Update local_features.py

Chapter04/local_features.py

@@ -20,6 +20,7 @@ def get_gauss_feat_im(im, sigma=1, normalize=True):
              vector for every pixel in the image.
     Author: vand@dtu.dk, 2022
     """
+    im = im.astype(float)
     orders = [0, 
         [0, 1], [1, 0], 
         [0, 2], [1, 1], [2, 0],