Volume Rendering Equation

• Light-emitting particles fill volume
• Emission-absorption mode
• Based on a physical model for radiation
• Interaction of light with matter at the macroscopic scale, neglecting Diffraction, Interference, Wave-character, Polarization, etc.
• $\kappa$ is fraction of absorbed light
• $g$ is fraction of emitted light
• $\frac{dL}{ds}=g(s)-\kappa (s)L(s)$
• aka Emission -Absorption
• $T(s_1,s_2)=e^{-{\int }_{s_1}^{s_2}\kappa (s^{\prime })d{s}^{\prime }}$
• $L_1^n=g(n)+T(n)L_1^{n-1}$