Vanishing Point and Horizon Line

Due to the limitation to plane transformations, it is possible to easily calculate the limits of the coordinates $x$ and $y$ through the transformation (8.27) as follows:

$$\begin{array}{rl} \lim_{x\to\infty}\mathbf{H} (x,y,1)^{\to... ...left( \frac{h_1}{h_7}, \frac{h_4}{h_7} \right) \\ \end{array}$$ (8.30)

These limits are the vanishing points (see section 8.2.2) of the image.