Patent ID: 8107089

Claim:
A method of measuring translation of a surface, the method comprising: the movement of the surface of an object to be measured having at least one primary direction of movement, detecting the surface repeatedly by at least one detector row of at least one detector, the direction of the detector row being the same as the surface's primary direction of movement; arranging, by a signal processing unit, successive response rows into a response matrix; determining, by a signal processing unit, the direction or directions of at least one curve or curve portion in each response matrix; and determining, by a signal processing unit, enlargement data from a known distance between the surface and the detector to produce enlargement data and response rows and the surface translation in the response matrices by comparing the direction or directions of at least one curve or curve portion in a response matrix formed by telecentric optics with the direction or directions of at least one curve or curve portion in a response matrix formed by non-telecentric optics on the basis of the enlargement data.