diff --git a/skimage/morphology/convex_hull.py b/skimage/morphology/convex_hull.py
index 6cb9f653..24b45db2 100644
--- a/skimage/morphology/convex_hull.py
+++ b/skimage/morphology/convex_hull.py
@@ -41,7 +41,7 @@ def convex_hull_image(image):
     for i, (x_offset, y_offset) in enumerate(zip((0, 0, -0.5, 0.5),
                                                  (-0.5, 0.5, 0, 0))):
         coords_corners[i * N:(i + 1) * N] = coords + [x_offset, y_offset]
-  
+
     coords = coords_corners
 
     try: