diff --git a/src/publisher_vision.cpp b/src/publisher_vision.cpp
index cdce28facf258c2eac73477b555bc3a89dda8370..8888c2048d758a7f0e350871418849e1d172f6a9 100644
--- a/src/publisher_vision.cpp
+++ b/src/publisher_vision.cpp
@@ -172,11 +172,11 @@ std::vector<int> PublisherVisionDebug::colorTrackAndFeatures(int _nb_feature_in_
     }
     else
     {
-        alpha = 1.0; // put "full luminosity as a default value"
+        alpha = 0; // put "full luminosity as a default value"
 //        alpha = 0.5; // put "half luminosity as a default value"
     }
 
-    double lum = (_min_lum + (_max_lum - _min_lum) * alpha);
+    double lum = (_min_lum + (_max_lum - _min_lum) * (1 - alpha));
     if (lum > 255)
     {
         color[0] = 255;