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C-Flow

C-Flow#

Cflow.

Real-Time Unsupervised Anomaly Detection via Conditional Normalizing Flows.

For more details, see the paper: Real-Time Unsupervised Anomaly Detection via Conditional Normalizing Flows.

class anomalib.models.image.cflow.lightning_model.Cflow(backbone='wide_resnet50_2', layers=('layer2', 'layer3', 'layer4'), pre_trained=True, fiber_batch_size=64, decoder='freia-cflow', condition_vector=128, coupling_blocks=8, clamp_alpha=1.9, permute_soft=False, lr=0.0001)#

Bases: AnomalyModule

PL Lightning Module for the CFLOW algorithm.

Parameters:

  • backbone (str, optional) – Backbone CNN architecture. Defaults to "wide_resnet50_2".

  • layers (Sequence[str], optional) – Layers to extract features from. Defaults to ("layer2", "layer3", "layer4").

  • pre_trained (bool, optional) – Whether to use pre-trained weights. Defaults to True.

  • fiber_batch_size (int, optional) – Fiber batch size. Defaults to 64.

  • decoder (str, optional) – Decoder architecture. Defaults to "freia-cflow".

  • condition_vector (int, optional) – Condition vector size. Defaults to 128.

  • coupling_blocks (int, optional) – Number of coupling blocks. Defaults to 8.

  • clamp_alpha (float, optional) – Clamping value for the alpha parameter. Defaults to 1.9.

  • permute_soft (bool, optional) – Whether to use soft permutation. Defaults to False.

  • lr (float, optional) – Learning rate. Defaults to 0.0001.

configure_optimizers()#

Configure optimizers for each decoder.

Returns:

Adam optimizer for each decoder

Return type:

Optimizer

property learning_type: LearningType#

Return the learning type of the model.

Returns:

Learning type of the model.

Return type:

LearningType

property trainer_arguments: dict[str, Any]#

C-FLOW specific trainer arguments.

training_step(batch, *args, **kwargs)#

Perform the training step of CFLOW.

For each batch, decoder layers are trained with a dynamic fiber batch size. Training step is performed manually as multiple training steps are involved

per batch of input images

Parameters:

  • batch (dict[str, str | torch.Tensor]) – Input batch

  • *args – Arguments.

  • **kwargs – Keyword arguments.

Return type:

Union[Tensor, Mapping[str, Any], None]

Returns:

Loss value for the batch

validation_step(batch, *args, **kwargs)#

Perform the validation step of CFLOW.

Similar to the training step, encoder features are extracted from the CNN for each batch, and anomaly map is computed.

Parameters:

  • batch (dict[str, str | torch.Tensor]) – Input batch

  • *args – Arguments.

  • **kwargs – Keyword arguments.

Return type:

Union[Tensor, Mapping[str, Any], None]

Returns:

Dictionary containing images, anomaly maps, true labels and masks. These are required in validation_epoch_end for feature concatenation.

PyTorch model for CFlow model implementation.

class anomalib.models.image.cflow.torch_model.CflowModel(backbone, layers, pre_trained=True, fiber_batch_size=64, decoder='freia-cflow', condition_vector=128, coupling_blocks=8, clamp_alpha=1.9, permute_soft=False)#

Bases: Module

CFLOW: Conditional Normalizing Flows.

Parameters:

  • backbone (str) – Backbone CNN architecture.

  • layers (Sequence[str]) – Layers to extract features from.

  • pre_trained (bool) – Whether to use pre-trained weights. Defaults to True.

  • fiber_batch_size (int) – Fiber batch size. Defaults to 64.

  • decoder (str) – Decoder architecture. Defaults to "freia-cflow".

  • condition_vector (int) – Condition vector size. Defaults to 128.

  • coupling_blocks (int) – Number of coupling blocks. Defaults to 8.

  • clamp_alpha (float) – Clamping value for the alpha parameter. Defaults to 1.9.

  • permute_soft (bool) – Whether to use soft permutation. Defaults to False.

forward(images)#

Forward-pass images into the network to extract encoder features and compute probability.

Parameters:

images (Tensor) – Batch of images.

Return type:

Tensor

Returns:

Predicted anomaly maps.

Anomaly Map Generator for CFlow model implementation.

class anomalib.models.image.cflow.anomaly_map.AnomalyMapGenerator(pool_layers)#

Bases: Module

Generate Anomaly Heatmap.

compute_anomaly_map(distribution, height, width, image_size)#

Compute the layer map based on likelihood estimation.

Parameters:

  • distribution (list[torch.Tensor]) – List of likelihoods for each layer.

  • height (list[int]) – List of heights of the feature maps.

  • width (list[int]) – List of widths of the feature maps.

  • image_size (tuple[int, int] | torch.Size | None) – Size of the input image.

Return type:

Tensor

Returns:

Final Anomaly Map

forward(**kwargs)#

Return anomaly_map.

Expects distribution, height and ‘width’ keywords to be passed explicitly

Example

>>> anomaly_map_generator = AnomalyMapGenerator(image_size=tuple(hparams.model.input_size),
>>>        pool_layers=pool_layers)
>>> output = self.anomaly_map_generator(distribution=dist, height=height, width=width)
Raises:

ValueError – distribution, height and ‘width’ keys are not found

Returns:

anomaly map

Return type:

torch.Tensor

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