Practical estimation of measurement noise and flatness deviation on focus variation microscopes

Draft ISO specification standards on the calibration of areal surface topography measuring instruments require a determination of the measurement noise and residual flatness error. However, due to the effect of the instrument transfer function of focus variation microscopes, it is not possible to use every material measure with the ISO-recommended procedure. A practical approach to estimating measurement noise and flatness deviation for focus variation microscopes is presented in this paper and example measurements are given.