Real-time measurements in optical metrology

Abstract

Methods as well as recording materials for real-time measurements were discussed. Electrooptical crystals can be used for nearly realtime contactless measuring techniques. The BSO was found appropriate for real-time holographic interferometry, contour line display and for deformation, displacement and vibration analysis. Furthermore, for real-time speckle photography the BSO was found to be very useful. For noise and vibration analysis of oscillating objects such as rotating car tyres, gearing boxes, turbines blades, a vibrometer based on Doppler shift measuring principles was found to be useful, leading to an amplitude and frequency analysis. For the analyse of rotating objects an image derotator is frequently used for compensation of the rotation. In optical metrology real-time methods will be useful for the engineer in future.