使用这个原型函数：

void dilate(InputArray src,OutputArray dst,InputArray kernel,Point anchor=Point(-1,-1),int iterations=1,int borderType=BORDER_CONSTANT,const Scalar& borderValue=morphologyDefaultBorderValue() )

这是我的代码：

#include "opencv2/opencv.hpp"

using namespace cv;

int main(int,char**)
{
    Mat edges;

    VideoCapture cap(0); // open the default camera
    if(!cap.isOpened())  // check if we succeeded
        return -1;


    for(;;)
    {

        Mat frame;
        cap >> frame; // get a new frame from camera
        cvtColor(frame,edges,CV_BGR2GRAY);
        GaussianBlur(edges,Size(7,7),1.5,1.5);
        //dilate(edges,NULL);
        Canny(edges,30,3);
        imshow("edges",frame);
        if(waitKey(30) >= 0) break;
    }
    // the camera will be deinitialized automatically in VideoCapture destructor
    return 0;
}