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OpenCV Mat实例详解三中详细介绍来了OpenCV Mat类的公有静态成员函数，下面介绍OpenCV Mat类的其他常用成员函数。

OpenCV Mat类常用成员函数

Mat & adjustROI (int dtop, int dbottom, int dleft, int dright)；

dtop ROI 上边界移动值，如果为正，上边界向上移动，如果值为负，则向下移动。

dbottom ROI 下边界移动值，如果为正，下边界向下移动，如果值为负则向上移动。

dleftm ROI 左边界移动值，如果为正，左边界向左移动，如果值为负，则向右移动。

dbottom ROI 右边界移动值，如果为正，右边界向右移动，如果值为负，则向左移动。

这是一个比较有用的函数，在机器视觉中作目标检测及尺寸量测时，在对ROI区域左动态调整时，会用到这个函数。

下面来演示该函数的使用方法，新建一个空的控制台程序，在程序中加入如下代码：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    Mat src = imread("1.bmp");
    if(src.empty())
    { 
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);
    /*
    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

我们感兴趣的是载入图片左下角的那颗IC，但取得ROI区域时，却取入了部分别的原件图像。这种情况下就需要用到adjustROI函数来调整ROI区域。下面将程序中注释掉的程序段的注释取消，让adjustROI函数起作用，注释去掉后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    Mat src = imread("1.bmp");
    if(src.empty())
    { 
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);
    
    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例最下面的图片即为调用adjustROI函数调整后的ROI区域，不再包含误选的元件。

void assignTo (Mat &m, int type=-1) const；

它提供了一种Mat type 转换方法，如果type为-1.则不做type转换，这是矩阵表达式引擎调用的内部使用的方法。

修改上面的示例代码，来演示该函数的使用，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    Mat src = imread("1.bmp");
    if(src.empty())
    { 
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    /*
    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);
    
    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */

    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改上面的示例代码，修改后如下：

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    Mat src = imread("1.bmp");
    if(src.empty())
    { 
        cout << "Load image failed!" << endl;
        return -1;
    }
    //imshow("src", src);
 
    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);
    
    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;

    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

可以看出已实现src的type转换。虽然可实现type的转换，但是对于已有数据的Mat对象，这种转换可能导致原有数据没法使用及原有图像无法显示。

at()

用以获取Mat对象数据矩阵某以元素的值或者给其赋值。其原型有以下几种形式;

template<typename _Tp > _Tp & at (int i0=0)

template<typename _Tp > _Tp & at (int i0=0) const

template<typename _Tp > _Tp & at (int row, int col)

template<typename _Tp > const _Tp & at (int row, int col) const

template<typename _Tp > _Tp & at (int i0, int i1, int i2)

template<typename _Tp > const _Tp & at (int i0, int i1, int i2) const

template<typename _Tp > _Tp & at (const int *idx)

template<typename _Tp > const _Tp & at (const int *idx) const

template<typename _Tp > _Tp & at (const Vec< int, n > &idx)

template<typename _Tp > const _Tp & at (const Vec< int, n > &idx) const

template<typename _Tp > _Tp & at (Point pt)

template<typename _Tp > const _Tp & at (Point pt) const

上面的at函数原型都有带const与不带const两种形式，二者的区别在于可接受的参数不同。

修改上面代码，来演示其应用，修改后得到代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    { 
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
 
    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);
    
    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改以上代码，修改后如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    { 
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
 
    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);
    
    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改以上代码，修改后如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    { 
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
 
    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);
    
    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }

    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改上面代码，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    Mat m = Mat(5, 5, CV_8UC1);
    int const length = m.cols * m.rows*m.channels();
    int mdata[25] = {};
    for (size_t i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    Mat m = Mat(5, 5, CV_8UC1);
    int const length = m.cols * m.rows*m.channels();
    Point mdata[25] = {};
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    
    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改上面代码，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    Mat m = Mat(5, 5, CV_8UC1);
    int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    Vec<int, 25> mdata;
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    
    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

template<typename _Tp > MatIterator_< _Tp > begin ()

template<typename _Tp > MatIterator_< _Tp > begin () const

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    Mat m = Mat(5, 5, CV_8UC1);
    typedef Vec<uchar, 1> vec;
    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout << *it1_start;
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改上面代码，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    Mat m = Mat(5, 5, CV_8UC1);
    //typedef Vec<uchar, 1> vec;
    MatIterator_<uchar> it_start = m.begin<uchar>();
    MatIterator_<uchar> it_end = m.end<uchar>();

    MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    MatConstIterator_<uchar> it1_end = m.end<uchar>();
    int i = 0;
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<(int) *it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改上面代码，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

int channels () const

返回Mat对象数据矩阵的通道数，该函数以多次出现再前面的示例中，这里就不再做演示。

int checkVector (int elemChannels, int depth=-1, bool requireContinuous=true) const

elemChannels 矩阵应具有的通道数或列数。对于2-D矩阵，当矩阵只有1列时，它应该具有elemChannels通道；当矩阵只有1个通道时，它应该有elemChannels列。对于三维矩阵，它应该只有一个通道。此外，如果平面的数量不是一个，那么每个平面内的行数必须是1；如果每个平面内的行数不是1，则平面数必须是1。

depth 矩阵元素位深度，缺省位-1，对任意深度设置位-1是合适的。

requireContinuous 如果设置位true，矩阵需是连续的。

返回值如果不满足需求条件返回-1，否则返回矩阵元素个数，注意元素可能有多个通道。

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    cout << src.checkVector(src.channels(), -1, true)<<endl;
    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

CV_NODISCARD_STD Mat clone () const

返回一个克隆的Mat对象。

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    //cout << src.checkVector(src.channels(), -1, true)<<endl;

    Mat dst = src.clone();

    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;
    cout << " dst channels:  " << dst.channels() << endl;
    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

Mat col (int x) const

为指定的Mat的对象创建矩阵列头，该方法为指定的矩阵生成一个新的头，这是一个O（1）运算，与矩阵大小无关，x无论输入多大（0~源的cols范围内），新生成的矩阵cols都为1。新矩阵的基础数据与原始矩阵共享。

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    /*
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    //cout << src.checkVector(src.channels(), -1, true)<<endl;

    Mat dst = src.clone();

    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;
    cout << " dst channels:  " << dst.channels() << endl;
    */

    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;

    Mat dst = src.col(5);
    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;

    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

再修改上面的示例代码，插入一行修改dst cols的代码，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    /*
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    //cout << src.checkVector(src.channels(), -1, true)<<endl;

    Mat dst = src.clone();

    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;
    cout << " dst channels:  " << dst.channels() << endl;
    */

    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;

    Mat dst = src.col(5); 

    dst.cols = 100;
    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;

    
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

可以看出，当生成新Mat矩阵头后可以通过修改cols值，来调整新生成的Mat对象的矩阵数据范围。

Mat colRange (int startcol, int endcol) const

Mat colRange (const Range &r) const

这两个函数与上一个函数的作用差不多，只不过是这两个一开始就指定cols范围。

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    /*
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    //cout << src.checkVector(src.channels(), -1, true)<<endl;

    Mat dst = src.clone();

    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;
    cout << " dst channels:  " << dst.channels() << endl;
    */

    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;

    //Mat dst = src.col(5); 

    Mat dst = src.colRange(5,150);
    Mat dst1 = src.colRange(Range(50,220));
    //dst.cols = 100;
    imshow("dst", dst);
    imshow("dst1", dst1);
    moveWindow("dst1", 0, 200);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;


    cout << " dst1 cols: " << dst1.cols << endl;
    cout << " dst1 rows: " << dst1.rows << endl;
    cout << " dst1 type: " << dst1.type() << endl;

    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

用上面三个函数生成的Mat对象能否调用adjustROI函数来调整ROI区域呢？答案是肯定的。

void convertTo (OutputArray m, int rtype, double alpha=1, double beta=0) const

m 输出目标Mat 对象，如果其类型及大小不合适，将会被重新分配

alpha 像素BGR值比例缩放因子，可改变图像的明暗，不能缩改变图像大小，缺省为1

beta 添加到缩放因子的可选增量。

该方法将源像素值转换为目标数据类型。 saturate_cast<> 应用在末尾以避免可能的溢出，如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

void copySize (const Mat &m)

内部使用函数；正确地重新分配 _size、_step 数组

m 源Mat对象

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    /*
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    //cout << src.checkVector(src.channels(), -1, true)<<endl;

    Mat dst = src.clone();

    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;
    cout << " dst channels:  " << dst.channels() << endl;
    */

    /**
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;

    //Mat dst = src.col(5); 

    Mat dst = src.colRange(5,150);
    Mat dst1 = src.colRange(Range(50,220));
    //dst.cols = 100;
    imshow("dst", dst);
    imshow("dst1", dst1);
    moveWindow("dst1", 0, 200);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;

    cout << " dst1 cols: " << dst1.cols << endl;
    cout << " dst1 rows: " << dst1.rows << endl;
    cout << " dst1 type: " << dst1.type() << endl;
    */
    
    /**
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    src.convertTo(src, src.type(), 1.2, 0);
    imshow("src new", src);
    */
    
    Mat src = Mat(5, 5, CV_8UC1);
    cout << src.size() << endl;

    Mat dst = Mat(8, 8, CV_8UC3);
    
    src.copySize(dst);
    cout << src.size() << endl;
    
   
    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

void copyTo (OutputArray m) const

void copyTo (OutputArray m, InputArray mask) const

拷贝到另一个Mat对象

m 目标Mat对象

mask 与 *this 大小相同的操作掩码。它的非零元素表示哪些矩阵元素需要复制。掩码必须为 CV_8U 类型，并且可以有 1 个或多个通道。

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：

// OpenCVMatTest4.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

int main()
{
    /*
    Mat src = imread("1.bmp");
    if(src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    /*
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    //cout << src.checkVector(src.channels(), -1, true)<<endl;

    Mat dst = src.clone();

    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;
    cout << " dst channels:  " << dst.channels() << endl;
    */

    /**
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;

    //Mat dst = src.col(5); 

    Mat dst = src.colRange(5,150);
    Mat dst1 = src.colRange(Range(50,220));
    //dst.cols = 100;
    imshow("dst", dst);
    imshow("dst1", dst1);
    moveWindow("dst1", 0, 200);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;

    cout << " dst1 cols: " << dst1.cols << endl;
    cout << " dst1 rows: " << dst1.rows << endl;
    cout << " dst1 type: " << dst1.type() << endl;
    */
    
    /**
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    src.convertTo(src, src.type(), 1.2, 0);
    imshow("src new", src);
    */
    
    /*
    Mat src = Mat(5, 5, CV_8UC1);
    cout << src.size() << endl;

    Mat dst = Mat(8, 8, CV_8UC3);
    
    src.copySize(dst);
    cout << src.size() << endl;
    */
   
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    Mat dst;
    src.copyTo(dst);
    imshow("dst", dst);

    Mat mask(src.size(), CV_8UC1, cv::Scalar(255));
    mask(Rect(0, 0, src.cols/2, src.rows / 2)) = Scalar(0);

    Mat dst1(src.size(), src.type());
    src.copyTo(dst1, mask);
    imshow("dst1", dst1);

    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

void create (int rows, int cols, int type)

void create (Size size, int type)

void create (int ndims, const int *sizes, int type)

void create (const std::vector< int > &sizes, int type)

以上四个函数都是用以生成新的Mat对象，差别仅是接受的参数不同。

rows 新Mat对象的rows

cols 新Mat对象的cols

type 新Mat兑现的type

size 含新Mat对象rows、cols的vector对象

修改上面的示例代码，来演示该函数的用法，修改后的代码如下：


        return -1;
    }
    imshow("src", src);

    cout << "src cols: "<<src.cols << endl;
    cout << "src rows: "<<src.rows << endl;
    cout << "src type: "<< src.type() << endl;
    */

    /*
    Rect rec(0, 130, 120,90);
    Mat roi = Mat(src, rec);
    imshow("roi", roi);
    moveWindow("roi", 300, 300);

    roi.adjustROI(-5, 0, -5, -10);
    imshow("roi adj", roi);
    moveWindow("roi adj", 500, 500);
    */
    /*
    Mat dst;
    src.assignTo(dst, -1);
    imshow("dst",dst);
    */

    /*
    src.assignTo(src, CV_16FC3);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    */

    /*
    int mdata[] = { 10,10 };
    Mat m = Mat(1, mdata, CV_8UC1);
    for (size_t i = 0; i < 10; i++)
    {
        m.at<uchar>(i) = i;
    }
    for (size_t i = 0; i < 10; i++)
    {
        cout << (int)m.at<uchar>(i) << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC1);
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            m.at<uchar>(i, j) = i + j;
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
            cout << (int)m.at<uchar>(i, j);
        cout << endl;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            m.at<uchar>((i, j),0) = j;
            m.at<uchar>((i, j), 1) = j + 1;
            m.at<uchar>((i, j), 2) = j+ 2;
        }
    }
    for (size_t i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            cout << (int)m.at<uchar>((i, j),0);
            cout << (int)m.at<uchar>((i, j), 1);
            cout << (int)m.at<uchar>((i, j), 2) << "  ";
        }
        cout << endl;
    }
    */
 
    
    //Mat m = Mat(5, 5, CV_8UC1);
    //int const length = m.cols * m.rows*m.channels();
    //Point mdata[25] = {};
    //Vec<int, 25> mdata;
   
    /*
    for (int i = 0; i < m.rows; i++)
    {
        for (int j = 0; j < m.cols; j++)
        {
            mdata[i * 5 + j].x = i;
            mdata[i * 5 + j].y = j;
        }
    }
    */

    /*
    for (int i = 0; i < length; i++)
    {
        mdata[i] = i;
    }
    for (size_t i = 0; i < length; i++)
    {
        m.at<uchar>(mdata[i]) = (uchar)i;
        
    }
    for (int i = 0; i < length; i++)
    {
        cout << (int)m.at<uchar>(mdata[i]) << endl;
    }
    */

    //Mat m = Mat(5, 5, CV_8UC1);
    
    //typedef Vec<uchar, 1> vec;
    
    //MatIterator_<uchar> it_start = m.begin<uchar>();
    //MatIterator_<uchar> it_end = m.end<uchar>();


    //MatConstIterator_<uchar> it1_start = m.begin<uchar>();
    //MatConstIterator_<uchar> it1_end = m.end<uchar>();

    
    /*
    while (it_start != it_end)
    {
        *it_start = i + 1;
        i++;
        it_start++;
    }
    */

    /*
    Mat m = Mat(5, 5, CV_8UC3);
    typedef Vec<uchar, 3> vec;

    MatIterator_<vec> it_start = m.begin<vec>();
    MatIterator_<vec> it_end = m.end<vec>();

    MatConstIterator_<vec> it1_start = m.begin<vec>();
    MatConstIterator_<vec> it1_end = m.end<vec>();
    int i = 0;
    while (it_start != it_end)
    {
        it_start[0] = 255-i;
        it_start[1] = 255 - 2 * i;
        it_start[1] = 255 - 3 * i;
        i++;
        it_start++;
    }
    while (it1_start != it1_end)
    {
        cout <<*it1_start<<"  ";
        it1_start++;
    }
    cout <<endl;
    cout << m << endl;
    */
    
    /*
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);

    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;
    cout << "src channels:  " << src.channels() << endl;
    //cout << src.checkVector(src.channels(), -1, true)<<endl;

    Mat dst = src.clone();

    imshow("dst", dst);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;
    cout << " dst channels:  " << dst.channels() << endl;
    */

    /**
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    cout << "src cols: " << src.cols << endl;
    cout << "src rows: " << src.rows << endl;
    cout << "src type: " << src.type() << endl;

    //Mat dst = src.col(5); 

    Mat dst = src.colRange(5,150);
    Mat dst1 = src.colRange(Range(50,220));
    //dst.cols = 100;
    imshow("dst", dst);
    imshow("dst1", dst1);
    moveWindow("dst1", 0, 200);

    cout << " dst cols: " << dst.cols << endl;
    cout << " dst rows: " << dst.rows << endl;
    cout << " dst type: " << dst.type() << endl;

    cout << " dst1 cols: " << dst1.cols << endl;
    cout << " dst1 rows: " << dst1.rows << endl;
    cout << " dst1 type: " << dst1.type() << endl;
    */
    
    /**
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    src.convertTo(src, src.type(), 1.2, 0);
    imshow("src new", src);
    */
    
    /*
    Mat src = Mat(5, 5, CV_8UC1);
    cout << src.size() << endl;

    Mat dst = Mat(8, 8, CV_8UC3);
    
    src.copySize(dst);
    cout << src.size() << endl;
    */
   
    /*
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src", src);
    Mat dst;
    src.copyTo(dst);
    imshow("dst", dst);

    Mat mask(src.size(), CV_8UC1, cv::Scalar(255));
    mask(Rect(0, 0, src.cols/2, src.rows / 2)) = Scalar(0);

    Mat dst1(src.size(), src.type());
    src.copyTo(dst1, mask);
    imshow("dst1", dst1);
    */
    
    Mat src = imread("1.bmp");
    if (src.empty())
    {
        cout << "Load image failed!" << endl;
        return -1;
    }
    imshow("src 1th", src);

    src.create(src.rows-10, src.cols-10, src.type());
    imshow("src 2th", src);

    src.create(Size(src.rows, src.cols + 10), src.type());
    imshow("src 3th", src);

    int size[] = { 250,230 };
    src.create(2, size, CV_8UC3);
    imshow("src 4th", src);

    vector<int> vec(2);
    vec[0] = 230;
    vec[1] = 250;
    
    src.create(vec, CV_8UC3);
    imshow("src 5th", src);
    

    waitKey(0);
    return 0;
}

试运行，结果如下：

OpenCV Mat实例详解四,opencv,人工智能,计算机视觉,OpenCV Mat实例详解四,Mat常用成员函数用法详解,Mat类成员函数用法示例

由于篇幅关系，OpenCV Mat类的其他常用成员函数就暂时介绍到这里，剩余部分函数将在下篇中介绍。

本篇博文示例是基于OpenCV4.8（opencv目录位于d盘根目录下）及VS2022。示例源码已上传到CSDN，其链接为：https://download.csdn.net/download/billliu66/88839772文章来源地址https://www.toymoban.com/news/detail-831799.html

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