ColorBalance

void  ColorBalance()
{
    char imageName[] = "C:\\Users\\24932\\Desktop\\landsat8\\20180620-tianjin.bmp";
    Mat M = imread(imageName, IMREAD_COLOR);   // 读入图片 
    if (M.empty())     // 判断文件是否正常打开  
    {
        cout << "open file error";
    }
    imshow("原始图像", M);
    int channel = M.channels();
    int rows = M.rows;
    int cols = M.cols;
    Mat mt(rows, cols, CV_8UC1);
    double Ysum = 0, Ymax = 0,Yaver=0;//亮度和，亮度最大值，平均亮度
   double SumR=0, SumG=0, SumB=0;//灰色点集中R,G,B分别的和
   double AverR = 0,AverG = 0, AverB = 0;//灰色点集中R,G,B分别的平均值
    for (int i = 0; i < M.rows; i++)
    {
        for (int j = 0; j < M.cols; j++)
        {
           mt.at<uchar>(i,j) = M.at<Vec3b>(i, j)[0] * 0.229 + M.at<Vec3b>(i, j)[1] * 0.587 + M.at<Vec3b>(i, j)[2] * 0.114;//利用公式将彩色图像转化为灰度图像
           Ysum += mt.at<uchar>(i, j);
           if (mt.at<uchar>(i, j) >Ymax)
           {
               Ymax = mt.at<uchar>(i, j);
           }
        }
    }
    Yaver = Ysum / (rows * cols) ;
    for (int i = 0; i < rows; i++)
    {
        for (int j = 0; j < cols; j++)
        {
            if (mt.at<uchar>(i,j)<0.95 * Ymax)//灰度
            {
                SumB += M.at<Vec3b>(i, j)[0];
                SumG += M.at<Vec3b>(i, j)[1];
                SumR += M.at<Vec3b>(i, j)[2];
            }
        }
    }
    AverB = SumB / (rows * cols) ;
    AverG = SumG / (rows * cols) ;
    AverR = SumR / (rows * cols) ;
   double Bmax = max(AverB, AverG);
   Bmax = max(Bmax, AverR);//最大的Bmax;
   //彩色平衡系数
    double  KR = Bmax / AverR;
    double KG = Bmax / AverG;
    double KB = Bmax / AverB;
    Mat Ms(rows, cols, CV_8UC3);
    for (int i = 0; i <rows; i++)
    {
        for (int j = 0; j < cols; j++)
        {
            Ms.at<Vec3b>(i, j)[0] = KB * M.at<Vec3b>(i, j)[0];
            Ms.at<Vec3b>(i, j)[1] = KB * M.at<Vec3b>(i, j)[1];
            Ms.at<Vec3b>(i, j)[1] = KB * M.at<Vec3b>(i, j)[1];
        }
    }
    imshow("色彩平衡后图像", Ms);
    imwrite("C:\\Users\\24932\\Desktop\\landsat8\\色彩平衡后.bmp", Ms);
    waitKey();
   
}