在Android中使用opencv绘制轮廓线

import org.opencv.android.OpenCVLoader;

public class ContourUtils {
    static {
        if (!OpenCVLoader.initDebug()) {
            // OpenCV initialization failed
        }
    }
}

import org.opencv.core.Mat;
import org.opencv.core.MatOfPoint;
import org.opencv.core.Scalar;
import org.opencv.imgproc.Imgproc;

public class ContourUtils {
    // ...

    public static Mat drawContours(Mat image) {
        Mat grayImage = new Mat();
        Mat cannyImage = new Mat();
        Mat hierarchy = new Mat();
        Mat contourImage = Mat.zeros(image.size(), image.type());

        // Convert image to grayscale
        Imgproc.cvtColor(image, grayImage, Imgproc.COLOR_BGR2GRAY);

        // Apply Canny edge detection
        Imgproc.Canny(grayImage, cannyImage, 50, 150);

        // Find contours
        List<MatOfPoint> contours = new ArrayList<>();
        Imgproc.findContours(cannyImage, contours, hierarchy, Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE);

        // Draw contours on contourImage
        Imgproc.drawContours(contourImage, contours, -1, new Scalar(0, 255, 0), 2);

        return contourImage;
    }
}

import org.opencv.android.Utils;
import org.opencv.core.Mat;
import org.opencv.core.CvType;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;

public class MainActivity extends AppCompatActivity implements CvCameraViewListener2 {
    private CameraBridgeViewBase mOpenCvCameraView;

    // ...

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // ...

        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.camera_view);
        mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);
        mOpenCvCameraView.setCvCameraViewListener(this);
    }

    // ...

    @Override
    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
        Mat rgbaImage = inputFrame.rgba();
        Mat contourImage = ContourUtils.drawContours(rgbaImage);

        // Convert contourImage to Bitmap for display
        Bitmap contourBitmap = Bitmap.createBitmap(contourImage.cols(), contourImage.rows(), Bitmap.Config.ARGB_8888);
        Utils.matToBitmap(contourImage, contourBitmap);

        // Display contourBitmap in an ImageView or other view

        return rgbaImage;
    }
}