Lecture 11: Radiometry & Photometry (8)
kzhang2

How is this response curve generated? Do they use extracted samples of human eye cells and throw light at them, or do they use some kind of fancy apparatus to figure out the light response? It seems like this would be a fairly difficult thing to measure given that rods and cones are on the inner layer of the eyeball.

HJQ2000

I think it is more like a subjective experimenting description from viewers saying what colored light is brighter or darker than other, and should not be considered as accurate. Link to wikepdia: https://en.wikipedia.org/wiki/Luminosity_function Please correct me if I misunderstood.

sutkarsh

@HJQ2000 is correct!

herojelly

What are the units for the luminous efficiency curve? I'm also having trouble understanding why we take the integral over the radiant flux * the luminous efficiency curve to obtain the luminous flux.

briana-jin-zhang

You multiply them because your eyes do that for the "red" "green" and "blue" curves and sums them up, I think. You are essentially projecting it to your eye's three basis essentially.

zhangyifei-chelsea

While in the previous slide, we see radiant and luminous energy/flux have the same unit and general definition, they are not equivalent. Radiant energy/flux are objective physical quantity, while luminous ones are human-perceived (more subjective).

alexkassil

Its interesting that there even exists such a class of units and measurements that are so human centric as opposed to the radiometric objective quantities

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