本文根据椭圆弦长的比值相对固定提出了弦长比法, 并运用SOM 神经网络对纽荷尔脐橙进行分级, 取得了一定的效果。-Based on the ratio of elliptical chord chord made relatively fixed ratio method, and the use of SOM neural network for classification of Newhall navel orange, and achieved some results.