Visible and NIR image of beetle in acrylic
An experiment to check the NIR transparency (translucence) of a beetle carapace using 850nm LED backlighting through a hole in Al foil.
The left image is taken with a visible camera while the right image is through an RG715 filter on a NIR camera with sensitivity up to 1000nm.
The backlighting in both images is the 850nm LED but, in the left image some leakage from an adjacent 660nm LED can be seen.
The beetle 'lights up' in the right hand image because, at 850nm, the scattering in the carapace greatly exceeds the absorption, allowing the body to capture a high instantaneous density of NIR photons due to the delay of the incoming photons by multiple scattering. The same process happens in both plant (leaf) and animal tissue in the NIR due to high scattering and low absorption.
Visible and NIR image of beetle in acrylic
An experiment to check the NIR transparency (translucence) of a beetle carapace using 850nm LED backlighting through a hole in Al foil.
The left image is taken with a visible camera while the right image is through an RG715 filter on a NIR camera with sensitivity up to 1000nm.
The backlighting in both images is the 850nm LED but, in the left image some leakage from an adjacent 660nm LED can be seen.
The beetle 'lights up' in the right hand image because, at 850nm, the scattering in the carapace greatly exceeds the absorption, allowing the body to capture a high instantaneous density of NIR photons due to the delay of the incoming photons by multiple scattering. The same process happens in both plant (leaf) and animal tissue in the NIR due to high scattering and low absorption.