一、简介
二、绘制点集的凸包
1 #include<opencv2/opencv.hpp> 2 using namespace cv; 3 4 void main() 5 { 6 //---绘制点集的凸包 7 Mat img(400, 400, CV_8UC3, Scalar::all(0)); //定义绘制图像 8 RNG rng; //定义随机数对象 9 while(1) 10 { 11 char key; 12 int count = (unsigned int)rng % 100; //定义点的个数 13 vector<Point> points; //定义点集 14 for(int i=0; i<count; i++) 15 { 16 Point pt; 17 pt.x = rng.uniform(img.cols/4, img.cols*3/4); //设定点的x范围 18 pt.y = rng.uniform(img.rows/4, img.rows*3/4); //设定点的y范围 19 points.push_back(pt); 20 } 21 22 //检测凸包 23 vector<int> hull; 24 convexHull(Mat(points), hull, true); 25 26 img = Scalar::all(0); 27 for(int i = 0; i < count; i++ ) 28 circle(img, points[i], 3, Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255)), CV_FILLED, CV_AA); 29 30 //准备参数 31 int hullcount = (int)hull.size(); //凸包的边数 32 Point point0 = points[hull[hullcount-1]]; //连接凸包边的坐标点 33 34 //绘制凸包的边 35 for(int i = 0; i < hullcount; i++ ) 36 { 37 Point point = points[hull[i]]; 38 circle(img, point, 8, Scalar(0, 255, 0), 2, 8); 39 line(img, point0, point, Scalar(255, 255, 255), 2, CV_AA); 40 point0 = point; 41 } 42 43 //显示效果图 44 imshow("img", img); 45 46 //按下ESC,Q,或者q，程序退出 47 key = (char)waitKey(); 48 if( key == 27 || key == 'q' || key == 'Q' ) 49 break; 50 } 51}
三、绘制轮廓的凸包
1 #include<opencv2/opencv.hpp> 2 using namespace cv; 3 4 void main() 5 { 6 Mat srcImg = imread("E://12.jpg"); 7 imshow("src", srcImg); 8 Mat dstImg2 = srcImg.clone(); 9 Mat tempImg(srcImg.rows, srcImg.cols, CV_8UC3, Scalar::all(0)); //用于绘制凸包 10 Mat dstImg(srcImg.rows, srcImg.cols, CV_8UC3, Scalar::all(0)); //用于绘制轮廓 11 cvtColor(srcImg, srcImg, CV_BGR2GRAY); 12 threshold(srcImg, srcImg, 100, 255, CV_THRESH_BINARY); //二值化 13 14 vector<vector<Point>> contours; 15 vector<Vec4i> hierarcy; 16 findContours(srcImg, contours, hierarcy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE); 17 vector<vector<Point>> hull(contours.size()); 18 for(int i=0; i<contours.size(); i++) 19 { 20 convexHull(Mat(contours[i]), hull[i], true); //查找凸包 21 drawContours(dstImg, contours, i, Scalar(255, 255, 255), -1, 8); //绘制轮廓 22 //drawContours(dstImg, hull, i, Scalar(rand()%255, rand()%255, rand()%255), 2, 8); 23 drawContours(tempImg, hull, i, Scalar(255, 255, 255), -1, 8); 24 } 25 imshow("hull", tempImg); 26 imshow("contours", dstImg); 27 28 Mat diffImg; 29 absdiff(tempImg, dstImg, diffImg); //图像相减 30 Mat element = getStructuringElement(MORPH_RECT, Size(3, 3), Point(-1, -1)); 31 erode(diffImg, diffImg, element); 32 imshow("diff", diffImg); 33 34 vector<vector<Point>> contours2; 35 vector<Vec4i> hierarcy2; 36 cvtColor(diffImg, diffImg, CV_BGR2GRAY); //转为灰度图 37 threshold(diffImg, diffImg, 100, 255, CV_THRESH_BINARY); //二值化 38 findContours(diffImg, contours2, hierarcy2, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE); 39 drawContours(dstImg2, contours2, -1, Scalar(0, 0, 255), 2, 8); //红色绘制缺陷轮廓 40 imshow("defects", dstImg2); 41 waitKey(0); 42 }
