vector<vector<Point>> vec_p;
vector<Vec4i> vec_4f;
findContours(img_canny1, vec_p, vec_4f,RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));
drawContours(img3, vec_p, i, color_1, 2, 8, vec_4f, 0, Point(0, 0));
原文：https://www.cnblogs.com/herd/p/9737387.html