Enlarge a tensor in tensorflow

Question

I\'m searching for a tensorflow python method to enlarge (resize) a tensor to double every element in each feature map along both axis e.g.:

Answer 1

a = tf.convert_to_tensor([[1, 2, 3],
                          [4, 5, 6],
                          [7, 8, 9]])
b = tf.reshape(a, [3, 3, 1])
c = tf.tile(b, [1, 1, 2])
d = tf.reshape(c, [3, 6])
print(d.eval())
array([[1, 1, 2, 2, 3, 3],
       [4, 4, 5, 5, 6, 6],
       [7, 7, 8, 8, 9, 9]], dtype=int32)

e = tf.reshape(d, [3, 6, 2])
f = tf.tile(e, [1, 1, 2])
g = tf.transpose(f, [0, 2, 1])
print(g.eval())
array([[[1, 1, 2, 2, 3, 3],
        [1, 1, 2, 2, 3, 3]],

       [[4, 4, 5, 5, 6, 6],
        [4, 4, 5, 5, 6, 6]],

       [[7, 7, 8, 8, 9, 9],
        [7, 7, 8, 8, 9, 9]]], dtype=int32)

h = tf.reshape(g, [6, 6])
print(h.eval())
array([[1, 1, 2, 2, 3, 3],
       [1, 1, 2, 2, 3, 3],
       [4, 4, 5, 5, 6, 6],
       [4, 4, 5, 5, 6, 6],
       [7, 7, 8, 8, 9, 9],
       [7, 7, 8, 8, 9, 9]], dtype=int32)

You can get a shape of the a tensor (if it's defined) using:

shape = a.get_shape().as_list()

Answer 2

Just use tf.image.ResizeMethod with Nearest Neighbor interpolation

array = tf.image.resize_images(old_array, (old_size*2, old_size*2),
                               method=tf.image.ResizeMethod.NEAREST_NEIGHBOR)

Input to the method must be 4-D Tensor of shape [batch, height, width, channels] or 3-D Tensor of shape [height, width, channels].

https://www.tensorflow.org/api_docs/python/tf/image/resize