Finalized changes. Added reference for non rotation-invariant uniform patterns. Added test case. Modified comments to clarify the process, and changed the code to make it more consistent with explanations and actuall encoding

skimage/feature/texture.py

@@ -249,7 +249,7 @@ def local_binary_pattern(image, P, R, method='default'):
             finer quantization of the angular space which is gray scale and
             rotation invariant.
         * 'nri_uniform': non rotation-invariant uniform patterns variant
-            which is only gray scale invariant.
+            which is only gray scale invariant [2].
         * 'var': rotation invariant variance measures of the contrast of local
             image texture which is rotation but not gray scale invariant.
 
@@ -265,6 +265,10 @@ def local_binary_pattern(image, P, R, method='default'):
            Timo Ojala, Matti Pietikainen, Topi Maenpaa.
            http://www.rafbis.it/biplab15/images/stories/docenti/Danielriccio/\
            Articoliriferimento/LBP.pdf, 2002.
+    .. [2] Face recognition with local binary patterns.
+           Timo Ahonen, Abdenour Hadid, Matti PietikainenAhonen,
+           http://masters.donntu.edu.ua/2011/frt/dyrul/library/article8.pdf,
+           2004.
     """
 
     methods = {