OpenCV基本图像容器Mat的几种创建方法_cv::mat 使用外部地址

参考文章：http://www.cnblogs.com/tornadomeet/archive/2012/07/19/2599376.html

实验说明： （引用）

　　本文主要讲一些opencv 2.0版本后出现的Mat矩形类，主要是参考opencv自带doc文件夹下的tutiol教材。通过这次实验觉得用Mat的话下面几点需要特别注意（在代码中可以体现出来）：

#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
 
using namespace std;
using namespace cv;
 
int demo_Mat()
{
    int next_num = 1;
	char tmp;
	while(next_num<7)
	{
		cout<<"-------- "<<next_num<<" --------"<<endl;
		waitKey(0);
		
		switch (next_num)
        {
           case 1:
            {
				Mat M( 2, 2, CV_8UC3, Scalar(0,255,0) );//其实是2*6的矩阵，因为每个元素有3个通道。
				cout<<"create by using the constructor..."<<endl;
				cout<<"M = \n "<<M<<endl;
 
				M.create( 4, 4, CV_8UC(2));//括号里面的2表示2通道
				cout<< "create by using create function..."<<endl;
				cout<<"M = \n "<<M<<endl;
				break;
            }//当case语句里面变量定义时，需要用括号括起来，否则会报错
           case 2:
            {
                int sz[3] = {2, 2, 2};
                Mat L( 3, sz, CV_8UC(1), Scalar::all(0) );
                cout<< "create multidimensional matrix..."<<endl;
                // cout<<"L =   "<<L<<endl;此处不能打印出来，因为那只适应二维数组
                break;
            }
            case 3:
            {
                Mat E = Mat::eye(4, 4, CV_64F);
                Mat O = Mat::ones(2, 3, CV_32F);
                Mat Z = Mat::zeros(3, 3, CV_8UC1);
                cout<< "using matlab stytle..."<<endl;
                cout<<"E = \n "<<E<<endl;
                cout<<"O = \n "<<O<<endl;
                cout<<"Z = \n "<<Z<<endl;
                break;
            }
			case 4:
			{
				Mat C =(Mat_<double>(3,3)<<0,-1,0,-1,5,-1,0,-1,0);//直接赋初始值的方法
				Mat row_clone = C.row(1).clone();
				cout<< "create 3*3 double-precision identity matrix..."<<endl;
				cout<<"C = \n "<<C<<endl;
				cout<<"row_clone =  "<<row_clone<<endl;
				break;
			}
            case 5:
            {
                Mat R = Mat( 3, 2, CV_8UC3 );
                randu( R, Scalar::all(0), Scalar::all(255) );
                cout<< "fill a matrix with rand numbers..."<<endl;
                cout<<"R (default) =  "<<R<<endl;
                cout<< "demonstrate the output formating options..."<<endl;
                cout<<"R (python) = \n "<<format(R, "python")<<endl;
                cout<<"R (numpy) = \n "<<format(R, "numpy")<<endl;//numpy是一个用python实现的科学计算包
                cout<<"R (csv) = \n "<<format(R, "csv")<<endl;//csv,逗号分隔符
                cout<<"R (c) = \n " <<format(R, "C")<<endl;
                break;
            }
			case 6:
			{
				cout<< "the point format output..."<<endl;
 
				Point2f P1(5, 1);
				cout<<"Point (2D) = "<<P1<<endl;
 
				Point3f P2(4, 5, 6);
				cout<<"Point (3D) = "<<P2<<endl;
 
				vector<float>v;
				v.push_back( (float)CV_PI);
				v.push_back( 2 );//push_back为在其尾部加入一个数据
				v.push_back( 3.01f );
				cout<<"vector of float: = "<<Mat(v)<<endl;//vector数据是没法单独输出的,因此可以借助mat输出
 
				int N = 20;
				vector<Point2f>vPoints(N);//vector可以用变量定义其长度，比数组好用
				for( size_t E = 0; E < vPoints.size(); ++E )    //size_t其实就是一个unsigned int类型
					vPoints[E] = Point2f((float)(E*5), (float)(E%7));
				cout<<"vPoints[] = \n"<<vPoints<<endl;//但是vector点确实可以直接输出的，因为这时候的vector本身就是
														//一个多维（至少2维）Mat了
				break;
			}
			default:
				break;
        }
		next_num++;
	}
	return 0;
}
 

运行结果：