- is the focal length of the camera
- is the lens radial distortion coefficient
- is the principal point and the center of radial lens distortion
- are rotation angles for the transformation between the world and camera coordinates
- are translation components for the transformation between the world and camera coordinates
- and
- and where
- Finally, the pixel coordinates are
and

The parameters of the Tsai model can be estimated either from

- a coplanar set of world points (a planar calibration object), or
- a non-coplanar set of world points

In the first case cannot be determined. In what follows we describe non-coplanar calibration, which is a two stage process:

- Linear estimation of a subset of parameters.
- Nonlinear optimization with the linear estimates as initial guess.