Highly improved measurement speed of white light interferometry

White light interferometry is a well established principle for shape measurements. It provides high accuracy on a great variety of surface materials. Though to accomplish future industrial tasks the measurement speed must be increased. The system we introduce can achieve scanning speeds up to 100 µm/sec, with a standard frame rate of 25 Hz. With an add-on to the hardware we achieve up to 10 times higher modulations in the signal compared to the standard setup. To cope with the sub-sampled signals, we introduce new evaluation methods. We achieve a measurement uncertainty of 230 nm on a mirror using a scanning speed of 100 µm/s. On optically rough surfaces we achieve an improvement of the scanning speed from 16 µm/sec to 78 µm/sec, without loss of accuracy.