Support (C, 1, 1) for fill argument

chainercv/transforms/image/random_expand.py

@@ -24,6 +24,9 @@ def random_expand(img, max_ratio=4, fill=0, return_param=False):
             paper, this value is 4.
         fill (float, tuple or ~numpy.ndarray): The value of padded pixels.
             In the original paper, this value is the mean of ImageNet.
+            If it is :class:`numpy.ndarray`,
+            its shape should be :math:`(C, 1, 1)`,
+            where :math:`C` is the number of channels of :obj:`img`.
         return_param (bool): Returns random parameters.
 
     Returns:

chainercv/transforms/image/resize_contain.py

@@ -19,6 +19,9 @@ def resize_contain(img, size, fill=0, return_param=False):
         size (tuple of two ints): A tuple of two elements:
             :obj:`height, width`. The size of the image after resizing.
         fill (float, tuple or ~numpy.ndarray): The value of padded pixels.
+            If it is :class:`numpy.ndarray`,
+            its shape should be :math:`(C, 1, 1)`,
+            where :math:`C` is the number of channels of :obj:`img`.
         return_param (bool): Returns information of resizing and offsetting.
 
     Returns:

tests/transforms_tests/image_tests/test_random_expand.py

@@ -38,7 +38,7 @@ def test_random_expand(self):
 @testing.parameterize(
     {'fill': 128},
     {'fill': (104, 117, 123)},
-    {'fill':  np.random.uniform(255, size=3)},
+    {'fill':  np.random.uniform(255, size=(3, 1, 1))},
 )
 class TestRandomExpandFill(unittest.TestCase):
 
@@ -53,11 +53,11 @@ def test_random_expand_fill(self):
                 break
 
         if isinstance(self.fill, int):
-            np.testing.assert_equal(
-                out[:, 0, 0], (self.fill,) * 3)
+            fill = (self.fill,) * 3
         else:
-            np.testing.assert_equal(
-                out[:, 0, 0], self.fill)
+            fill = self.fill
+        np.testing.assert_equal(
+            out[:, 0, 0], np.array(fill).flatten())
 
 
 testing.run_module(__name__, __file__)

tests/transforms_tests/image_tests/test_resize_contain.py

@@ -9,7 +9,7 @@
 @testing.parameterize(
     {'fill': 128},
     {'fill': (104, 117, 123)},
-    {'fill':  np.random.uniform(255, size=3)},
+    {'fill':  np.random.uniform(255, size=(3, 1, 1))},
 )
 class TestResizeContain(unittest.TestCase):
 
@@ -20,7 +20,14 @@ def test_resize_contain(self):
             img, (48, 96), fill=self.fill, return_param=True)
 
         np.testing.assert_array_equal(img, out[:, 8:40, 16:80])
-        np.testing.assert_array_equal(self.fill, out[:, 0, 0])
+
+        if isinstance(self.fill, int):
+            fill = (self.fill,) * 3
+        else:
+            fill = self.fill
+        np.testing.assert_array_equal(
+            out[:, 0, 0], np.array(fill).flatten())
+
         self.assertEqual(param['scaled_size'], (32, 64))
         self.assertEqual(param['y_offset'], 8)
         self.assertEqual(param['x_offset'], 16)