Heart rate measurement was attempted by measuring variations in the red colour of the eye i.e. with each pulse, the increase in blood flow should change the red colour signal of the eye.
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The steps used include:
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(i) A 20s video of my eye was imported into Mathematica.
(ii) The red channel of each red frame was extracted.
(iii) The pupil was used as a region of interest (ROI) in each frame. This is because I thought it would allow me to measure signals from the retina; tissue rich in blood.
(iv) Mean red pixel values were plotted and noise reduced using a low-pass signal.
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ROI
Noisy average pixel values of the ROI
Noise reduction using a low-pass filter
Pulses assumed to be local maxima
Approx heart rate: 42 bpm.
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Actual: roughly 55bpm
Problems:
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1. Light interference from external sources reflecting on the cornea.
2. Loss of information by the low pass filter causing the calculated bpm to be less than the actual value.