Is OpenCV for Python or C++ a good library to use for detecting the blinking rate/frequency of an LED diode lights?

asked 2018-05-17 03:38:07 -0600

masterenol gravatar image

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In the picture, we can see a frame which tells us where the LEDs are located on an Oculus Rift headset and the blinking rate of the each LED.

I would like to build something like in the picture shown, but with a NOIR (no infrared) camera of 640x480 resolution and 15 to 30 frames per second (FPS). Can OpenCV be used to determine the LED blink frequency (Hertz Hz I believe) of a different number of LEDS and track their locations very similarly as shown in the picture above and the video below?:

If I need a camera with higher resolution and frame rate, would I be able to accomplish my goal with a video capture feed of 1080x1920 60 fps?

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forget youtube videos, but look at nyquist

(you'll need at least twice the sampling frequency of your blink rate)

berak gravatar imageberak ( 2018-05-17 03:41:32 -0600 )edit

This is an interesting response berak, thank you.

masterenol gravatar imagemasterenol ( 2018-05-17 04:02:35 -0600 )edit

@LBerger, thanks!

masterenol gravatar imagemasterenol ( 2018-05-17 20:11:05 -0600 )edit

@berak. If my understanding is correct, the numeric value of the frames per second of a webcam (30 for example) is equal to or approximately equal to the numeric value of the sampling frequency I can work with (30). So if I have a set LEDs with a blink rate under 15 blinks per second, I should be able to use OpenCV and a webcam to track the position of each unique LED by identifying each LED's unique blink rate. Is this correct? The concept of sampling is new to me, so I thank you for your help and patience.

masterenol gravatar imagemasterenol ( 2018-05-18 00:19:01 -0600 )edit

yes, that's correct. however, tracking the position is independant of that. (will work with a slower cam, too)

you may want to read a bit about (1d) signal processing, like filtering and fft, too.

berak gravatar imageberak ( 2018-05-18 00:58:26 -0600 )edit