访问像素

#include <opencv.hpp>
using namespace cv;
using namespace std;
int main()
{
	//指针访问每个像素并赋值
	Mat img = imread("001.jpg");
	for (int i = 0; i < img.rows; i++)
	{
		uchar* data = img.ptr<uchar>(i); // 获取每i行的首地址
		for (int j = 0; j < (img.cols*img.channels())/*列数乘以通道数*/; j++)
			data[j] = 200;
	}
	imshow("2", img);
	waitKey(0);
	
	return 0;
}

#include <opencv.hpp>
using namespace cv;
using namespace std;
int main()
{
	//使用迭代器
	Mat img = imread("001.jpg");
	Mat_<Vec3b>::iterator it = img.begin<Vec3b>(); // 迭代器的初始位置
	Mat_<Vec3b>::iterator itend = img.end<Vec3b>(); // 迭代器的终止位置
	for (; it != itend; it++)
	{
		(*it)[0] = 0;
		(*it)[2] = 0;
		(*it)[1] = 255;
	}
	imshow("2", img);
	waitKey(0);
	
	return 0;
}

#include <opencv.hpp>
using namespace cv;
using namespace std;
int main()
{
	//动态地址计算 use .at
	Mat img = imread("001.jpg");
	for (int i = 0; i < img.rows; i++)
	for (int j = 0; j < img.cols; j++)
	{
		img.at<Vec3b>(i, j)[0] = 0;
		img.at<Vec3b>(i, j)[1] = 0;
		img.at<Vec3b>(i, j)[2] = 244;
	}
	imshow("2", img);
	waitKey(0);
	
	return 0;
}