diff --git a/skimage/filter/rank/generic.py b/skimage/filter/rank/generic.py
index 6341b822..ba45a898 100644
--- a/skimage/filter/rank/generic.py
+++ b/skimage/filter/rank/generic.py
@@ -558,12 +558,12 @@ def sum(image, selem, out=None, mask=None, shift_x=False, shift_y=False):
     >>> # Local mean
     >>> from skimage.morphology import square
     >>> import skimage.filter.rank as rank
-    >>> ima = 255 * np.array([[0, 0, 0, 0, 0],
+    >>> ima = np.array([[0, 0, 0, 0, 0],
     ...                       [0, 1, 1, 1, 0],
     ...                       [0, 1, 1, 1, 0],
     ...                       [0, 1, 1, 1, 0],
     ...                       [0, 0, 0, 0, 0]], dtype=np.uint8)
-    >>> rank.pop(ima, square(3))
+    >>> rank.sum(ima, square(3))
     array([[1, 2, 3, 2, 1],
            [2, 4, 6, 4, 2],
            [3, 6, 9, 6, 3],