Find background color of an article image

kmeans.cpp

#include <stdio.h>
#include <opencv\cv.h>
#include <opencv\highgui.h>

int main(int argc, char* argv[])
{
    cv::Mat img = cv::imread("E:\\stuff\\articles\\Test Articles\\article_25.jpg", 
                            CV_LOAD_IMAGE_UNCHANGED);

    if (img.empty())
    {
        std::cout << "can not read image!" << std::endl;
        return -1;
    }

    cv::cvtColor(img, img, cv::COLOR_BGR2RGB);
    img = img.reshape(3, img.rows * img.cols);
    img.convertTo(img, CV_32F);
  
    int clusterCount = 2;
    int dimensions = 3;
    cv::Mat labels, centers(2, 1, CV_32F);
    std::cout << "dimensionality " << img.dims << std::endl;
    std::cout << "type " << (img.type() == CV_32F ? "true" : "false") << std::endl;
    
    try
    {
      cv::kmeans(img, 
                clusterCount, 
                labels, 
                cv::TermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 50, 30.0), 
                10, 
                cv::KMEANS_PP_CENTERS, centers);
    }
    catch (std::exception e)
    {
      std::cout << e.what() << std::endl;
    }
    //  dump centers
    std::cout << "Center: \n" << centers << std::endl;
    //  output Mats
    cv::Mat backgound(200, 200, CV_8UC3), foreground(200, 200, CV_8UC3);
    cv::Scalar center1 = cv::Scalar(centers.at<float>(0, 2), 
                        centers.at<float>(0, 1), 
                        centers.at<float>(0, 0));
    cv::Scalar center2 = cv::Scalar(centers.at<float>(1, 2), 
                        centers.at<float>(1, 1), 
                        centers.at<float>(1, 0));
    if (center1.val[0] > center2.val[0] && 
        center1.val[1] > center2.val[1] && 
        center1.val[2] > center2.val[2])
    {
      //  center 1 is background
      backgound.setTo(center1);
      foreground.setTo(center2);
    }
    else
    {
      //  center 2 is background
      backgound.setTo(center2);
      foreground.setTo(center1);
    }

  cv::namedWindow("background", CV_WINDOW_AUTOSIZE);
  imshow("background", backgound);
  cv::namedWindow("foreground", CV_WINDOW_AUTOSIZE);
  imshow("foreground", foreground);
  cv::waitKey();
  cv::destroyAllWindows();
  return 0;
}