Renamed graph.py to rag.py

skimage/graph/_construct.pyx

@@ -1,4 +1,4 @@
-import networkx as nx
+import rag
 cimport numpy as cnp
 import numpy as np
 
@@ -10,7 +10,7 @@ def construct_rag_meancolor_3d( img, arr):
     b = arr.shape[1]
     h = arr.shape[2]
 
-    g = nx.Graph()
+    g = rag.RAG()
 
     i = 0
     while i < l - 1:
@@ -81,7 +81,7 @@ def construct_rag_meancolor_2d(img, arr):
     l = arr.shape[0]
     b = arr.shape[1]
 
-    g = nx.Graph()
+    g = rag.RAG()
 
     i = 0
     while i < l - 1:

skimage/graph/rag.py

@@ -0,0 +1,35 @@
+import networkx as nx
+import _construct
+from skimage import util
+
+class RAG(nx.Graph):
+
+    def merge_nodes(i,j):
+        if not self.has_edge(i, j):
+            raise ValueError('Cant merge non adjacent nodes')
+
+        # print "before ",self.order()
+        for x in self.neighbors(i):
+            if x == j:
+                continue
+            w1 = self.get_edge_data(x, i)['weight']
+            w2 = -1
+            if self.has_edge(x, j):
+                w2 = self.get_edge_data(x, j)['weight']
+
+            w = max(w1, w2)
+
+            self.add_edge(x, j, weight=w)
+
+        self.node[j]['labels'] += self.node[i]['labels'] 
+        self.remove_node(i)
+
+def rag_meancolor(img,labels):
+
+    img = util.img_as_ubyte(img)
+    if img.ndim == 3 :
+        return _construct.construct_rag_meancolor_3d(img,labels)
+    elif img.ndim == 2 :
+        return _construct.construct_rag_meancolor_2d(img,labels)
+    else :
+        raise ValueError("Image dimension not supported")

skimage/graph/tests/test_rag.py

@@ -0,0 +1,10 @@
+import numpy as np
+
+def test_threshold_cut():
+    arr = np.array((100,100,3),dtype='uint8')
+    arr[:50,:50] = 0
+    arr[:50,50:] = 1
+    arr[50:,50:] = 2
+    arr[50:,50:] = 3
+
+