From c0a53262624fad63ad33f1c89fc63cb15d4f1753 Mon Sep 17 00:00:00 2001
From: towsey <m.towsey@qut.edu.au>
Date: Wed, 10 Jun 2020 09:16:52 +1000
Subject: [PATCH] Finish work on Australasian Pipit recognizer

Issue #321 Finish work on Australasian Pipit recognizer. THis recognizer still has a FP rate of 60 on the noise data set. THis can be improved with better characterisation of the event content.

NOTE WARNING @ line 350 in EventExtentions.cs
---
 .../Birds/AnthusNovaeseelandiae.cs            | 17 +++++++++++++---
 .../Events/EventExtentions.cs                 | 20 +------------------
 2 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/src/AnalysisPrograms/Recognizers/Birds/AnthusNovaeseelandiae.cs b/src/AnalysisPrograms/Recognizers/Birds/AnthusNovaeseelandiae.cs
index 77fd1fcba..e6dafc7e0 100644
--- a/src/AnalysisPrograms/Recognizers/Birds/AnthusNovaeseelandiae.cs
+++ b/src/AnalysisPrograms/Recognizers/Birds/AnthusNovaeseelandiae.cs
@@ -150,13 +150,18 @@ public override RecognizerResults Recognize(
         /// <returns>A list of composite events.</returns>
         public static List<EventCommon> FilterEventsOnFrequencyProfile(List<EventCommon> events)
         {
+            if (events.Count == 0)
+            {
+                return events;
+            }
+
             // select only the composite events.
             //var compositeEvents = events.Select(x => (CompositeEvent)x).ToList();
             var (compositeEvents, others) = events.FilterForEventType<CompositeEvent, EventCommon>();
 
-            if (compositeEvents == null)
+            if (compositeEvents == null || compositeEvents.Count == 0)
             {
-                return null;
+                return events;
             }
 
             // get the composite track for each composite event.
@@ -165,7 +170,13 @@ public static List<EventCommon> FilterEventsOnFrequencyProfile(List<EventCommon>
             {
                 var componentEvents = ev.ComponentEvents;
                 var points = EventExtentions.GetCompositeTrack(componentEvents).ToArray();
-                var length = points.Length - 1;
+
+                // For Pipit require minimum of four frames duration.
+                var length = points.Length;
+                if (length < 4)
+                {
+                    continue;
+                }
 
                 //WriteFrequencyProfile(points);
 
diff --git a/src/AudioAnalysisTools/Events/EventExtentions.cs b/src/AudioAnalysisTools/Events/EventExtentions.cs
index 5d6f63a25..ee7e0fc74 100644
--- a/src/AudioAnalysisTools/Events/EventExtentions.cs
+++ b/src/AudioAnalysisTools/Events/EventExtentions.cs
@@ -64,16 +64,6 @@ public static List<EventCommon> FilterOnBandwidth(List<EventCommon> events, doub
         public static List<EventCommon> FilterOnBandwidth(List<EventCommon> events, double minBandwidth, double maxBandwidth)
         {
             var outputEvents = events.Where(ev => ((SpectralEvent)ev).BandWidthHertz > minBandwidth && ((SpectralEvent)ev).BandWidthHertz < maxBandwidth).ToList();
-
-            //var outputEvents = new List<EventCommon>();
-            //foreach (var ev in events)
-            //{
-            //    if (((SpectralEvent)ev).BandWidthHertz > minBandwidth && ((SpectralEvent)ev).BandWidthHertz < maxBandwidth)
-            //    {
-            //        outputEvents.Add(ev);
-            //    }
-            //}
-
             return outputEvents;
         }
 
@@ -101,15 +91,6 @@ public static List<SpectralEvent> FilterLongEvents(List<SpectralEvent> events, d
         public static List<EventCommon> FilterOnDuration(List<EventCommon> events, double minimumDurationSeconds, double maximumDurationSeconds)
         {
             var outputEvents = events.Where(ev => ((SpectralEvent)ev).EventDurationSeconds > minimumDurationSeconds && ((SpectralEvent)ev).EventDurationSeconds < maximumDurationSeconds).ToList();
-
-            //foreach (var ev in events)
-            //{
-            //    if (((SpectralEvent)ev).EventDurationSeconds > minimumDurationSeconds && ((SpectralEvent)ev).EventDurationSeconds < maximumDurationSeconds)
-            //    {
-            //        outputEvents.Add(ev);
-            //    }
-            //}
-
             return outputEvents;
         }
 
@@ -366,6 +347,7 @@ public static List<EventCommon> FilterEventsOnCompositeContent(
         /// Combines all the tracks in all the events in the passed list into a single track.
         /// Each frame in the composite event is assigned the spectral point having maximum amplitude.
         /// The points in the returned array are in temporal order.
+        /// TODO TODO WARNING!  This method needs to be generalised from WhipEvent - see first line.
         /// </summary>
         /// <param name="events">List of spectral events.</param>
         public static IEnumerable<ISpectralPoint> GetCompositeTrack(List<EventCommon> events)