in tensorflow_examples/profiling/resnet_model.py [0:0]
def resnet50(num_classes,
batch_size=None,
use_l2_regularizer=True,
rescale_inputs=False):
"""Instantiates the ResNet50 architecture.
Args:
num_classes: `int` number of classes for image classification.
batch_size: Size of the batches for each step.
use_l2_regularizer: whether to use L2 regularizer on Conv/Dense layer.
rescale_inputs: whether to rescale inputs from 0 to 1.
Returns:
A Keras model instance.
"""
input_shape = (224, 224, 3)
img_input = layers.Input(shape=input_shape, batch_size=batch_size)
if rescale_inputs:
# Hub image modules expect inputs in the range [0, 1]. This rescales these
# inputs to the range expected by the trained model.
x = layers.Lambda(
lambda x: x * 255.0 - backend.constant(
imagenet_preprocessing_ineffecient_input_pipeline.CHANNEL_MEANS,
shape=[1, 1, 3],
dtype=x.dtype),
name='rescale')(
img_input)
else:
x = img_input
if backend.image_data_format() == 'channels_first':
x = layers.Lambda(
lambda x: backend.permute_dimensions(x, (0, 3, 1, 2)),
name='transpose')(x)
bn_axis = 1
else: # channels_last
bn_axis = 3
x = layers.ZeroPadding2D(padding=(3, 3), name='conv1_pad')(x)
x = layers.Conv2D(
64, (7, 7),
strides=(2, 2),
padding='valid',
use_bias=False,
kernel_initializer='he_normal',
kernel_regularizer=_gen_l2_regularizer(use_l2_regularizer),
name='conv1')(
x)
x = layers.BatchNormalization(
axis=bn_axis,
momentum=BATCH_NORM_DECAY,
epsilon=BATCH_NORM_EPSILON,
name='bn_conv1')(
x)
x = layers.Activation('relu')(x)
x = layers.MaxPooling2D((3, 3), strides=(2, 2), padding='same')(x)
x = conv_block(
x,
3, [64, 64, 256],
stage=2,
block='a',
strides=(1, 1),
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [64, 64, 256],
stage=2,
block='b',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [64, 64, 256],
stage=2,
block='c',
use_l2_regularizer=use_l2_regularizer)
x = conv_block(
x,
3, [128, 128, 512],
stage=3,
block='a',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [128, 128, 512],
stage=3,
block='b',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [128, 128, 512],
stage=3,
block='c',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [128, 128, 512],
stage=3,
block='d',
use_l2_regularizer=use_l2_regularizer)
x = conv_block(
x,
3, [256, 256, 1024],
stage=4,
block='a',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [256, 256, 1024],
stage=4,
block='b',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [256, 256, 1024],
stage=4,
block='c',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [256, 256, 1024],
stage=4,
block='d',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [256, 256, 1024],
stage=4,
block='e',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [256, 256, 1024],
stage=4,
block='f',
use_l2_regularizer=use_l2_regularizer)
x = conv_block(
x,
3, [512, 512, 2048],
stage=5,
block='a',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [512, 512, 2048],
stage=5,
block='b',
use_l2_regularizer=use_l2_regularizer)
x = identity_block(
x,
3, [512, 512, 2048],
stage=5,
block='c',
use_l2_regularizer=use_l2_regularizer)
rm_axes = [1, 2] if backend.image_data_format() == 'channels_last' else [2, 3]
x = layers.Lambda(lambda x: backend.mean(x, rm_axes), name='reduce_mean')(x)
x = layers.Dense(
num_classes,
kernel_initializer=initializers.RandomNormal(stddev=0.01),
kernel_regularizer=_gen_l2_regularizer(use_l2_regularizer),
bias_regularizer=_gen_l2_regularizer(use_l2_regularizer),
name='fc1000')(
x)
# A softmax that is followed by the model loss must be done cannot be done
# in float16 due to numeric issues. So we pass dtype=float32.
x = layers.Activation('softmax', dtype='float32')(x)
# Create model.
return models.Model(img_input, x, name='resnet50')