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| Identification of eggshell crack using BPNN and GA-BPNN in dynamic frequency analysis |
Department of Biosystems Engineering, Zhejiang University, Hangzhou, Zhejiang 310029, China）
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Abstract The eggshell cracks were detected by dynamical frequency response of an egg excited with light mechanical impacts on different locations of the eggshell using flexible piezoelectric film sensors. As a result, the dominant resonance frequency can be observed and the frequency value is lower in the intact eggs. From the cracked eggs, some peak frequencies were found, the magnitudes of those frequencies were approximated, and the values are higher. In normalization average of frequency domain, 10 or 20 magnitudes of interval frequency, 10 magnitudes in turn and frequencies by magnitude in turn were extracted as eigenvalues. In order to investigate whether the dynamical frequency response was able to distinguish between intact egg and eggshell crack, BP neural network （BPNN） and the combination of genetic algorithm and BP neural network （GA-BPNN） were used. The results show that the dynamical frequency response could better distinguish between intact egg and cracked egg using BPNN and GABPNN by magnitudes and frequencies, and more distinguishing effect can be obtained by frequencies and magnitudes,and by using GA-BPNN.
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2009, Vol. 30 
