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So I have a basic understanding that blood is red due to the chemical bond between iron and oxygen, and how both elements together reflect light, but out of cur
by conphill 11y ago
So I have a basic understanding that blood is red due to the chemical bond between iron and oxygen, and how both elements together reflect light, but out of curiosity, can anyone touch on the significance of green light?
- draven 11y agoThe section "The science behind Apple's sensors" in the article contains some details about that. Quick google search returned this: https://en.wikipedia.org/wiki/Photoplethysmogram https://en.wikipedia.org/wiki/Photoplethysmogram According to this: http://bsn2014.org/poster/BSN2014-poster09s-maeda.pdf http://bsn2014.org/poster/BSN2014-poster09s-maeda.pdf Green light seems to be used to lessen the impact of motion on the measurements.
- conphill 11y agoAwesome resources. Thanks for providing this.
- deleted 11y ago[deleted]
- conphill 11y agoInteresting. Thanks for the short and sweet answer.
- detaro 11y agoGreen light absorbed by the red blood, heartbeats change how much blood is below the sensor -> be measuring how much light is (not) reflected it can work out the pulse. (it also has a mode using infrared light, but that is used only in special cases)