“…Many of the microstructures, such as those in micro gears and micro lens arrays, have periodic forms with short pitches and large amplitudes (high-aspect-ratios) as well as steep surface slopes (6,7) . The measurement of the surface form of such kind of microstructures is an important task for the precision manufacturing of the microstructures (8,9) . Commercial measuring instruments such as scanning electron microscopes (SEMs), optical microscopes, scanning probe microscopes (SPMs) and mechanical stylus profilers are being used to measure workpieces with microstructures.…”