Neus代码的理解
NeRF与Neus相机坐标系的对比：
| Method | Pixel to Camera coordinate |
|---|---|
| NeRF | $\vec d = \begin{pmatrix} \frac{i-\frac{W}{2}}{f} \\ -\frac{j-\frac{H}{2}}{f} \\ -1 \\ \end{pmatrix}$ , $intrinsics = K = \begin{bmatrix} f & 0 & \frac{W}{2} \\ 0 & f & \frac{H}{2} \\ 0 & 0 & 1 \\ \end{bmatrix}$ |
| Neus | $\vec d = intrinsics^{-1} \times pixel = \begin{bmatrix} \frac{1}{f} & 0 & -\frac{W}{2 \cdot f} \\ 0 & \frac{1}{f} & -\frac{H}{2 \cdot f} \\ 0 & 0 & 1 \\ \end{bmatrix} \begin{pmatrix} i \\ j \\ 1 \\ \end{pmatrix} = \begin{pmatrix} \frac{i-\frac{W}{2}}{f} \\ \frac{j-\frac{H}{2}}{f} \\ 1 \\ \end{pmatrix}$ |
