关键词: 开心果, 机器视觉, 分级

Abstract: To improve the quality of pistachio nuts, it is necessary to remove the closed shell pistachio nuts. A single row equally spacing method was taken to carry the pistachio nuts on the conveyor belt, and every pistachio nut image was captured by camera during the transmission. Then the image processing algorithm was used to detect whether its shell was open or not. Finally, gas nozzle, which was at the end of the conveyor belt, was used to blow away the closed shell pistachio nuts. Pistachio image was reduced to 0.2 times, and then the centroid of binary pistachio image was searched. After that, three horizontal pixel lines were described from the binary pistachio image, which was positioned in the centroid of pistachio, the middle of the upper part of pistachio and the middle of the lower part of pistachio. The gray value changes of all pixels of three lines were calculated respectively, and the features of those three pixel lines were integrated to judge whether the pistachio shell was open or not. Experiment results prove that the correct discrimination rates of the open shell pistachio nuts and the closed shell pistachio nuts are 93% and 100% respectively.

Key words: pistachio nut, machine vision, sorting