9.simple特征提取并导出

Mat src = Imgcodecs.imread("2023.jpg");
        // 创建SimpleBlobDetector对象
        SimpleBlobDetector detector = SimpleBlobDetector.create();
        // 检测关键点
        MatOfKeyPoint keyPoints = new MatOfKeyPoint();
        detector.detect(src, keyPoints);
        Mat descriptors = new Mat();
        detector.compute(src, keyPoints, descriptors);
        String filename = "features1.xml";
        Document doc = DocumentHelper.createDocument();
        Element root = doc.addElement("features");
        for (KeyPoint keyPoint : keyPoints.toArray()) {
            Element student = root.addElement("feature");
            student.addAttribute("x", String.valueOf(keyPoint.pt.x));
            student.addAttribute("y", String.valueOf(keyPoint.pt.y));
            student.addAttribute("size", String.valueOf(keyPoint.size));
            student.addAttribute("angle", String.valueOf(keyPoint.angle));
            student.addAttribute("response", String.valueOf(keyPoint.response));
            student.addAttribute("octave", String.valueOf(keyPoint.octave));
            student.addAttribute("class_id", String.valueOf(keyPoint.class_id));
            double[] descriptorBytes = descriptors.get(keyPoint.class_id, 0);
            byte[] byteArray = new byte[descriptorBytes.length * 8];

            ByteBuffer buffer = ByteBuffer.wrap(byteArray);
            for (double value : descriptorBytes) {
                buffer.putDouble(value);
            }
            student.setText(new String(buffer.array(), Charset.forName("UTF-8")));
        }
        doc2XmlFile(doc, filename);


public static boolean doc2XmlFile(Document document, String filename) {
        boolean flag = true;
        try {
            XMLWriter writer = new XMLWriter(new OutputStreamWriter(
                    new FileOutputStream(filename), "UTF-8"));
            writer.write(document);
            writer.close();
        } catch (Exception ex) {
            flag = false;
            ex.printStackTrace();
        }
        System.out.println(flag);
        return flag;
    }