Move region polygon simplification to later point in vectorization

partially resolves #319

kraken/lib/segmentation.py

@@ -347,13 +347,13 @@ def vectorize_regions(im: np.ndarray, threshold: float = 0.5):
     for x in regionprops(labelled):
         boundary = boundary_tracing(x)
         if len(boundary) > 2:
-            boundaries.append(geom.Polygon(boundary).simplify(10))
+            boundaries.append(geom.Polygon(boundary))
     # merge regions that overlap after simplification
     boundaries = unary_union(boundaries)
     if boundaries.type == 'Polygon':
-        boundaries = [boundaries.boundary]
+        boundaries = [boundaries.boundary.simplify(10)]
     else:
-        boundaries = [x.boundary for x in unary_union(boundaries)]
+        boundaries = [x.boundary.simplify(10) for x in unary_union(boundaries)]
     return [np.array(x.coords, dtype=np.uint)[:, [1, 0]].tolist() for x in boundaries]