Module keras.applications.mobilenet
MobileNet v1 models for Keras.
MobileNet is a general architecture and can be used for multiple use cases. Depending on the use case, it can use different input layer size and different width factors. This allows different width models to reduce the number of multiply-adds and thereby reduce inference cost on mobile devices.
MobileNets support any input size greater than 32 x 32, with larger image sizes
offering better performance.
The number of parameters and number of multiply-adds
can be modified by using the alpha
parameter,
which increases/decreases the number of filters in each layer.
By altering the image size and alpha
parameter,
all 16 models from the paper can be built, with ImageNet weights provided.
The paper demonstrates the performance of MobileNets using alpha
values of
1.0 (also called 100 % MobileNet), 0.75, 0.5 and 0.25.
For each of these alpha
values, weights for 4 different input image sizes
are provided (224, 192, 160, 128).
The following table describes the size and accuracy of the 100% MobileNet on size 224 x 224:
Width Multiplier (alpha) | ImageNet Acc | Multiply-Adds (M) | Params (M)
| 1.0 MobileNet-224 | 70.6 % | 529 | 4.2 | | 0.75 MobileNet-224 | 68.4 % | 325 | 2.6 | | 0.50 MobileNet-224 | 63.7 % | 149 | 1.3 | | 0.25 MobileNet-224 | 50.6 % | 41 | 0.5 |
The following table describes the performance of the 100 % MobileNet on various input sizes:
Resolution | ImageNet Acc | Multiply-Adds (M) | Params (M)
| 1.0 MobileNet-224 | 70.6 % | 569 | 4.2 | | 1.0 MobileNet-192 | 69.1 % | 418 | 4.2 | | 1.0 MobileNet-160 | 67.2 % | 290 | 4.2 | | 1.0 MobileNet-128 | 64.4 % | 186 | 4.2 |
Reference
Expand source code
# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
# pylint: disable=invalid-name
"""MobileNet v1 models for Keras.
MobileNet is a general architecture and can be used for multiple use cases.
Depending on the use case, it can use different input layer size and
different width factors. This allows different width models to reduce
the number of multiply-adds and thereby
reduce inference cost on mobile devices.
MobileNets support any input size greater than 32 x 32, with larger image sizes
offering better performance.
The number of parameters and number of multiply-adds
can be modified by using the `alpha` parameter,
which increases/decreases the number of filters in each layer.
By altering the image size and `alpha` parameter,
all 16 models from the paper can be built, with ImageNet weights provided.
The paper demonstrates the performance of MobileNets using `alpha` values of
1.0 (also called 100 % MobileNet), 0.75, 0.5 and 0.25.
For each of these `alpha` values, weights for 4 different input image sizes
are provided (224, 192, 160, 128).
The following table describes the size and accuracy of the 100% MobileNet
on size 224 x 224:
----------------------------------------------------------------------------
Width Multiplier (alpha) | ImageNet Acc | Multiply-Adds (M) | Params (M)
----------------------------------------------------------------------------
| 1.0 MobileNet-224 | 70.6 % | 529 | 4.2 |
| 0.75 MobileNet-224 | 68.4 % | 325 | 2.6 |
| 0.50 MobileNet-224 | 63.7 % | 149 | 1.3 |
| 0.25 MobileNet-224 | 50.6 % | 41 | 0.5 |
----------------------------------------------------------------------------
The following table describes the performance of
the 100 % MobileNet on various input sizes:
------------------------------------------------------------------------
Resolution | ImageNet Acc | Multiply-Adds (M) | Params (M)
------------------------------------------------------------------------
| 1.0 MobileNet-224 | 70.6 % | 569 | 4.2 |
| 1.0 MobileNet-192 | 69.1 % | 418 | 4.2 |
| 1.0 MobileNet-160 | 67.2 % | 290 | 4.2 |
| 1.0 MobileNet-128 | 64.4 % | 186 | 4.2 |
------------------------------------------------------------------------
Reference:
- [MobileNets: Efficient Convolutional Neural Networks
for Mobile Vision Applications](
https://arxiv.org/abs/1704.04861)
"""
import tensorflow.compat.v2 as tf
from keras import backend
from keras.applications import imagenet_utils
from keras.engine import training
from keras.layers import VersionAwareLayers
from keras.utils import data_utils
from keras.utils import layer_utils
from tensorflow.python.platform import tf_logging as logging
from tensorflow.python.util.tf_export import keras_export
BASE_WEIGHT_PATH = ('https://storage.googleapis.com/tensorflow/'
'keras-applications/mobilenet/')
layers = None
@keras_export('keras.applications.mobilenet.MobileNet',
'keras.applications.MobileNet')
def MobileNet(input_shape=None,
alpha=1.0,
depth_multiplier=1,
dropout=1e-3,
include_top=True,
weights='imagenet',
input_tensor=None,
pooling=None,
classes=1000,
classifier_activation='softmax',
**kwargs):
"""Instantiates the MobileNet architecture.
Reference:
- [MobileNets: Efficient Convolutional Neural Networks
for Mobile Vision Applications](
https://arxiv.org/abs/1704.04861)
This function returns a Keras image classification model,
optionally loaded with weights pre-trained on ImageNet.
For image classification use cases, see
[this page for detailed examples](
https://keras.io/api/applications/#usage-examples-for-image-classification-models).
For transfer learning use cases, make sure to read the
[guide to transfer learning & fine-tuning](
https://keras.io/guides/transfer_learning/).
Note: each Keras Application expects a specific kind of input preprocessing.
For MobileNet, call `tf.keras.applications.mobilenet.preprocess_input`
on your inputs before passing them to the model.
`mobilenet.preprocess_input` will scale input pixels between -1 and 1.
Args:
input_shape: Optional shape tuple, only to be specified if `include_top`
is False (otherwise the input shape has to be `(224, 224, 3)` (with
`channels_last` data format) or (3, 224, 224) (with `channels_first`
data format). It should have exactly 3 inputs channels, and width and
height should be no smaller than 32. E.g. `(200, 200, 3)` would be one
valid value. Default to `None`.
`input_shape` will be ignored if the `input_tensor` is provided.
alpha: Controls the width of the network. This is known as the width
multiplier in the MobileNet paper. - If `alpha` < 1.0, proportionally
decreases the number of filters in each layer. - If `alpha` > 1.0,
proportionally increases the number of filters in each layer. - If
`alpha` = 1, default number of filters from the paper are used at each
layer. Default to 1.0.
depth_multiplier: Depth multiplier for depthwise convolution. This is
called the resolution multiplier in the MobileNet paper. Default to 1.0.
dropout: Dropout rate. Default to 0.001.
include_top: Boolean, whether to include the fully-connected layer at the
top of the network. Default to `True`.
weights: One of `None` (random initialization), 'imagenet' (pre-training
on ImageNet), or the path to the weights file to be loaded. Default to
`imagenet`.
input_tensor: Optional Keras tensor (i.e. output of `layers.Input()`) to
use as image input for the model. `input_tensor` is useful for sharing
inputs between multiple different networks. Default to None.
pooling: Optional pooling mode for feature extraction when `include_top`
is `False`.
- `None` (default) means that the output of the model will be
the 4D tensor output of the last convolutional block.
- `avg` means that global average pooling
will be applied to the output of the
last convolutional block, and thus
the output of the model will be a 2D tensor.
- `max` means that global max pooling will be applied.
classes: Optional number of classes to classify images into, only to be
specified if `include_top` is True, and if no `weights` argument is
specified. Defaults to 1000.
classifier_activation: A `str` or callable. The activation function to use
on the "top" layer. Ignored unless `include_top=True`. Set
`classifier_activation=None` to return the logits of the "top" layer.
When loading pretrained weights, `classifier_activation` can only
be `None` or `"softmax"`.
**kwargs: For backwards compatibility only.
Returns:
A `keras.Model` instance.
"""
global layers
if 'layers' in kwargs:
layers = kwargs.pop('layers')
else:
layers = VersionAwareLayers()
if kwargs:
raise ValueError('Unknown argument(s): %s' % (kwargs,))
if not (weights in {'imagenet', None} or tf.io.gfile.exists(weights)):
raise ValueError('The `weights` argument should be either '
'`None` (random initialization), `imagenet` '
'(pre-training on ImageNet), '
'or the path to the weights file to be loaded.')
if weights == 'imagenet' and include_top and classes != 1000:
raise ValueError('If using `weights` as `"imagenet"` with `include_top` '
'as true, `classes` should be 1000')
# Determine proper input shape and default size.
if input_shape is None:
default_size = 224
else:
if backend.image_data_format() == 'channels_first':
rows = input_shape[1]
cols = input_shape[2]
else:
rows = input_shape[0]
cols = input_shape[1]
if rows == cols and rows in [128, 160, 192, 224]:
default_size = rows
else:
default_size = 224
input_shape = imagenet_utils.obtain_input_shape(
input_shape,
default_size=default_size,
min_size=32,
data_format=backend.image_data_format(),
require_flatten=include_top,
weights=weights)
if backend.image_data_format() == 'channels_last':
row_axis, col_axis = (0, 1)
else:
row_axis, col_axis = (1, 2)
rows = input_shape[row_axis]
cols = input_shape[col_axis]
if weights == 'imagenet':
if depth_multiplier != 1:
raise ValueError('If imagenet weights are being loaded, '
'depth multiplier must be 1')
if alpha not in [0.25, 0.50, 0.75, 1.0]:
raise ValueError('If imagenet weights are being loaded, '
'alpha can be one of'
'`0.25`, `0.50`, `0.75` or `1.0` only.')
if rows != cols or rows not in [128, 160, 192, 224]:
rows = 224
logging.warning('`input_shape` is undefined or non-square, '
'or `rows` is not in [128, 160, 192, 224]. '
'Weights for input shape (224, 224) will be'
' loaded as the default.')
if input_tensor is None:
img_input = layers.Input(shape=input_shape)
else:
if not backend.is_keras_tensor(input_tensor):
img_input = layers.Input(tensor=input_tensor, shape=input_shape)
else:
img_input = input_tensor
x = _conv_block(img_input, 32, alpha, strides=(2, 2))
x = _depthwise_conv_block(x, 64, alpha, depth_multiplier, block_id=1)
x = _depthwise_conv_block(
x, 128, alpha, depth_multiplier, strides=(2, 2), block_id=2)
x = _depthwise_conv_block(x, 128, alpha, depth_multiplier, block_id=3)
x = _depthwise_conv_block(
x, 256, alpha, depth_multiplier, strides=(2, 2), block_id=4)
x = _depthwise_conv_block(x, 256, alpha, depth_multiplier, block_id=5)
x = _depthwise_conv_block(
x, 512, alpha, depth_multiplier, strides=(2, 2), block_id=6)
x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=7)
x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=8)
x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=9)
x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=10)
x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=11)
x = _depthwise_conv_block(
x, 1024, alpha, depth_multiplier, strides=(2, 2), block_id=12)
x = _depthwise_conv_block(x, 1024, alpha, depth_multiplier, block_id=13)
if include_top:
if backend.image_data_format() == 'channels_first':
shape = (int(1024 * alpha), 1, 1)
else:
shape = (1, 1, int(1024 * alpha))
x = layers.GlobalAveragePooling2D()(x)
x = layers.Reshape(shape, name='reshape_1')(x)
x = layers.Dropout(dropout, name='dropout')(x)
x = layers.Conv2D(classes, (1, 1), padding='same', name='conv_preds')(x)
x = layers.Reshape((classes,), name='reshape_2')(x)
imagenet_utils.validate_activation(classifier_activation, weights)
x = layers.Activation(activation=classifier_activation,
name='predictions')(x)
else:
if pooling == 'avg':
x = layers.GlobalAveragePooling2D()(x)
elif pooling == 'max':
x = layers.GlobalMaxPooling2D()(x)
# Ensure that the model takes into account
# any potential predecessors of `input_tensor`.
if input_tensor is not None:
inputs = layer_utils.get_source_inputs(input_tensor)
else:
inputs = img_input
# Create model.
model = training.Model(inputs, x, name='mobilenet_%0.2f_%s' % (alpha, rows))
# Load weights.
if weights == 'imagenet':
if alpha == 1.0:
alpha_text = '1_0'
elif alpha == 0.75:
alpha_text = '7_5'
elif alpha == 0.50:
alpha_text = '5_0'
else:
alpha_text = '2_5'
if include_top:
model_name = 'mobilenet_%s_%d_tf.h5' % (alpha_text, rows)
weight_path = BASE_WEIGHT_PATH + model_name
weights_path = data_utils.get_file(
model_name, weight_path, cache_subdir='models')
else:
model_name = 'mobilenet_%s_%d_tf_no_top.h5' % (alpha_text, rows)
weight_path = BASE_WEIGHT_PATH + model_name
weights_path = data_utils.get_file(
model_name, weight_path, cache_subdir='models')
model.load_weights(weights_path)
elif weights is not None:
model.load_weights(weights)
return model
def _conv_block(inputs, filters, alpha, kernel=(3, 3), strides=(1, 1)):
"""Adds an initial convolution layer (with batch normalization and relu6).
Args:
inputs: Input tensor of shape `(rows, cols, 3)` (with `channels_last`
data format) or (3, rows, cols) (with `channels_first` data format).
It should have exactly 3 inputs channels, and width and height should
be no smaller than 32. E.g. `(224, 224, 3)` would be one valid value.
filters: Integer, the dimensionality of the output space (i.e. the
number of output filters in the convolution).
alpha: controls the width of the network. - If `alpha` < 1.0,
proportionally decreases the number of filters in each layer. - If
`alpha` > 1.0, proportionally increases the number of filters in each
layer. - If `alpha` = 1, default number of filters from the paper are
used at each layer.
kernel: An integer or tuple/list of 2 integers, specifying the width and
height of the 2D convolution window. Can be a single integer to
specify the same value for all spatial dimensions.
strides: An integer or tuple/list of 2 integers, specifying the strides
of the convolution along the width and height. Can be a single integer
to specify the same value for all spatial dimensions. Specifying any
stride value != 1 is incompatible with specifying any `dilation_rate`
value != 1. # Input shape
4D tensor with shape: `(samples, channels, rows, cols)` if
data_format='channels_first'
or 4D tensor with shape: `(samples, rows, cols, channels)` if
data_format='channels_last'. # Output shape
4D tensor with shape: `(samples, filters, new_rows, new_cols)` if
data_format='channels_first'
or 4D tensor with shape: `(samples, new_rows, new_cols, filters)` if
data_format='channels_last'. `rows` and `cols` values might have
changed due to stride.
Returns:
Output tensor of block.
"""
channel_axis = 1 if backend.image_data_format() == 'channels_first' else -1
filters = int(filters * alpha)
x = layers.Conv2D(
filters,
kernel,
padding='same',
use_bias=False,
strides=strides,
name='conv1')(inputs)
x = layers.BatchNormalization(axis=channel_axis, name='conv1_bn')(x)
return layers.ReLU(6., name='conv1_relu')(x)
def _depthwise_conv_block(inputs,
pointwise_conv_filters,
alpha,
depth_multiplier=1,
strides=(1, 1),
block_id=1):
"""Adds a depthwise convolution block.
A depthwise convolution block consists of a depthwise conv,
batch normalization, relu6, pointwise convolution,
batch normalization and relu6 activation.
Args:
inputs: Input tensor of shape `(rows, cols, channels)` (with
`channels_last` data format) or (channels, rows, cols) (with
`channels_first` data format).
pointwise_conv_filters: Integer, the dimensionality of the output space
(i.e. the number of output filters in the pointwise convolution).
alpha: controls the width of the network. - If `alpha` < 1.0,
proportionally decreases the number of filters in each layer. - If
`alpha` > 1.0, proportionally increases the number of filters in each
layer. - If `alpha` = 1, default number of filters from the paper are
used at each layer.
depth_multiplier: The number of depthwise convolution output channels
for each input channel. The total number of depthwise convolution
output channels will be equal to `filters_in * depth_multiplier`.
strides: An integer or tuple/list of 2 integers, specifying the strides
of the convolution along the width and height. Can be a single integer
to specify the same value for all spatial dimensions. Specifying any
stride value != 1 is incompatible with specifying any `dilation_rate`
value != 1.
block_id: Integer, a unique identification designating the block number.
# Input shape
4D tensor with shape: `(batch, channels, rows, cols)` if
data_format='channels_first'
or 4D tensor with shape: `(batch, rows, cols, channels)` if
data_format='channels_last'. # Output shape
4D tensor with shape: `(batch, filters, new_rows, new_cols)` if
data_format='channels_first'
or 4D tensor with shape: `(batch, new_rows, new_cols, filters)` if
data_format='channels_last'. `rows` and `cols` values might have
changed due to stride.
Returns:
Output tensor of block.
"""
channel_axis = 1 if backend.image_data_format() == 'channels_first' else -1
pointwise_conv_filters = int(pointwise_conv_filters * alpha)
if strides == (1, 1):
x = inputs
else:
x = layers.ZeroPadding2D(((0, 1), (0, 1)), name='conv_pad_%d' % block_id)(
inputs)
x = layers.DepthwiseConv2D((3, 3),
padding='same' if strides == (1, 1) else 'valid',
depth_multiplier=depth_multiplier,
strides=strides,
use_bias=False,
name='conv_dw_%d' % block_id)(
x)
x = layers.BatchNormalization(
axis=channel_axis, name='conv_dw_%d_bn' % block_id)(
x)
x = layers.ReLU(6., name='conv_dw_%d_relu' % block_id)(x)
x = layers.Conv2D(
pointwise_conv_filters, (1, 1),
padding='same',
use_bias=False,
strides=(1, 1),
name='conv_pw_%d' % block_id)(
x)
x = layers.BatchNormalization(
axis=channel_axis, name='conv_pw_%d_bn' % block_id)(
x)
return layers.ReLU(6., name='conv_pw_%d_relu' % block_id)(x)
@keras_export('keras.applications.mobilenet.preprocess_input')
def preprocess_input(x, data_format=None):
return imagenet_utils.preprocess_input(x, data_format=data_format, mode='tf')
@keras_export('keras.applications.mobilenet.decode_predictions')
def decode_predictions(preds, top=5):
return imagenet_utils.decode_predictions(preds, top=top)
preprocess_input.__doc__ = imagenet_utils.PREPROCESS_INPUT_DOC.format(
mode='',
ret=imagenet_utils.PREPROCESS_INPUT_RET_DOC_TF,
error=imagenet_utils.PREPROCESS_INPUT_ERROR_DOC)
decode_predictions.__doc__ = imagenet_utils.decode_predictions.__doc__
Functions
def MobileNet(input_shape=None, alpha=1.0, depth_multiplier=1, dropout=0.001, include_top=True, weights='imagenet', input_tensor=None, pooling=None, classes=1000, classifier_activation='softmax', **kwargs)
-
Instantiates the MobileNet architecture.
Reference: - MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications
This function returns a Keras image classification model, optionally loaded with weights pre-trained on ImageNet.
For image classification use cases, see this page for detailed examples.
For transfer learning use cases, make sure to read the guide to transfer learning & fine-tuning.
Note: each Keras Application expects a specific kind of input preprocessing. For MobileNet, call
tf.keras.applications.mobilenet.preprocess_input
on your inputs before passing them to the model.mobilenet.preprocess_input
will scale input pixels between -1 and 1.Args
input_shape
- Optional shape tuple, only to be specified if
include_top
is False (otherwise the input shape has to be(224, 224, 3)
(withchannels_last
data format) or (3, 224, 224) (withchannels_first
data format). It should have exactly 3 inputs channels, and width and height should be no smaller than 32. E.g.(200, 200, 3)
would be one valid value. Default toNone
.input_shape
will be ignored if theinput_tensor
is provided. alpha
- Controls the width of the network. This is known as the width
multiplier in the MobileNet paper. - If
alpha
< 1.0, proportionally decreases the number of filters in each layer. - Ifalpha
> 1.0, proportionally increases the number of filters in each layer. - Ifalpha
= 1, default number of filters from the paper are used at each layer. Default to 1.0. depth_multiplier
- Depth multiplier for depthwise convolution. This is called the resolution multiplier in the MobileNet paper. Default to 1.0.
dropout
- Dropout rate. Default to 0.001.
include_top
- Boolean, whether to include the fully-connected layer at the
top of the network. Default to
True
. weights
- One of
None
(random initialization), 'imagenet' (pre-training on ImageNet), or the path to the weights file to be loaded. Default toimagenet
. input_tensor
- Optional Keras tensor (i.e. output of
layers.Input()
) to use as image input for the model.input_tensor
is useful for sharing inputs between multiple different networks. Default to None. pooling
- Optional pooling mode for feature extraction when
include_top
isFalse
. -None
(default) means that the output of the model will be the 4D tensor output of the last convolutional block. -avg
means that global average pooling will be applied to the output of the last convolutional block, and thus the output of the model will be a 2D tensor. -max
means that global max pooling will be applied. classes
- Optional number of classes to classify images into, only to be
specified if
include_top
is True, and if noweights
argument is specified. Defaults to 1000. classifier_activation
- A
str
or callable. The activation function to use on the "top" layer. Ignored unlessinclude_top=True
. Setclassifier_activation=None
to return the logits of the "top" layer. When loading pretrained weights,classifier_activation
can only beNone
or"softmax"
. **kwargs
- For backwards compatibility only.
Returns
A
keras.Model
instance.Expand source code
@keras_export('keras.applications.mobilenet.MobileNet', 'keras.applications.MobileNet') def MobileNet(input_shape=None, alpha=1.0, depth_multiplier=1, dropout=1e-3, include_top=True, weights='imagenet', input_tensor=None, pooling=None, classes=1000, classifier_activation='softmax', **kwargs): """Instantiates the MobileNet architecture. Reference: - [MobileNets: Efficient Convolutional Neural Networks for Mobile Vision Applications]( https://arxiv.org/abs/1704.04861) This function returns a Keras image classification model, optionally loaded with weights pre-trained on ImageNet. For image classification use cases, see [this page for detailed examples]( https://keras.io/api/applications/#usage-examples-for-image-classification-models). For transfer learning use cases, make sure to read the [guide to transfer learning & fine-tuning]( https://keras.io/guides/transfer_learning/). Note: each Keras Application expects a specific kind of input preprocessing. For MobileNet, call `tf.keras.applications.mobilenet.preprocess_input` on your inputs before passing them to the model. `mobilenet.preprocess_input` will scale input pixels between -1 and 1. Args: input_shape: Optional shape tuple, only to be specified if `include_top` is False (otherwise the input shape has to be `(224, 224, 3)` (with `channels_last` data format) or (3, 224, 224) (with `channels_first` data format). It should have exactly 3 inputs channels, and width and height should be no smaller than 32. E.g. `(200, 200, 3)` would be one valid value. Default to `None`. `input_shape` will be ignored if the `input_tensor` is provided. alpha: Controls the width of the network. This is known as the width multiplier in the MobileNet paper. - If `alpha` < 1.0, proportionally decreases the number of filters in each layer. - If `alpha` > 1.0, proportionally increases the number of filters in each layer. - If `alpha` = 1, default number of filters from the paper are used at each layer. Default to 1.0. depth_multiplier: Depth multiplier for depthwise convolution. This is called the resolution multiplier in the MobileNet paper. Default to 1.0. dropout: Dropout rate. Default to 0.001. include_top: Boolean, whether to include the fully-connected layer at the top of the network. Default to `True`. weights: One of `None` (random initialization), 'imagenet' (pre-training on ImageNet), or the path to the weights file to be loaded. Default to `imagenet`. input_tensor: Optional Keras tensor (i.e. output of `layers.Input()`) to use as image input for the model. `input_tensor` is useful for sharing inputs between multiple different networks. Default to None. pooling: Optional pooling mode for feature extraction when `include_top` is `False`. - `None` (default) means that the output of the model will be the 4D tensor output of the last convolutional block. - `avg` means that global average pooling will be applied to the output of the last convolutional block, and thus the output of the model will be a 2D tensor. - `max` means that global max pooling will be applied. classes: Optional number of classes to classify images into, only to be specified if `include_top` is True, and if no `weights` argument is specified. Defaults to 1000. classifier_activation: A `str` or callable. The activation function to use on the "top" layer. Ignored unless `include_top=True`. Set `classifier_activation=None` to return the logits of the "top" layer. When loading pretrained weights, `classifier_activation` can only be `None` or `"softmax"`. **kwargs: For backwards compatibility only. Returns: A `keras.Model` instance. """ global layers if 'layers' in kwargs: layers = kwargs.pop('layers') else: layers = VersionAwareLayers() if kwargs: raise ValueError('Unknown argument(s): %s' % (kwargs,)) if not (weights in {'imagenet', None} or tf.io.gfile.exists(weights)): raise ValueError('The `weights` argument should be either ' '`None` (random initialization), `imagenet` ' '(pre-training on ImageNet), ' 'or the path to the weights file to be loaded.') if weights == 'imagenet' and include_top and classes != 1000: raise ValueError('If using `weights` as `"imagenet"` with `include_top` ' 'as true, `classes` should be 1000') # Determine proper input shape and default size. if input_shape is None: default_size = 224 else: if backend.image_data_format() == 'channels_first': rows = input_shape[1] cols = input_shape[2] else: rows = input_shape[0] cols = input_shape[1] if rows == cols and rows in [128, 160, 192, 224]: default_size = rows else: default_size = 224 input_shape = imagenet_utils.obtain_input_shape( input_shape, default_size=default_size, min_size=32, data_format=backend.image_data_format(), require_flatten=include_top, weights=weights) if backend.image_data_format() == 'channels_last': row_axis, col_axis = (0, 1) else: row_axis, col_axis = (1, 2) rows = input_shape[row_axis] cols = input_shape[col_axis] if weights == 'imagenet': if depth_multiplier != 1: raise ValueError('If imagenet weights are being loaded, ' 'depth multiplier must be 1') if alpha not in [0.25, 0.50, 0.75, 1.0]: raise ValueError('If imagenet weights are being loaded, ' 'alpha can be one of' '`0.25`, `0.50`, `0.75` or `1.0` only.') if rows != cols or rows not in [128, 160, 192, 224]: rows = 224 logging.warning('`input_shape` is undefined or non-square, ' 'or `rows` is not in [128, 160, 192, 224]. ' 'Weights for input shape (224, 224) will be' ' loaded as the default.') if input_tensor is None: img_input = layers.Input(shape=input_shape) else: if not backend.is_keras_tensor(input_tensor): img_input = layers.Input(tensor=input_tensor, shape=input_shape) else: img_input = input_tensor x = _conv_block(img_input, 32, alpha, strides=(2, 2)) x = _depthwise_conv_block(x, 64, alpha, depth_multiplier, block_id=1) x = _depthwise_conv_block( x, 128, alpha, depth_multiplier, strides=(2, 2), block_id=2) x = _depthwise_conv_block(x, 128, alpha, depth_multiplier, block_id=3) x = _depthwise_conv_block( x, 256, alpha, depth_multiplier, strides=(2, 2), block_id=4) x = _depthwise_conv_block(x, 256, alpha, depth_multiplier, block_id=5) x = _depthwise_conv_block( x, 512, alpha, depth_multiplier, strides=(2, 2), block_id=6) x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=7) x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=8) x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=9) x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=10) x = _depthwise_conv_block(x, 512, alpha, depth_multiplier, block_id=11) x = _depthwise_conv_block( x, 1024, alpha, depth_multiplier, strides=(2, 2), block_id=12) x = _depthwise_conv_block(x, 1024, alpha, depth_multiplier, block_id=13) if include_top: if backend.image_data_format() == 'channels_first': shape = (int(1024 * alpha), 1, 1) else: shape = (1, 1, int(1024 * alpha)) x = layers.GlobalAveragePooling2D()(x) x = layers.Reshape(shape, name='reshape_1')(x) x = layers.Dropout(dropout, name='dropout')(x) x = layers.Conv2D(classes, (1, 1), padding='same', name='conv_preds')(x) x = layers.Reshape((classes,), name='reshape_2')(x) imagenet_utils.validate_activation(classifier_activation, weights) x = layers.Activation(activation=classifier_activation, name='predictions')(x) else: if pooling == 'avg': x = layers.GlobalAveragePooling2D()(x) elif pooling == 'max': x = layers.GlobalMaxPooling2D()(x) # Ensure that the model takes into account # any potential predecessors of `input_tensor`. if input_tensor is not None: inputs = layer_utils.get_source_inputs(input_tensor) else: inputs = img_input # Create model. model = training.Model(inputs, x, name='mobilenet_%0.2f_%s' % (alpha, rows)) # Load weights. if weights == 'imagenet': if alpha == 1.0: alpha_text = '1_0' elif alpha == 0.75: alpha_text = '7_5' elif alpha == 0.50: alpha_text = '5_0' else: alpha_text = '2_5' if include_top: model_name = 'mobilenet_%s_%d_tf.h5' % (alpha_text, rows) weight_path = BASE_WEIGHT_PATH + model_name weights_path = data_utils.get_file( model_name, weight_path, cache_subdir='models') else: model_name = 'mobilenet_%s_%d_tf_no_top.h5' % (alpha_text, rows) weight_path = BASE_WEIGHT_PATH + model_name weights_path = data_utils.get_file( model_name, weight_path, cache_subdir='models') model.load_weights(weights_path) elif weights is not None: model.load_weights(weights) return model
def decode_predictions(preds, top=5)
-
Decodes the prediction of an ImageNet model.
Args
preds
- Numpy array encoding a batch of predictions.
top
- Integer, how many top-guesses to return. Defaults to 5.
Returns
A list of lists of top class prediction tuples
(class_name, class_description, score)
. One list of tuples per sample in batch input.Raises
ValueError
- In case of invalid shape of the
pred
array (must be 2D).
Expand source code
@keras_export('keras.applications.mobilenet.decode_predictions') def decode_predictions(preds, top=5): return imagenet_utils.decode_predictions(preds, top=top)
def preprocess_input(x, data_format=None)
-
Preprocesses a tensor or Numpy array encoding a batch of images.
Usage example with
applications.MobileNet
:i = tf.keras.layers.Input([None, None, 3], dtype = tf.uint8) x = tf.cast(i, tf.float32) x = tf.keras.applications.mobilenet.preprocess_input(x) core = tf.keras.applications.MobileNet() x = core(x) model = tf.keras.Model(inputs=[i], outputs=[x]) image = tf.image.decode_png(tf.io.read_file('file.png')) result = model(image)
Args
x
- A floating point
numpy.array
or atf.Tensor
, 3D or 4D with 3 color channels, with values in the range [0, 255]. The preprocessed data are written over the input data if the data types are compatible. To avoid this behaviour,numpy.copy(x)
can be used. data_format
- Optional data format of the image tensor/array. Defaults to
None, in which case the global setting
tf.keras.backend.image_data_format()
is used (unless you changed it, it defaults to "channels_last").
Returns
Preprocessed
numpy.array
or atf.Tensor
with typefloat32
.The inputs pixel values are scaled between -1 and 1, sample-wise.
Raises
ValueError
- In case of unknown
data_format
argument.
Expand source code
@keras_export('keras.applications.mobilenet.preprocess_input') def preprocess_input(x, data_format=None): return imagenet_utils.preprocess_input(x, data_format=data_format, mode='tf')