OpenCV4查找绘制点集/轮廓的最小外接矩形、最小外接圆、最小外接三角形 C++代码

OpenCV4查找绘制点集的最小外接矩形、最小外接圆、最小外接三角形 C++代码：

#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <iostream>
using namespace cv;
using namespace std;
static void help()
{
  cout << "This program demonstrates finding the minimum enclosing box, triangle or circle of a set\n"
    << "of points using functions: minAreaRect() minEnclosingTriangle() minEnclosingCircle().\n"
    << "Random points are generated and then enclosed.\n\n"
    << "Press ESC, 'q' or 'Q' to exit and any other key to regenerate the set of points.\n\n";
}
int main(int /*argc*/, char** /*argv*/)
{
  help();
  Mat img(500, 500, CV_8UC3, Scalar::all(0));
  RNG& rng = theRNG();
  for (;;)
  {
    int i, count = rng.uniform(1, 101);
    vector<Point> points;
    // Generate a random set of points
    for (i = 0; i < count; i++)
    {
      Point pt;
      pt.x = rng.uniform(img.cols / 4, img.cols * 3 / 4);
      pt.y = rng.uniform(img.rows / 4, img.rows * 3 / 4);
      points.push_back(pt);
    }
    // Find the minimum area enclosing bounding box
    Point2f vtx[4];
    RotatedRect box = minAreaRect(points);
    box.points(vtx);
    // Find the minimum area enclosing triangle
    vector<Point2f> triangle;
    minEnclosingTriangle(points, triangle);
    // Find the minimum area enclosing circle
    Point2f center;
    float radius = 0;
    minEnclosingCircle(points, center, radius);
    img = Scalar::all(0);
    // Draw the points
    for (i = 0; i < count; i++)
      circle(img, points[i], 3, Scalar(0, 0, 255), FILLED, LINE_AA);
    // Draw the bounding box
    for (i = 0; i < 4; i++)
      line(img, vtx[i], vtx[(i + 1) % 4], Scalar(0, 255, 0), 1, LINE_AA);
    // Draw the triangle
    for (i = 0; i < 3; i++)
      line(img, triangle[i], triangle[(i + 1) % 3], Scalar(255, 255, 0), 1, LINE_AA);
    // Draw the circle
    circle(img, center, cvRound(radius), Scalar(0, 255, 255), 1, LINE_AA);
    imshow("Rectangle, triangle & circle", img);
    char key = (char)waitKey();
    if (key == 27 || key == 'q' || key == 'Q') // 'ESC'
      break;
  }
  return 0;
}

OpenCV4查找绘制轮廓的最小外接矩形、最小外接圆、最小外接三角形 C++代码：

#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <iostream>
using namespace cv;
using namespace std;

int main()
{
  Mat img = imread("1.png");
  Mat gray;
  cvtColor(img, gray, COLOR_BGR2GRAY);
  threshold(gray, gray, 0, 255, THRESH_BINARY | THRESH_OTSU);
  imshow("thres_otsu", gray);
  vector<vector<Point>>contours;
  findContours(gray, contours, RETR_EXTERNAL, CHAIN_APPROX_NONE);
  for(int k = 0; k < contours.size(); k++)
  { 
    // Find the minimum area enclosing bounding box
    Point2f vtx[4];
    RotatedRect box = minAreaRect(contours[k]);
    box.points(vtx);
    // Find the minimum area enclosing triangle
    vector<Point2f> triangle;
    minEnclosingTriangle(contours[k], triangle);
    // Find the minimum area enclosing circle
    Point2f center;
    float radius = 0;
    minEnclosingCircle(contours[k], center, radius);
    // Draw the bounding box
    for (int i = 0; i < 4; i++)
      line(img, vtx[i], vtx[(i + 1) % 4], Scalar(0, 255, 0), 1, LINE_AA);
    // Draw the triangle
    for (int i = 0; i < 3; i++)
      line(img, triangle[i], triangle[(i + 1) % 3], Scalar(255, 255, 0), 1, LINE_AA);
    // Draw the circle
    circle(img, center, cvRound(radius), Scalar(0, 255, 255), 1, LINE_AA);
  }
  imshow("Rectangle, triangle & circle", img);
  char key = (char)waitKey();
  return 0;
}