to determine a better candidate. Sure Fourier transforms could be used as well, but that might not always provide the simplest solution as it points to a sum of trigonometric-functions. – String Aug 16 '22 at 08:35
  • I have a theory that the deceleration at the peak is the camera sensor automatically adjusting exposure. – spuder Aug 16 '22 at 22:25
  • This formula is really really close period ((exp(sin(x/1205* pi))-1/e+55)*(200/(e-1/e))) – spuder Aug 17 '22 at 03:30

0 Answers0