ImageClassifier
classkeras_hub.models.ImageClassifier(
backbone,
num_classes,
preprocessor=None,
pooling="avg",
activation=None,
dropout=0.0,
head_dtype=None,
**kwargs
)
Base class for all image classification tasks.
ImageClassifier
tasks wrap a keras_hub.models.Backbone
and
a keras_hub.models.Preprocessor
to create a model that can be used for
image classification. ImageClassifier
tasks take an additional
num_classes
argument, controlling the number of predicted output classes.
To fine-tune with fit()
, pass a dataset containing tuples of (x, y)
labels where x
is a string and y
is a integer from [0, num_classes)
.
All ImageClassifier
tasks include a from_preset()
constructor which can
be used to load a pre-trained config and weights.
Arguments
keras_hub.models.Backbone
instance or a keras.Model
.None
, a keras_hub.models.Preprocessor
instance,
a keras.Layer
instance, or a callable. If None
no preprocessing
will be applied to the inputs."avg"
or "max"
. The type of pooling to apply on backbone
output. Defaults to average pooling.None
, str, or callable. The activation function to use on
the Dense
layer. Set activation=None
to return the output
logits. Defaults to "softmax"
.None
, str, or keras.mixed_precision.DTypePolicy
. The
dtype to use for the classification head's computations and weights.Examples
Call predict()
to run inference.
# Load preset and train
images = np.random.randint(0, 256, size=(2, 224, 224, 3))
classifier = keras_hub.models.ImageClassifier.from_preset(
"resnet_50_imagenet"
)
classifier.predict(images)
Call fit()
on a single batch.
# Load preset and train
images = np.random.randint(0, 256, size=(2, 224, 224, 3))
labels = [0, 3]
classifier = keras_hub.models.ImageClassifier.from_preset(
"resnet_50_imagenet"
)
classifier.fit(x=images, y=labels, batch_size=2)
Call fit()
with custom loss, optimizer and backbone.
classifier = keras_hub.models.ImageClassifier.from_preset(
"resnet_50_imagenet"
)
classifier.compile(
loss=keras.losses.SparseCategoricalCrossentropy(from_logits=True),
optimizer=keras.optimizers.Adam(5e-5),
)
classifier.backbone.trainable = False
classifier.fit(x=images, y=labels, batch_size=2)
Custom backbone.
images = np.random.randint(0, 256, size=(2, 224, 224, 3))
labels = [0, 3]
backbone = keras_hub.models.ResNetBackbone(
stackwise_num_filters=[64, 64, 64],
stackwise_num_blocks=[2, 2, 2],
stackwise_num_strides=[1, 2, 2],
block_type="basic_block",
use_pre_activation=True,
pooling="avg",
)
classifier = keras_hub.models.ImageClassifier(
backbone=backbone,
num_classes=4,
)
classifier.fit(x=images, y=labels, batch_size=2)
from_preset
methodImageClassifier.from_preset(preset, load_weights=True, **kwargs)
Instantiate a keras_hub.models.Task
from a model preset.
A preset is a directory of configs, weights and other file assets used
to save and load a pre-trained model. The preset
can be passed as
one of:
'bert_base_en'
'kaggle://user/bert/keras/bert_base_en'
'hf://user/bert_base_en'
'./bert_base_en'
For any Task
subclass, you can run cls.presets.keys()
to list all
built-in presets available on the class.
This constructor can be called in one of two ways. Either from a task
specific base class like keras_hub.models.CausalLM.from_preset()
, or
from a model class like keras_hub.models.BertTextClassifier.from_preset()
.
If calling from the a base class, the subclass of the returning object
will be inferred from the config in the preset directory.
Arguments
True
, saved weights will be loaded into
the model architecture. If False
, all weights will be
randomly initialized.Examples
# Load a Gemma generative task.
causal_lm = keras_hub.models.CausalLM.from_preset(
"gemma_2b_en",
)
# Load a Bert classification task.
model = keras_hub.models.TextClassifier.from_preset(
"bert_base_en",
num_classes=2,
)
Preset name | Parameters | Description |
---|---|---|
densenet_121_imagenet | 7.04M | 121-layer DenseNet model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
densenet_169_imagenet | 12.64M | 169-layer DenseNet model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
densenet_201_imagenet | 18.32M | 201-layer DenseNet model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
vgg_11_imagenet | 9.22M | 11-layer vgg model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
vgg_13_imagenet | 9.40M | 13-layer vgg model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
vgg_16_imagenet | 14.71M | 16-layer vgg model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
vgg_19_imagenet | 20.02M | 19-layer vgg model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
mit_b0_ade20k_512 | 3.32M | MiT (MixTransformer) model with 8 transformer blocks. |
mit_b1_ade20k_512 | 13.16M | MiT (MixTransformer) model with 8 transformer blocks. |
mit_b2_ade20k_512 | 24.20M | MiT (MixTransformer) model with 16 transformer blocks. |
mit_b3_ade20k_512 | 44.08M | MiT (MixTransformer) model with 28 transformer blocks. |
mit_b4_ade20k_512 | 60.85M | MiT (MixTransformer) model with 41 transformer blocks. |
mit_b5_ade20k_640 | 81.45M | MiT (MixTransformer) model with 52 transformer blocks. |
mit_b0_cityscapes_1024 | 3.32M | MiT (MixTransformer) model with 8 transformer blocks. |
mit_b1_cityscapes_1024 | 13.16M | MiT (MixTransformer) model with 8 transformer blocks. |
mit_b2_cityscapes_1024 | 24.20M | MiT (MixTransformer) model with 16 transformer blocks. |
mit_b3_cityscapes_1024 | 44.08M | MiT (MixTransformer) model with 28 transformer blocks. |
mit_b4_cityscapes_1024 | 60.85M | MiT (MixTransformer) model with 41 transformer blocks. |
mit_b5_cityscapes_1024 | 81.45M | MiT (MixTransformer) model with 52 transformer blocks. |
resnet_18_imagenet | 11.19M | 18-layer ResNet model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_50_imagenet | 23.56M | 50-layer ResNet model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_101_imagenet | 42.61M | 101-layer ResNet model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_152_imagenet | 58.30M | 152-layer ResNet model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_v2_50_imagenet | 23.56M | 50-layer ResNetV2 model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_v2_101_imagenet | 42.61M | 101-layer ResNetV2 model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_vd_18_imagenet | 11.72M | 18-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_vd_34_imagenet | 21.84M | 34-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_vd_50_imagenet | 25.63M | 50-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_vd_50_ssld_imagenet | 25.63M | 50-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution with knowledge distillation. |
resnet_vd_50_ssld_v2_imagenet | 25.63M | 50-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution with knowledge distillation and AutoAugment. |
resnet_vd_50_ssld_v2_fix_imagenet | 25.63M | 50-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution with knowledge distillation, AutoAugment and additional fine-tuning of the classification head. |
resnet_vd_101_imagenet | 44.67M | 101-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_vd_101_ssld_imagenet | 44.67M | 101-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution with knowledge distillation. |
resnet_vd_152_imagenet | 60.36M | 152-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
resnet_vd_200_imagenet | 74.93M | 200-layer ResNetVD (ResNet with bag of tricks) model pre-trained on the ImageNet 1k dataset at a 224x224 resolution. |
compile
methodImageClassifier.compile(optimizer="auto", loss="auto", metrics="auto", **kwargs)
Configures the ImageClassifier
task for training.
The ImageClassifier
task extends the default compilation signature of
keras.Model.compile
with defaults for optimizer
, loss
, and
metrics
. To override these defaults, pass any value
to these arguments during compilation.
Arguments
"auto"
, an optimizer name, or a keras.Optimizer
instance. Defaults to "auto"
, which uses the default optimizer
for the given model and task. See keras.Model.compile
and
keras.optimizers
for more info on possible optimizer
values."auto"
, a loss name, or a keras.losses.Loss
instance.
Defaults to "auto"
, where a
keras.losses.SparseCategoricalCrossentropy
loss will be
applied for the classification task. See
keras.Model.compile
and keras.losses
for more info on
possible loss
values."auto"
, or a list of metrics to be evaluated by
the model during training and testing. Defaults to "auto"
,
where a keras.metrics.SparseCategoricalAccuracy
will be
applied to track the accuracy of the model during training.
See keras.Model.compile
and keras.metrics
for
more info on possible metrics
values.keras.Model.compile
for a full list of arguments
supported by the compile method.save_to_preset
methodImageClassifier.save_to_preset(preset_dir)
Save task to a preset directory.
Arguments
preprocessor
propertykeras_hub.models.ImageClassifier.preprocessor
A keras_hub.models.Preprocessor
layer used to preprocess input.
backbone
propertykeras_hub.models.ImageClassifier.backbone
A keras_hub.models.Backbone
model with the core architecture.