1 #include "opencv2/imgproc/imgproc.hpp" 2 #include "opencv2/highgui/highgui.hpp" 3  4 #include <stdio.h> 5  6 using namespace cv; 7 using namespace std; 8  9 int edgeThresh = 1;10 Mat image, gray, edge, cedge;11 12 // define a trackbar callback13 void onTrackbar(int, void*)14 {15     blur(gray, edge, Size(3,3));16 17     // Run the edge detector on grayscale18     Canny(edge, edge, edgeThresh, edgeThresh*3, 3);19     cedge = Scalar::all(0);20     21     image.copyTo(cedge, edge);22     imshow("Edge map", cedge);23 }24 25 int main( int argc, const char** argv )26 {27 28     image = imread("fruits.jpg", 1);//读取图片到mat29     cedge.create(image.size(), image.type());//用image生成一个cedge30     //void cvCvtColor( const CvArr* src, CvArr* dst, int code );31     //src 输入的 8-bit , 16-bit 或 32-bit 单倍精度浮点数影像. 32     //dst 输出的 8-bit , 16-bit 或 32-bit 单倍精度浮点数影像. 33     //code 色彩空间转换，通过定义 CV_<src_color_space>2<dst_color_space> 常数 (见下面). 34     //函数 cvCvtColor 将输入图像从一个色彩空间转换为另外一个色彩空间。35     cvtColor(image, gray, CV_BGR2GRAY);//转换为灰度图[色彩空间转换]36     37     // Create a window38     namedWindow("Edge map", 1);39     // create a toolbar40     createTrackbar("Canny threshold", "Edge map", &edgeThresh, 100, onTrackbar);41     // Show the image42     onTrackbar(0, 0);43 44     // Wait for a key stroke; the same function arranges events processing45     waitKey(0);46     return 0;47 }