Each has its pluses and minuses. Choosing the right tool requires knowing what each does well. Microscopes are excellent for visual inspection but collecting quantifiable measurements requires the operator to manipulate x and y measurement stages. Some microscopes provide overall height measurement. However, determining z at a particular point on the target is laborious and time-consuming.
Measurements are operator-dependent, but produce quantifiable x and y measurement data.
Comparators are more appropriate for flat surfaces than for highly contoured forms. Making cross-sectional measurements often requires cutting a sample in half and fixturing it for inspection. Because a camera does not measure height, these systems work best on relatively flat objects or features. Laser-triangulation sensors measure only z, and therefore are used when height measurements are required. Combined with x and y measurement stages, 3-D data can be obtained.