From 71a3af0c86a50e78cffce57be653a7d6d3c972c8 Mon Sep 17 00:00:00 2001
From: Alberto Griggio <agriggio@users.noreply.github.com>
Date: Tue, 30 Jan 2018 10:06:57 +0100
Subject: [PATCH] improve generated curve in histogram matching on underexposed
 pictures

---
 rtengine/histmatching.cc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/rtengine/histmatching.cc b/rtengine/histmatching.cc
index 1870d3180..6728e70ee 100644
--- a/rtengine/histmatching.cc
+++ b/rtengine/histmatching.cc
@@ -120,6 +120,15 @@ void mappingToCurve(const std::vector<int> &mapping, std::vector<double> &curve)
         curve.pop_back();
         curve.pop_back();
     }
+    // remove the plateau at the end (if any)
+    size_t j = curve.size() / 2;
+    for (; j > 1; --j) {
+        if (std::abs(curve[2*(j-1)-1] - curve.back()) > 0.01) {
+            break;
+        }
+    }
+    curve.resize(2*j);
+        
     curve.push_back(1.0);
     curve.push_back(1.0);