Author: Kumar
Year: 2008
- Use planar mirrors to enable the camera network to see the same calibration target
- the 4 DoF of mirrors is introduced (3D normal vector
$n$ + distance to camera$d$ ) as free parameters in the calibration process - In the process, the cameras and the target remain fixed, only the mirror is moving
- each camera in front of a mirror is equivalent to a mirrored camera (fig2)
- the mirrored camera has striclty the same intrinsic and distortion parameters as the initial camera
- knowing the 4dof pose of the mirror, he derives an expression to obtain that links pose of the camera
$C, R$ and the pose of a mirrored camera$C', R'$ - Augmenting the parameters to 15 to handle non linearity, this requires at least 5 mirror poses to compute
$C, R$ in closed form - Protocol :
- The intrinsics and the mirrored camera poses are computed using a standard calibration toolbox
- The camera poses are then computed using the
$AX = B$ equation - then a BA including the mirror parameters is performed