找到圖形的’極點‘，然後根據圖形的幾何關係便可以得到結果。程式碼如下。（如有錯誤還請指出）

/********************************************************************
** 文  件  名：幾何圖形的簡單判斷
** 創  建  人：yk
** 最後修改時間：2018年9月1日
*********************************************************************/

#include "stdafx.h"
#include <iostream>
#include <stdio.h>
#include "opencv2/core.hpp"
#include "opencv2/core/utility.hpp"
#include "opencv2/core/ocl.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"

void YKrectangle(Mat &image, Point Start, Point End, int flog)
{
	if (flog == 0)
	{

		for (int i = Start.y; i <= End.y; i++)
		{
			for (int j = Start.x; j <= End.x; j++)
			{

				image.at<Vec3b>(i, j)[0] = 0;
				image.at<Vec3b>(i, j)[1] = 255;
				image.at<Vec3b>(i, j)[2] = 0;


			}
		}
	}
	else if (flog == 1)
	{

		for (int i = Start.y; i <= End.y; i++)
		{
			for (int j = Start.x; j <= End.x; j++)
			{
				if (i == Start.y || i == End.y || j == Start.x || j == End.x)
				{
					image.at<Vec3b>(i, j)[0] = i;
					image.at<Vec3b>(i, j)[1] = j;
					image.at<Vec3b>(i, j)[2] = (i + j) / 2;
				}

			}
		}
	}

}




int main()
{
	int x = 0, y = 0, x1 = 0, y1 = 0;
	Mat img = imread("G:\\yk\\Desktop\\檔案\\aI\\opencv\\opencv圖\\3.bmp", 0);
	Mat img2 = imread("G:\\yk\\Desktop\\檔案\\aI\\opencv\\opencv圖\\3.bmp", 0);;
	Mat img1 = Mat::zeros(img.rows, img.cols, CV_8UC3);

	vector<vector<Point>>conts;

	vector<Vec4i>hicouts;
	threshold(img, img, 100, 254, 1);
	blur(img, img, Size(3, 3));
	imshow("3", img2);
	img = ~img;
	imshow("1", img);
	for (int i = 0; i < img2.rows; i++)//畫到原圖上
	{
		for (int j = 0; j < img2.cols; j++)
		{
			if ((int)img2.at<uchar>(i, j) > 0)
			{
				img2.at<uchar>(i, j) = 255;
			}
		}
	}


	for (int i = 0; i < img.rows; i++)//畫到原圖上
	{
		for (int j = 0; j < img.cols; j++)
		{
			img1.at<Vec3b>(i, j)[0] = img.at<uchar>(i, j);
			img1.at<Vec3b>(i, j)[1] = img.at<uchar>(i, j);
			img1.at<Vec3b>(i, j)[2] = img.at<uchar>(i, j);
			//cout << (int)img.at<uchar>(i, j) << endl;
		}
	}

	Canny(img, img, 30, 70);
	findContours(img, conts, hicouts, CV_RETR_TREE, CHAIN_APPROX_SIMPLE);

	for (int i = 0; i < conts.size(); i++)
	{
		int temp = conts[i][0].x, temp1 = conts[i][0].y, temp2 = conts[i][0].x, temp3 = conts[i][0].y;
		for (int j = 0; j < conts[i].size(); j++)
		{

			if (conts[i][j].x < temp)
			{
				temp = conts[i][j].x;
			}
			if (conts[i][j].y < temp1)
			{
				temp1 = conts[i][j].y;
			}
			if (conts[i][j].x > temp2)
			{
				temp2 = conts[i][j].x;
			}
			if (conts[i][j].y > temp3)
			{
				temp3 = conts[i][j].y;
			}



		}
		//cout << (int)img.at<uchar>(temp - 10, temp1 - 10) << endl;
		if (fabs((temp3 - temp1) - (temp2 - temp)) < 5)
		{
			Scalar color(0, 255, 0);
			drawContours(img1, conts, i, color, -1, 8, hicouts);
		}

		else if ((int)img2.at<uchar>(temp + 50, temp1 + 3) == 0)
		{
			Scalar color(255, 0, 0);
			drawContours(img1, conts, i, color, -1, 8, hicouts);
		}
		else
		{
			Scalar color(0, 0, 255);
			drawContours(img1, conts, i, color, -1, 8, hicouts);
		}
		Point start(temp - 5, temp1 - 5), end(temp2 + 5, temp3 + 5);
		YKrectangle(img1, start, end, 1);
	}

	imshow("s", img1);
	imwrite("G:\\yk\\Desktop\\檔案\\aI\\opencv\\opencv圖\\3result.bmp", img1);

	waitKey(0);

}