public Histogram findHistogram(Mat mat, int numBins, boolean normalize){
MatOfInt channels = new MatOfInt(0);
MatOfInt histSize = new MatOfInt(numBins);
float[] r = {0f, 256f};
MatOfFloat ranges = new MatOfFloat(r);
Mat hist = new Mat();
ArrayList<Mat> images = new ArrayList<Mat>();
images.add(mat);