The findContours function is significantly slower in version 4.11 compared to version 4.7. #26775
Description
Describe the feature and motivation
Thank you for your work, but I tested and found that the speed of this function in version 4.11 is slower than in version 4.7.
Here are the test images and test results.
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;
int main()
{
Mat img = imread("111.bmp", cv::IMREAD_GRAYSCALE);
cv::Mat mask;
inRange(img, 110, 120, mask);
std::vector<std::vector<cv::Point>> v_cont;
for (int i = 0; i < 10; i++)
{
v_cont.clear();
auto start = chrono::system_clock::now();
cv::findContours(mask, v_cont, cv::RETR_EXTERNAL, cv::CHAIN_APPROX_SIMPLE);
auto end = chrono::system_clock::now();
auto duration = chrono::duration_cast<chrono::microseconds>(end - start) / 1000.;
cout << "4.11 findContours cost" << double(duration.count()) << "ms" << endl;
}
}
Additional context
No response