The last two points above can be used to design a simple calibration
device as follows. The image of three squares on three different
planes (not necessarily orthogonal) are sufficient to give calibration.
Consider the following steps:
- For each square compute the homography
that maps its corner
to their imaged points.
- Compute the imaged circular points for the plane of that square as
- Fit a conic
through the six imaged points. Note
that five points are sufficient to define a conic.
using Cholesky decomposition.