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diacriticalyesterday at 8:37 PM1 replyview on HN

Don't humans and other warm objects also radiate IR?


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somatyesterday at 8:45 PM

That is far-IR, thermal stuff, Near-IR, 700 nanometer-ish is right below red in human vision.

Camera sensors can pick up a little near-IR so they have have a filter to block it. If that filter was removed and a filter to block visable light was used in place you would have a camera that can only see non-visable light. Poorly, the camera was not engineered to operate in this bandwidth, but it might be good enough for a mask. A mask that does not interfere with any visible colors.

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