Release MobileDet code and model, and require tf_slim installation for OD API. (#8562)

* Merged commit includes the following changes:
311933687  by Sergio Guadarrama:

    Removes spurios use of tf.compat.v2, which results in spurious tf.compat.v1.compat.v2. Adds basic test to nasnet_utils.
    Replaces all remaining import tensorflow as tf with import tensorflow.compat.v1 as tf

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311766063  by Sergio Guadarrama:

    Removes explicit tf.compat.v1 in all call sites (we already import tf.compat.v1, so this code was  doing tf.compat.v1.compat.v1). The existing code worked in latest version of tensorflow, 2.2, (and 1.15) but not in 1.14 or in 2.0.0a, this CL fixes it.

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311624958  by Sergio Guadarrama:

    Updates README that doesn't render properly in github documentation

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310980959  by Sergio Guadarrama:

    Moves research_models/slim off tf.contrib.slim/layers/framework to tf_slim

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310263156  by Sergio Guadarrama:

    Adds model breakdown for MobilenetV3

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308640516  by Sergio Guadarrama:

    Internal change

308244396  by Sergio Guadarrama:

    GroupNormalization support for MobilenetV3.

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307475800  by Sergio Guadarrama:

    Internal change

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302077708  by Sergio Guadarrama:

    Remove `disable_tf2` behavior from slim py_library targets

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301208453  by Sergio Guadarrama:

    Automated refactoring to make code Python 3 compatible.

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300816672  by Sergio Guadarrama:

    Internal change

299433840  by Sergio Guadarrama:

    Internal change

299221609  by Sergio Guadarrama:

    Explicitly disable Tensorflow v2 behaviors for all TF1.x binaries and tests

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297670468  by Sergio Guadarrama:

    Internal change.

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297350326  by Sergio Guadarrama:

    Explicitly replace "import tensorflow" with "tensorflow.compat.v1" for TF2.x migration

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297201668  by Sergio Guadarrama:

    Explicitly replace "import tensorflow" with "tensorflow.compat.v1" for TF2.x migration

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294483372  by Sergio Guadarrama:

    Internal change

PiperOrigin-RevId: 311933687

* Merged commit includes the following changes:
312578615  by Menglong Zhu:

    Modify the LSTM feature extractors to be python 3 compatible.

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311264357  by Menglong Zhu:

    Removes contrib.slim

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308957207  by Menglong Zhu:

    Automated refactoring to make code Python 3 compatible.

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306976470  by yongzhe:

    Internal change

306777559  by Menglong Zhu:

    Internal change

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299232507  by lzyuan:

    Internal update.

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299221735  by lzyuan:

    Add small epsilon on max_range for quantize_op to prevent range collapse.

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PiperOrigin-RevId: 312578615

* Merged commit includes the following changes:
310447280  by lzc:

    Internal changes.

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PiperOrigin-RevId: 310447280

Co-authored-by: Sergio Guadarrama <sguada@google.com>
Co-authored-by: Menglong Zhu <menglong@google.com>

Author: 3 people

research/lstm_object_detection/README.md

@@ -1,6 +1,3 @@
-![TensorFlow Requirement: 1.x](https://img.shields.io/badge/TensorFlow%20Requirement-1.x-brightgreen)
-![TensorFlow 2 Not Supported](https://img.shields.io/badge/TensorFlow%202%20Not%20Supported-%E2%9C%95-red.svg)
-
 # Tensorflow Mobile Video Object Detection
 
 Tensorflow mobile video object detection implementation proposed in the
@@ -35,6 +32,7 @@ https://scholar.googleusercontent.com/scholar.bib?q=info:rLqvkztmWYgJ:scholar.go
 * yinxiao@google.com
 * menglong@google.com
 * yongzhe@google.com
+* lzyuan@google.com
 
 
 ## Table of Contents

research/lstm_object_detection/inputs/seq_dataset_builder.py

@@ -23,7 +23,8 @@
 that wraps the build function.
 """
 import tensorflow.compat.v1 as tf
-from tensorflow.contrib import slim as contrib_slim
+import tf_slim as slim
+
 from tensorflow.contrib.training.python.training import sequence_queueing_state_saver as sqss
 from lstm_object_detection.inputs import tf_sequence_example_decoder
 from lstm_object_detection.protos import input_reader_google_pb2
@@ -33,7 +34,7 @@
 from object_detection.protos import input_reader_pb2
 from object_detection.utils import ops as util_ops
 
-parallel_reader = contrib_slim.parallel_reader
+parallel_reader = slim.parallel_reader
 # TODO(yinxiao): Make the following variable into configurable proto.
 # Padding size for the labeled objects in each frame. Here we assume each
 # frame has a total number of objects less than _PADDING_SIZE.