RotatedRect 校正带旋转角度的矩形

#include "opencv2/highgui/highgui.hpp"
#include <cv.h> 
 
using namespace cv;
 
void main()
{
	Mat img = imread("C:/rect1.png");
	Mat img_gray;
	cvtColor(img, img_gray, CV_BGR2GRAY);
	Mat thresh_img(img.size(), CV_8UC1);
	threshold(img_gray, thresh_img, 230, 255, THRESH_BINARY_INV);
 
	imshow("thresh", thresh_img);
	waitKey();
	vector<vector<Point>> contours;
	findContours(thresh_img, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);
	RotatedRect mr = minAreaRect(Mat(contours[0]));
	Mat DrawImg(img.size(), img.type(), Scalar(255, 255, 255));
	Point2f vectpoint[4];
	mr.points(vectpoint);
	for (int i = 0; i<4; i++)
	{
		line(DrawImg, vectpoint[i], vectpoint[(i + 1) % 4], Scalar(255, 0, 0), 2);
	}
 
	imshow("drawimg", DrawImg);
	waitKey();
	float angle = 0.0;
	Size si = mr.size;
	if (mr.size.width <= mr.size.height)
	{
		angle = mr.angle + 90;
		int tm = si.width;
		si.width = si.height;
		si.height = tm;
		//swap(si.width, si.height);
	}
	else
	{
		angle = mr.angle;
	}
	Mat rotmat = getRotationMatrix2D(mr.center, angle, 1);
	Mat deal_img;
	warpAffine(img, deal_img, rotmat, img.size(), CV_INTER_CUBIC);
 
	imshow("deal_img", deal_img);
	waitKey();
	Mat rRect;
	getRectSubPix(deal_img, si, mr.center, rRect);
	imshow("截取的矩形区域", rRect);
	waitKey();
}