Photometry（光度学）：度量感知量
Radiometry（辐射度量学）：度量物理量
| Radiometric | Symbol | Unit | Photometric | Symbol | Unit |
|---|---|---|---|---|---|
| 辐射能量 Radiant energy | \(Q=\frac{hc}{\lambda}\) | \(J\) | |||
| 辐射通量 Radiant flux | \(\Phi=\frac{\text{d}Q}{\text{d}t}\) | \(W=J/s\) | 光通量 Luminous flux | \(lm\) | |
| 照度 Irradiance | \(E=\frac{\text{d}\Phi}{\text{d}A}\) | \(W/m^2\) | Illuminance | \(lx=lm/{m^2}\) | |
| 强度 Radiant intensity | \(I=\frac{\text{d}\Phi}{\text{d}\omega}\) | \(W/sr\) | 光强 Luminous intensity | \(cd=lm/sr\) | |
| 亮度 Radiance | \(L=\frac{\text{d}\Phi}{\text{d}A\text{d}\omega}\) | \(W/(m^2 sr)\) | 亮度 Luminance | \(Y=\int_{\lambda}L(\lambda)V(\lambda)\text{d}\lambda\) | \(nit=cd/m^2=lm/(m^2sr)\) |