Internal change

PiperOrigin-RevId: 341693911

official/vision/beta/configs/backbones.py

@@ -26,6 +26,8 @@ from official.modeling import hyperparams
 class ResNet(hyperparams.Config):
   """ResNet config."""
   model_id: int = 50
+  stem_type: str = 'v0'
+  se_ratio: float = 0.0
 
 
 @dataclasses.dataclass

official/vision/beta/modeling/backbones/factory_test.py

@@ -35,11 +35,11 @@ class FactoryTest(tf.test.TestCase, parameterized.TestCase):
     """Test creation of ResNet models."""
 
     network = backbones.ResNet(
-        model_id=model_id, norm_momentum=0.99, norm_epsilon=1e-5)
+        model_id=model_id, se_ratio=0.0, norm_momentum=0.99, norm_epsilon=1e-5)
 
     backbone_config = backbones_cfg.Backbone(
         type='resnet',
-        resnet=backbones_cfg.ResNet(model_id=model_id))
+        resnet=backbones_cfg.ResNet(model_id=model_id, se_ratio=0.0))
     norm_activation_config = common_cfg.NormActivation(
         norm_momentum=0.99, norm_epsilon=1e-5, use_sync_bn=False)
     model_config = retinanet_cfg.RetinaNet(

official/vision/beta/modeling/backbones/resnet.py

@@ -78,6 +78,8 @@ class ResNet(tf.keras.Model):
   def __init__(self,
                model_id,
                input_specs=layers.InputSpec(shape=[None, None, None, 3]),
+               stem_type='v0',
+               se_ratio=None,
                activation='relu',
                use_sync_bn=False,
                norm_momentum=0.99,
@@ -91,6 +93,9 @@ class ResNet(tf.keras.Model):
     Args:
       model_id: `int` depth of ResNet backbone model.
       input_specs: `tf.keras.layers.InputSpec` specs of the input tensor.
+      stem_type: `str` stem type of ResNet. Default to `v0`. If set to `v1`,
+        use ResNet-C type stem (https://arxiv.org/abs/1812.01187).
+      se_ratio: `float` or None. Ratio of the Squeeze-and-Excitation layer.
       activation: `str` name of the activation function.
       use_sync_bn: if True, use synchronized batch normalization.
       norm_momentum: `float` normalization omentum for the moving average.
@@ -105,6 +110,8 @@ class ResNet(tf.keras.Model):
     """
     self._model_id = model_id
     self._input_specs = input_specs
+    self._stem_type = stem_type
+    self._se_ratio = se_ratio
     self._use_sync_bn = use_sync_bn
     self._activation = activation
     self._norm_momentum = norm_momentum
@@ -125,8 +132,13 @@ class ResNet(tf.keras.Model):
     # Build ResNet.
     inputs = tf.keras.Input(shape=input_specs.shape[1:])
 
+    if stem_type == 'v0':
       x = layers.Conv2D(
-        filters=64, kernel_size=7, strides=2, use_bias=False, padding='same',
+          filters=64,
+          kernel_size=7,
+          strides=2,
+          use_bias=False,
+          padding='same',
           kernel_initializer=self._kernel_initializer,
           kernel_regularizer=self._kernel_regularizer,
           bias_regularizer=self._bias_regularizer)(
@@ -135,6 +147,52 @@ class ResNet(tf.keras.Model):
           axis=bn_axis, momentum=norm_momentum, epsilon=norm_epsilon)(
               x)
       x = tf_utils.get_activation(activation)(x)
+    elif stem_type == 'v1':
+      x = layers.Conv2D(
+          filters=32,
+          kernel_size=3,
+          strides=2,
+          use_bias=False,
+          padding='same',
+          kernel_initializer=self._kernel_initializer,
+          kernel_regularizer=self._kernel_regularizer,
+          bias_regularizer=self._bias_regularizer)(
+              inputs)
+      x = self._norm(
+          axis=bn_axis, momentum=norm_momentum, epsilon=norm_epsilon)(
+              x)
+      x = tf_utils.get_activation(activation)(x)
+      x = layers.Conv2D(
+          filters=32,
+          kernel_size=3,
+          strides=1,
+          use_bias=False,
+          padding='same',
+          kernel_initializer=self._kernel_initializer,
+          kernel_regularizer=self._kernel_regularizer,
+          bias_regularizer=self._bias_regularizer)(
+              x)
+      x = self._norm(
+          axis=bn_axis, momentum=norm_momentum, epsilon=norm_epsilon)(
+              x)
+      x = tf_utils.get_activation(activation)(x)
+      x = layers.Conv2D(
+          filters=64,
+          kernel_size=3,
+          strides=1,
+          use_bias=False,
+          padding='same',
+          kernel_initializer=self._kernel_initializer,
+          kernel_regularizer=self._kernel_regularizer,
+          bias_regularizer=self._bias_regularizer)(
+              x)
+      x = self._norm(
+          axis=bn_axis, momentum=norm_momentum, epsilon=norm_epsilon)(
+              x)
+      x = tf_utils.get_activation(activation)(x)
+    else:
+      raise ValueError('Stem type {} not supported.'.format(stem_type))
+
     x = layers.MaxPool2D(pool_size=3, strides=2, padding='same')(x)
 
     # TODO(xianzhi): keep a list of blocks to make blocks accessible.
@@ -184,6 +242,7 @@ class ResNet(tf.keras.Model):
         filters=filters,
         strides=strides,
         use_projection=True,
+        se_ratio=self._se_ratio,
         kernel_initializer=self._kernel_initializer,
         kernel_regularizer=self._kernel_regularizer,
         bias_regularizer=self._bias_regularizer,
@@ -198,6 +257,7 @@ class ResNet(tf.keras.Model):
           filters=filters,
           strides=1,
           use_projection=False,
+          se_ratio=self._se_ratio,
           kernel_initializer=self._kernel_initializer,
           kernel_regularizer=self._kernel_regularizer,
           bias_regularizer=self._bias_regularizer,
@@ -212,7 +272,9 @@ class ResNet(tf.keras.Model):
   def get_config(self):
     config_dict = {
         'model_id': self._model_id,
+        'stem_type': self._stem_type,
         'activation': self._activation,
+        'se_ratio': self._se_ratio,
         'use_sync_bn': self._use_sync_bn,
         'norm_momentum': self._norm_momentum,
         'norm_epsilon': self._norm_epsilon,
@@ -247,6 +309,8 @@ def build_resnet(
   return ResNet(
       model_id=backbone_cfg.model_id,
       input_specs=input_specs,
+      stem_type=backbone_cfg.stem_type,
+      se_ratio=backbone_cfg.se_ratio,
       activation=norm_activation_config.activation,
       use_sync_bn=norm_activation_config.use_sync_bn,
       norm_momentum=norm_activation_config.norm_momentum,

official/vision/beta/modeling/backbones/resnet_test.py

@@ -83,6 +83,21 @@ class ResNetTest(parameterized.TestCase, tf.test.TestCase):
       network = resnet.ResNet(model_id=50, use_sync_bn=use_sync_bn)
       _ = network(inputs)
 
+  @parameterized.parameters(
+      (128, 34, 1, 'v0', None),
+      (128, 34, 1, 'v1', 0.25),
+      (128, 50, 4, 'v0', None),
+      (128, 50, 4, 'v1', 0.25),
+  )
+  def test_resnet_addons(self, input_size, model_id, endpoint_filter_scale,
+                         stem_type, se_ratio):
+    """Test creation of ResNet family models."""
+    tf.keras.backend.set_image_data_format('channels_last')
+    network = resnet.ResNet(
+        model_id=model_id, stem_type=stem_type, se_ratio=se_ratio)
+    inputs = tf.keras.Input(shape=(input_size, input_size, 3), batch_size=1)
+    _ = network(inputs)
+
   @parameterized.parameters(1, 3, 4)
   def test_input_specs(self, input_dim):
     """Test different input feature dimensions."""
@@ -98,6 +113,8 @@ class ResNetTest(parameterized.TestCase, tf.test.TestCase):
     # Create a network object that sets all of its config options.
     kwargs = dict(
         model_id=50,
+        stem_type='v0',
+        se_ratio=None,
         use_sync_bn=False,
         activation='relu',
         norm_momentum=0.99,

official/vision/beta/modeling/layers/nn_blocks.py

@@ -62,6 +62,7 @@ class ResidualBlock(tf.keras.layers.Layer):
                filters,
                strides,
                use_projection=False,
+               se_ratio=None,
                stochastic_depth_drop_rate=None,
                kernel_initializer='VarianceScaling',
                kernel_regularizer=None,
@@ -82,6 +83,7 @@ class ResidualBlock(tf.keras.layers.Layer):
         shortcut (versus the default identity shortcut). This is usually `True`
         for the first block of a block group, which may change the number of
         filters and the resolution.
+      se_ratio: `float` or None. Ratio of the Squeeze-and-Excitation layer.
       stochastic_depth_drop_rate: `float` or None. if not None, drop rate for
         the stochastic depth layer.
       kernel_initializer: kernel_initializer for convolutional layers.
@@ -101,6 +103,7 @@ class ResidualBlock(tf.keras.layers.Layer):
     self._filters = filters
     self._strides = strides
     self._use_projection = use_projection
+    self._se_ratio = se_ratio
     self._use_sync_bn = use_sync_bn
     self._activation = activation
     self._stochastic_depth_drop_rate = stochastic_depth_drop_rate
@@ -163,6 +166,17 @@ class ResidualBlock(tf.keras.layers.Layer):
         momentum=self._norm_momentum,
         epsilon=self._norm_epsilon)
 
+    if self._se_ratio and self._se_ratio > 0 and self._se_ratio <= 1:
+      self._squeeze_excitation = nn_layers.SqueezeExcitation(
+          in_filters=self._filters,
+          out_filters=self._filters,
+          se_ratio=self._se_ratio,
+          kernel_initializer=self._kernel_initializer,
+          kernel_regularizer=self._kernel_regularizer,
+          bias_regularizer=self._bias_regularizer)
+    else:
+      self._squeeze_excitation = None
+
     if self._stochastic_depth_drop_rate:
       self._stochastic_depth = nn_layers.StochasticDepth(
           self._stochastic_depth_drop_rate)
@@ -176,6 +190,7 @@ class ResidualBlock(tf.keras.layers.Layer):
         'filters': self._filters,
         'strides': self._strides,
         'use_projection': self._use_projection,
+        'se_ratio': self._se_ratio,
         'stochastic_depth_drop_rate': self._stochastic_depth_drop_rate,
         'kernel_initializer': self._kernel_initializer,
         'kernel_regularizer': self._kernel_regularizer,
@@ -201,6 +216,9 @@ class ResidualBlock(tf.keras.layers.Layer):
     x = self._conv2(x)
     x = self._norm2(x)
 
+    if self._squeeze_excitation:
+      x = self._squeeze_excitation(x)
+
     if self._stochastic_depth:
       x = self._stochastic_depth(x, training=training)
 
@@ -216,6 +234,7 @@ class BottleneckBlock(tf.keras.layers.Layer):
                strides,
                dilation_rate=1,
                use_projection=False,
+               se_ratio=None,
                stochastic_depth_drop_rate=None,
                kernel_initializer='VarianceScaling',
                kernel_regularizer=None,
@@ -237,6 +256,7 @@ class BottleneckBlock(tf.keras.layers.Layer):
         shortcut (versus the default identity shortcut). This is usually `True`
         for the first block of a block group, which may change the number of
         filters and the resolution.
+      se_ratio: `float` or None. Ratio of the Squeeze-and-Excitation layer.
       stochastic_depth_drop_rate: `float` or None. if not None, drop rate for
         the stochastic depth layer.
       kernel_initializer: kernel_initializer for convolutional layers.
@@ -257,6 +277,7 @@ class BottleneckBlock(tf.keras.layers.Layer):
     self._strides = strides
     self._dilation_rate = dilation_rate
     self._use_projection = use_projection
+    self._se_ratio = se_ratio
     self._use_sync_bn = use_sync_bn
     self._activation = activation
     self._stochastic_depth_drop_rate = stochastic_depth_drop_rate
@@ -331,6 +352,17 @@ class BottleneckBlock(tf.keras.layers.Layer):
         momentum=self._norm_momentum,
         epsilon=self._norm_epsilon)
 
+    if self._se_ratio and self._se_ratio > 0 and self._se_ratio <= 1:
+      self._squeeze_excitation = nn_layers.SqueezeExcitation(
+          in_filters=self._filters * 4,
+          out_filters=self._filters * 4,
+          se_ratio=self._se_ratio,
+          kernel_initializer=self._kernel_initializer,
+          kernel_regularizer=self._kernel_regularizer,
+          bias_regularizer=self._bias_regularizer)
+    else:
+      self._squeeze_excitation = None
+
     if self._stochastic_depth_drop_rate:
       self._stochastic_depth = nn_layers.StochasticDepth(
           self._stochastic_depth_drop_rate)
@@ -345,6 +377,7 @@ class BottleneckBlock(tf.keras.layers.Layer):
         'strides': self._strides,
         'dilation_rate': self._dilation_rate,
         'use_projection': self._use_projection,
+        'se_ratio': self._se_ratio,
         'stochastic_depth_drop_rate': self._stochastic_depth_drop_rate,
         'kernel_initializer': self._kernel_initializer,
         'kernel_regularizer': self._kernel_regularizer,
@@ -374,6 +407,9 @@ class BottleneckBlock(tf.keras.layers.Layer):
     x = self._conv3(x)
     x = self._norm3(x)
 
+    if self._squeeze_excitation:
+      x = self._squeeze_excitation(x)
+
     if self._stochastic_depth:
       x = self._stochastic_depth(x, training=training)
 

official/vision/beta/modeling/layers/nn_blocks_test.py

@@ -39,11 +39,11 @@ def distribution_strategy_combinations() -> Iterable[Tuple[Any, ...]]:
 class NNBlocksTest(parameterized.TestCase, tf.test.TestCase):
 
   @parameterized.parameters(
-      (nn_blocks.ResidualBlock, 1, False, 0.0),
-      (nn_blocks.ResidualBlock, 2, True, 0.2),
+      (nn_blocks.ResidualBlock, 1, False, 0.0, None),
+      (nn_blocks.ResidualBlock, 2, True, 0.2, 0.25),
   )
-  def test_residual_block_creation(
-      self, block_fn, strides, use_projection, stochastic_depth_drop_rate):
+  def test_residual_block_creation(self, block_fn, strides, use_projection,
+                                   stochastic_depth_drop_rate, se_ratio):
     input_size = 128
     filter_size = 256
     inputs = tf.keras.Input(
@@ -52,6 +52,7 @@ class NNBlocksTest(parameterized.TestCase, tf.test.TestCase):
         filter_size,
         strides,
         use_projection=use_projection,
+        se_ratio=se_ratio,
         stochastic_depth_drop_rate=stochastic_depth_drop_rate,
     )
 
@@ -62,11 +63,11 @@ class NNBlocksTest(parameterized.TestCase, tf.test.TestCase):
         features.shape.as_list())
 
   @parameterized.parameters(
-      (nn_blocks.BottleneckBlock, 1, False, 0.0),
-      (nn_blocks.BottleneckBlock, 2, True, 0.2),
+      (nn_blocks.BottleneckBlock, 1, False, 0.0, None),
+      (nn_blocks.BottleneckBlock, 2, True, 0.2, 0.25),
   )
-  def test_bottleneck_block_creation(
-      self, block_fn, strides, use_projection, stochastic_depth_drop_rate):
+  def test_bottleneck_block_creation(self, block_fn, strides, use_projection,
+                                     stochastic_depth_drop_rate, se_ratio):
     input_size = 128
     filter_size = 256
     inputs = tf.keras.Input(
@@ -75,8 +76,8 @@ class NNBlocksTest(parameterized.TestCase, tf.test.TestCase):
         filter_size,
         strides,
         use_projection=use_projection,
-        stochastic_depth_drop_rate=stochastic_depth_drop_rate
-    )
+        se_ratio=se_ratio,
+        stochastic_depth_drop_rate=stochastic_depth_drop_rate)
 
     features = block(inputs)