diff --git a/skimage/util/dtype.py b/skimage/util/dtype.py
index 4a5a6f23..0ca3197b 100644
--- a/skimage/util/dtype.py
+++ b/skimage/util/dtype.py
@@ -344,7 +344,7 @@ def img_as_bool(image, force_copy=False):
 
     Returns
     -------
-    out : ndarray of bool (bool_)
+    out : ndarray of bool (`bool_`)
         Output image.
 
     Notes