测试图像
左侧Edge map : Canny default (Sobel gradient)
右侧Edge map : Canny with custom gradient (Scharr)
源码:
#include "opencv2/core/utility.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include
using namespace cv;
using namespace std;
int edgeThresh = 1;//sobel梯度 canny边缘检测的阈值 最小值
int edgeThreshScharr = 1;//Scharr自定义梯度 canny边缘检测最小阈值
Mat image, gray, blurImage, edge1, edge2, cedge;
const char* window_name1 = "Edge map : Canny default (Sobel gradient)";
const char* window_name2 = "Edge map : Canny with custom gradient (Scharr)";
// define a trackbar callback
static void onTrackbar(int, void*)
{
blur(gray, blurImage, Size(3, 3));//滤波
// 在灰度图上运行边缘检测器Run the edge detector on grayscale
Canny(blurImage, edge1, edgeThresh, edgeThresh * 3, 3);//Sobel算子的孔径大小3
cedge = Scalar::all(0);
image.copyTo(cedge, edge1);
imshow(window_name1, cedge);
///带 scharr 的 Canny 探测器 Canny detector with scharr
Mat dx, dy;
Scharr(blurImage, dx, CV_16S, 1, 0);
Scharr(blurImage, dy, CV_16S, 0, 1);
Canny(dx, dy, edge2, edgeThreshScharr, edgeThreshScharr * 3);
///使用 Canny 的输出作为掩码,我们显示我们的结果 Using Canny's output as a mask, we display our result
cedge = Scalar::all(0);
image.copyTo(cedge, edge2);
imshow(window_name2, cedge);
}
static void help(const char** argv)
{
printf("\nThis sample demonstrates Canny edge detection\n"
"Call:\n"
" %s [image_name -- Default is fruits.jpg]\n\n", argv[0]);
}
const char* keys =
{
"{help h||}{@image |apple.jpg|input image name}"//fruits.jpg
};
int main(int argc, const char** argv)
{
help(argv);
CommandLineParser parser(argc, argv, keys);
string filename = parser.get(0);
image = imread(samples::findFile(filename), IMREAD_COLOR);//读取彩色图像
if (image.empty())
{
printf("Cannot read image file: %s\n", filename.c_str());
help(argv);
return -1;
}
cedge.create(image.size(), image.type());
cvtColor(image, gray, COLOR_BGR2GRAY);//灰度图
// Create a window
namedWindow(window_name1, 1);
namedWindow(window_name2, 1);
// create a toolbar
createTrackbar("Canny threshold default", window_name1, &edgeThresh, 100, onTrackbar);
createTrackbar("Canny threshold Scharr", window_name2, &edgeThreshScharr, 400, onTrackbar);
// Show the image
onTrackbar(0, 0);
// Wait for a key stroke; the same function arranges events processing
waitKey(0);
return 0;
}