像素操作就是更改图片的像素值

代码如下：

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

using namespace cv;
using namespace std;

int main(int argc, char** argv) {
cout << "hello world!" << endl;
Mat src = imread("D:/OpenCVprj/image/test.png");
namedWindow("input image", CV_WINDOW_AUTOSIZE);
imshow("input image", src);

//pixel opration
Mat src_gray;
cvtColor(src, src_gray, CV_BGR2GRAY);
int rows = src_gray.rows;
int cols = src_gray.cols;
int channel = src.channels();
namedWindow("src_gray", CV_WINDOW_AUTOSIZE);
imshow("src_gray", src_gray);

Mat dst;
dst.create(src.size(), src.type());

for (int row = 0; row < rows; row++) {
for (int col = 0; col < cols; col++) {
if (channel == 1) {
int gray = src_gray.at<uchar>(row, col);
dst.at<uchar>(row, col) = 255 - gray;
}
else if (channel == 3) {
int b = src.at<Vec3b>(row, col)[0];
int g = src.at<Vec3b>(row, col)[1];
int r = src.at<Vec3b>(row, col)[2];
dst.at<Vec3b>(row, col)[0] = 255 - b;
dst.at<Vec3b>(row, col)[1] = 255 - g;
dst.at<Vec3b>(row, col)[2] = 255 - r;
}
}
}

namedWindow("dst", CV_WINDOW_AUTOSIZE);
imshow("dst", dst);
waitKey(0);
return 0;
}

结果：

 

 

该操作相当于bitwise_not(image, dst);

即把每个像素点的值 作 255 - pixel；

代码如下：

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

using namespace std;
using namespace cv;

int main(int argc, char** argv) {
cout << "hello world!" << endl;
Mat src = imread("D:/OpenCVprj/image/test.png");
namedWindow("src", CV_WINDOW_AUTOSIZE);
imshow("src", src);

Mat dst;
bitwise_not(src, dst);
namedWindow("dst", CV_WINDOW_AUTOSIZE);
imshow("dst", dst);
waitKey(0);
return 0;
}

结果如下：

 

进行其它操作可看到不同效果

 

结果如下：