22. The system according to claim 16 , wherein, in determining position errors, the processor is configured to: determine maximum and minimum values of line or character spacing based on the detected positions.
22. The system according to claim 16 , wherein, in determining position errors, the processor is configured to: determine maximum and minimum values of line or character spacing based on the detected positions. 23. The system according to claim 22 , wherein the processor is configured to: determine the amplitude of the line or character spacing errors by taking the difference between the maximum and minimum values.