char fname[MAX_PATH];
	openFileDlg(fname);
	Mat img = imread(fname, CV_LOAD_IMAGE_GRAYSCALE);
	int *a = histogramaaux(img);

	Mat cont = img.clone();
	int gOUTmin, gOUTmax;
	printf("Constrast:\n");
	printf("goutmin = ");
	scanf("%d", &gOUTmin);
	printf("goutmax = ");
	scanf("%d", &gOUTmax);

	int imax = 0;
	int imin = 255;

	for (int i = 0; i < 256; i++){
		if (a[i] != 0){
			imin = i;
			break;
		}

	}

	for (int i = 255; i >0; i--){
		if (a[i] != 0){
			imax = i;
			break;
		}

	}

	Mat contrast = img.clone();

	float factor = (imax - imin);
	for (int i = 0; i < img.rows; i++)
		for (int j = 0; j < img.cols; j++){
			float aux = gOUTmin + (img.at<uchar>(i, j) - imin)*(gOUTmax - gOUTmin) / factor;
			contrast.at<uchar>(i, j) = (int)aux;
		}
	imshow("src", img);
	imshow("Contrast", contrast);
	waitKey(0);