OpenCV 改变图像的对比度和亮度

 #include <opencv2/core/core.hpp>
 #include <opencv2/highgui/highgui.hpp>
 #include <iostream>

 using namespace std;
 using namespace cv;

 double alpha; /**< 控制对比度 */
 int beta;  /**< 控制亮度 */

 int main( int argc, char** argv )
 {
     /// 读入用户提供的图像
     Mat image = imread( argv[] );
     Mat new_image = Mat::zeros( image.size(), image.type() );

     /// 初始化
     cout << " Basic Linear Transforms " << endl;
     cout << "-------------------------" << endl;
     cout << "* Enter the alpha value [1.0-3.0]: ";
     cin >> alpha;
     cout << "* Enter the beta value [0-100]: ";
     cin >> beta;

     /// 执行运算 new_image(i,j) = alpha*image(i,j) + beta
     for( int y = ; y < image.rows; y++ )
     {
         for( int x = ; x < image.cols; x++ )
         {
             for( int c = ; c < ; c++ )
             {
                 new_image.at<Vec3b>(y,x)[c] = saturate_cast<uchar>( alpha*( image.at<Vec3b>(y,x)[c] ) + beta );
             }
         }
     }

     /// 创建窗口
     namedWindow("Original Image", );
     namedWindow("New Image", );

     /// 显示图像
     imshow("Original Image", image);
     imshow("New Image", new_image);

     /// 等待用户按键
     waitKey();
     return ;
 }