Homogeneous Coordinates

Overview

The camera coordinate space simply provides us a camera centric coordinate space with which to describe the distances of visible objects away from the camera origin (i.e., the camera). It is just like any other Euclidean coordinate space. However, this coordinate space is still not ideal when we wish to understand how our 3D coordinates project to images. Before we understand the intricacies of projection, we first need to understand homogeneous coordinates and so-called projective geometry.

Projection and scale

Take a look at this picture of a small dog.