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

--
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.

--
311624958  by Sergio Guadarrama:

    Updates README that doesn't render properly in github documentation

--
310980959  by Sergio Guadarrama:

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

--
310263156  by Sergio Guadarrama:

    Adds model breakdown for MobilenetV3

--
308640...

research/object_detection/predictors/heads/box_head_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """Tests for object_detection.predictors.heads.box_head."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/heads/class_head.py

@@ -20,13 +20,11 @@ All the class prediction heads have a predict function that receives the
 `features` as the first argument and returns class predictions with background.
 """
 import functools
-import tensorflow as tf
-from tensorflow.contrib import slim as contrib_slim
+import tensorflow.compat.v1 as tf
+import tf_slim as slim
 
 from object_detection.predictors.heads import head
 
-slim = contrib_slim
-
 
 class MaskRCNNClassHead(head.Head):
   """Mask RCNN class prediction head.

research/object_detection/predictors/heads/class_head_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """Tests for object_detection.predictors.heads.class_head."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/heads/head.py

@@ -36,7 +36,7 @@ Mask RCNN box predictor.
 """
 from abc import abstractmethod
 
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 
 class Head(object):

research/object_detection/predictors/heads/keras_box_head.py

@@ -19,7 +19,7 @@ Contains Box prediction head classes for different meta architectures.
 All the box prediction heads have a _predict function that receives the
 `features` as the first argument and returns `box_encodings`.
 """
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from object_detection.predictors.heads import head
 

research/object_detection/predictors/heads/keras_box_head_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """Tests for object_detection.predictors.heads.box_head."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/heads/keras_class_head.py

@@ -19,7 +19,7 @@ Contains Class prediction head classes for different meta architectures.
 All the class prediction heads have a predict function that receives the
 `features` as the first argument and returns class predictions with background.
 """
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from object_detection.predictors.heads import head
 

research/object_detection/predictors/heads/keras_class_head_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """Tests for object_detection.predictors.heads.class_head."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/heads/keras_mask_head.py

@@ -26,7 +26,7 @@ from __future__ import print_function
 
 import math
 from six.moves import range
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from object_detection.predictors.heads import head
 from object_detection.utils import ops

research/object_detection/predictors/heads/keras_mask_head_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """Tests for object_detection.predictors.heads.mask_head."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/heads/keypoint_head.py

@@ -28,11 +28,10 @@ from __future__ import division
 from __future__ import print_function
 
 from six.moves import range
-import tensorflow as tf
-from tensorflow.contrib import slim as contrib_slim
+import tensorflow.compat.v1 as tf
+import tf_slim as slim
 
 from object_detection.predictors.heads import head
-slim = contrib_slim
 
 
 class MaskRCNNKeypointHead(head.Head):

research/object_detection/predictors/heads/keypoint_head_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """Tests for object_detection.predictors.heads.keypoint_head."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/heads/mask_head.py

@@ -26,14 +26,12 @@ from __future__ import print_function
 
 import math
 from six.moves import range
-import tensorflow as tf
-from tensorflow.contrib import slim as contrib_slim
+import tensorflow.compat.v1 as tf
+import tf_slim as slim
 
 from object_detection.predictors.heads import head
 from object_detection.utils import ops
 
-slim = contrib_slim
-
 
 class MaskRCNNMaskHead(head.Head):
   """Mask RCNN mask prediction head.

research/object_detection/predictors/heads/mask_head_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """Tests for object_detection.predictors.heads.mask_head."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/mask_rcnn_box_predictor.py

@@ -14,11 +14,8 @@
 # ==============================================================================
 
 """Mask R-CNN Box Predictor."""
-from tensorflow.contrib import slim as contrib_slim
-
 from object_detection.core import box_predictor
 
-slim = contrib_slim
 
 BOX_ENCODINGS = box_predictor.BOX_ENCODINGS
 CLASS_PREDICTIONS_WITH_BACKGROUND = (

research/object_detection/predictors/mask_rcnn_box_predictor_test.py

@@ -15,7 +15,7 @@
 
 """Tests for object_detection.predictors.mask_rcnn_box_predictor."""
 import numpy as np
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import box_predictor_builder

research/object_detection/predictors/mask_rcnn_keras_box_predictor_test.py

@@ -15,7 +15,7 @@
 
 """Tests for object_detection.predictors.mask_rcnn_box_predictor."""
 import numpy as np
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import box_predictor_builder

research/object_detection/predictors/rfcn_box_predictor.py

@@ -14,12 +14,11 @@
 # ==============================================================================
 
 """RFCN Box Predictor."""
-import tensorflow as tf
-from tensorflow.contrib import slim as contrib_slim
+import tensorflow.compat.v1 as tf
+import tf_slim as slim
 from object_detection.core import box_predictor
 from object_detection.utils import ops
 
-slim = contrib_slim
 
 BOX_ENCODINGS = box_predictor.BOX_ENCODINGS
 CLASS_PREDICTIONS_WITH_BACKGROUND = (

research/object_detection/predictors/rfcn_box_predictor_test.py

@@ -15,7 +15,7 @@
 
 """Tests for object_detection.predictors.rfcn_box_predictor."""
 import numpy as np
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 
 from google.protobuf import text_format
 from object_detection.builders import hyperparams_builder

research/object_detection/predictors/rfcn_keras_box_predictor.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """RFCN Box Predictor."""
-import tensorflow as tf
+import tensorflow.compat.v1 as tf
 from object_detection.core import box_predictor
 from object_detection.utils import ops