samples/cpp/edge.cpp

该程序演示了 Canny 边缘检测器的使用方式

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#include "opencv2/core/utility.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
 
#include <stdio.h>
 
using namespace cv;
using namespace std;
 
int edgeThresh = 1;
int edgeThreshScharr=1;
 
Mat image, gray, blurImage, edge1, edge2, cedge;
 
const char* window_name1 = "边缘图：Canny 默认（Sobel 梯度）";
const char* window_name2 = "边缘图：带有自定义梯度的 Canny（Scharr）";
 
// 定义一个轨迹条回调函数
static void onTrackbar(int, void*)
{
blur(gray, blurImage, Size(3,3));
 
    // 在灰度图像上运行边缘检测器
Canny(blurImage, edge1, edgeThresh, edgeThresh*3, 3);
cedge = Scalar::all(0);
 
image.copyTo(cedge, edge1);
imshow(window_name1, cedge);
 
    Mat dx,dy;
Scharr(blurImage,dx,CV_16S,1,0);
Scharr(blurImage,dy,CV_16S,0,1);
Canny( dx,dy, edge2, edgeThreshScharr, edgeThreshScharr*3 );
cedge = Scalar::all(0);
image.copyTo(cedge, edge2);
imshow(window_name2, cedge);
}
 
static void help(const char** argv)
{
printf("\n该示例演示了 Canny 边缘检测\n"
           "调用方式：\n"
           " %s [图像名称 - 默认值为 fruits.jpg]\n\n", argv[0]);
}
 
const char* keys =
{
    "{help h||}{@image |fruits.jpg|输入图像名称}"
};
 
int main( int argc, const char** argv )
{
help(argv);
    CommandLineParser parser(argc, argv, keys);
    string filename = parser.get<string>(0);
 
image = imread(samples::findFile(filename), IMREAD_COLOR);
    if(image.empty())
    {
printf("无法读取图像文件：%s\n", filename.c_str());
help(argv);
        return -1;
    }
cedge.create(image.size(), image.type());
    cvtColor(image, gray, COLOR_BGR2GRAY);
 
    // 创建一个窗口
    namedWindow(window_name1, 1);
    namedWindow(window_name2, 1);
 
    // 创建一个工具栏
    createTrackbar("Canny 阈值默认", window_name1, &edgeThresh, 100, onTrackbar);
    createTrackbar("Canny 阈值 Scharr", window_name2, &edgeThreshScharr, 400, onTrackbar);
 
    // 显示图像
onTrackbar(0, 0);
 
    // 等待按键输入；该函数也处理事件
    waitKey(0);
 
    return 0;
}