Background removal improvement

edit

I would like to remove the background of bees to be able to do further analyses with them. Input file My current solution is:

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>

using namespace cv;
using namespace std;


int main(int argc, char** argv)
{
    Mat mat = imread("./mite2.jpg ");
    Mat preimgThresholded, hsv_image;
    cvtColor(mat, hsv_image, CV_BGR2HSV);
    inRange(hsv_image, Scalar(13, 30, 30), Scalar(180, 250, 250), preimgThresholded);

    erode(preimgThresholded, preimgThresholded, getStructuringElement(MORPH_ELLIPSE, Size(6, 6)) );
    dilate( preimgThresholded, preimgThresholded, getStructuringElement(MORPH_ELLIPSE, Size(6, 6)) );

    //morphological closing (fill small holes in the foreground)
    dilate( preimgThresholded, preimgThresholded, getStructuringElement(MORPH_ELLIPSE, Size(50, 50)) );
    //morphological opening (remove small objects from the foreground)
    erode(preimgThresholded, preimgThresholded, getStructuringElement(MORPH_ELLIPSE, Size(50, 50)) );

    //morphological opening (remove small objects from the foreground)
    erode(preimgThresholded, preimgThresholded, getStructuringElement(MORPH_ELLIPSE, Size(70, 70)) );
    dilate( preimgThresholded, preimgThresholded, getStructuringElement(MORPH_ELLIPSE, Size(70, 70)) );

    Mat mat_filtered;
    mat.copyTo(mat_filtered, preimgThresholded);
    cvtColor(mat_filtered, hsv_image, CV_BGR2HSV);

    imshow("Cells", mat_filtered);
    waitKey();
}

This is the current output:

My current solution doesn't robust at all. (depends on color and doesn't work properly)

I would really appreciate if someone could help me how to improve my current solution. Any ideas, suggestions are welcomed.