OpenCV图像处理专栏三 | 灰度世界算法原理和实现

Mat GrayWorld(Mat src) {
  vector <Mat> bgr;
  cv::split(src, bgr);
  double B = 0;
  double G = 0;
  double R = 0;
  int row = src.rows;
  int col = src.cols;
  Mat dst(row, col, CV_8UC3);
  for (int i = 0; i < row; i++) {
    for (int j = 0; j < col; j++) {
      B += 1.0 * src.at<Vec3b>(i, j)[0];
      G += 1.0 * src.at<Vec3b>(i, j)[1];
      R += 1.0 * src.at<Vec3b>(i, j)[2];
    }
  }
  B /= (row * col);
  G /= (row * col);
  R /= (row * col);
  printf("%.5f %.5f %.5f\n", B, G, R);
  double GrayValue = (B + G + R) / 3;
  printf("%.5f\n", GrayValue);
  double kr = GrayValue / R;
  double kg = GrayValue / G;
  double kb = GrayValue / B;
  printf("%.5f %.5f %.5f\n", kb, kg, kr);
  for (int i = 0; i < row; i++) {
    for (int j = 0; j < col; j++) {
      dst.at<Vec3b>(i, j)[0] = (int)(kb * src.at<Vec3b>(i, j)[0]) > 255 ? 255 : (int)(kb * src.at<Vec3b>(i, j)[0]);
      dst.at<Vec3b>(i, j)[1] = (int)(kg * src.at<Vec3b>(i, j)[1]) > 255 ? 255 : (int)(kg * src.at<Vec3b>(i, j)[1]);
      dst.at<Vec3b>(i, j)[2] = (int)(kr * src.at<Vec3b>(i, j)[2]) > 255 ? 255 : (int)(kr * src.at<Vec3b>(i, j)[2]);
    }
  }
  return dst;
}