A wavelet-based method for measuring particulate velocity by an active electrostatic sensor

In this paper, a wavelet-based method for measuring the particulate velocities in a duct via an active electrostatic sensor is presented. The main motivation behind this paper is to avoid the known problems which exist with cross-correlation signal processing techniques; i.e., they are sensitive to the distortion of the output waveforms and the variance of the output pulse width from the detecting electrode of the sensor. Instead of cross-correlation techniques, the signal rising edges from the wavelet transforms of the signals of the electric charger and the detecting electrode of the sensor are used to determine the particulate velocity in the duct. As a consequence, the proposed method is robust to the distortion of the output waveforms and the variance of the output pulsewidth, so that it is specifically suitable for measuring the particulate velocity with the spread of velocities within a conveyor. Experimental results confirm the effectiveness of the proposed method and show that the new method can achieve a better measured result than that of the cross-correlation techniques.