Cannot open object detection model using tf.keras.models.load

[ChowderII]

Prerequisites

Please answer the following questions for yourself before submitting an issue.

• I am using the latest TensorFlow Model Garden release and TensorFlow 2.
• I am reporting the issue to the correct repository. (Model Garden official or research directory)
• I checked to make sure that this issue has not already been filed.

1. The entire URL of the file you are using

http://download.tensorflow.org/models/object_detection/tf2/20200711/ssd_mobilenet_v2_320x320_coco17_tpu-8.tar.gz

2. Describe the bug

tf.keras.models.load fails to open the model with error:

Traceback (most recent call last):
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\IPython\core\interactiveshell.py", line 3343, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-5-a1fec4d829cb>", line 1, in <module>
    loaded_model = tf.keras.models.load_model('resources/ssd_mobilenetv2/saved_model')
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\keras\saving\save.py", line 150, in load_model
    return saved_model_load.load(filepath, compile)
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\keras\saving\saved_model\load.py", line 89, in load
    model = tf_load.load_internal(path, loader_cls=KerasObjectLoader)
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\saved_model\load.py", line 552, in load_internal
    export_dir)
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\keras\saving\saved_model\load.py", line 118, in __init__
    super(KerasObjectLoader, self).__init__(*args, **kwargs)
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\saved_model\load.py", line 121, in __init__
    self._load_all()
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\saved_model\load.py", line 239, in _load_all
    node, setter = self._recreate(proto)
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\saved_model\load.py", line 322, in _recreate
    return factory[kind]()
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\saved_model\load.py", line 309, in <lambda>
    "user_object": lambda: self._recreate_user_object(proto.user_object),
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\saved_model\load.py", line 328, in _recreate_user_object
    return self._recreate_base_user_object(proto)
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\keras\saving\saved_model\load.py", line 216, in _recreate_base_user_object
    return revived_cls._init_from_metadata(metadata)  # pylint: disable=protected-access
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\keras\saving\saved_model\load.py", line 297, in _init_from_metadata
    revived_obj = cls(**init_args)
  File "C:\Users\brackman\Anaconda3\envs\tf-gpu\lib\site-packages\tensorflow_core\python\keras\engine\input_layer.py", line 86, in __init__
    batch_size = batch_input_shape[0]
KeyError: 0

3. Steps to reproduce

1. Download the model from the above link.
2. Run this:

import tensorflow as tf
loaded_model = tf.keras.models.load_model('resources/ssd_mobilenetv2/saved_model')
# keep in mind my path is probably different than yours

4. Expected behavior

I expect to have a Keras instance of the model.

5. Additional context

I am quite new to this and I don't quite know what can be useful to you. Let me know if there are additional information I can provide to help you.

I am fairly certain I am not using that correctly. If it helps you understand why I am trying to do this, I am trying to generate an .hdf5 model for another purpose.

6. System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): Windows 10
• Mobile device name if the issue happens on a mobile device: N/A
• TensorFlow installed from (source or binary): binary (conda)
• TensorFlow version (use command below): 2.2.0
• Python version: 3.7.7
• Bazel version (if compiling from source): N/A
• GCC/Compiler version (if compiling from source): N/A
• CUDA version: release 10.1 V10.1.243,
• cuDNN version: 7.6.5
• GPU model and memory: GeForce GTX 1060 6GB

[ravikyram]

@ChowderII

I have tried in colab with TF nightly version (2.4.0-dev20200811) and i am seeing different error message.
TypeError: 'module' object is not callable
Please, find the gist here.Thanks!

[ChowderII]

Even if your error is different, it still implies there is something wrong with the load function right?
(I don't know if the tag awaiting response is for me or the tensorflow gods)

[saberkun]

I don't think we can always expect the customized subclass models be able to load with keras API.
Instead, could you first try the savedmodel API: https://www.tensorflow.org/api_docs/python/tf/saved_model/load?

[ChowderII]

I did try to load it that way, it gives me an AutoTrackable object that I can't seem to interact with the way I want. I want to save the as .h5 for another application but I get the same error message as my first post when I try to save it that way.
In the README of object detection, they state that their model for TF2 is built using keras, why can't we load it using keras too?

[ChowderII]

#9026
@ravikyram
It seems this user is trying to do what I am trying to do as well. But we cannot perform tf.keras.models.load_model it crashes every time.

[ChowderII]

I'm very sorry to multi post but is there anything I can do to help you help me?
Let me know if my problem is not clear or needs clarification. Thank you!