diff --git a/multilayer_stixel_world.h b/multilayer_stixel_world.h
index d6c2e51..7e3263b 100644
--- a/multilayer_stixel_world.h
+++ b/multilayer_stixel_world.h
@@ -100,6 +100,7 @@ class MultiLayerStixelWorld
 		CameraParameters camera;
 
 		// scale down factor in height
+		// this reduces the computation time significantly
 		float verticalScaleDown;
 
 		// default settings
@@ -119,7 +120,7 @@ class MultiLayerStixelWorld
 
 			// camera height and tilt uncertainty
 			sigmaH = 0.01f;
-			sigmaA = 0.01f * static_cast<float>(CV_PI) / 180.f;
+			sigmaA = 0.001f;
 
 			// outlier rate
 			pOutG = 0.15f;