ABSTRACT
This chapter deals with obtaining geometrical information from the surface by means of a pick-up and converting it into an electrical signal suitable for processing by means of a transducer. It begins with a short discussion of some of the basic principles of instrument design without which any attempt to recover the very small-scale roughness information would be doomed to failure. The chapter considers the stylus technique. The development of instruments for examining surfaces began in about 1929. In parallel with and feeding the instrument developments were calls for surface characterization; it is difficult to control surfaces if they cannot be measured and numerically assessed. In surface metrology instruments kinematics are most often used in generating straight line movements or accurate rotations. The notion of measurement loops and force loops is fundamental in the design of instruments for surface metrology.
