def __init__(
self,
min_level=3,
max_level=7,
fpn_feat_dims=256,
use_separable_conv=False,
activation='relu',
use_batch_norm=True,
norm_activation=nn_ops.norm_activation_builder(activation='relu')):
"""FPN initialization function.
Args:
min_level: `int` minimum level in FPN output feature maps.
max_level: `int` maximum level in FPN output feature maps.
fpn_feat_dims: `int` number of filters in FPN layers.
use_separable_conv: `bool`, if True use separable convolution for
convolution in FPN layers.
activation: the activation function.
use_batch_norm: 'bool', indicating whether batchnorm layers are added.
norm_activation: an operation that includes a normalization layer
followed by an optional activation layer.
"""
self._min_level = min_level
self._max_level = max_level
self._fpn_feat_dims = fpn_feat_dims
if use_separable_conv:
self._conv2d_op = functools.partial(
tf.keras.layers.SeparableConv2D, depth_multiplier=1)
else:
self._conv2d_op = tf.keras.layers.Conv2D
if activation == 'relu':
self._activation_op = tf.nn.relu
elif activation == 'swish':
self._activation_op = tf.nn.swish
else:
raise ValueError('Unsupported activation `{}`.'.format(activation))
self._use_batch_norm = use_batch_norm
self._norm_activation = norm_activation
self._norm_activations = {}
self._lateral_conv2d_op = {}
self._post_hoc_conv2d_op = {}
self._coarse_conv2d_op = {}
for level in range(self._min_level, self._max_level + 1):
if self._use_batch_norm:
self._norm_activations[level] = norm_activation(
use_activation=False, name='p%d-bn' % level)
self._lateral_conv2d_op[level] = self._conv2d_op(
filters=self._fpn_feat_dims,
kernel_size=(1, 1),
padding='same',
name='l%d' % level)
self._post_hoc_conv2d_op[level] = self._conv2d_op(
filters=self._fpn_feat_dims,
strides=(1, 1),
kernel_size=(3, 3),
padding='same',
name='post_hoc_d%d' % level)
self._coarse_conv2d_op[level] = self._conv2d_op(
filters=self._fpn_feat_dims,
strides=(2, 2),
kernel_size=(3, 3),
padding='same',
name='p%d' % level)
def __init__(
self,
resnet_depth,
activation='relu',
norm_activation=nn_ops.norm_activation_builder(activation='relu'),
data_format='channels_last'):
"""ResNet initialization function.
Args:
resnet_depth: `int` depth of ResNet backbone model.
activation: the activation function.
norm_activation: an operation that includes a normalization layer followed
by an optional activation layer.
data_format: `str` either "channels_first" for `[batch, channels, height,
width]` or "channels_last for `[batch, height, width, channels]`.
"""
self._resnet_depth = resnet_depth
if activation == 'relu':
self._activation_op = tf.nn.relu
elif activation == 'swish':
self._activation_op = tf.nn.swish
else:
raise ValueError('Unsupported activation `{}`.'.format(activation))
self._norm_activation = norm_activation
self._data_format = data_format
model_params = {
10: {
'block': self.residual_block,
'layers': [1, 1, 1, 1]
},
18: {
'block': self.residual_block,
'layers': [2, 2, 2, 2]
},
34: {
'block': self.residual_block,
'layers': [3, 4, 6, 3]
},
50: {
'block': self.bottleneck_block,
'layers': [3, 4, 6, 3]
},
101: {
'block': self.bottleneck_block,
'layers': [3, 4, 23, 3]
},
152: {
'block': self.bottleneck_block,
'layers': [3, 8, 36, 3]
},
200: {
'block': self.bottleneck_block,
'layers': [3, 24, 36, 3]
}
}
if resnet_depth not in model_params:
valid_resnet_depths = ', '.join(
[str(depth) for depth in sorted(model_params.keys())])
raise ValueError(
'The resnet_depth should be in [%s]. Not a valid resnet_depth:'
% (valid_resnet_depths), self._resnet_depth)
params = model_params[resnet_depth]
self._resnet_fn = self.resnet_v1_generator(params['block'],
params['layers'])
def norm_activation_generator(params):
return nn_ops.norm_activation_builder(
momentum=params.batch_norm_momentum,
epsilon=params.batch_norm_epsilon,
trainable=params.batch_norm_trainable,
activation=params.activation)