Merge remote-tracking branch 'origin/master'
This commit is contained in:
commit
6f78836c4d
3
Notiz.txt
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3
Notiz.txt
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@ -0,0 +1,3 @@
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Sensor als Service einrichten, der aus Activity heraus gestartet werden kann.
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Stichwort: Intent
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Siehe Skript Teil 1
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@ -0,0 +1,108 @@
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package com.example.ueberwachungssystem.Detection;
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import static java.lang.Math.sqrt;
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import android.content.Context;
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import android.hardware.Sensor;
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import android.hardware.SensorEvent;
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import android.hardware.SensorEventListener;
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import android.hardware.SensorManager;
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/**
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* Accelerometer inherits some methods from abstract Detector class (more info there)
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*
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*
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* USE FROM MAIN ACTIVITY:
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*
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* Accelerometer beschleunigungssensor = new Accelerometer(this);
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* onCreate:
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* //Accelerometer Setup
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* beschleunigungssensor = new Accelerometer(this, logger, textViewLog); //logger and textview only for debugging necessary
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* beschleunigungssensor.getSensor();
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*
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* //Starting Detection:
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* beschleunigungssensor.startDetection();
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* //Stopping Detection: also recommended at onPause to avoid unnecessary battery consumption
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* beschleunigungssensor.stopDetection();
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*
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* */
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public class Accelerometer extends Detector implements SensorEventListener {
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public SensorManager sensorManager;
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private static final int sensorType = Sensor.TYPE_LINEAR_ACCELERATION;
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private Sensor accelerometer;
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private Context context;
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boolean alarm = false;
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//Preallocate memory for the data of each axis of the acceleration sensor
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float x;
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float y;
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float z;
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float betrag; //Betrag aller drei Achsen sqrt(x*x + y*y + z*z)
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private DetectionReport detectionReport;
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// In constructor pass Activity, Context and TextView from MainActivity in Accelerometer class
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public Accelerometer(Context context){
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super(); //von Detektor
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this.context = context;
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}
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public void getSensor(){
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sensorManager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
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if(sensorManager.getSensorList(sensorType).size()==0) {
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accelerometer = null;
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}
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else {
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accelerometer = sensorManager.getSensorList(sensorType).get(0);
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}
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}
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@Override
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public void onSensorChanged(SensorEvent event) {
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try {
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checkAlarm(event);
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} catch (InterruptedException e) {
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throw new RuntimeException(e);
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}
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}
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public void checkAlarm (SensorEvent event) throws InterruptedException {
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x = event.values[0];
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y = event.values[1];
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z = event.values[2];
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betrag = (float) sqrt(x*x + y*y + z*z);
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float threshold = 1.5F;
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if (!alarm) {
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if (betrag > threshold) {
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alarm = true;
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reportViolation("Bewegung", betrag);
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}
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} else {
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if (betrag < threshold) {
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alarm = false;
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} else {
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}
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}
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}
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@Override
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public void onAccuracyChanged(Sensor sensor, int accuracy) {
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}
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@Override
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public void startDetection() {
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// entspricht void start()
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//getSensor();
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if (accelerometer != null) {
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sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_GAME);
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}
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}
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@Override
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public void stopDetection() {
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// entspricht void stop()
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sensorManager.unregisterListener(this, accelerometer);
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}
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}
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@ -0,0 +1,382 @@
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package com.example.ueberwachungssystem.Detection;
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import static java.lang.Math.*;
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import android.Manifest;
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import android.annotation.SuppressLint;
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import android.app.Activity;
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import android.content.Context;
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import android.content.pm.PackageManager;
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import android.media.AudioFormat;
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import android.media.AudioRecord;
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import android.media.MediaRecorder;
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import android.os.AsyncTask;
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import android.util.Log;
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import androidx.core.app.ActivityCompat;
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import androidx.core.content.ContextCompat;
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import com.example.ueberwachungssystem.Detection.Signalverarbeitung.Complex;
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import com.example.ueberwachungssystem.Detection.Signalverarbeitung.FFT;
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import com.example.ueberwachungssystem.Detection.DetectionReport;
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import com.example.ueberwachungssystem.Detection.Detector;
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public class MicrophoneDetector extends Detector {
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/**
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* Constructor - takes context of current activity
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*
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* @param context
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*/
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private static final int RECHTEANFORDERUNG_MIKROFON = 1;
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private AufnahmeTask aufnahmeTask;
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public boolean armed = false;
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public int Schwellwert_Alarm = 100;
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private Context context;
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public MicrophoneDetector(Context context) {
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super();
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this.context = context;
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}
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||||
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||||
@Override
|
||||
public void startDetection() {
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aufnahmeTask = new AufnahmeTask();
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aufnahmeTask.execute();
|
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}
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||||
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||||
@Override
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public void stopDetection() {
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if (aufnahmeTask != null) {
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aufnahmeTask.cancel(true);
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}
|
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}
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class AufnahmeTask extends AsyncTask<Long, Verarbeitungsergebnis, Void> {
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private AudioRecord recorder;
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private final int sampleRateInHz = 44100;
|
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private final int channelConfig = AudioFormat.CHANNEL_IN_MONO;
|
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private final int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
|
||||
private int minPufferGroesseInBytes;
|
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private int pufferGroesseInBytes;
|
||||
private RingPuffer ringPuffer = new RingPuffer(10);
|
||||
private float kalibierWert;
|
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private com.example.ueberwachungssystem.Detection.DetectionReport detectionReport;
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||||
|
||||
@SuppressLint("MissingPermission")
|
||||
AufnahmeTask() {
|
||||
minPufferGroesseInBytes = AudioRecord.getMinBufferSize(sampleRateInHz, channelConfig, audioFormat);
|
||||
pufferGroesseInBytes = minPufferGroesseInBytes * 2;
|
||||
try {
|
||||
recorder = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRateInHz, channelConfig, audioFormat, pufferGroesseInBytes);
|
||||
} catch (Exception e) {
|
||||
e.printStackTrace();
|
||||
}
|
||||
Log.d("0","Puffergroeße: "+ minPufferGroesseInBytes + " " + pufferGroesseInBytes);
|
||||
Log.d("0","Recorder (SR, CH): "+ recorder.getSampleRate() + " " + recorder.getChannelCount());
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||||
|
||||
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();
|
||||
}
|
||||
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||||
switch (recorder.getChannelConfiguration()) {
|
||||
case AudioFormat.CHANNEL_IN_MONO:
|
||||
s = "Mono";
|
||||
break;
|
||||
case AudioFormat.CHANNEL_IN_STEREO:
|
||||
s = "Stereo";
|
||||
anzahlBytesProAbtastwert *= 2;
|
||||
break;
|
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case AudioFormat.CHANNEL_INVALID:
|
||||
s = "ungültig";
|
||||
break;
|
||||
default:
|
||||
throw new IllegalArgumentException();
|
||||
}
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||||
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||||
Log.d("0","Konfiguration: "+ s);
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||||
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||||
int pufferGroesseInAnzahlAbtastwerten = pufferGroesseInBytes / anzahlBytesProAbtastwert;
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||||
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||||
}
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@Override
|
||||
protected Void doInBackground(Long... params) {
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recorder.startRecording();
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short[] puffer = new short[pufferGroesseInBytes / 2];
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long lastTime = System.currentTimeMillis();
|
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float verarbeitungsrate = 0;
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final int maxZaehlerZeitMessung = 10;
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int zaehlerZeitMessung = 0;
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||||
int anzahlVerarbeitet = 0;
|
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GleitenderMittelwert gleitenderMittelwert = new GleitenderMittelwert(0.3f);
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||||
//Kalibrierung
|
||||
try {
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||||
Thread.sleep(3000); // Time to lay down the phone
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} catch (InterruptedException e) {
|
||||
e.printStackTrace();
|
||||
}
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||||
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 {
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||||
Thread.sleep(50);
|
||||
} catch (InterruptedException e) {
|
||||
e.printStackTrace();
|
||||
}
|
||||
}
|
||||
kalibierWert = kalibierWert/i;
|
||||
|
||||
// __Part of FFT__
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||||
// 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);
|
||||
|
||||
for (; ; ) {
|
||||
if (aufnahmeTask.isCancelled()) {
|
||||
break;
|
||||
} else {
|
||||
int n = recorder.read(puffer, 0, puffer.length);
|
||||
Verarbeitungsergebnis ergebnis = verarbeiten(puffer, n);
|
||||
anzahlVerarbeitet += n;
|
||||
|
||||
// __Part of FFT__
|
||||
// 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);
|
||||
// }
|
||||
|
||||
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(10);
|
||||
} 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];
|
||||
}
|
||||
}
|
||||
|
||||
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);
|
||||
float maxAmpPrint = round(20*log10(abs(progress[0].maxAmp/1.0)));
|
||||
float kalibierWertPrint = round(20*log10(abs(kalibierWert)));
|
||||
Log.d("0","VR, Max, Kal:" + progress[0].verarbeitungsrate + ", " + maxAmpPrint
|
||||
+ " dB, " + kalibierWertPrint + " dB");
|
||||
|
||||
if (progress[0].maxAmp >= Schwellwert_Alarm+kalibierWert && armed == true) {
|
||||
armed = false;
|
||||
detectionReport = new DetectionReport(true, "Audio", maxAmpPrint);
|
||||
reportViolation("Audio", maxAmpPrint);
|
||||
Log.d("1",detectionReport.toString());
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
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 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);
|
||||
|
||||
for(int i = 0; i < (mNumberOfFFTPoints/2); i++)
|
||||
{
|
||||
absSignal[i] = y[i].abs();
|
||||
}
|
||||
|
||||
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;
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,148 @@
|
||||
package com.example.ueberwachungssystem.Detection.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.Detection.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.Detection.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.Detection.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.Detection.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.Detection.Signalverarbeitung.Complex object whose value is the conjugate of this
|
||||
public Complex conjugate() {
|
||||
return new Complex(re, -im);
|
||||
}
|
||||
|
||||
// return a new com.example.ueberwachungssystem.Detection.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.Detection.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.Detection.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.Detection.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.Detection.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());
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,246 @@
|
||||
package com.example.ueberwachungssystem.Detection.Signalverarbeitung;
|
||||
// Source: https://introcs.cs.princeton.edu/java/97data/FFT.java.html
|
||||
|
||||
/******************************************************************************
|
||||
* Compilation: javac FFT.java
|
||||
* Execution: java FFT n
|
||||
* Dependencies: com.example.ueberwachungssystem.Detection.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.Detection.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)");
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
// Top-level build file where you can add configuration options common to all sub-projects/modules.
|
||||
plugins {
|
||||
id 'com.android.application' version '7.4.2' apply false
|
||||
id 'com.android.library' version '7.4.2' apply false
|
||||
id 'com.android.application' version '8.0.0' apply false
|
||||
id 'com.android.library' version '8.0.0' apply false
|
||||
}
|
||||
@ -18,4 +18,6 @@ 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.defaults.buildfeatures.buildconfig=true
|
||||
android.nonFinalResIds=false
|
||||
2
gradle/wrapper/gradle-wrapper.properties
vendored
2
gradle/wrapper/gradle-wrapper.properties
vendored
@ -1,6 +1,6 @@
|
||||
#Thu May 11 15:04:30 CEST 2023
|
||||
distributionBase=GRADLE_USER_HOME
|
||||
distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-bin.zip
|
||||
distributionUrl=https\://services.gradle.org/distributions/gradle-8.0-bin.zip
|
||||
distributionPath=wrapper/dists
|
||||
zipStorePath=wrapper/dists
|
||||
zipStoreBase=GRADLE_USER_HOME
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user