一:Point类
Point是一个模板类,其模板类的定义如下
template<typename _Tp> class Point_
{
public:
typedef _Tp value_type;
//! default constructor
Point_();
Point_(_Tp _x, _Tp _y);
Point_(const Point_& pt);
Point_(const Size_<_Tp>& sz);
Point_(const Vec<_Tp, 2>& v);
Point_& operator = (const Point_& pt);
//默认构造函数
template<typename _Tp2> operator Point_<_Tp2>() const;
//转换为旧式的C结构
operator Vec<_Tp, 2>() const;
//点积
_Tp dot(const Point_& pt) const;
//用双精度算术计算的点积
double ddot(const Point_& pt) const;
//叉积
double cross(const Point_& pt) const;
//检查点是否在指定矩形内
bool inside(const Rect_<_Tp>& r) const;
_Tp x; //点的x坐标
_Tp y; //点的y坐标
};
在OpenCV中使用重命名进行了如下定义
typedef Point_<int> Point2i; //int类型Point_
typedef Point_<int64> Point2l; //int64类型Point_
typedef Point_<float> Point2f; //flota类型Point_
typedef Point_<double> Point2d; //double类型Point_
typedef Point2i Point; //int类型Point,因为int类型使用相对多些,再次重取名,编
下面结合一些例子进行理解
#pragma once
#include
#include
#include
using namespace std;
using namespace cv;
int main() {
//使用默认构造函数
Point2i p1;//[0,0]
Point2l p2;//[0,0]
Point2f p3;//[0,0]
Point2d p4;//[0,0]
//使用默认构造函数进行赋值操作
Point2i p5(1,3);//[1, 3]
Point2l p6(256,300);//[256, 300]
Point2f p7(2.9,3.6);//[2.9, 3.6]
Point2d p8(2.69,5.36);//[2.69, 5.36]
Point3i p9(1, 2, 3);//[1, 2, 3]
Point3f p10(1, 2, 3);//[1, 2, 3]
Point3d p11(1, 2, 3);//[1, 2, 3]
//进行隐式类型转换,转换为Vec3i
Vec3i p12 = p9;
cout << p12 << endl;//[1, 2, 3]
//访问成员函数
cout << p5.x << " " << p5.y << endl;//1 3
cout << p9.x << " " << p9.y << " " << p9.z << endl;//1 2 3
//点乘--计算向量之间的夹角
Point3f f1(2.1, 2.2, 2.3);
Point3f f2(4.1, 4.2, 4.3);
float f1_f2;
f1_f2 = f1.dot(f2);//2.1*4.1+2.2*4.2+2.3*4.3=27.74
cout << f1_f2 << endl;
//叉乘,计算三维点影像
//结果是两个向量的垂直向量
Point3i i1(1, 2, 3);
Point3i i2(5, 6, 7);
Point3i i1xi2;
i1xi2 = i1.cross(i2);
cout << i1xi2 << endl;//[-4, 8, -4],该向量与i1和i2分别相乘的结果均为0,表示该向量与另外两个向量分别垂直
//判断一个点是否在矩阵内
Rect2f rest(1, 1, 2, 2);
Point2f f3(1.5, 1.5);
bool flag = f3.inside(rest);
cout << flag << endl;//true
//改变一下点的位置
f3.y = 6.2;
flag = f3.inside(rest);
cout << flag << endl;//false
return 0;
}
下面说一说
这几种输出类型
vector<vector<Point>>
vector<Rect>
vector<Vec4i>
vector<RotateRect>
先把实验图像放上去
然后上代码,代码不是我敲的,我用的是opencv4,懒得敲了,借用了作者:Ahuuua链接https://blog.csdn.net/Ahuuua/article/details/80593388的代码,代码不难,之前我的一篇博客计算轮廓区域面积中都用到过,都是opencv自带的函数,不过里面通过for循环找轮廓点的地方值得大家看一下。
#include
#include
using namespace cv;
using namespace std;
int demovector() {
Mat src, gray_src, drawImg, bin_output;
src = imread("apple.jpg");
//namedWindow("input", CV_WINDOW_AUTOSIZE);
//namedWindow("output", CV_WINDOW_AUTOSIZE);
imshow("input", src);
cvtColor(src, gray_src, COLOR_BGR2GRAY);
blur(gray_src, gray_src, Size(10, 10), Point(-1, -1), BORDER_DEFAULT);
//这些个类型
vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
threshold(gray_src, bin_output, 144, 255, 0); //二值化
findContours(bin_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0)); //找轮廓
//这些个类型
vector<vector<Point>> contours_poly(contours.size());
vector<Rect> poly_rects(contours.size());
vector<RotatedRect> minRect(contours.size());
//取点
for (size_t i = 0; i < contours.size(); i++)
{
approxPolyDP(Mat(contours[i]), contours_poly[i], 3, true); //减少轮廓点数
poly_rects[i] = boundingRect(contours_poly[i]);//获取绘制矩形数据
if (contours_poly[i].size() > 5) {
minRect[i] = minAreaRect(contours_poly[i]);//获取绘制旋转矩形数据
}
}
//开始绘制
src.copyTo(drawImg);
Point2f pst[4];//储存单个旋转矩形的四个点
cout << "----------Point2f pst[4]------------" << endl;
for (size_t i = 0; i < contours.size(); i++)
{
rectangle(drawImg, poly_rects[i], Scalar(255, 0, 0), 2, 8);//绘制矩形框
minRect[i].points(pst);//用线段画矩形,将RotatedRect类型转化为四个点
for (size_t u = 0; u < 4; u++)
{
line(drawImg, pst[u], pst[(u + 1) % 4], Scalar(0, 255, 0), 2, 8);
cout << pst[u]; //显示pst的数据
}
cout << endl;
Rect brect = minRect[i].boundingRect(); //返回包含旋转矩形的最小矩形
rectangle(drawImg, brect, Scalar(0, 0, 255));
}
cout << endl;
imshow("output", drawImg);
cout << "----------vector> contours_poly------------" << endl;
for (size_t i = 0; i < contours_poly.size(); i++)
{
cout << "第" << i << "行:";
for (size_t j = 0; j < contours_poly[i].size(); j++)
{
cout << contours_poly[i][j];
}
cout << endl;
}
cout << endl;
cout << "----------vector hierarchy------------" << endl;
for (size_t i = 0; i < hierarchy.size(); i++)
{
cout << hierarchy[i] << endl;
}
cout << endl;
cout << "----------vector poly_rects------------" << endl;
for (size_t i = 0; i < poly_rects.size(); i++)
{
cout << poly_rects[i] << endl;
}
cout << endl;
cout << "---------vector minRect------------" << endl;
for (size_t i = 0; i < minRect.size(); i++) //显示一下点minRect
{
cout << "angle:" << minRect[i].angle << " center:" << minRect[i].center << " size:" << minRect[i].size << endl;
}
cout << endl;
waitKey(0);
return 0;
}
vector<vector<Point>>
vector<Vec4i>
vector<Rect>
vector<RotateRect>