public static void imgConverter(String filename) { Mat m1 = Imgcodecs.imread(filename, Imgcodecs.CV_LOAD_IMAGE_ANYCOLOR); Displayer t1 = new Displayer(m1, "test mat to bfd"); BufferedImage image = null; try { image = ImageIO.read(new File(filename)); } catch (Exception e) { e.printStackTrace(); System.exit(0); } Mat m2 = ImgConverter.bfd2Mat(image); Displayer t2 = new Displayer(m2, "test bfd to mat"); }