Crop a Region of Interest; RotatedRect

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void detect_text(string input){ Mat large = imread(input);

Mat rgb;
// downsample and use it for processing
pyrDown(large, rgb);
pyrDown(rgb, rgb);
Mat small;
cvtColor(rgb, small, CV_BGR2GRAY);
// morphological gradient
Mat grad;
Mat morphKernel = getStructuringElement(MORPH_ELLIPSE, Size(3, 3));
morphologyEx(small, grad, MORPH_GRADIENT, morphKernel);
// binarize
Mat bw;
threshold(grad, bw, 0.0, 255.0, THRESH_BINARY | THRESH_OTSU);
// connect horizontally oriented regions
Mat connected;
morphKernel = getStructuringElement(MORPH_RECT, Size(9, 1));
morphologyEx(bw, connected, MORPH_CLOSE, morphKernel);
// find contours
Mat mask = Mat::zeros(bw.size(), CV_8UC1);
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
findContours(connected, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));
// filter contours
for(int idx = 0; idx >= 0; idx = hierarchy[idx][0]){
    Rect rect = boundingRect(contours[idx]);
    Mat maskROI(mask, rect);
    maskROI = Scalar(0, 0, 0);
    // fill the contour
    drawContours(mask, contours, idx, Scalar(255, 255, 255), CV_FILLED);

    RotatedRect rrect = minAreaRect(contours[idx]);
    double r = (double)countNonZero(maskROI) / (rrect.size.width * rrect.size.height);

    Scalar color;
    int thickness = 1;
    // assume at least 25% of the area is filled if it contains text
    if (r > 0.25 &&
    (rrect.size.height > 8 && rrect.size.width > 8) // constraints on region size
    // these two conditions alone are not very robust. better to use something
    //like the number of significant peaks in a horizontal projection as a third condition
    ){
        thickness = 2;
        color = Scalar(0, 255, 0);

    }
    else
    {
        thickness = 1;
        color = Scalar(0, 0, 255);
    }


    Point2f pts[4];
    rrect.points(pts);
    for (int i = 0; i < 4; i++)
    {
        line(rgb, Point((int)pts[i].x, (int)pts[i].y), Point((int)pts[(i+1)%4].x, (int)pts[(i+1)%4].y), color, thickness);

    }

}

imwrite("contdd.jpg", rgb);

}

Hi I have a question about cropping an image with square detection/text recognition function applied to the image. Here is the result image . However, I want to save each text wrapped within the green squares individually like this:

Can anyone please help me with this?