Affine Camera

Synonyms

Affine projection

Related Concepts

Perspective Camera; Perspective Transformation; Weak Perspective Projection

Definition

An affine camera is a linear mathematical model to approximate the perspective projection followed by an ideal pinhole camera.

Background

Perspective projections give accurate models for a wide range of existing cameras, especially after calibration for a limited volume of workspace. However, the relationship from a 3D point to its 2D image point is nonlinear due to a scalar factor dependent of each individual point (see entry “Perspective Camera” for details). Affine camerasare introduced to make the projection model more mathematically tractable. An affine camera model is a first-order approximation obtained from Taylor expansion of the perspective camera model around a reference point. The reference point can be any point, but it may be set to the centroid of the 3D points, which results in a more accurate approximation. There are three important...