Added Audio Recorder. Its working

# Conflicts:
#	app/build.gradle
#	app/src/main/AndroidManifest.xml
#	app/src/main/java/com/example/ueberwachungssystem/MainActivity.java
#	app/src/main/res/layout/activity_main.xml

app/build.gradle

@@ -51,4 +51,7 @@ dependencies {
     implementation "androidx.camera:camera-video:${camerax_version}"
     implementation "androidx.camera:camera-view:${camerax_version}"
     implementation "androidx.camera:camera-extensions:${camerax_version}"
+
+
+    implementation 'com.jjoe64:graphview:4.2.2'
 }

app/src/main/AndroidManifest.xml

@@ -6,6 +6,11 @@
     <uses-permission android:name="android.permission.CAMERA"/>
     <uses-permission android:name="android.permission.RECORD_AUDIO" />
 
+    <!--<uses-permission android:name="android.permission.BLUETOOTH"/>-->
+    <!--<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>-->
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+    <uses-permission android:name="android.permission.INTERNET" />
+
     <application
         android:allowBackup="true"
         android:dataExtractionRules="@xml/data_extraction_rules"

app/src/main/java/com/example/ueberwachungssystem/AudioRecorder.java

@@ -0,0 +1,83 @@
+package com.example.ueberwachungssystem;
+
+import android.content.Context;
+import android.media.MediaPlayer;
+import android.media.MediaRecorder;
+
+import java.io.File;
+import java.io.IOException;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
+public class AudioRecorder {
+    private final Context context;
+    private MediaRecorder mediaRecorder = null;
+    private boolean isRecording = false;
+    private File outputDir;      // Default: in app files directory
+
+
+    public AudioRecorder (Context context) {
+        this.context = context;
+        this.outputDir = context.getFilesDir();
+    }
+
+    public void startRecording() {
+        // Handle logic
+        if (outputDir == null)
+            return;
+        if (isRecording)
+            return;
+        isRecording = true;
+
+        // Setup Audio Recorder for output Format: 3GP
+        mediaRecorder = new MediaRecorder();
+        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
+        mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
+        mediaRecorder.setOutputFile(outputDir + "/" + generateFileName() + ".3gp");
+        mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
+        try {
+            mediaRecorder.prepare();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        mediaRecorder.start();
+    }
+
+    public void stopRecording() {
+        if (mediaRecorder != null) {
+            mediaRecorder.stop();
+            mediaRecorder.reset();
+            mediaRecorder.release();
+            mediaRecorder = null;
+            isRecording = false;
+        }
+    }
+
+    public boolean isRecording(){
+        return isRecording;
+    }
+
+    public void setOutputDir(File outputDir) {
+        this.outputDir = outputDir;
+    }
+
+    private String generateFileName(){
+        // Get the current timestamp
+        LocalDateTime currentTime = LocalDateTime.now();
+        // Define the format for the timestamp
+        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd_HHmmss");
+        // Return the timestamp as a string
+        return currentTime.format(formatter);
+    }
+
+    public void playAudio() {
+        MediaPlayer mp = new MediaPlayer();
+        try {
+            mp.setDataSource(context.getFilesDir() + "/audio.3gp");
+            mp.prepare();
+            mp.start();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}

app/src/main/java/com/example/ueberwachungssystem/DetectionReport.java

@@ -0,0 +1,36 @@
+package com.example.ueberwachungssystem;
+
+import android.util.Log;
+
+import java.util.Calendar;
+
+/** Detection Report Class */
+public class DetectionReport {
+    public String timeStamp;
+    public String detectionType;
+    public float detectedValue;
+    public String detectorID;
+
+    public DetectionReport(String detectorID, String detectionType, float detectedAmplitude) {
+        this.timeStamp = String.valueOf(Calendar.getInstance().getTime());
+        this.detectionType = detectionType;
+        this.detectedValue = detectedAmplitude;
+        this.detectorID = detectorID;
+    }
+
+
+    /** Get Detection Report in String format */
+    public String toString() {
+        String time = "Time: " + "[" + this.timeStamp + "]";
+        String type = "Type: " + "[" + this.detectionType + "]";
+        String value = "Value: " + "[" + this.detectedValue + "]";
+        String id = "ID: " + "[" + this.detectorID + "]";
+
+        return String.join("\t", time, type, value, id);
+    }
+
+    /** Debug Report */
+    public void log(String tag) {
+        Log.d(tag, this.toString());
+    }
+}

app/src/main/java/com/example/ueberwachungssystem/Detector.java

@@ -0,0 +1,40 @@
+package com.example.ueberwachungssystem;
+
+import android.app.Activity;
+import android.content.Context;
+import androidx.annotation.NonNull;
+
+
+abstract public class Detector {
+    private OnDetectionListener listener;
+
+    /** Constructor - takes context of current activity */
+    public Detector(Context context) {};
+
+
+    /** On Detection Listener - runs when violation is reported */
+    public interface OnDetectionListener {
+        void onDetection(@NonNull DetectionReport detectionReport);
+    }
+    public void setOnDetectionListener(@NonNull OnDetectionListener listener) {
+        this.listener = listener;
+    }
+
+
+    /** Triggers onDetectionListener - call this to trigger violation/alarm */
+    private void reportViolation(String detectorID, String detectionType, float amplitude) {
+        if (listener != null) {
+            DetectionReport detectionReport = new DetectionReport(detectorID, detectionType, amplitude);
+            listener.onDetection(detectionReport);
+        } else {
+            throw new IllegalStateException("No listener set for violation reporting");
+        }
+    }
+
+
+    /** Starts Detection (abstract method: needs to be overridden in child class) */
+    public abstract void startDetection();
+
+    /** Stops Detection (abstract method: needs to be overridden in child class) */
+    public abstract void stopDetection();
+}

app/src/main/java/com/example/ueberwachungssystem/MainActivity.java

@@ -9,11 +9,14 @@ import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.ImageView;
+import android.widget.TextView;
 import android.widget.ToggleButton;
 
 import com.example.ueberwachungssystem.Detection.DetectionReport;
 import com.example.ueberwachungssystem.Detection.Detector;
 import com.example.ueberwachungssystem.Detection.VideoDetector;
+import com.example.ueberwachungssystem.logger.Logger;
+import com.jjoe64.graphview.GraphView;
 
 @ExperimentalGetImage
 public class MainActivity extends AppCompatActivity {
@@ -29,6 +32,18 @@ public class MainActivity extends AppCompatActivity {
         PreviewView previewView = findViewById(R.id.previewView);
 
 
+        // Mic stuff
+        TextView textView= (TextView) findViewById(R.id.textView); //Set textview for showing logged content
+        Logger logger = new Logger(this.getClass().getSimpleName(), textView, "");
+        GraphView graph = (GraphView) findViewById(R.id.graph);
+        MicrophoneDetector mic = new MicrophoneDetector(this, logger, graph);
+        mic.startDetection();
+
+
+
+        AudioRecorder audioRecorder = new AudioRecorder(this);
+
+        // video Stuff
         VideoDetector vd = new VideoDetector(this);
         //vd.setPreviewView(previewView);
         vd.debugProcessing(inputImageView, outputImageView);
@@ -41,7 +56,6 @@ public class MainActivity extends AppCompatActivity {
         vd.startDetection();
 
 
-
         ToggleButton toggleButton = findViewById(R.id.toggleButton);
         toggleButton.setOnClickListener(new View.OnClickListener() {
             @Override
@@ -50,10 +64,13 @@ public class MainActivity extends AppCompatActivity {
                 {
                     //vd.startDetection();
                     vd.startRecording();
+                    audioRecorder.startRecording();
+
                 }
                 else {
                     //vd.stopDetection();
                     vd.stopRecording();
+                    audioRecorder.stopRecording();
                 }
             }
         });

app/src/main/java/com/example/ueberwachungssystem/MicrophoneDetector.java

@@ -0,0 +1,445 @@
+package com.example.ueberwachungssystem;
+
+import static java.lang.Math.*;
+
+import android.Manifest;
+import android.app.Activity;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.media.AudioFormat;
+import android.media.AudioRecord;
+import android.media.MediaRecorder;
+import android.os.AsyncTask;
+
+import androidx.core.app.ActivityCompat;
+import androidx.core.content.ContextCompat;
+
+import com.example.ueberwachungssystem.Signalverarbeitung.Complex;
+import com.example.ueberwachungssystem.Signalverarbeitung.FFT;
+import com.example.ueberwachungssystem.logger.Logger;
+import com.jjoe64.graphview.GraphView;
+import com.jjoe64.graphview.series.DataPoint;
+import com.jjoe64.graphview.series.LineGraphSeries;
+
+public class MicrophoneDetector extends Detector {
+    /**
+     * Constructor - takes context of current activity
+     *
+     * @param context
+     */
+
+    private static final int RECHTEANFORDERUNG_MIKROFON = 1;
+
+    private AufnahmeTask aufnahmeTask;
+    public boolean armed = false;
+    public int Schwellwert_Alarm = 100;
+    GraphView graph;
+
+    Logger logger;
+    private Activity MainActivityForClass;
+
+    public MicrophoneDetector(Context context, Logger MainLogger, GraphView MainGraph) {
+        super(context);
+        MainActivityForClass = (Activity) context;
+        logger = MainLogger; //Class uses the same logger as the MainActivity
+        logger.log(this.getClass().getSimpleName() + ".onCreate");
+        graph = MainGraph;
+
+        if (!istZugriffAufMikrofonErlaubt()) {
+            zugriffAufMikrofonAnfordern();
+        }
+    }
+
+    @Override
+    public void startDetection() {
+        logger.log(this.getClass().getSimpleName() + ".startDetection");
+
+        if (!istZugriffAufMikrofonErlaubt()) {
+            zugriffAufMikrofonAnfordern();
+        }
+        if (istZugriffAufMikrofonErlaubt()) {
+            aufnahmeTask = new AufnahmeTask();
+            aufnahmeTask.execute();
+        }
+    }
+
+    @Override
+    public void stopDetection() {
+        logger.log(this.getClass().getSimpleName() + ".stopDetection");
+        if (aufnahmeTask != null) {
+            aufnahmeTask.cancel(true);
+            // aufnahmeTask = null; // if aufnahmeTask = null, break in for loop would not work (Nullpointer Exception)
+        }
+    }
+
+    private boolean istZugriffAufMikrofonErlaubt() {
+        if (ContextCompat.checkSelfPermission(MainActivityForClass, android.Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
+            logger.log("Zugriff auf Mikrofon ist verboten.");
+            return false;
+        } else {
+            logger.log("Zugriff auf Mikrofon ist erlaubt.");
+            return true;
+        }
+    }
+
+    private void zugriffAufMikrofonAnfordern() {
+        ActivityCompat.requestPermissions(MainActivityForClass, new String[]{Manifest.permission.RECORD_AUDIO}, RECHTEANFORDERUNG_MIKROFON);
+    }
+
+    class AufnahmeTask extends AsyncTask<Long, Verarbeitungsergebnis, Void> {
+        private AudioRecord recorder;
+        private final int sampleRateInHz = 44100;
+        private final int channelConfig = AudioFormat.CHANNEL_IN_MONO;
+        private final int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
+        private int minPufferGroesseInBytes;
+        private int pufferGroesseInBytes;
+        private RingPuffer ringPuffer = new RingPuffer(10);
+        private float kalibierWert;
+        private DetectionReport detectionReport;
+
+        AufnahmeTask() {
+            minPufferGroesseInBytes = AudioRecord.getMinBufferSize(sampleRateInHz, channelConfig, audioFormat);
+            pufferGroesseInBytes = minPufferGroesseInBytes * 2;
+            if (ActivityCompat.checkSelfPermission(MainActivityForClass, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
+                // TODO: Consider calling
+                //    ActivityCompat#requestPermissions
+                // here to request the missing permissions, and then overriding
+                //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
+                //                                          int[] grantResults)
+                // to handle the case where the user grants the permission. See the documentation
+                // for ActivityCompat#requestPermissions for more details.
+                ActivityCompat.requestPermissions(MainActivityForClass, new String[]{Manifest.permission.RECORD_AUDIO}, RECHTEANFORDERUNG_MIKROFON);
+            }
+
+            recorder = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRateInHz, channelConfig, audioFormat, pufferGroesseInBytes);
+
+//            textViewMinPufferGroesseInBytes.setText("" + minPufferGroesseInBytes);
+//            textViewPufferGroesseInBytes.setText("" + pufferGroesseInBytes);
+//            textViewAbtastrate.setText("" + recorder.getSampleRate());
+//            textViewAnzahlKanaele.setText("" + recorder.getChannelCount());
+
+            logger.log("Puffergroeße: "+ minPufferGroesseInBytes + " " + pufferGroesseInBytes);
+            logger.log("Recorder (SR, CH): "+ recorder.getSampleRate() + " " + recorder.getChannelCount());
+
+            int anzahlBytesProAbtastwert;
+            String s;
+            switch (recorder.getAudioFormat()) {
+                case AudioFormat.ENCODING_PCM_8BIT:
+                    s = "8 Bit PCM ";
+                    anzahlBytesProAbtastwert = 1;
+                    break;
+                case AudioFormat.ENCODING_PCM_16BIT:
+                    s = "16 Bit PCM";
+                    anzahlBytesProAbtastwert = 2;
+                    break;
+                case AudioFormat.ENCODING_PCM_FLOAT:
+                    s = "Float PCM";
+                    anzahlBytesProAbtastwert = 4;
+                    break;
+                default:
+                    throw new IllegalArgumentException();
+            }
+//            textViewAudioFormat.setText(s);
+
+            switch (recorder.getChannelConfiguration()) {
+                case AudioFormat.CHANNEL_IN_MONO:
+                    s = "Mono";
+                    break;
+                case AudioFormat.CHANNEL_IN_STEREO:
+                    s = "Stereo";
+                    anzahlBytesProAbtastwert *= 2;
+                    break;
+                case AudioFormat.CHANNEL_INVALID:
+                    s = "ungültig";
+                    break;
+                default:
+                    throw new IllegalArgumentException();
+            }
+//            textViewKanalKonfiguration.setText(s);
+            logger.log("Konfiguration: "+ s);
+
+            int pufferGroesseInAnzahlAbtastwerten = pufferGroesseInBytes / anzahlBytesProAbtastwert;
+            int pufferGroesseInMillisekunden = 1000 * pufferGroesseInAnzahlAbtastwerten / recorder.getSampleRate();
+
+//            textViewPufferGroesseInAnzahlAbtastwerte.setText("" + pufferGroesseInAnzahlAbtastwerten);
+//            textViewPufferGroesseInMillisekunden.setText("" + pufferGroesseInMillisekunden);
+        }
+
+        @Override
+        protected Void doInBackground(Long... params) {
+            recorder.startRecording();
+            short[] puffer = new short[pufferGroesseInBytes / 2];
+            long lastTime = System.currentTimeMillis();
+            float verarbeitungsrate = 0;
+            final int maxZaehlerZeitMessung = 10;
+            int zaehlerZeitMessung = 0;
+            int anzahlVerarbeitet = 0;
+            GleitenderMittelwert gleitenderMittelwert = new GleitenderMittelwert(0.3f);
+
+            //Kalibrierung
+            try {
+                Thread.sleep(3000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+            int i = 0;
+            for (i = 0; i < 20; i++) {
+                int n = recorder.read(puffer, 0, puffer.length);
+                Verarbeitungsergebnis kalibrierErgebnis = verarbeiten(puffer, n);
+                kalibierWert += kalibrierErgebnis.maxAmp;
+                try {
+                    Thread.sleep(50);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+            kalibierWert = kalibierWert/i;
+
+//            Complex[] zeitSignal = new Complex[puffer.length];
+//            for (int j = 0; j < puffer.length; j++) {
+//                zeitSignal[j] = new Complex(puffer[j], 0);
+//            }
+//            Complex[] spektrum = FFT.fft(zeitSignal);
+            double[] spektrum = calculateFFT(puffer);
+            DataPoint AddPoint;
+//            LineGraphSeries<DataPoint> series = new LineGraphSeries<DataPoint>(new DataPoint[]{});
+//            for (i = 0; i < spektrum.length; i++) {
+//                AddPoint = new DataPoint(i, spektrum[i]);
+//                series.appendData(AddPoint, true, spektrum.length);
+//            }
+//            graph.addSeries(series);
+            // logger.log(spektrum.toString());
+
+            for (; ; ) {
+                if (aufnahmeTask.isCancelled()) {
+                    break;
+                } else {
+                    int n = recorder.read(puffer, 0, puffer.length);
+                    Verarbeitungsergebnis ergebnis = verarbeiten(puffer, n);
+                    anzahlVerarbeitet += n;
+
+                    spektrum = calculateFFT(puffer);
+                    LineGraphSeries<DataPoint> newseries = new LineGraphSeries<DataPoint>(new DataPoint[]{});
+                    for (i = 0; i < spektrum.length; i++) {
+                        AddPoint = new DataPoint(i, spektrum[i]);
+                        newseries.appendData(AddPoint, true, spektrum.length);
+                    }
+                    graph.removeAllSeries();
+                    graph.addSeries(newseries);
+                    zaehlerZeitMessung++;
+                    if (zaehlerZeitMessung == maxZaehlerZeitMessung) {
+                        long time = System.currentTimeMillis();
+                        long deltaTime = time - lastTime;
+                        verarbeitungsrate = 1000.0f * anzahlVerarbeitet / deltaTime;
+                        verarbeitungsrate = gleitenderMittelwert.mittel(verarbeitungsrate);
+                        zaehlerZeitMessung = 0;
+                        anzahlVerarbeitet = 0;
+                        lastTime = time;
+                    }
+
+
+                    ergebnis.verarbeitungsrate = (int) verarbeitungsrate;
+                    publishProgress(ergebnis);
+
+                    try {
+                        Thread.sleep(100);
+                    } catch (InterruptedException e) {
+                        e.printStackTrace();
+                    }
+                }
+            }
+            recorder.release();
+            return null;
+        }
+
+        private Verarbeitungsergebnis verarbeiten(short[] daten, int n) {
+            String status;
+            short maxAmp = -1;
+            if (n == AudioRecord.ERROR_INVALID_OPERATION) {
+                status = "ERROR_INVALID_OPERATION";
+            } else if (n == AudioRecord.ERROR_BAD_VALUE) {
+                status = "ERROR_BAD_VALUE";
+            } else {
+                status = "OK";
+                short max = 0;
+                for (int i = 0; i < n; i++) {
+                    if (daten[i] > max) {
+                        max = daten[i];
+                        //max = 20 * log10(abs(daten[i]) / 32768);
+                    }
+                }
+
+                ringPuffer.hinzufuegen(max);
+                maxAmp = ringPuffer.maximum();
+                if (maxAmp <= Schwellwert_Alarm+kalibierWert) {
+                    armed = true;
+                }
+            }
+
+            return new Verarbeitungsergebnis(status, maxAmp, 0);
+        }
+
+        @Override
+        protected void onProgressUpdate(Verarbeitungsergebnis... progress) {
+            super.onProgressUpdate(progress);
+//            textViewMaxAmp.setText("" + progress[0].maxAmp);
+//            textViewVerarbeitungsrate.setText("" + progress[0].verarbeitungsrate);
+            float maxAmpPrint = round(20*log10(abs(progress[0].maxAmp/1.0)));
+            float kalibierWertPrint = round(20*log10(abs(kalibierWert)));
+            logger.overwriteLastlog("VR, Max, Kal:" + progress[0].verarbeitungsrate + ", " + maxAmpPrint
+            + " dB, " + kalibierWertPrint + " dB");
+
+            if (progress[0].maxAmp >= Schwellwert_Alarm+kalibierWert && armed == true) {
+                armed = false;
+                detectionReport = new DetectionReport("Mic1", "Audio", maxAmpPrint);
+                logger.log("");
+                logger.log("Alarm!");
+                logger.log(detectionReport.toString());
+                logger.log("");
+            }
+        }
+    }
+
+    private double[] calculateFFT(short[] zeitsignal)
+    {
+        byte signal[] = new byte[zeitsignal.length];
+        // loops through all the values of a Short
+        for (int i = 0; i < zeitsignal.length-1; i++) {
+            signal[i] = (byte) (zeitsignal[i]);
+            signal[i+1] = (byte) (zeitsignal[i] >> 8);
+        }
+
+        final int mNumberOfFFTPoints =1024;
+        double mMaxFFTSample;
+
+        double temp;
+        Complex[] y;
+        Complex[] complexSignal = new Complex[mNumberOfFFTPoints];
+        double[] absSignal = new double[mNumberOfFFTPoints/2];
+
+        for(int i = 0; i < mNumberOfFFTPoints; i++){
+            temp = (double)((signal[2*i] & 0xFF) | (signal[2*i+1] << 8)) / 32768.0F;
+            complexSignal[i] = new Complex(temp,0.0);
+        }
+
+        y = FFT.fft(complexSignal);
+
+        mMaxFFTSample = 0.0;
+        // mPeakPos = 0;
+        for(int i = 0; i < (mNumberOfFFTPoints/2); i++)
+        {
+            absSignal[i] = y[i].abs();
+//            absSignal[i] = Math.sqrt(Math.pow(y[i].re(), 2) + Math.pow(y[i].im(), 2));
+//            if(absSignal[i] > mMaxFFTSample)
+//            {
+//                mMaxFFTSample = absSignal[i];
+//                // mPeakPos = i;
+//            }
+        }
+
+        return absSignal;
+
+    }
+
+    class Verarbeitungsergebnis {
+        String status;
+        short maxAmp;
+        int verarbeitungsrate;
+        Verarbeitungsergebnis(String status, short maxAmp, int verarbeitungsrate) {
+            this.status = status;
+            this.maxAmp = maxAmp;
+            this.verarbeitungsrate = verarbeitungsrate;
+        }
+    }
+
+    class RingPuffer {
+        private short[] puffer;
+        private final int laenge;
+        private int anzahlEnthaltenerDaten;
+        private int position;
+
+        public RingPuffer(int n) {
+            laenge = n;
+            anzahlEnthaltenerDaten = 0;
+            position = 0;
+            puffer = new short[laenge];
+        }
+
+        public void hinzufuegen(short wert) {
+            puffer[position] = wert;
+            position++;
+            if (position >= laenge) {
+                position = 0;
+            }
+            if (anzahlEnthaltenerDaten < laenge) {
+                anzahlEnthaltenerDaten++;
+            }
+        }
+
+        public void hinzufuegen(short[] daten) {
+            for (short d : daten) {
+                puffer[position] = d;
+                position++;
+                if (position >= laenge) {
+                    position = 0;
+                }
+            }
+            if (anzahlEnthaltenerDaten < laenge) {
+                anzahlEnthaltenerDaten += daten.length;
+                if (anzahlEnthaltenerDaten >= laenge) {
+                    anzahlEnthaltenerDaten = laenge;
+                }
+            }
+        }
+
+        public short maximum() {
+            short max = 0;
+            for (int i = 0; i < anzahlEnthaltenerDaten; i++) {
+                if (puffer[i] > max) {
+                    max = puffer[i];
+                }
+            }
+            return max;
+        }
+
+        public float mittelwert() {
+            float summe = 0;
+            for (int i = 0; i < anzahlEnthaltenerDaten; i++) {
+                summe += puffer[i];
+            }
+            return summe / anzahlEnthaltenerDaten;
+        }
+    }
+
+    class GleitenderMittelwert {
+        private final float wichtungNeuerWert;
+        private final float wichtungAlterWert;
+        private float mittelwert = 0;
+        private boolean istMittelwertGesetzt = false;
+
+        GleitenderMittelwert(float wichtungNeuerWert) {
+            this.wichtungNeuerWert = wichtungNeuerWert;
+            this.wichtungAlterWert = 1 - this.wichtungNeuerWert;
+        }
+
+        float MittelwertPuffer(short[] puffer) {
+
+            for (int i = 0; i < puffer.length; i++) {
+                mittelwert = Math.abs(puffer[i]);
+            }
+            mittelwert = mittelwert/puffer.length;
+
+            return mittelwert;
+        }
+
+        float mittel(float wert) {
+            if (istMittelwertGesetzt) {
+                mittelwert = wert * wichtungNeuerWert + mittelwert * wichtungAlterWert;
+            } else {
+                mittelwert = wert;
+                istMittelwertGesetzt = true;
+            }
+            return mittelwert;
+        }
+    }
+}

app/src/main/java/com/example/ueberwachungssystem/Signalverarbeitung/Complex.java

@@ -0,0 +1,148 @@
+package com.example.ueberwachungssystem.Signalverarbeitung;
+
+import java.util.Objects;
+
+public class Complex {
+    private final double re;   // the real part
+    private final double im;   // the imaginary part
+
+    // create a new object with the given real and imaginary parts
+    public Complex(double real, double imag) {
+        re = real;
+        im = imag;
+    }
+
+    // return a string representation of the invoking com.example.ueberwachungssystem.Signalverarbeitung.Complex object
+    public String toString() {
+        if (im == 0) return re + "";
+        if (re == 0) return im + "i";
+        if (im < 0) return re + " - " + (-im) + "i";
+        return re + " + " + im + "i";
+    }
+
+    // return abs/modulus/magnitude
+    public double abs() {
+        return Math.hypot(re, im);
+    }
+
+    // return angle/phase/argument, normalized to be between -pi and pi
+    public double phase() {
+        return Math.atan2(im, re);
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is (this + b)
+    public Complex plus(Complex b) {
+        Complex a = this;             // invoking object
+        double real = a.re + b.re;
+        double imag = a.im + b.im;
+        return new Complex(real, imag);
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is (this - b)
+    public Complex minus(Complex b) {
+        Complex a = this;
+        double real = a.re - b.re;
+        double imag = a.im - b.im;
+        return new Complex(real, imag);
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is (this * b)
+    public Complex times(Complex b) {
+        Complex a = this;
+        double real = a.re * b.re - a.im * b.im;
+        double imag = a.re * b.im + a.im * b.re;
+        return new Complex(real, imag);
+    }
+
+    // return a new object whose value is (this * alpha)
+    public Complex scale(double alpha) {
+        return new Complex(alpha * re, alpha * im);
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is the conjugate of this
+    public Complex conjugate() {
+        return new Complex(re, -im);
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is the reciprocal of this
+    public Complex reciprocal() {
+        double scale = re * re + im * im;
+        return new Complex(re / scale, -im / scale);
+    }
+
+    // return the real or imaginary part
+    public double re() {
+        return re;
+    }
+
+    public double im() {
+        return im;
+    }
+
+    // return a / b
+    public Complex divides(Complex b) {
+        Complex a = this;
+        return a.times(b.reciprocal());
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is the complex exponential of this
+    public Complex exp() {
+        return new Complex(Math.exp(re) * Math.cos(im), Math.exp(re) * Math.sin(im));
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is the complex sine of this
+    public Complex sin() {
+        return new Complex(Math.sin(re) * Math.cosh(im), Math.cos(re) * Math.sinh(im));
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is the complex cosine of this
+    public Complex cos() {
+        return new Complex(Math.cos(re) * Math.cosh(im), -Math.sin(re) * Math.sinh(im));
+    }
+
+    // return a new com.example.ueberwachungssystem.Signalverarbeitung.Complex object whose value is the complex tangent of this
+    public Complex tan() {
+        return sin().divides(cos());
+    }
+
+    // a static version of plus
+    public static Complex plus(Complex a, Complex b) {
+        double real = a.re + b.re;
+        double imag = a.im + b.im;
+        Complex sum = new Complex(real, imag);
+        return sum;
+    }
+
+    // See Section 3.3.
+    public boolean equals(Object x) {
+        if (x == null) return false;
+        if (this.getClass() != x.getClass()) return false;
+        Complex that = (Complex) x;
+        return (this.re == that.re) && (this.im == that.im);
+    }
+
+    // See Section 3.3.
+    public int hashCode() {
+        return Objects.hash(re, im);
+    }
+
+    // sample client for testing
+    public static void main(String[] args) {
+        Complex a = new Complex(5.0, 6.0);
+        Complex b = new Complex(-3.0, 4.0);
+
+        System.out.println("a            = " + a);
+        System.out.println("b            = " + b);
+        System.out.println("Re(a)        = " + a.re());
+        System.out.println("Im(a)        = " + a.im());
+        System.out.println("b + a        = " + b.plus(a));
+        System.out.println("a - b        = " + a.minus(b));
+        System.out.println("a * b        = " + a.times(b));
+        System.out.println("b * a        = " + b.times(a));
+        System.out.println("a / b        = " + a.divides(b));
+        System.out.println("(a / b) * b  = " + a.divides(b).times(b));
+        System.out.println("conj(a)      = " + a.conjugate());
+        System.out.println("|a|          = " + a.abs());
+        System.out.println("tan(a)       = " + a.tan());
+    }
+}

app/src/main/java/com/example/ueberwachungssystem/Signalverarbeitung/FFT.java

@@ -0,0 +1,248 @@
+package com.example.ueberwachungssystem.Signalverarbeitung;
+// Source: https://introcs.cs.princeton.edu/java/97data/FFT.java.html
+
+import android.util.Log;
+
+/******************************************************************************
+ *  Compilation:  javac FFT.java
+ *  Execution:    java FFT n
+ *  Dependencies: com.example.ueberwachungssystem.Signalverarbeitung.Complex.java
+ *
+ *  Compute the FFT and inverse FFT of a length n complex sequence
+ *  using the radix 2 Cooley-Tukey algorithm.
+ *  Bare bones implementation that runs in O(n log n) time and O(n)
+ *  space. Our goal is to optimize the clarity of the code, rather
+ *  than performance.
+ *
+ *  This implementation uses the primitive root of unity w = e^(-2 pi i / n).
+ *  Some resources use w = e^(2 pi i / n).
+ *
+ *  Reference: https://www.cs.princeton.edu/~wayne/kleinberg-tardos/pdf/05DivideAndConquerII.pdf
+ *
+ *  Limitations
+ *  -----------
+ *   -  assumes n is a power of 2
+ *
+ *   -  not the most memory efficient algorithm (because it uses
+ *      an object type for representing complex numbers and because
+ *      it re-allocates memory for the subarray, instead of doing
+ *      in-place or reusing a single temporary array)
+ *
+ *  For an in-place radix 2 Cooley-Tukey FFT, see
+ *  https://introcs.cs.princeton.edu/java/97data/InplaceFFT.java.html
+ *
+ ******************************************************************************/
+
+public class FFT {
+
+    // compute the FFT of x[], assuming its length n is a power of 2
+    public static Complex[] fft(Complex[] x) {
+        int n = x.length;
+
+        // base case
+        if (n == 1) return new Complex[]{x[0]};
+
+        // radix 2 Cooley-Tukey FFT
+        if (n % 2 != 0) {
+            throw new IllegalArgumentException("n is not a power of 2");
+        }
+
+        // compute FFT of even terms
+        Complex[] even = new Complex[n / 2];
+        for (int k = 0; k < n / 2; k++) {
+            even[k] = x[2 * k];
+        }
+        Complex[] evenFFT = fft(even);
+
+        // compute FFT of odd terms
+        Complex[] odd = even;  // reuse the array (to avoid n log n space)
+        for (int k = 0; k < n / 2; k++) {
+            odd[k] = x[2 * k + 1];
+        }
+        Complex[] oddFFT = fft(odd);
+
+        // combine
+        Complex[] y = new Complex[n];
+        for (int k = 0; k < n / 2; k++) {
+            double kth = -2 * k * Math.PI / n;
+            Complex wk = new Complex(Math.cos(kth), Math.sin(kth));
+            y[k] = evenFFT[k].plus(wk.times(oddFFT[k]));
+            y[k + n / 2] = evenFFT[k].minus(wk.times(oddFFT[k]));
+        }
+        return y;
+    }
+
+
+    // compute the inverse FFT of x[], assuming its length n is a power of 2
+    public static Complex[] ifft(Complex[] x) {
+        int n = x.length;
+        Complex[] y = new Complex[n];
+
+        // take conjugate
+        for (int i = 0; i < n; i++) {
+            y[i] = x[i].conjugate();
+        }
+
+        // compute forward FFT
+        y = fft(y);
+
+        // take conjugate again
+        for (int i = 0; i < n; i++) {
+            y[i] = y[i].conjugate();
+        }
+
+        // divide by n
+        for (int i = 0; i < n; i++) {
+            y[i] = y[i].scale(1.0 / n);
+        }
+
+        return y;
+
+    }
+
+    // compute the circular convolution of x and y
+    public static Complex[] cconvolve(Complex[] x, Complex[] y) {
+
+        // should probably pad x and y with 0s so that they have same length
+        // and are powers of 2
+        if (x.length != y.length) {
+            throw new IllegalArgumentException("Dimensions don't agree");
+        }
+
+        int n = x.length;
+
+        // compute FFT of each sequence
+        Complex[] a = fft(x);
+        Complex[] b = fft(y);
+
+        // point-wise multiply
+        Complex[] c = new Complex[n];
+        for (int i = 0; i < n; i++) {
+            c[i] = a[i].times(b[i]);
+        }
+
+        // compute inverse FFT
+        return ifft(c);
+    }
+
+
+    // compute the linear convolution of x and y
+    public static Complex[] convolve(Complex[] x, Complex[] y) {
+        Complex ZERO = new Complex(0, 0);
+
+        Complex[] a = new Complex[2 * x.length];
+        for (int i = 0; i < x.length; i++) a[i] = x[i];
+        for (int i = x.length; i < 2 * x.length; i++) a[i] = ZERO;
+
+        Complex[] b = new Complex[2 * y.length];
+        for (int i = 0; i < y.length; i++) b[i] = y[i];
+        for (int i = y.length; i < 2 * y.length; i++) b[i] = ZERO;
+
+        return cconvolve(a, b);
+    }
+
+    // compute the DFT of x[] via brute force (n^2 time)
+    public static Complex[] dft(Complex[] x) {
+        int n = x.length;
+        Complex ZERO = new Complex(0, 0);
+        Complex[] y = new Complex[n];
+        for (int k = 0; k < n; k++) {
+            y[k] = ZERO;
+            for (int j = 0; j < n; j++) {
+                int power = (k * j) % n;
+                double kth = -2 * power * Math.PI / n;
+                Complex wkj = new Complex(Math.cos(kth), Math.sin(kth));
+                y[k] = y[k].plus(x[j].times(wkj));
+            }
+        }
+        return y;
+    }
+
+    // display an array of com.example.ueberwachungssystem.Signalverarbeitung.Complex numbers to standard output
+    public static void show(Complex[] x, String title) {
+        System.out.println(title);
+        System.out.println("-------------------");
+        for (int i = 0; i < x.length; i++) {
+            System.out.println(x[i]);
+        }
+        System.out.println();
+    }
+
+    /***************************************************************************
+     *  Test client and sample execution
+     *
+     *  % java FFT 4
+     *  x
+     *  -------------------
+     *  -0.03480425839330703
+     *  0.07910192950176387
+     *  0.7233322451735928
+     *  0.1659819820667019
+     *
+     *  y = fft(x)
+     *  -------------------
+     *  0.9336118983487516
+     *  -0.7581365035668999 + 0.08688005256493803i
+     *  0.44344407521182005
+     *  -0.7581365035668999 - 0.08688005256493803i
+     *
+     *  z = ifft(y)
+     *  -------------------
+     *  -0.03480425839330703
+     *  0.07910192950176387 + 2.6599344570851287E-18i
+     *  0.7233322451735928
+     *  0.1659819820667019 - 2.6599344570851287E-18i
+     *
+     *  c = cconvolve(x, x)
+     *  -------------------
+     *  0.5506798633981853
+     *  0.23461407150576394 - 4.033186818023279E-18i
+     *  -0.016542951108772352
+     *  0.10288019294318276 + 4.033186818023279E-18i
+     *
+     *  d = convolve(x, x)
+     *  -------------------
+     *  0.001211336402308083 - 3.122502256758253E-17i
+     *  -0.005506167987577068 - 5.058885073636224E-17i
+     *  -0.044092969479563274 + 2.1934338938072244E-18i
+     *  0.10288019294318276 - 3.6147323062478115E-17i
+     *  0.5494685269958772 + 3.122502256758253E-17i
+     *  0.240120239493341 + 4.655566391833896E-17i
+     *  0.02755001837079092 - 2.1934338938072244E-18i
+     *  4.01805098805014E-17i
+     *
+     ***************************************************************************/
+
+    public static void main(String[] args) {
+        int n = Integer.parseInt(args[0]);
+        Complex[] x = new Complex[n];
+
+        // original data
+        for (int i = 0; i < n; i++) {
+            x[i] = new Complex(i, 0);
+        }
+        show(x, "x");
+
+        // FFT of original data
+        Complex[] y = fft(x);
+        show(y, "y = fft(x)");
+
+        // FFT of original data
+        Complex[] y2 = dft(x);
+        show(y2, "y2 = dft(x)");
+
+        // take inverse FFT
+        Complex[] z = ifft(y);
+        show(z, "z = ifft(y)");
+
+        // circular convolution of x with itself
+        Complex[] c = cconvolve(x, x);
+        show(c, "c = cconvolve(x, x)");
+
+        // linear convolution of x with itself
+        Complex[] d = convolve(x, x);
+        show(d, "d = convolve(x, x)");
+    }
+}
+
+

app/src/main/java/com/example/ueberwachungssystem/logger/Logger.java

@@ -0,0 +1,61 @@
+package com.example.ueberwachungssystem.logger;
+
+import android.util.Log;
+import android.widget.TextView;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+public class Logger {
+    private TextView textView; 
+    private StringBuffer sb = new StringBuffer(); 
+    private String tag;
+    private int lengthOfLastLog = 0;
+    private boolean overwrite = false;
+
+    public Logger(String tag, TextView textView, String logInitText)  {
+        this.tag = tag;
+        this.textView = textView;
+        sb.append(logInitText);
+    }
+
+    public void log(String s)  {
+        overwrite = false;
+        Log.d(tag, s);
+        sb.append(s).append("\n");
+        if (textView != null) {
+            textView.setText(sb.toString());
+        }
+    }
+
+    public void overwriteLastlog(String s)  {
+        Log.d(tag, s);
+        lengthOfLastLog = s.length();
+        if (overwrite)
+        {
+            sb.setLength(sb.length() - (lengthOfLastLog + 1));
+        }
+        sb.append(s).append("\n");
+        overwrite = true;
+        if (textView != null) {
+            textView.setText(sb.toString());
+        }
+    }
+
+    public void log(Exception e)  {
+        StringWriter sw = new StringWriter();
+        e.printStackTrace(new PrintWriter(sw));
+        log(sw.toString());
+    }
+
+    public void clearLog()  {
+        sb.setLength(0);
+        if (textView != null) {
+            textView.setText("");
+        }
+    }
+
+    public String getLoggedText()  {
+        return sb.toString();
+    }
+}

app/src/main/res/layout/activity_main.xml

@@ -10,6 +10,12 @@
     tools:context=".MainActivity">
 
 
+    <TextView
+        android:id="@+id/textView"
+        android:layout_width="match_parent"
+        android:layout_height="100dp"
+        android:text="TextView" />
+
     <androidx.camera.view.PreviewView
         android:id="@+id/previewView"
         android:layout_width="match_parent"
@@ -31,8 +37,20 @@
     <ImageView
         android:id="@+id/outputImageView"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
+        android:layout_height="1dp"
         tools:srcCompat="@tools:sample/avatars" />
 
+    <com.jjoe64.graphview.GraphView
+        android:id="@+id/graph"
+        android:layout_width="match_parent"
+        android:layout_height="200dip"
+        android:layout_marginStart="16dp"
+        android:layout_marginEnd="16dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintVertical_bias="0.499" />
+
 
 </LinearLayout>

gradle.properties

@@ -18,4 +18,5 @@ android.useAndroidX=true
 # Enables namespacing of each library's R class so that its R class includes only the
 # resources declared in the library itself and none from the library's dependencies,
 # thereby reducing the size of the R class for that library
-android.nonTransitiveRClass=true
+android.nonTransitiveRClass=true
+android.enableJetifier=true