Strip speed measurement using distributed infrared detectors

An instrument has been developed using inexpensive pyroelectric infrared detectors which measures the speed of non-metallic (copper) strip in the range 0.1-5 m s^-1. The instrument has been tested on an experimental rig designed to simulate works conditions as closely as possible, particularly in regard to vibration, strip wobble and sudden speed changes. For high emissivity (coated) strip an accuracy of 0.4% is obtained using wavelength control. For low emissivity (polished) metal however, the system does not operate reliably due to the low S/N ratio