Investigation on the Sugar Content Distribution of Grape Using Refraction and Vision Processing Model

According to the refractive distinctiveness of the soluble solids, the refraction index of light will increase in a certain proportion in accordance with the increase of the concentration of the soluble solid, which provides a feasible method for measuring the variation of the sugar content. The critical angle had been applied to express the concentration variation of soluble solids in normal refraction system; thus the final result of soluble solids in every grape will be defined by Brix degree, which represents the sugar content of grape. In the experiments, the standard reference wavelength of refraction is 589.3 nm, the circumstance temperature will be set at 20°C, and then the Brix degree of many red grapes will be investigated in the above refraction system. This work focus on the upper, the middle and the bottom positions of each bunch red grape, many randomly selected grapes were used to test by refraction-based optical method. Through the experiments, the sugar content results show that the sugar content of the upper part of the grape fruits is relative higher than that of the bottom fruits.