#include <opencv2\\opencv.hpp>
using namespace cv;

int main()
{
    Mat3b img = imread("path_to_image");
    Mat1b binary;
    cvtColor(img, binary, CV_BGR2GRAY);
    threshold(binary, binary, 1, 255, THRESH_BINARY);

    Mat1b morph;
    Mat kernel = getStructuringElement(MORPH_ELLIPSE, Size(11,11));
    morphologyEx(binary, morph, MORPH_CLOSE, kernel, Point(-1,-1), 3);

    vector<vector<Point>> contours;
    findContours(morph.clone(), contours, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE);

    /// Draw contours
    Mat3b draw = img.clone();
    for (int i = 0; i < contours.size(); i++)
    {
        drawContours(draw, contours, i, Scalar(0,0,255), 2);
    }

    return 0;
}