在opencv的环境下，测试图像预处理结果，亮点是测试了对灰度图先进行形态学处理再阈值分割和先阈值分割再形态学的区别。-Opencv environment in the test image pre-processing the results, highlight the first test for morphological processing of gray-scale thresholding and then thresholding again before morphological differences.