将rotated_rect旋转到正矩形的方法记录

1、直接使用
cv::getRotationMatrix2D()
2、将四个顶点旋转角度
基本原理参考：这里写链接内容
1）先平移到center
2）进行旋转
3）重新加上偏移量

                double cosv=cos(abs(rotated_rect.angle*3.1415926/180));                double sinv=sin(abs(rotated_rect.angle*3.1415926/180));                cv::Point2f rect_points[4];                rotated_rect.points(rect_points);                cout<<"angle="<<rotated_rect.angle<<",cosv="<<cosv<<",sinv="<<sinv<<endl;                for(int l=0;l<4;l++){                    cv::Point2f p=rect_points[l];                    p.x-=rotated_rect.center.x;                    p.y-=rotated_rect.center.y;                    cv::Point2f np;                    np.x=cosv*p.x-sinv*p.y;                    np.y=sinv*p.x+cosv*p.y;                    np.x+=rotated_rect.center.x;                    np.y+=rotated_rect.center.y;                    cout<<"p["<<l<<"]="<<rect_points[l]<<",np="<<np<<endl;                                 }