Detection of metal, glass and plastic pieces in bottled beverages using ultrasound

Quality parameters of mango and potential of non-destructive techniques for their measurement — a review

“…Ultrasound: There has been interest of late in using ultrasound to investigate factors such as physical change and contamination in food products (Javanaud 1998, Zhao et al 2003, Bamberger and Greenwood 2004. One reason for this is that changes in acoustic properties can be related to density changes in the food product (McClements 1995, Gan et al 2001.…”

Ultrasound based glass fragments detection in glass containers filled with beverages using neural networks and short time Fourier transform

“…A second reflection (P 2 ) and reverberation (P 3 ) occur if the second medium is of limited thickness, which is the case of a container/bottle wall. The pressure ratios are calculated by (Zhao et al, 2003a): Fig. 1.…”

“…By consequence, FBs cannot be detected by the echo amplitude of the bottle inner surface either. In previous work (Zhao et al, 2003a(Zhao et al, , 2003bJiang et al, 2003), a center frequency pressure ratio between the inner and exterior surfaces echoes was proposed as a criterion for FB detection. The ratio is calculated using short time Fourier transform (STFT).…”

“…For example, the sensor in test may not be strictly perpendicular to the bottle surface. The deviation from the normal of incident angle will lead to signal center frequency ''low-shifting'' in the spectrum (Zhao et al, 2003a) and may provide faulty results. Another factor that makes frequency shift and faults detection is the frequency-dependant attenuation of ultrasound: high frequency decays energy faster than that of low frequency.…”

Low intensity ultrasound

“…This approach can be used to detect (or image) the presence of fluid in a pipe (e.g., to make certain product is not accidentally dumped during a cleaning operation), fouling on the inside surface of a pipe (Withers, 1996), the fill level of a tank, the presence of glass fragments at the bottom of a beverage container (Zhao, Basir, & Mittal, 2003a), or to measure the thickness of a fat layer in an animal and thereby estimate carcass composition (Fisher, 1997). Alternatively the thermal expansion of a delay line can be used to measure the temperature of fluid in contact with it (Richardson & Povery, 1990).…”