CODEWITHSUNDEEP
pythontensorflowbase64
James
James

Reputation: 4052

Why would tensorflow.decode_base64 fail due to invalid character, but base64.b64decode(image_base64) succeeds

I am converting some Image transformation code to use tensorflow.

My image is passed in as a base64 string. Using the following function the base64 string can be decoded and opened as a np.array:


def load_color_image_base64(image_base64):
  img_pil = Image.open(BytesIO(base64.b64decode(image_base64))).convert("RGB")
  return np.array(img_pil)

However, when I pass the same string to the following tensorflow code I get an error:


self._image = tf.image.decode_jpeg(tf.decode_base64(self._image_b64), channels=3)

The error I get is:

  tf.decode_base64(self._image_b64), channels=3)
  File "/Users/jameskelly/anaconda/envs/im2volume/lib/python2.7/site-packages/tensorflow/python/ops/gen_string_ops.py", line 106, in decode_base64
    "DecodeBase64", input=input, name=name)
  File "/Users/jameskelly/anaconda/envs/im2volume/lib/python2.7/site-packages/tensorflow/python/framework/op_def_library.py", line 787, in _apply_op_helper
    op_def=op_def)
  File "/Users/jameskelly/anaconda/envs/im2volume/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 2956, in create_op
    op_def=op_def)
  File "/Users/jameskelly/anaconda/envs/im2volume/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1470, in __init__
    self._traceback = self._graph._extract_stack()  # pylint: disable=protected-access

InvalidArgumentError (see above for traceback): Invalid character found in base64.
     [[Node: DecodeBase64 = DecodeBase64[_device="/job:localhost/replica:0/task:0/device:CPU:0"](_arg_Placeholder_2_0_2)]]

It should be noted that this code is behind a flask api. When I run the class directly, loading the image from disk and converting it directly to base64, both cases work.

I have also converted the base64 string to a python str type, as it was being passed in as unicode, the error message did not change.

Upvotes: 2

Views: 1667

Answers (2)

user
user

Reputation: 199

You must use base64.urlsafe_b64encode which, as Debangshu Paul mentions, uses '-' instead of '+' and '_' instead of '/'.

See https://docs.python.org/3/library/base64.html#base64.urlsafe_b64encode for more info.

Upvotes: 2

Debangshu Paul
Debangshu Paul

Reputation: 344

Replace "/" with "_" and "+" with "-" in the base64 string. Worked for me. For more info refer this: https://www.tensorflow.org/versions/r1.14/api_docs/python/tf/io/decode_base64

Upvotes: 0

Related Questions