diff --git a/skimage/filter/__init__.py b/skimage/filter/__init__.py
index e98583ff..bd9c94cc 100644
--- a/skimage/filter/__init__.py
+++ b/skimage/filter/__init__.py
@@ -2,7 +2,7 @@ from .lpi_filter import *
 from .ctmf import median_filter
 from ._canny import canny
 from .edges import (sobel, hsobel, vsobel, scharr, hscharr, vscharr, prewitt,
-                    hprewitt, vprewitt, roberts , pdroberts, ndroberts)
+                    hprewitt, vprewitt, roberts , roberts_positive_diagonal, roberts_negative_diagonal)
 from ._denoise import denoise_tv_chambolle, tv_denoise
 from ._denoise_cy import denoise_bilateral, denoise_tv_bregman
 from ._rank_order import rank_order
diff --git a/skimage/filter/edges.py b/skimage/filter/edges.py
index 73215d71..0e1fcda0 100644
--- a/skimage/filter/edges.py
+++ b/skimage/filter/edges.py
@@ -357,10 +357,10 @@ def roberts(image, mask=None):
     output : ndarray
         The Roberts' Cross edge map.
     """
-    return np.sqrt(pdroberts(image, mask)**2 + ndroberts(image, mask)**2)
+    return np.sqrt(roberts_positive_diagonal(image, mask)**2 + roberts_negative_diagonal(image, mask)**2)
 
 
-def pdroberts(image, mask=None):
+def roberts_positive_diagonal(image, mask=None):
     """Find the cross edges of an image using the Roberts' Cross operator.
 
     The kernel is applied to the input image, to produce separate measurements
@@ -396,7 +396,7 @@ def pdroberts(image, mask=None):
     return _mask_filter_result(result, mask)
 
 
-def ndroberts(image, mask=None):
+def roberts_negative_diagonal(image, mask=None):
     """Find the cross edges of an image using the Roberts' Cross operator.
     The kernel is applied to the input image, to produce separate measurements
     of the gradient component one orientation.