C++ OpenCV透视变换综合练习

//重新排序旋转矩形坐标点void SortRotatedRectPoints(Point2f vetPoints[], RotatedRect rect){  rect.points(vetPoints);
  cout << vetPoints[0] << vetPoints[1] << vetPoints[2] << vetPoints[3] << endl;  cout << rect.angle << endl;
  Point2f curpoint;  //根据Rect的坐标点，Y轴最大的为P[0]，p[0]围着center顺时针旋转,   //旋转角度为负的话即是P[0]在左下角，为正P[0]是右下角    //重新排序坐标点  if (rect.angle > 0) {    curpoint = vetPoints[0];    vetPoints[0] = vetPoints[2];    vetPoints[2] = curpoint;    curpoint = vetPoints[1];    vetPoints[1] = vetPoints[3];    vetPoints[3] = curpoint;  }  else if (rect.angle < 0) {    curpoint = vetPoints[0];    vetPoints[0] = vetPoints[1];    vetPoints[1] = vetPoints[2];    vetPoints[2] = vetPoints[3];    vetPoints[3] = curpoint;  }
}

//根据最小矩形点找最近的四边形点//第一参数为输出的点，第二个参数为矩形的4个点，第三个为多边形拟合的点 void GetPointsFromRect(Point2f vetPoints[], Point2f rectPoints[], vector<Point> convex){  //定义最远的4个点，0--左上， 1--右上， 2--右下  3--左下  float ltdist = 99999999.9f;  //左上的最大距离   float rtdist = 99999999.9f;  //右上的最大距离   float rbdist = 99999999.9f;  //右下的最大距离   float lbdist = 99999999.9f;  //左下的最大距离  float curdist = 0.0f; //当前点的计算距离  
  for (auto curpoint : convex) {    //计算左上点的距离     curdist = CalcPointDistance(rectPoints[0], curpoint);    if (curdist < ltdist) {      ltdist = curdist;      vetPoints[0] = curpoint;    }    //计算右上角的点距离    curdist = CalcPointDistance(rectPoints[1], curpoint);    if (curdist < rtdist) {      rtdist = curdist;      vetPoints[1] = curpoint;    }    //计算右下角点的距离    curdist = CalcPointDistance(rectPoints[2], curpoint);    if (curdist < rbdist) {      rbdist = curdist;      vetPoints[2] = curpoint;    }    //计算左下角点的距离    curdist = CalcPointDistance(rectPoints[3], curpoint);    if (curdist < lbdist) {      lbdist = curdist;      vetPoints[3] = curpoint;    }  }}
//计算两点间的距离float CalcPointDistance(Point2f point1, Point2f point2){  //计算两个点的Point差值  Point2f tmppoint = point1 - point2;  //利用欧几里德距离计算H  return sqrt(pow(tmppoint.x, 2) + pow(tmppoint.y, 2));}

#include<iostream>#include<opencv2/opencv.hpp>
using namespace std;using namespace cv;
//根据中心点找四角最远的点void GetRectPoints(Point2f vetPoints[], Point2f center, vector<Point> convex);//根据最小矩形点找最近的四边形点void GetPointsFromRect(Point2f vetPoints[], Point2f rectPoints[], vector<Point> convex);
//排序旋转矩形坐标点void SortRotatedRectPoints(Point2f vetPoints[], RotatedRect rect);//计算距离float CalcPointDistance(Point2f point1, Point2f point2);


int main(int argc, char** argv) {
  Mat src = imread("E:/DCIM/tsnew.jpg");  Mat gray, dst, dst2, result;  //图像缩放  resize(src, gray, Size(0, 0), 0.2, 0.2);  imshow("src", gray);
  //灰度图  cvtColor(gray, dst, COLOR_BGRA2GRAY);
  //高斯滤波  GaussianBlur(dst, dst, Size(3, 3), 0.5, 0.5);  imshow("gray", dst);
  //二值化  threshold(dst, dst2, 0, 255, THRESH_BINARY | THRESH_OTSU);  imshow("thresh", dst2);
  //形态学开操作  Mat kernel = getStructuringElement(MORPH_RECT, Size(5, 5), Point(-1, -1));  morphologyEx(dst2, dst2, MORPH_OPEN, kernel);  imshow("morph", dst2);
  //Canny边缘检测  Canny(dst2, result, 127, 255, 7, true);  imshow("canny", result);
  //查找轮廓  vector<vector<Point>> contours;  findContours(result, contours, RETR_LIST, CHAIN_APPROX_SIMPLE);
  cout << contours.size() << endl;  vector<vector<Point>> contours_poly(contours.size());  Mat tmpgray;  gray.copyTo(tmpgray);  for (int i = 0; i < contours.size(); ++i) {    //计算轮廓周长，大于图像宽度的才算主体    double dlen = arcLength(contours[i], true);    if (dlen > gray.cols) {      //多边形拟合      approxPolyDP(Mat(contours[i]), contours_poly[i], 10, true);
      cout << "当前：" << i << " 点数：" << contours_poly[i].size() << endl;            if (contours_poly[i].size() >= 4) {        //获取最小旋转矩形        RotatedRect rRect = minAreaRect(contours_poly[i]);        Point2f vertices[4];        //重新排序矩形坐标点，按左上，右上，右下，左下顺序        SortRotatedRectPoints(vertices, rRect);
        cout << vertices[0] << vertices[1] << vertices[2] << vertices[3] << endl;
        //根据获得的4个点画线        for (int k = 0; k < 4; ++k) {          line(gray, vertices[k], vertices[(k + 1) % 4], Scalar(255, 0, 0));        }
        //多边形拟合的画出轮廓        drawContours(gray, contours_poly, i, Scalar(0, 0, 255));
        //计算四边形的四点坐标        Point2f rPoints[4];        //GetRectPoints(rPoints, rRect.center, contours_poly[i]);        GetPointsFromRect(rPoints, vertices, contours_poly[i]);        for (int k = 0; k < 4; ++k) {          line(gray, rPoints[k], rPoints[(k + 1) % 4], Scalar(255, 255, 255));        }

        //根据最小矩形和多边形拟合的最大四个点计算透视变换矩阵            //重新排序多边形拟合的4点        Rect rect = rRect.boundingRect();        rectangle(gray, rect, Scalar(0, 0, 0));
        Point2f rectPoint[4];        rectPoint[0] = Point2f(rect.x, rect.y);        rectPoint[1] = Point2f(rect.x + rect.width, rect.y);        rectPoint[2] = Point2f(rect.x + rect.width, rect.y + rect.height);        rectPoint[3] = Point2f(rect.x, rect.y + rect.height);               //vector<Point> vecpt(vertices, vertices + 4);        //GetRectPoints(vertices, rRect.center, vecpt);
        //计算透视变换矩阵            Mat warpmatrix = getPerspectiveTransform(rPoints, rectPoint);        Mat resultimg;                //透视变换        warpPerspective(tmpgray, resultimg, warpmatrix, resultimg.size(), INTER_LINEAR);        imshow("resultimg", resultimg);
      }    }  }  imshow("src2", gray);
  waitKey(0);  return 0;}
//根据中心点找最远的四个点void GetRectPoints(Point2f vetPoints[], Point2f center, vector<Point> convex){  //定义最远的4个点，0--左上， 1--右上， 2--右下  3--左下  float ltdist = 0.0f;  //左上的最大距离   float rtdist = 0.0f;  //右上的最大距离   float rbdist = 0.0f;  //右下的最大距离   float lbdist = 0.0f;  //左下的最大距离
  for (auto curpoint : convex) {    //计算点的距离     float curdist = CalcPointDistance(center, curpoint);
    if (curpoint.x < center.x && curpoint.y < center.y)    {      //判断是否在左上      if (curdist > ltdist) {        ltdist = curdist;        vetPoints[0] = curpoint;      }    }    else if (curpoint.x > center.x && curpoint.y < center.y) {      //判断在右上      if (curdist > rtdist) {        rtdist = curdist;        vetPoints[1] = curpoint;      }    }    else if (curpoint.x > center.x && curpoint.y > center.y) {      //判断在右下      if (curdist > rbdist) {        rbdist = curdist;        vetPoints[2] = curpoint;      }    }    else if (curpoint.x < center.x && curpoint.y > center.y) {      //判断在左下      if (curdist > lbdist) {        lbdist = curdist;        vetPoints[3] = curpoint;      }    }
  }  }
//根据最小矩形点找最近的四边形点//第一参数为输出的点，第二个参数为矩形的4个点，第三个为多边形拟合的点 void GetPointsFromRect(Point2f vetPoints[], Point2f rectPoints[], vector<Point> convex){  //定义最远的4个点，0--左上， 1--右上， 2--右下  3--左下  float ltdist = 99999999.9f;  //左上的最大距离   float rtdist = 99999999.9f;  //右上的最大距离   float rbdist = 99999999.9f;  //右下的最大距离   float lbdist = 99999999.9f;  //左下的最大距离  float curdist = 0.0f; //当前点的计算距离  
  for (auto curpoint : convex) {    //计算左上点的距离     curdist = CalcPointDistance(rectPoints[0], curpoint);    if (curdist < ltdist) {      ltdist = curdist;      vetPoints[0] = curpoint;    }    //计算右上角的点距离    curdist = CalcPointDistance(rectPoints[1], curpoint);    if (curdist < rtdist) {      rtdist = curdist;      vetPoints[1] = curpoint;    }    //计算右下角点的距离    curdist = CalcPointDistance(rectPoints[2], curpoint);    if (curdist < rbdist) {      rbdist = curdist;      vetPoints[2] = curpoint;    }    //计算左下角点的距离    curdist = CalcPointDistance(rectPoints[3], curpoint);    if (curdist < lbdist) {      lbdist = curdist;      vetPoints[3] = curpoint;    }  }}
//重新排序旋转矩形坐标点void SortRotatedRectPoints(Point2f vetPoints[], RotatedRect rect){  rect.points(vetPoints);
  cout << vetPoints[0] << vetPoints[1] << vetPoints[2] << vetPoints[3] << endl;  cout << rect.angle << endl;
  Point2f curpoint;  //根据Rect的坐标点，Y轴最大的为P[0]，p[0]围着center顺时针旋转,   //旋转角度为负的话即是P[0]在左下角，为正P[0]是右下角    //重新排序坐标点  if (rect.angle > 0) {    curpoint = vetPoints[0];    vetPoints[0] = vetPoints[2];    vetPoints[2] = curpoint;    curpoint = vetPoints[1];    vetPoints[1] = vetPoints[3];    vetPoints[3] = curpoint;  }  else if (rect.angle < 0) {    curpoint = vetPoints[0];    vetPoints[0] = vetPoints[1];    vetPoints[1] = vetPoints[2];    vetPoints[2] = vetPoints[3];    vetPoints[3] = curpoint;  }
}
//计算两点间的距离float CalcPointDistance(Point2f point1, Point2f point2){  //计算两个点的Point差值  Point2f tmppoint = point1 - point2;  //利用欧几里德距离计算H  return sqrt(pow(tmppoint.x, 2) + pow(tmppoint.y, 2));}