Add use_keras_layer flag for FPN.

PiperOrigin-RevId: 448849223

official/vision/configs/decoders.py

@@ -33,6 +33,7 @@ class FPN(hyperparams.Config):
   num_filters: int = 256
   fusion_type: str = 'sum'
   use_separable_conv: bool = False
+  use_keras_layer: bool = False
 
 
 @dataclasses.dataclass

official/vision/modeling/decoders/fpn.py

@@ -44,6 +44,7 @@ class FPN(tf.keras.Model):
       num_filters: int = 256,
       fusion_type: str = 'sum',
       use_separable_conv: bool = False,
+      use_keras_layer: bool = False,
       activation: str = 'relu',
       use_sync_bn: bool = False,
       norm_momentum: float = 0.99,
@@ -64,6 +65,7 @@ class FPN(tf.keras.Model):
         concat for feature fusion.
       use_separable_conv: A `bool`.  If True use separable convolution for
         convolution in FPN layers.
+      use_keras_layer: A `bool`. If Ture use keras layers as many as possible.
       activation: A `str` name of the activation function.
       use_sync_bn: A `bool`. If True, use synchronized batch normalization.
       norm_momentum: A `float` of normalization momentum for the moving average.
@@ -82,6 +84,7 @@ class FPN(tf.keras.Model):
         'num_filters': num_filters,
         'fusion_type': fusion_type,
         'use_separable_conv': use_separable_conv,
+        'use_keras_layer': use_keras_layer,
         'activation': activation,
         'use_sync_bn': use_sync_bn,
         'norm_momentum': norm_momentum,
@@ -98,8 +101,7 @@ class FPN(tf.keras.Model):
       norm = tf.keras.layers.experimental.SyncBatchNormalization
     else:
       norm = tf.keras.layers.BatchNormalization
-    activation_fn = tf.keras.layers.Activation(
-        tf_utils.get_activation(activation))
+    activation_fn = tf_utils.get_activation(activation, use_keras_layer=True)
 
     # Build input feature pyramid.
     if tf.keras.backend.image_data_format() == 'channels_last':
@@ -128,13 +130,20 @@ class FPN(tf.keras.Model):
     feats = {str(backbone_max_level): feats_lateral[str(backbone_max_level)]}
     for level in range(backbone_max_level - 1, min_level - 1, -1):
       feat_a = spatial_transform_ops.nearest_upsampling(
-          feats[str(level + 1)], 2)
+          feats[str(level + 1)], 2, use_keras_layer=use_keras_layer)
       feat_b = feats_lateral[str(level)]
 
       if fusion_type == 'sum':
-        feats[str(level)] = feat_a + feat_b
+        if use_keras_layer:
+          feats[str(level)] = tf.keras.layers.Add()([feat_a, feat_b])
+        else:
+          feats[str(level)] = feat_a + feat_b
       elif fusion_type == 'concat':
-        feats[str(level)] = tf.concat([feat_a, feat_b], axis=-1)
+        if use_keras_layer:
+          feats[str(level)] = tf.keras.layers.Concatenate(axis=-1)(
+              [feat_a, feat_b])
+        else:
+          feats[str(level)] = tf.concat([feat_a, feat_b], axis=-1)
       else:
         raise ValueError('Fusion type {} not supported.'.format(fusion_type))
 
@@ -239,6 +248,7 @@ def build_fpn_decoder(
       num_filters=decoder_cfg.num_filters,
       fusion_type=decoder_cfg.fusion_type,
       use_separable_conv=decoder_cfg.use_separable_conv,
+      use_keras_layer=decoder_cfg.use_keras_layer,
       activation=norm_activation_config.activation,
       use_sync_bn=norm_activation_config.use_sync_bn,
       norm_momentum=norm_activation_config.norm_momentum,

official/vision/modeling/decoders/fpn_test.py

@@ -26,11 +26,13 @@ from official.vision.modeling.decoders import fpn
 class FPNTest(parameterized.TestCase, tf.test.TestCase):
 
   @parameterized.parameters(
-      (256, 3, 7, False, 'sum'),
-      (256, 3, 7, True, 'concat'),
+      (256, 3, 7, False, False, 'sum'),
+      (256, 3, 7, False, True, 'sum'),
+      (256, 3, 7, True, False, 'concat'),
+      (256, 3, 7, True, True, 'concat'),
   )
   def test_network_creation(self, input_size, min_level, max_level,
-                            use_separable_conv, fusion_type):
+                            use_separable_conv, use_keras_layer, fusion_type):
     """Test creation of FPN."""
     tf.keras.backend.set_image_data_format('channels_last')
 
@@ -42,7 +44,8 @@ class FPNTest(parameterized.TestCase, tf.test.TestCase):
         min_level=min_level,
         max_level=max_level,
         fusion_type=fusion_type,
-        use_separable_conv=use_separable_conv)
+        use_separable_conv=use_separable_conv,
+        use_keras_layer=use_keras_layer)
 
     endpoints = backbone(inputs)
     feats = network(endpoints)
@@ -54,11 +57,14 @@ class FPNTest(parameterized.TestCase, tf.test.TestCase):
           feats[str(level)].shape.as_list())
 
   @parameterized.parameters(
-      (256, 3, 7, False),
-      (256, 3, 7, True),
+      (256, 3, 7, False, False),
+      (256, 3, 7, False, True),
+      (256, 3, 7, True, False),
+      (256, 3, 7, True, True),
   )
   def test_network_creation_with_mobilenet(self, input_size, min_level,
-                                           max_level, use_separable_conv):
+                                           max_level, use_separable_conv,
+                                           use_keras_layer):
     """Test creation of FPN with mobilenet backbone."""
     tf.keras.backend.set_image_data_format('channels_last')
 
@@ -69,7 +75,8 @@ class FPNTest(parameterized.TestCase, tf.test.TestCase):
         input_specs=backbone.output_specs,
         min_level=min_level,
         max_level=max_level,
-        use_separable_conv=use_separable_conv)
+        use_separable_conv=use_separable_conv,
+        use_keras_layer=use_keras_layer)
 
     endpoints = backbone(inputs)
     feats = network(endpoints)
@@ -89,6 +96,7 @@ class FPNTest(parameterized.TestCase, tf.test.TestCase):
         num_filters=256,
         fusion_type='sum',
         use_separable_conv=False,
+        use_keras_layer=False,
         use_sync_bn=False,
         activation='relu',
         norm_momentum=0.99,