What optical techniques are used in industrial measurement?

Optical measurement techniques include: Pyrometry (non-contact temperature from thermal radiation), LiDAR (laser ranging for distance/profiling), Machine vision (dimensional measurement, inspection), Laser interferometry (sub-micron displacement), Fiber optic sensors (distributed temperature/strain), Spectroscopy (material composition), Optical encoders (position with high resolution), and PIV (Particle Image Velocimetry for flow visualization). Advantages include non-contact operation, high speed, immunity to EMI, and ability to measure in hostile environments. Challenges include alignment sensitivity, optical access requirements, and environmental effects (dust, vibration).