Why is L's numerator $d^2\phi$? Shouldn't it be just $d\phi$?
dvernet
@aznshodan It's because we're computing the differential of Erradiance $E(p)$ which is defined in this slide as $E(p) = \frac{d\Phi(p)}{dA}$. My question is why is it not a $d^{2}A$ in the denominator.
kayvonf
Irradiance E is power per unit area: dPower/dA.
Radiance L is power per unit area per unit solid angle or equivalently, irradiance per unit solid angle: dE/dw = d(dPower/dA)/dw.
aznshodan
@kayvonf
d(dPower/dA)/dw is not change in irradiance per unit solid angle. It's the rate of change of the change in irrandiance per unit solid angle.
change in irradiance is dPower/dA.
kayvonf
@aznshodan. You should change irradiance to power in your post. (I updated my post to be more clear as well.)
Why is L's numerator $d^2\phi$? Shouldn't it be just $d\phi$?
@aznshodan It's because we're computing the differential of Erradiance $E(p)$ which is defined in this slide as $E(p) = \frac{d\Phi(p)}{dA}$. My question is why is it not a $d^{2}A$ in the denominator.
Irradiance E is power per unit area: dPower/dA.
Radiance L is power per unit area per unit solid angle or equivalently, irradiance per unit solid angle: dE/dw = d(dPower/dA)/dw.
@kayvonf
d(dPower/dA)/dw is not change in irradiance per unit solid angle. It's the rate of change of the change in irrandiance per unit solid angle.
change in irradiance is dPower/dA.
@aznshodan. You should change irradiance to power in your post. (I updated my post to be more clear as well.)