Understanding volume rendering with radiance fields

Volume rendering allows you to create a 2D projection of a 3D image or scene. In this section, we will learn about rendering a 3D scene from different viewpoints. For the purposes of this section, assume that the NeRF model is fully trained and that it accurately maps the input coordinates (x, y, z, d­­­x, dy, dz) to an output (r, g, b, σ). Here are the definitions of these input and output coordinates:

• (x, y, z): A point in the 3D scene in the World Coordinates
• (d­­­x, dy, dz): This is a unit vector that represents the direction along which we are viewing the point (x, y, z)
• (r, g, b): This is the radiance value (or the emitted color) of the point (x, y, z)
• σ: The volume density at the point (x, y, z)

In the previous chapter, you came to understand the concepts underlying volumetric rendering. You used the technique of ray sampling to get volume densities and colors...