<pre name="code" class="cpp"><span style="font-size:18px;">#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace std;  
using namespace cv; 
void readimageinat(Mat &image);


int main()
{
	Mat image = imread("boldt.jpg");//載入圖片
	Mat grayframe;
	if (!image.data)//測試是否載入
	{
		cout<<"fail to open!"<<endl;
	}
	if (image.channels() == 3)//變為灰度影象
	{
		cvtColor(image,grayframe,CV_RGB2GRAY);
	}
	if (!grayframe.data)
	{
		cout << "影象未建立"<<endl;
	}
	cout << "image.rows = "<< image.rows <<endl; //360//獲得影象的大小
	cout << "image.cols = "<< image.cols <<endl; //480
	Mat imageROI;//定義和初始化ROI區域，而且Rect（）範圍需要根據實際情況選取</span>
 

<span style="font-size:18px;">        int roiup = 20;
<span style="white-space:pre">	</span>int roidown = 30;
<span style="white-space:pre">	</span>int roileft = 20;
<span style="white-space:pre">	</span>int roiright = 30;
	imageROI = grayframe(Rect(roiup,roileft,roidown,roiright));
	//通過圓來測試roi的工作原理
	//圓心
	Point center = Point(10,10);
	//半徑
	int r = 10;
	circle(imageROI,center,r,Scalar(0,0,0));//在ROI上畫圓
	readimageinat(imageROI);
	//readimageinat(grayframe);

	imshow("grayframe",grayframe);//顯示和儲存圖片
	imwrite("grayframe.jpg",grayframe);
	imshow("imageROI",imageROI);
	imwrite("imageROI.jpg",imageROI);
	waitKey(0);
}</span>
 

           

<span style="font-size:18px;">void readimageinat(Mat &image)
{
	for (int i = 0;i < image.rows; i++)
	{ 
		cout << "i  = "<< i << " ";
		for (int j = 0;j <image.cols; j++)
		{
			image.at<uchar>(j) = 0;
		}
		cout << endl;
	}

}</span><span style="font-size: 24px;">
</span>