QH6228 Bug fix - remove offset from coords

skimage/morphology/convex_hull.py

@@ -54,6 +54,10 @@ def convex_hull_image(image):
         raise ImportError('Could not import scipy.spatial, only available in '
                           'scipy >= 0.9.')
 
+    # Subtract offset 
+    offset = coords.mean(axis=0)
+    coords -= offset
+    
     # Find the convex hull
     chull = Delaunay(coords).convex_hull
     v = coords[np.unique(chull)]
@@ -63,6 +67,9 @@ def convex_hull_image(image):
     angles = np.arctan2(v_centred[:, 0], v_centred[:, 1])
     v = v[np.argsort(angles)]
 
+    # Add back offset 
+    v += offset
+
     # For each pixel coordinate, check whether that pixel
     # lies inside the convex hull
     mask = grid_points_inside_poly(image.shape[:2], v)