OpenCV官方文档学习记录（3）

 1 #include <opencv2\opencv.hpp>
 2 #include <iostream>
 3 #include <string>
 4 
 5 #pragma comment( linker, "/subsystem:\"windows\" /entry:\"mainCRTStartup\"" )
 6 
 7 using namespace std;
 8 using namespace cv;
 9 
10 void Show(std::string name,Mat img)
11 {
12     namedWindow(name, CV_WINDOW_AUTOSIZE);
13     imshow(name, img);
14 }
15 
16 int main()
17 {
18     Mat img = imread("lena.png");
19     Mat new_img = Mat::zeros(img.size(), img.type());
20 
21     double alpha = 2.2;
22     int beta = 50;
23     for (int y = 0; y < img.rows; ++y)
24     {
25         for (int x = 0; x < img.cols; ++x)
26         {
27             for (int c = 0; c < 3; ++c)
28             {
29                 new_img.at<Vec3b>(y, x)[c] = static_cast<uchar>(alpha*(img.at<Vec3b>(y, x)[c]) + beta);
30             }
31         }
32     }
33     Show("Re", img);
34     Show("Bright", new_img);
35     imwrite("./after/bright.png", new_img);
36     waitKey();
37     return 0;
38 }

new_img.at<Vec3b>(y, x)[c]

 1 #include <opencv2\opencv.hpp>
 2 #include <iostream>
 3 #include <string>
 4 
 5 #pragma comment( linker, "/subsystem:\"windows\" /entry:\"mainCRTStartup\"" )
 6 
 7 using namespace std;
 8 using namespace cv;
 9 
10 void Show(std::string name,Mat img)
11 {
12     namedWindow(name, CV_WINDOW_AUTOSIZE);
13     imshow(name, img);
14 }
15 
16 int main()
17 {
18     Mat img = imread("lena.png");
19     Mat new_img = Mat::zeros(img.size(), img.type());
20     double alpha = 2.2;
21     int beta = 50;
22     img.convertTo(new_img, -1, alpha, beta);
23     Show("After", new_img);
24     waitKey();
25     return 0;
26 }