Ndtyjky

I was trying to run this code to take a photo and recognize tho photo owner, at first the user clicks the button Train and takes a picture than enter its name, after that he clicks on Recognize button and take a picture if the picture was saved the apps recognize its face if not it shows unknown person for example. The app runs good but when it crashes sometimes with this error:

FATAL EXCEPTION: main

    Process: com.facedetection.app, PID: 7442

    java.lang.RuntimeException: Unable to stop activity {com.facedetection.app/com.facedetection.app.TrainActivity}: CvException [org.opencv.core.CvException: cv::Exception: OpenCV(4.0.0-pre) E:AssemCoursesopencv-mastermodulescoresrcmatrix.cpp:235: error: (-215:Assertion failed) s >= 0 in function 'setSize'

    ]

        at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4852)

        at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:4915)

        at android.app.ActivityThread.access$1600(ActivityThread.java:211)

        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1759)

        at android.os.Handler.dispatchMessage(Handler.java:102)

        at android.os.Looper.loop(Looper.java:145)

        at android.app.ActivityThread.main(ActivityThread.java:6946)

        at java.lang.reflect.Method.invoke(Native Method)

        at java.lang.reflect.Method.invoke(Method.java:372)

        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)

        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)

     Caused by: CvException [org.opencv.core.CvException: cv::Exception: OpenCV(4.0.0-pre) E:AssemCoursesopencv-mastermodulescoresrcmatrix.cpp:235: error: (-215:Assertion failed) s >= 0 in function 'setSize'

    ]

        at org.opencv.face.FaceRecognizer.train_0(Native Method)

        at org.opencv.face.FaceRecognizer.train(FaceRecognizer.java:133)

        at com.facedetection.app.TrainActivity.trainfaces(TrainActivity.java:95)

        at com.facedetection.app.TrainActivity.onStop(TrainActivity.java:351)

        at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1305)

        at android.app.Activity.performStop(Activity.java:6777)

        at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4847)

Here is the classe mentionned in the error logcat:

Class TrainActivity.java:

    import android.Manifest;

import android.annotation.SuppressLint;

import android.content.DialogInterface;

import android.content.pm.ActivityInfo;

import android.content.pm.PackageManager;

import android.graphics.Bitmap;

import android.os.Build;

import android.os.Bundle;

import android.os.Environment;

import android.support.annotation.NonNull;

import android.support.annotation.Nullable;

import android.support.v7.app.AlertDialog;

import android.support.v7.app.AppCompatActivity;

import android.text.InputType;

import android.util.Log;

import android.view.SurfaceView;

import android.view.View;

import android.view.ViewGroup;

import android.view.WindowManager;

import android.widget.AdapterView;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.EditText;

import android.widget.ListView;

import android.widget.TextView;

import android.widget.Toast;



import com.facebook.stetho.Stetho;



import org.opencv.android.BaseLoaderCallback;

import org.opencv.android.CameraBridgeViewBase;

import org.opencv.android.OpenCVLoader;

import org.opencv.core.Core;

import org.opencv.core.CvType;

import org.opencv.core.Mat;

import org.opencv.core.MatOfRect;



import org.opencv.core.Rect;

import org.opencv.core.Size;

import org.opencv.face.Face;

import org.opencv.face.FaceRecognizer;

import org.opencv.face.LBPHFaceRecognizer;

import org.opencv.imgcodecs.Imgcodecs;

import org.opencv.imgproc.Imgproc;

import org.opencv.objdetect.CascadeClassifier;



import java.io.File;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Date;

import java.util.HashSet;

import java.util.List;

import java.util.Locale;

import java.util.Set;

import static org.opencv.objdetect.Objdetect.CASCADE_SCALE_IMAGE;



/**

 * Created by Assem Abozaid on 6/2/2018.

 */



public class TrainActivity extends AppCompatActivity implements CameraBridgeViewBase.CvCameraViewListener2 {

    private static String TAG = TrainActivity.class.getSimpleName();

    private CameraBridgeViewBase openCVCamera;

    private Mat rgba,gray;

    private CascadeClassifier classifier;

    private MatOfRect faces;

    private static final int PERMS_REQUEST_CODE = 123;

    private ArrayList<Mat> images;

    private ArrayList<String> imagesLabels;

    private Storage local;

    private String uniqueLabels;

    FaceRecognizer recognize;

    private boolean trainfaces() {

        if(images.isEmpty())

            return false;

        List<Mat> imagesMatrix = new ArrayList<>();

        for (int i = 0; i < images.size(); i++)

            imagesMatrix.add(images.get(i));

        Set<String> uniqueLabelsSet = new HashSet<>(imagesLabels); // Get all unique labels

        uniqueLabels = uniqueLabelsSet.toArray(new String[uniqueLabelsSet.size()]); // Convert to String array, so we can read the values from the indices



        int classesNumbers = new int[uniqueLabels.length];

        for (int i = 0; i < classesNumbers.length; i++)

            classesNumbers[i] = i + 1; // Create incrementing list for each unique label starting at 1

        int classes = new int[imagesLabels.size()];

        for (int i = 0; i < imagesLabels.size(); i++) {

            String label = imagesLabels.get(i);

            for (int j = 0; j < uniqueLabels.length; j++) {

                if (label.equals(uniqueLabels[j])) {

                    classes[i] = classesNumbers[j]; // Insert corresponding number

                    break;

                }

            }

        }

        Mat vectorClasses = new Mat(classes.length, 1, CvType.CV_32SC1); // CV_32S == int

        vectorClasses.put(0, 0, classes); // Copy int array into a vector



        recognize = LBPHFaceRecognizer.create(3,8,8,8,200);

        recognize.train(imagesMatrix, vectorClasses);

        if(SaveImage())

            return true;



        return false;

    }

    public void showLabelsDialog() {

        Set<String> uniqueLabelsSet = new HashSet<>(imagesLabels); // Get all unique labels

        if (!uniqueLabelsSet.isEmpty()) {

            AlertDialog.Builder builder = new AlertDialog.Builder(this);

            builder.setTitle("Select label:");

            builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {

                @Override

                public void onClick(DialogInterface dialog, int which) {

                    dialog.dismiss();

                    images.remove(images.size()-1);

                }

            });

            builder.setCancelable(false); // Prevent the user from closing the dialog



            String uniqueLabels = uniqueLabelsSet.toArray(new String[uniqueLabelsSet.size()]); // Convert to String array for ArrayAdapter

            Arrays.sort(uniqueLabels); // Sort labels alphabetically

            final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, uniqueLabels) {

                @Override

                public @NonNull

                View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

                    TextView textView = (TextView) super.getView(position, convertView, parent);

                    if (getResources().getBoolean(R.bool.isTablet))

                        textView.setTextSize(20); // Make text slightly bigger on tablets compared to phones

                    else

                        textView.setTextSize(18); // Increase text size a little bit

                    return textView;

                }

            };

            ListView mListView = new ListView(this);

            mListView.setAdapter(arrayAdapter); // Set adapter, so the items actually show up

            builder.setView(mListView); // Set the ListView



            final AlertDialog dialog = builder.show(); // Show dialog and store in final variable, so it can be dismissed by the ListView



            mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                @Override

                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                    dialog.dismiss();

                    addLabel(arrayAdapter.getItem(position));

                    Log.i(TAG, "Labels Size "+imagesLabels.size()+"");

                }

            });

        } else {

            showEnterLabelDialog();

        }



    }

    private void showEnterLabelDialog() {

        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        builder.setTitle("Please enter your name:");



        final EditText input = new EditText(this);

        input.setInputType(InputType.TYPE_CLASS_TEXT);

        builder.setView(input);



        builder.setPositiveButton("Submit", null); // Set up positive button, but do not provide a listener, so we can check the string before dismissing the dialog

        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {

            @Override

            public void onClick(DialogInterface dialog, int which) {

                dialog.dismiss();

                images.remove(images.size()-1);

            }

        });

        builder.setCancelable(false); // User has to input a name

        AlertDialog dialog = builder.create();



        // Source: http://stackoverflow.com/a/7636468/2175837

        dialog.setOnShowListener(new DialogInterface.OnShowListener() {

            @Override

            public void onShow(final DialogInterface dialog) {

                Button mButton = ((AlertDialog) dialog).getButton(AlertDialog.BUTTON_POSITIVE);

                mButton.setOnClickListener(new View.OnClickListener() {

                    @Override

                    public void onClick(View view) {

                        String string = input.getText().toString().trim();

                        if (!string.isEmpty()) { // Make sure the input is valid

                            // If input is valid, dismiss the dialog and add the label to the array

                            dialog.dismiss();

                            addLabel(string);

                        }

                    }

                });

            }

        });

        // Show keyboard, so the user can start typing straight away

        dialog.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);



        dialog.show();

    }

    private void addLabel(String string) {

        String label = string.substring(0, 1).toUpperCase(Locale.US) + string.substring(1).trim().toLowerCase(Locale.US); // Make sure that the name is always uppercase and rest is lowercase

        imagesLabels.add(label); // Add label to list of labels

        Log.i(TAG, "Label: " + label);



    }

    public boolean SaveImage() {

        File path = new File(Environment.getExternalStorageDirectory(), "TrainedData");

        path.mkdirs();

        String filename = "lbph_trained_data.xml";

        File file = new File(path, filename);

        recognize.save(file.toString());

        if(file.exists())

            return true;

        return false;

    }

    public void cropedImages(Mat mat) {

        Rect rect_Crop=null;

        for(Rect face: faces.toArray()) {

            rect_Crop = new Rect(face.x, face.y, face.width, face.height);

        }

        Mat croped = new Mat(mat, rect_Crop);

        images.add(croped);

    }

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.train_main);

        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

        Stetho.initializeWithDefaults(this);



        if (hasPermissions()){

            Toast.makeText(this, "Permission Granted", Toast.LENGTH_SHORT).show();

            Log.i(TAG, "Permission Granted Before");



        }

        else {

            requestPerms();

        }



        openCVCamera = (CameraBridgeViewBase)findViewById(R.id.java_camera_view);

        openCVCamera.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_FRONT);

        openCVCamera.setVisibility(SurfaceView.VISIBLE);

        openCVCamera.setCvCameraViewListener(this);

        local = new Storage(this);

        Button detect = (Button)findViewById(R.id.take_picture_button);

        detect.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View view) {

                if(gray.total() == 0)

                    Toast.makeText(getApplicationContext(), "Can't Detect Faces", Toast.LENGTH_SHORT).show();

                classifier.detectMultiScale(gray,faces,1.1,3,0|CASCADE_SCALE_IMAGE, new Size(30,30));

                if(!faces.empty()) {

                    if(faces.toArray().length > 1)

                        Toast.makeText(getApplicationContext(), "Mutliple Faces Are not allowed", Toast.LENGTH_SHORT).show();

                    else {

                        if(gray.total() == 0) {

                            Log.i(TAG, "Empty gray image");

                            return;

                        }

                        cropedImages(gray);

                        showLabelsDialog();

                        Toast.makeText(getApplicationContext(), "Face Detected", Toast.LENGTH_SHORT).show();

                    }

                }else

                    Toast.makeText(getApplicationContext(), "Unknown Face", Toast.LENGTH_SHORT).show();

            }

        });

    }

    @SuppressLint("WrongConstant")

    private boolean hasPermissions(){

        int res = 0;

        //string array of permissions,

        String permissions = new String{Manifest.permission.CAMERA};



        for (String perms : permissions){

            res = checkCallingOrSelfPermission(perms);

            if (!(res == PackageManager.PERMISSION_GRANTED)){

                return false;

            }

        }

        return true;

    }

    private void requestPerms(){

        String permissions = new String{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE};

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){

            requestPermissions(permissions,PERMS_REQUEST_CODE);



        }

    }

    @Override

    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions, @NonNull int grantResults) {

        boolean allowed = true;

        switch (requestCode){

            case PERMS_REQUEST_CODE:

                for (int res : grantResults){

                    // if user granted all permissions.

                    allowed = allowed && (res == PackageManager.PERMISSION_GRANTED);

                }

                break;

            default:

                // if user not granted permissions.

                allowed = false;

                break;

        }

        if (allowed){

            //user granted all permissions we can perform our task.

            Log.i(TAG, "Permission has been added");

        }

        else {

            // we will give warning to user that they haven't granted permissions.

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

                if (shouldShowRequestPermissionRationale(Manifest.permission.CAMERA) || shouldShowRequestPermissionRationale(Manifest.permission.WRITE_EXTERNAL_STORAGE) ||

                        shouldShowRequestPermissionRationale(Manifest.permission.READ_EXTERNAL_STORAGE)){

                    Toast.makeText(this, "Permission Denied.", Toast.LENGTH_SHORT).show();

                }

            }

        }

    }

    private BaseLoaderCallback callbackLoader = new BaseLoaderCallback(this) {

        @Override

        public void onManagerConnected(int status) {

            switch(status) {

                case BaseLoaderCallback.SUCCESS:

                    faces = new MatOfRect();

                    openCVCamera.enableView();



                    images = local.getListMat("images");

                    imagesLabels = local.getListString("imagesLabels");



                    break;

                default:

                    super.onManagerConnected(status);

                    break;

            }

        }

    };



    @Override

    protected void onPause() {

        super.onPause();

        if(openCVCamera != null)

            openCVCamera.disableView();





    }

    @Override

    protected void onStop() {

        super.onStop();

        if (images != null && imagesLabels != null) {

            local.putListMat("images", images);

            local.putListString("imagesLabels", imagesLabels);

            Log.i(TAG, "Images have been saved");

            if(trainfaces()) {

                images.clear();

                imagesLabels.clear();

            }

        }

    }

    @Override

    protected void onDestroy(){

        super.onDestroy();

        if(openCVCamera != null)

            openCVCamera.disableView();

    }

    @Override

    protected void onResume(){

        super.onResume();

        if(OpenCVLoader.initDebug()) {

            Log.i(TAG, "System Library Loaded Successfully");

            callbackLoader.onManagerConnected(BaseLoaderCallback.SUCCESS);

        } else {

            Log.i(TAG, "Unable To Load System Library");

            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION, this, callbackLoader);

        }

    }



    @Override

    public void onCameraViewStarted(int width, int height) {

        rgba = new Mat();

        gray = new Mat();

        classifier = FileUtils.loadXMLS(this, "lbpcascade_frontalface_improved.xml");

    }



    @Override

    public void onCameraViewStopped() {

        rgba.release();

        gray.release();

    }



    @Override

    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {

        Mat mGrayTmp = inputFrame.gray();

        Mat mRgbaTmp = inputFrame.rgba();



        int orientation = openCVCamera.getScreenOrientation();

        if (openCVCamera.isEmulator()) // Treat emulators as a special case

            Core.flip(mRgbaTmp, mRgbaTmp, 1); // Flip along y-axis

        else {

            switch (orientation) { // RGB image

                case ActivityInfo.SCREEN_ORIENTATION_PORTRAIT:

                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT:

                    Core.flip(mRgbaTmp, mRgbaTmp, 0); // Flip along x-axis

                    break;

                case ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE:

                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE:

                    Core.flip(mRgbaTmp, mRgbaTmp, 1); // Flip along y-axis

                    break;

            }

            switch (orientation) { // Grayscale image

                case ActivityInfo.SCREEN_ORIENTATION_PORTRAIT:

                    Core.transpose(mGrayTmp, mGrayTmp); // Rotate image

                    Core.flip(mGrayTmp, mGrayTmp, -1); // Flip along both axis

                    break;

                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT:

                    Core.transpose(mGrayTmp, mGrayTmp); // Rotate image

                    break;

                case ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE:

                    Core.flip(mGrayTmp, mGrayTmp, 1); // Flip along y-axis

                    break;

                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE:

                    Core.flip(mGrayTmp, mGrayTmp, 0); // Flip along x-axis

                    break;

            }

        }

        gray = mGrayTmp;

        rgba = mRgbaTmp;

        Imgproc.resize(gray, gray, new Size(200,200.0f/ ((float)gray.width()/ (float)gray.height())));

        return rgba;

    }

}

The Lines of Errors mentionned in the logcat refers to those java code lines:

In TrainActivity.java:

    recognize = LBPHFaceRecognizer.create(3,8,8,8,200);

    recognize.train(imagesMatrix, vectorClasses);

And

     if(trainfaces()) {

            images.clear();

            imagesLabels.clear();

        }

Do you guys have any idea about this problem and how to fix it?

PS: I am a beginner with OpenCv.

You can solve it by reset preferences onCreate TrainActivity

// -------------------------------

// reset preferences

local = new Storage(this);

images = new ArrayList<>();

imagesLabels = new ArrayList<>();

local.putListMat("images", images);

local.putListString("imagesLabels", imagesLabels);

// -------------------------------