Spectral Sensitivity of Human Cone Cells §

Spectral sensitivities of human cone cells, S, M, and L types

---

Luminous Efficiency Function: Photopic (black) and scotopic (green)

Luminous Efficiency Function describes the human eye’s sensitivity to light at different wavelengths.

For photopic vision, i.e., at sufficiently highlighted levels, the human eye uses the cone receptors, of which it has three different kinds (L, M and S). Their output signals are combined to determine the total received brightness. (https://www.rp-photonics.com/luminosity_functions.html) Scotopic vision occurs at low light levels, where only the rod photoreceptors are involved because the cones are unable to provide sufficiently strong signals