From 1fc07c2b662aad7aa481a4efe92ff8875ce5f880 Mon Sep 17 00:00:00 2001
From: Daniel Girardeau-Montaut <daniel.girardeau@gmail.com>
Date: Fri, 22 Mar 2019 15:02:28 +0100
Subject: [PATCH] MEDIAN stat operation added

---
 FeaturesInterface.h |  3 +++
 PointFeature.cpp    | 20 ++++++++++++++++++--
 q3DMASCTools.cpp    |  5 +++++
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/FeaturesInterface.h b/FeaturesInterface.h
index 788d90a..be5703c 100644
--- a/FeaturesInterface.h
+++ b/FeaturesInterface.h
@@ -65,6 +65,7 @@ namespace masc
 			NO_STAT,
 			MEAN,
 			MODE, //number with the highest frequency
+			MEDIAN,
 			STD,
 			RANGE,
 			SKEW //(SKEW = (MEAN - MODE)/STD)
@@ -78,6 +79,8 @@ namespace masc
 				return "MEAN";
 			case MODE:
 				return "MODE";
+			case MEDIAN:
+				return "MEDIAN";
 			case STD:
 				return "STD";
 			case RANGE:
diff --git a/PointFeature.cpp b/PointFeature.cpp
index 6892dd0..3eaee21 100644
--- a/PointFeature.cpp
+++ b/PointFeature.cpp
@@ -372,7 +372,7 @@ static bool ExtractStatFromSF(	const CCVector3& queryPoint,
 	else
 	{
 		bool withSums = (stat == Feature::MEAN || stat == Feature::STD);
-		bool storeValues = (stat == Feature::MODE || stat == Feature::SKEW);
+		bool storeValues = (stat == Feature::MEDIAN || stat == Feature::MODE || stat == Feature::SKEW);
 		double sum = 0.0;
 		double sum2 = 0.0;
 
@@ -424,6 +424,14 @@ static bool ExtractStatFromSF(	const CCVector3& queryPoint,
 		}
 		break;
 
+		case Feature::MEDIAN:
+		{
+			size_t medianIndex = values.size() / 2;
+			std::nth_element(values.begin(), values.begin() + medianIndex, values.end());
+			outputValue = values[medianIndex];
+		}
+		break;
+
 		case Feature::STD:
 		{
 			outputValue = sqrt(std::abs(sum2 * kNN - sum * sum)) / kNN;
@@ -670,7 +678,7 @@ bool PointFeature::computeStat(const CCLib::DgmOctree::NeighboursSet& pointsInNe
 	else
 	{
 		bool withSums = (stat == Feature::MEAN || stat == Feature::STD);
-		bool storeValues = (stat == Feature::MODE || stat == Feature::SKEW);
+		bool storeValues = (stat == Feature::MEDIAN || stat == Feature::MODE || stat == Feature::SKEW);
 		double sum = 0.0;
 		double sum2 = 0.0;
 
@@ -722,6 +730,14 @@ bool PointFeature::computeStat(const CCLib::DgmOctree::NeighboursSet& pointsInNe
 		}
 		break;
 
+		case Feature::MEDIAN:
+		{
+			size_t medianIndex = values.size() / 2;
+			std::nth_element(values.begin(), values.begin() + medianIndex, values.end());
+			outputValue = values[medianIndex];
+		}
+		break;
+
 		case Feature::STD:
 		{
 			outputValue = sqrt(std::abs(sum2 * kNN - sum * sum)) / kNN;
diff --git a/q3DMASCTools.cpp b/q3DMASCTools.cpp
index 991f366..0a477d2 100644
--- a/q3DMASCTools.cpp
+++ b/q3DMASCTools.cpp
@@ -269,6 +269,11 @@ static bool CreateFeaturesFromCommand(const QString& command, int lineNumber, co
 				feature->stat = Feature::MODE;
 				statDefined = true;
 			}
+			else if (token == "MEDIAN")
+			{
+				feature->stat = Feature::MEDIAN;
+				statDefined = true;
+			}
 			else if (token == "STD")
 			{
 				feature->stat = Feature::STD;