Method for automatically restoring a calibrated state of a projection system

Method for automatically restoring a calibrated state of a projection system, allowing simple and error-free alignment of a projection system in an original error-free state of the system. A calibrated state of a projection system is automatically restored by calculating a position and orientation of at least one camera within the projection system, using fixed points, subsequently m times n markers (9′) are projected onto the projection area, using the markers by cameras to determine a reduced number, compared with the calibration, of second measurement points (QI′) that have one X, Y and Z coordinate each, the reduced number of second measurement points (QI′) is used to perform a calculation of the differences between the second measurement points (QI′) and the associated first measurement points (QI′), a displacement vector is formed, the association between the projector coordinates and 3D coordinates is adapted with the displacement vector.