1 #include "opencv2/opencv.hpp"
 2 using namespace cv;
 3 
 4 void main()
 5 {
 6     //Canny边缘检测
 7     Mat srcImg = imread("E://1.png",0); //0表示以灰度图读入,彩色图和灰度图进行边缘检测时略有不同,建议使用灰度图
 8     //medianBlur(srcImg, srcImg,5);//中值滤波
 9     imshow("src", srcImg);
10 
11     Mat dstImg;
12     Canny(srcImg, dstImg, 30, 80);
13     imshow("Canny", dstImg);
14     waitKey(0);
15 }

 1 #include "opencv2/opencv.hpp"
 2 using namespace cv;
 3 
 4 Mat src,dst;
 5 int min_thres=30,max_thres=100;//不能直接命名为min，max，标准库std里有min和max方法
 6 
 7 void onCanny(int,void*){
 8     Canny(src, dst,min_thres,max_thres);
 9     imshow("src",src);    
10     imshow("Canny", dst);
11 }
12 
13 void main()
14 {
15     src=imread("E://9.jpg",0);
16     namedWindow("Canny",CV_WINDOW_AUTOSIZE);
17     createTrackbar("min_thres","Canny",&min_thres,255,onCanny,0);
18     createTrackbar("max_thres","Canny",&max_thres,255,onCanny,0);
19 
20     onCanny(min_thres,0);//回调函数初始化
21     onCanny(max_thres,0);
22 
23     waitKey(0);
24     destroyAllWindows();
25 }

 1 #include "opencv2/opencv.hpp"
 2 using namespace cv;
 3 
 4 void main()
 5 {
 6     Mat grad_x, grad_y;
 7     Mat abs_grad_x, abs_grad_y, dst;
 8 
 9     Mat src = imread("E://5.jpg", 0);
10     imshow("src", src);
11 
12     Sobel(src, grad_x, CV_16S, 1, 0, 3);//16位有符号（求导时有正负），x方向参数设置为1,0
13     convertScaleAbs(grad_x, abs_grad_x);//转为无符号
14     imshow("X方向", abs_grad_x);
15 
16     Sobel(src, grad_y, CV_16S, 0, 1, 3);//y方向参数设置为0,1
17     convertScaleAbs(grad_y, abs_grad_y);
18     imshow("Y方向", abs_grad_y);
19 
20     addWeighted(abs_grad_x, 0.5, abs_grad_y, 0.5, 0, dst);
21     imshow("合并效果", dst);
22 
23     waitKey(0);
24     destroyAllWindows();
25 }

 1 #include "opencv2/opencv.hpp"
 2 using namespace cv;
 3 
 4 void main()
 5 {
 6     Mat src,dst,abs_dst;
 7     src = imread("E://lena.jpg", 0);
 8     imshow("src", src);
 9 
10     Laplacian(src, dst, CV_16S, 3);
11     convertScaleAbs(dst, abs_dst);
12     imshow("Laplacian", abs_dst);
13 
14     waitKey(0);
15     destroyAllWindows();
16 }