Improve TapLatencyAnalyzer to detect TAP and TONE peaks separately

Signed-off-by: celadon <celadon@intel.com>

Author: celadon

apps/OboeTester/app/src/main/java/com/mobileer/oboetester/TapLatencyAnalyser.java

@@ -16,12 +16,13 @@
 package com.mobileer.oboetester;
 
 import java.util.ArrayList;
-
+import android.util.Log; 
 /**
  * Analyze a recording and extract edges for latency analysis.
  */
 public class TapLatencyAnalyser {
     public static final int TYPE_TAP = 0;
+    public static final int TYPE_TONE =1;
     float[] mHighPassBuffer;
 
     private float mDroop = 0.995f;
@@ -90,25 +91,43 @@ private TapLatencyEvent[] scanForEdges(float[] peakBuffer, int numSamples) {
         float fast = 0.0f;
         final float slowCoefficient = 0.01f;
         final float fastCoefficient = 0.10f;
-        float lowThreshold = EDGE_THRESHOLD;
+    	final float EDGE_THRESHOLD = 0.01f;     // trigger threshold for tap
+        final float REARM_FRACTION = 0.3f;      // fraction of last peak to rearm
+        final int MIN_TONE_DELAY = 2000;
+        float lastPeak = 0.0f;
         boolean armed = true;
+        boolean tapDetected = false;
+        boolean toneDetected = false;
+        int lastTapIndex = -1;
+
         int sampleIndex = 0;
+
         for (float level : peakBuffer) {
-            slow = slow + (level - slow) * slowCoefficient; // low pass filter
-            fast = fast + (level - fast) * fastCoefficient; // low pass filter
-            if (armed && (fast > EDGE_THRESHOLD) && (fast > (2.0 * slow))) {
-                events.add(new TapLatencyEvent(TYPE_TAP, sampleIndex));
-                armed = false;
-                // Set a new, lower threshold based on the height of the detected peak.
-                // This allows us to detect a second, smaller peak, but not to trigger
-                // on the smaller variations that occur after the initial peak.
-                lowThreshold = fast * LOW_FRACTION;
-            }
-            // Use hysteresis when rearming.
-            if (fast < lowThreshold) {
-                armed = true;
-            }
-            sampleIndex++;
+		slow = slow + (level - slow) * slowCoefficient; // low pass filter
+		fast = fast + (level - fast) * fastCoefficient; // low pass filter
+		if (armed && !tapDetected && (fast > EDGE_THRESHOLD) && (fast > 2.0f * slow)) {
+			Log.i("TTL", "TTL Event of TYPE_TAP detected at " + sampleIndex + " fast=" + fast);
+			events.add(new TapLatencyEvent(TYPE_TAP, sampleIndex));
+			armed = false;
+			tapDetected = true;
+			lastPeak = fast;
+               	 	lastTapIndex = sampleIndex;
+            	}
+
+	    	if (tapDetected && !toneDetected && !armed && (sampleIndex - lastTapIndex) > MIN_TONE_DELAY) {
+                	if ((fast > EDGE_THRESHOLD) && (fast > 1.5f * slow)) {
+                    		Log.i("TTL", "TTL Event of TYPE_TONE detected at " + sampleIndex + " fast=" + fast);
+                    		events.add(new TapLatencyEvent(TYPE_TONE, sampleIndex));
+                    		toneDetected = true;
+                	}
+            	}
+
+            	// Rearm only when signal has fallen enough
+            	if (!armed && (fast < lastPeak * REARM_FRACTION)) {
+                	Log.i("TTL", "Signal has settled, rearming now (fast=" + fast + ")");
+    			armed = true;
+            	}
+            	sampleIndex++;
         }
         return events.toArray(new TapLatencyEvent[0]);
     }