Because of the increasing need for extremely high accuracy it has become desirable to apply laser based velocimeters throughout the metals rolling process to measure both speed and length.
However, as a class, traditional Laser Doppler Velocimeters (LDVs) have not been universally successful because of factors including:
- Good accuracy at high target speeds but poor accuracy at low target speeds
- Succeptibility to physical damage due to mounting too close to moving strip
- Overheating in inhospitable mill environments
- Inability to measure low reflectance targets
- Poor length accuracy for long strips