Speed measurement by cross correlation--Theoretical aspects and applications in the paper industry

Based on the cross correlation of two signals, the speed measurement method presented in this paper is to be used on materials whose structure is stable (railway, papersheet, etc.) or not (turbulent flows). There is not only a time delay between the signals, but more generally a filtering effect which may be regarded as linear. In these conditions, the theoretical characteristics (bias, variance) of the estimation are given. They are compared with simulation results. The influence of the computational rapidity of the electronic circuit on the quality of the estimation is studied.