v3.0

* Refactor

Author: KalebKE

build.gradle

@@ -1,23 +1,27 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
-
 buildscript {
     repositories {
-        jcenter()
         google()
+        mavenCentral()
+        maven { url 'https://jitpack.io' }
     }
+
+    ext.kotlin_version = '1.9.22'
+
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.3'
-        classpath 'com.github.dcendents:android-maven-gradle-plugin:1.5'
+        classpath 'com.android.tools.build:gradle:8.1.4'
+
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.22"
     }
 }
 
+plugins {}
+
 allprojects {
     repositories {
-        jcenter()
+        maven { url "https://maven.google.com" }
+        maven { url "https://jitpack.io" }
         google()
+        mavenCentral();
     }
-}
-
-task clean(type: Delete) {
-    delete rootProject.buildDir
-}
+}

documentation/USAGE.md

@@ -29,16 +29,16 @@ public void onSensorChanged(SensorEvent event) {
 
 ```
 // Stil a BaseFilter under the hood
-private AveragingFilter averagingFilter;
+private AveragingFilter sensorFilter;
 private LinearAcceleration linearAccelerationFilter;
 
 private void init() {
-  averagingFilter = new ... // LowPassFilter(), MeanFilter(), MedianFilter();
+  sensorFilter = new ... // LowPassFilter(), MeanFilter(), MedianFilter();
   // Make the filter "stiff" with a large time constant since gravity is a constant (mostly)
-  averagingFilter.setTimeConstant(5);
+  sensorFilter.setTimeConstant(5);
   
   // Initialize the linear acceleration filter with the averaging filter
-  linearAccelerationFilter = new LinearAccelerationAveraging(averagingFilter);
+  linearAccelerationFilter = new LinearAccelerationAveraging(sensorFilter);
 }
 
 @Override
@@ -51,7 +51,7 @@ public void onSensorChanged(SensorEvent event) {
       // You need to drive *both* filters. The input and the outputs can be driven at different rates...
       // For instance, once your averaging filter has essentially converged on gravity, it doesn't
       // need anymore inputs...
-      averagingFilter.filter(acceleration);
+      sensorFilter.filter(acceleration);
       linearAccelerationFilter.filter(acceleration);
     } 
 }

fsensor/build.gradle

@@ -1,19 +1,18 @@
 apply plugin: 'com.android.library'
-apply plugin: 'com.github.dcendents.android-maven'
-
-group='com.github.KalebKE'
 
 android {
-    compileSdkVersion 29
+    compileSdkVersion 34
     buildToolsVersion "29.0.3"
 
+    namespace = "com.kircherelectronics.fsensor"
+
     lintOptions {
         abortOnError false
     }
 
     defaultConfig {
         minSdkVersion 14
-        targetSdkVersion 29
+        targetSdkVersion 33
         versionCode 9
         versionName "2.2"
 
@@ -37,5 +36,5 @@ dependencies {
     })
     testImplementation 'junit:junit:4.12'
 
-    api files('libs/commons-math3-3.6.1.jar')
+    implementation 'org.apache.commons:commons-math3:3.6.1'
 }

fsensor/libs/commons-math3-3.6.1.jar

@@ -1,7 +1,7 @@
-package com.kircherelectronics.fsensor.filter.averaging;
+package com.kircherelectronics.fsensor.filter;
 
 /*
- * Copyright 2018, Kircher Electronics, LLC
+ * Copyright 2024, Tracqi Technology, LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,75 +25,51 @@
  * dt) where the time constant is the length of signals the fusedOrientation should act on
  * and dt is the sample period (1/frequency) of the sensor.
  *
- * http://developer.android.com/reference/android/hardware/SensorEvent.html
- * @author Kaleb
+ * @author Kaleb Kircher
  */
-public class LowPassFilter extends AveragingFilter
-{
+public class LowPassFilter extends SensorFilter {
     private static final String tag = LowPassFilter.class.getSimpleName();
 
-    // Gravity and linear accelerations components for the
-    // Wikipedia low-pass fusedOrientation
-    private float[] output;
-
-    public LowPassFilter() {
-        this(DEFAULT_TIME_CONSTANT);
-    }
+    public LowPassFilter() {}
 
     public LowPassFilter(float timeConstant) {
         this.timeConstant = timeConstant;
-        reset();
     }
 
     /**
      * Add a sample.
      *
-     * @param values
-     *            The acceleration data. A 1x3 matrix containing the data from the X, Y and Z axis of the sensor
-     *            noting that order is arbitrary.
+     * @param values The acceleration data. A 1x3 matrix containing the data from the X, Y and Z axis of the sensor
+     *               noting that order is arbitrary.
      * @return Returns the output of the fusedOrientation.
      */
-    public float[] filter(float[] values)
-    {
+    public float[] filter(float[] values) {
         // Initialize the start time.
-        if (startTime == 0)
-        {
+        if (startTime == 0) {
             startTime = System.nanoTime();
         }
 
-        timestamp = System.nanoTime();
-
         // Find the sample period (between updates) and convert from
         // nanoseconds to seconds. Note that the sensor delivery rates can
         // individually vary by a relatively large time frame, so we use an
         // averaging technique with the number of sensor updates to
         // determine the delivery rate.
-        float dt = 1 / (count++ / ((timestamp - startTime) / 1000000000.0f));
+        float dt = 1 / (count++ / ((System.nanoTime() - startTime) / 1000000000.0f));
 
         float alpha = timeConstant / (timeConstant + dt);
+        float oneMinusAlpha = 1 - alpha;
 
-        output[0] = alpha * output[0] + (1 - alpha) * values[0];
-        output[1] = alpha * output[1] + (1 - alpha) * values[1];
-        output[2] = alpha * output[2] + (1 - alpha) * values[2];
+        output[0] = alpha * output[0] + oneMinusAlpha * values[0];
+        output[1] = alpha * output[1] + oneMinusAlpha * values[1];
+        output[2] = alpha * output[2] + oneMinusAlpha * values[2];
 
-        return output;
-    }
+        if(filter != null) {
+            float[] filteredOutput = filter.filter(output);
+            output[0] = filteredOutput[0];
+            output[1] = filteredOutput[1];
+            output[2] = filteredOutput[2];
+        }
 
-    @Override
-    public float[] getOutput() {
         return output;
     }
-
-    public void setTimeConstant(float timeConstant)
-    {
-        this.timeConstant = timeConstant;
-    }
-
-    public void reset()
-    {
-        super.reset();
-        this.output = new float[]
-                { 0, 0, 0 };
-
-    }
 }

fsensor/src/main/java/com/kircherelectronics/fsensor/filter/averaging/LowPassFilter.java fsensor/src/main/java/com/kircherelectronics/fsensor/filter/LowPassFilter.java

@@ -1,10 +1,10 @@
-package com.kircherelectronics.fsensor.filter.averaging;
+package com.kircherelectronics.fsensor.filter;
 
 import java.util.ArrayDeque;
 import java.util.Arrays;
 
 /*
- * Copyright 2018, Kircher Electronics, LLC
+ * Copyright 2024, Tracqi Technology, LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,12 +33,11 @@
  *
  * @author Kaleb
  */
-public class MeanFilter extends AveragingFilter {
+public class MeanFilter extends SensorFilter {
 
     private static final String tag = MeanFilter.class.getSimpleName();
 
-    private final ArrayDeque<float[]> values;
-    private float[] output;
+    private final ArrayDeque<float[]> values = new ArrayDeque<>();
 
     /**
      * Initialize a new MeanFilter object.
@@ -49,7 +48,6 @@ public MeanFilter() {
 
     public MeanFilter(float timeConstant) {
         super(timeConstant);
-        values = new ArrayDeque<>();
     }
 
     /**
@@ -64,14 +62,12 @@ public float[] filter(float[] data) {
             startTime = System.nanoTime();
         }
 
-        timestamp = System.nanoTime();
-
         // Find the sample period (between updates) and convert from
         // nanoseconds to seconds. Note that the sensor delivery rates can
         // individually vary by a relatively large time frame, so we use an
         // averaging technique with the number of sensor updates to
         // determine the delivery rate.
-        float hz = (count++ / ((timestamp - startTime) / 1000000000.0f));
+        float hz = (count++ / ((System.nanoTime() - startTime) / 1000000000.0f));
 
         int filterWindow = (int) Math.ceil(hz * timeConstant);
 
@@ -82,20 +78,15 @@ public float[] filter(float[] data) {
         }
 
         if(!values.isEmpty()) {
-            output = getMean(values);
+            float[] mean = getMean(values);
+            System.arraycopy(mean, 0, output, 0, output.length);
         } else {
-            output = new float[data.length];
             System.arraycopy(data, 0, output, 0, data.length);
         }
 
         return output;
     }
 
-    @Override
-    public float[] getOutput() {
-        return output;
-    }
-
     /**
      * Get the mean of the data set.
      *
@@ -118,15 +109,8 @@ private float[] getMean(ArrayDeque<float[]> data) {
         return mean;
     }
 
-    public void setTimeConstant(float timeConstant) {
-        this.timeConstant = timeConstant;
-    }
-
     public void reset() {
         super.reset();
-
-        if(values != null) {
-            this.values.clear();
-        }
+        this.values.clear();
     }
 }

fsensor/src/main/java/com/kircherelectronics/fsensor/filter/averaging/MeanFilter.java fsensor/src/main/java/com/kircherelectronics/fsensor/filter/MeanFilter.java

@@ -1,12 +1,12 @@
-package com.kircherelectronics.fsensor.filter.averaging;
+package com.kircherelectronics.fsensor.filter;
 
 import org.apache.commons.math3.stat.StatUtils;
 
 import java.util.ArrayDeque;
 import java.util.Arrays;
 
 /*
- * Copyright 2018, Kircher Electronics, LLC
+ * Copyright 2024, Tracqi Technology, LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,14 +37,12 @@
  * @author Kaleb
  * @version %I%, %G%
  */
-public class MedianFilter extends AveragingFilter {
+public class MedianFilter extends SensorFilter {
 
     private static final String tag = MedianFilter.class
             .getSimpleName();
 
-    private final ArrayDeque<float[]> values;
-    private float[] output;
-
+    private final ArrayDeque<float[]> values = new ArrayDeque<>();;
 
     /**
      * Initialize a new MeanFilter object.
@@ -55,9 +53,6 @@ public MedianFilter() {
 
     public MedianFilter(float timeConstant) {
         this.timeConstant = timeConstant;
-        this.values = new ArrayDeque<>();
-
-        reset();
     }
 
     /**
@@ -72,14 +67,12 @@ public float[] filter(float[] data) {
             startTime = System.nanoTime();
         }
 
-        timestamp = System.nanoTime();
-
         // Find the sample period (between updates) and convert from
         // nanoseconds to seconds. Note that the sensor delivery rates can
         // individually vary by a relatively large time frame, so we use an
         // averaging technique with the number of sensor updates to
         // determine the delivery rate.
-        float hz = (count++ / ((timestamp - startTime) / 1000000000.0f));
+        float hz = (count++ / ((System.nanoTime() - startTime) / 1000000000.0f));
 
         int filterWindow = (int) Math.ceil(hz * timeConstant);
 
@@ -90,17 +83,19 @@ public float[] filter(float[] data) {
         }
 
         if(!values.isEmpty()) {
-            output = getMean(values);
+            float[] median = getMedian(values);
+            System.arraycopy(median, 0, output, 0, output.length);
         } else {
-            output = new float[data.length];
             System.arraycopy(data, 0, output, 0, data.length);
         }
 
-        return output;
-    }
+        if(filter != null) {
+            float[] filteredOutput = filter.filter(output);
+            output[0] = filteredOutput[0];
+            output[1] = filteredOutput[1];
+            output[2] = filteredOutput[2];
+        }
 
-    @Override
-    public float[] getOutput() {
         return output;
     }
 
@@ -110,7 +105,7 @@ public float[] getOutput() {
      * @param data the data set.
      * @return the mean of the data set.
      */
-    private float[] getMean(ArrayDeque<float[]> data) {
+    private float[] getMedian(ArrayDeque<float[]> data) {
         float[] mean = new float[data.getFirst().length];
 
         double[][] values = new double[data.getFirst().length][data.size()];
@@ -130,10 +125,6 @@ private float[] getMean(ArrayDeque<float[]> data) {
         return mean;
     }
 
-    public void setTimeConstant(float timeConstant) {
-        this.timeConstant = timeConstant;
-    }
-
     public void reset() {
         super.reset();