Nondestructive measurement for mango inspection

This research aims to develop a dielectric property measurement system to classify and inspect dielectric objects (here mango). The moment method and geometric theory of diffraction are combined in the calculation process of inverse scattering measurement to improve accuracy. Then, a system utilizing such a method is developed to operate at 12.4 GHz and calibrated with the measured results in the literature. Measurement results show that the dimension of the object under test should not be too large as compared to the wavelength of the operating frequency, to obtain acceptable accurate results in a reasonably short calculation time. For mango measurement, the frequency of 2.45 GHz in the industrial scientific and medical (ISM) band is selected to comply with the mentioned condition. Measured dielectric properties of Namdokmai, Rad and Keausawuay mangoes for various days after harvested are compared to chemical properties, namely, fructose and pH. An obvious relationship can be found and it is possible to develop a low cost fruit inspection system.