minEnclosingCircle is much slower than minAreaRect

C++
1

when I use minEnclosingCircle and minAreaRect function in win10 x64,I found that minEnclosingCircle is much slower than minAreaRect.My opencv version is 4.5.3.this is my code.

void pre_process(Mat &img)
{
	cvtColor(img, img, COLOR_BGR2GRAY);
	img = 255 - img;
	threshold(img, img, 0, 240, THRESH_BINARY);
	Mat element = getStructuringElement(MORPH_RECT, Size(5, 5));

	for(int i = 0;i<5;i++)
		morphologyEx(img, img, MORPH_ERODE, element);
	
}

int main()
{
	Mat templateImg = imread("../TestImg/FF.bmp");
	pre_process(templateImg);
	vector<vector<Point>> contours_base;
	findContours(templateImg, contours_base, RETR_EXTERNAL, CHAIN_APPROX_NONE);

	Point2f center_temp;
	float   radius_temp;

	double start = (double)getTickCount() / getTickFrequency();
	minEnclosingCircle(contours_base[26], center_temp, radius_temp);
	double end = (double)getTickCount() / getTickFrequency();
	cout << "minEnclosingCircle use time: " << end - start << "s" << endl;

	start = (double)getTickCount() / getTickFrequency();
	RotatedRect rect_base = minAreaRect(contours_base[26]);
	end = (double)getTickCount() / getTickFrequency();
	cout << "minAreaRect use time: " << end - start << "s" << endl;
}

This is the output.

minEnclosingCircle use time: 1.09211s
minAreaRect use time: 0.000266s

This is my input img.

FF
FF1920×1440 55.1 KB

Is this normal for the lost time?