diff --git a/lib/mask.cpp b/lib/mask.cpp
index 2508b9b..bd1f1c0 100644
--- a/lib/mask.cpp
+++ b/lib/mask.cpp
@@ -15,7 +15,7 @@ namespace Mask
 			for (int y = 0; y < size; ++y)
 			{
 				newMask->mask[y*size+x] = 
-					(sqrt( pow(x - x/2, 2) + pow(y - y/2, 2)) < size / 2)
+					(sqrt( pow(x - size/2, 2) + pow(y - size/2, 2)) <= size / 2 )
 					? 255 : 0;
 			}
 		}
diff --git a/qt/aigoqt.cpp b/qt/aigoqt.cpp
index 4b8ab6d..db3fcc6 100644
--- a/qt/aigoqt.cpp
+++ b/qt/aigoqt.cpp
@@ -27,11 +27,11 @@ void AigoQt::updateImage( void )
 	cam->update();
 	SDL_Surface *s = cam->getSurface();
 
-	Image::threshold(s, blackImageThreshold->value(), whiteImageThreshold->value());
+	if (checkThreshold->isChecked()) Image::threshold(s, blackImageThreshold->value(), whiteImageThreshold->value());
 	SDL_BlitSurface(s, NULL, copy, NULL);
 
-	Mask::mask *mask = Mask::createCircleMask(10);
-	Mask::printMask(mask);
+	Mask::mask *mask = Mask::createCircleMask(19);
+	//Mask::printMask(mask);
 
 	if (checkErosion->isChecked()) Image::erosion(s, copy, mask);
 	if (checkDilation->isChecked()) Image::dilation(s, copy, mask);
diff --git a/qt/main.ui b/qt/main.ui
index e2cadd1..4d7abbf 100644
--- a/qt/main.ui
+++ b/qt/main.ui
@@ -185,6 +185,13 @@
          </property>
         </widget>
        </item>
+       <item>
+        <widget class="QCheckBox" name="checkThreshold" >
+         <property name="text" >
+          <string>Threshold</string>
+         </property>
+        </widget>
+       </item>
        <item>
         <spacer>
          <property name="orientation" >
@@ -247,7 +254,7 @@
      <x>0</x>
      <y>0</y>
      <width>942</width>
-     <height>29</height>
+     <height>31</height>
     </rect>
    </property>
    <widget class="QMenu" name="menu_File" >