Shortcuts

Source code for torchvision.models.segmentation.deeplabv3

from functools import partial
from typing import Any, List, Optional

import torch
from torch import nn
from torch.nn import functional as F

from ...transforms._presets import SemanticSegmentation
from .._api import register_model, Weights, WeightsEnum
from .._meta import _VOC_CATEGORIES
from .._utils import _ovewrite_value_param, handle_legacy_interface, IntermediateLayerGetter
from ..mobilenetv3 import mobilenet_v3_large, MobileNet_V3_Large_Weights, MobileNetV3
from ..resnet import ResNet, resnet101, ResNet101_Weights, resnet50, ResNet50_Weights
from ._utils import _SimpleSegmentationModel
from .fcn import FCNHead


__all__ = [
    "DeepLabV3",
    "DeepLabV3_ResNet50_Weights",
    "DeepLabV3_ResNet101_Weights",
    "DeepLabV3_MobileNet_V3_Large_Weights",
    "deeplabv3_mobilenet_v3_large",
    "deeplabv3_resnet50",
    "deeplabv3_resnet101",
]


class DeepLabV3(_SimpleSegmentationModel):
    """
    Implements DeepLabV3 model from
    `"Rethinking Atrous Convolution for Semantic Image Segmentation"
    <https://arxiv.org/abs/1706.05587>`_.

    Args:
        backbone (nn.Module): the network used to compute the features for the model.
            The backbone should return an OrderedDict[Tensor], with the key being
            "out" for the last feature map used, and "aux" if an auxiliary classifier
            is used.
        classifier (nn.Module): module that takes the "out" element returned from
            the backbone and returns a dense prediction.
        aux_classifier (nn.Module, optional): auxiliary classifier used during training
    """

    pass


class DeepLabHead(nn.Sequential):
    def __init__(self, in_channels: int, num_classes: int) -> None:
        super().__init__(
            ASPP(in_channels, [12, 24, 36]),
            nn.Conv2d(256, 256, 3, padding=1, bias=False),
            nn.BatchNorm2d(256),
            nn.ReLU(),
            nn.Conv2d(256, num_classes, 1),
        )


class ASPPConv(nn.Sequential):
    def __init__(self, in_channels: int, out_channels: int, dilation: int) -> None:
        modules = [
            nn.Conv2d(in_channels, out_channels, 3, padding=dilation, dilation=dilation, bias=False),
            nn.BatchNorm2d(out_channels),
            nn.ReLU(),
        ]
        super().__init__(*modules)


class ASPPPooling(nn.Sequential):
    def __init__(self, in_channels: int, out_channels: int) -> None:
        super().__init__(
            nn.AdaptiveAvgPool2d(1),
            nn.Conv2d(in_channels, out_channels, 1, bias=False),
            nn.BatchNorm2d(out_channels),
            nn.ReLU(),
        )

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        size = x.shape[-2:]
        for mod in self:
            x = mod(x)
        return F.interpolate(x, size=size, mode="bilinear", align_corners=False)


class ASPP(nn.Module):
    def __init__(self, in_channels: int, atrous_rates: List[int], out_channels: int = 256) -> None:
        super().__init__()
        modules = []
        modules.append(
            nn.Sequential(nn.Conv2d(in_channels, out_channels, 1, bias=False), nn.BatchNorm2d(out_channels), nn.ReLU())
        )

        rates = tuple(atrous_rates)
        for rate in rates:
            modules.append(ASPPConv(in_channels, out_channels, rate))

        modules.append(ASPPPooling(in_channels, out_channels))

        self.convs = nn.ModuleList(modules)

        self.project = nn.Sequential(
            nn.Conv2d(len(self.convs) * out_channels, out_channels, 1, bias=False),
            nn.BatchNorm2d(out_channels),
            nn.ReLU(),
            nn.Dropout(0.5),
        )

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        _res = []
        for conv in self.convs:
            _res.append(conv(x))
        res = torch.cat(_res, dim=1)
        return self.project(res)


def _deeplabv3_resnet(
    backbone: ResNet,
    num_classes: int,
    aux: Optional[bool],
) -> DeepLabV3:
    return_layers = {"layer4": "out"}
    if aux:
        return_layers["layer3"] = "aux"
    backbone = IntermediateLayerGetter(backbone, return_layers=return_layers)

    aux_classifier = FCNHead(1024, num_classes) if aux else None
    classifier = DeepLabHead(2048, num_classes)
    return DeepLabV3(backbone, classifier, aux_classifier)


_COMMON_META = {
    "categories": _VOC_CATEGORIES,
    "min_size": (1, 1),
    "_docs": """
        These weights were trained on a subset of COCO, using only the 20 categories that are present in the Pascal VOC
        dataset.
    """,
}


[docs]class DeepLabV3_ResNet50_Weights(WeightsEnum): COCO_WITH_VOC_LABELS_V1 = Weights( url="https://download.pytorch.org/models/deeplabv3_resnet50_coco-cd0a2569.pth", transforms=partial(SemanticSegmentation, resize_size=520), meta={ **_COMMON_META, "num_params": 42004074, "recipe": "https://github.com/pytorch/vision/tree/main/references/segmentation#deeplabv3_resnet50", "_metrics": { "COCO-val2017-VOC-labels": { "miou": 66.4, "pixel_acc": 92.4, } }, "_ops": 178.722, "_file_size": 160.515, }, ) DEFAULT = COCO_WITH_VOC_LABELS_V1
[docs]class DeepLabV3_ResNet101_Weights(WeightsEnum): COCO_WITH_VOC_LABELS_V1 = Weights( url="https://download.pytorch.org/models/deeplabv3_resnet101_coco-586e9e4e.pth", transforms=partial(SemanticSegmentation, resize_size=520), meta={ **_COMMON_META, "num_params": 60996202, "recipe": "https://github.com/pytorch/vision/tree/main/references/segmentation#fcn_resnet101", "_metrics": { "COCO-val2017-VOC-labels": { "miou": 67.4, "pixel_acc": 92.4, } }, "_ops": 258.743, "_file_size": 233.217, }, ) DEFAULT = COCO_WITH_VOC_LABELS_V1
[docs]class DeepLabV3_MobileNet_V3_Large_Weights(WeightsEnum): COCO_WITH_VOC_LABELS_V1 = Weights( url="https://download.pytorch.org/models/deeplabv3_mobilenet_v3_large-fc3c493d.pth", transforms=partial(SemanticSegmentation, resize_size=520), meta={ **_COMMON_META, "num_params": 11029328, "recipe": "https://github.com/pytorch/vision/tree/main/references/segmentation#deeplabv3_mobilenet_v3_large", "_metrics": { "COCO-val2017-VOC-labels": { "miou": 60.3, "pixel_acc": 91.2, } }, "_ops": 10.452, "_file_size": 42.301, }, ) DEFAULT = COCO_WITH_VOC_LABELS_V1
def _deeplabv3_mobilenetv3( backbone: MobileNetV3, num_classes: int, aux: Optional[bool], ) -> DeepLabV3: backbone = backbone.features # Gather the indices of blocks which are strided. These are the locations of C1, ..., Cn-1 blocks. # The first and last blocks are always included because they are the C0 (conv1) and Cn. stage_indices = [0] + [i for i, b in enumerate(backbone) if getattr(b, "_is_cn", False)] + [len(backbone) - 1] out_pos = stage_indices[-1] # use C5 which has output_stride = 16 out_inplanes = backbone[out_pos].out_channels aux_pos = stage_indices[-4] # use C2 here which has output_stride = 8 aux_inplanes = backbone[aux_pos].out_channels return_layers = {str(out_pos): "out"} if aux: return_layers[str(aux_pos)] = "aux" backbone = IntermediateLayerGetter(backbone, return_layers=return_layers) aux_classifier = FCNHead(aux_inplanes, num_classes) if aux else None classifier = DeepLabHead(out_inplanes, num_classes) return DeepLabV3(backbone, classifier, aux_classifier)
[docs]@register_model() @handle_legacy_interface( weights=("pretrained", DeepLabV3_ResNet50_Weights.COCO_WITH_VOC_LABELS_V1), weights_backbone=("pretrained_backbone", ResNet50_Weights.IMAGENET1K_V1), ) def deeplabv3_resnet50( *, weights: Optional[DeepLabV3_ResNet50_Weights] = None, progress: bool = True, num_classes: Optional[int] = None, aux_loss: Optional[bool] = None, weights_backbone: Optional[ResNet50_Weights] = ResNet50_Weights.IMAGENET1K_V1, **kwargs: Any, ) -> DeepLabV3: """Constructs a DeepLabV3 model with a ResNet-50 backbone. .. betastatus:: segmentation module Reference: `Rethinking Atrous Convolution for Semantic Image Segmentation <https://arxiv.org/abs/1706.05587>`__. Args: weights (:class:`~torchvision.models.segmentation.DeepLabV3_ResNet50_Weights`, optional): The pretrained weights to use. See :class:`~torchvision.models.segmentation.DeepLabV3_ResNet50_Weights` below for more details, and possible values. By default, no pre-trained weights are used. progress (bool, optional): If True, displays a progress bar of the download to stderr. Default is True. num_classes (int, optional): number of output classes of the model (including the background) aux_loss (bool, optional): If True, it uses an auxiliary loss weights_backbone (:class:`~torchvision.models.ResNet50_Weights`, optional): The pretrained weights for the backbone **kwargs: unused .. autoclass:: torchvision.models.segmentation.DeepLabV3_ResNet50_Weights :members: """ weights = DeepLabV3_ResNet50_Weights.verify(weights) weights_backbone = ResNet50_Weights.verify(weights_backbone) if weights is not None: weights_backbone = None num_classes = _ovewrite_value_param("num_classes", num_classes, len(weights.meta["categories"])) aux_loss = _ovewrite_value_param("aux_loss", aux_loss, True) elif num_classes is None: num_classes = 21 backbone = resnet50(weights=weights_backbone, replace_stride_with_dilation=[False, True, True]) model = _deeplabv3_resnet(backbone, num_classes, aux_loss) if weights is not None: model.load_state_dict(weights.get_state_dict(progress=progress)) return model
[docs]@register_model() @handle_legacy_interface( weights=("pretrained", DeepLabV3_ResNet101_Weights.COCO_WITH_VOC_LABELS_V1), weights_backbone=("pretrained_backbone", ResNet101_Weights.IMAGENET1K_V1), ) def deeplabv3_resnet101( *, weights: Optional[DeepLabV3_ResNet101_Weights] = None, progress: bool = True, num_classes: Optional[int] = None, aux_loss: Optional[bool] = None, weights_backbone: Optional[ResNet101_Weights] = ResNet101_Weights.IMAGENET1K_V1, **kwargs: Any, ) -> DeepLabV3: """Constructs a DeepLabV3 model with a ResNet-101 backbone. .. betastatus:: segmentation module Reference: `Rethinking Atrous Convolution for Semantic Image Segmentation <https://arxiv.org/abs/1706.05587>`__. Args: weights (:class:`~torchvision.models.segmentation.DeepLabV3_ResNet101_Weights`, optional): The pretrained weights to use. See :class:`~torchvision.models.segmentation.DeepLabV3_ResNet101_Weights` below for more details, and possible values. By default, no pre-trained weights are used. progress (bool, optional): If True, displays a progress bar of the download to stderr. Default is True. num_classes (int, optional): number of output classes of the model (including the background) aux_loss (bool, optional): If True, it uses an auxiliary loss weights_backbone (:class:`~torchvision.models.ResNet101_Weights`, optional): The pretrained weights for the backbone **kwargs: unused .. autoclass:: torchvision.models.segmentation.DeepLabV3_ResNet101_Weights :members: """ weights = DeepLabV3_ResNet101_Weights.verify(weights) weights_backbone = ResNet101_Weights.verify(weights_backbone) if weights is not None: weights_backbone = None num_classes = _ovewrite_value_param("num_classes", num_classes, len(weights.meta["categories"])) aux_loss = _ovewrite_value_param("aux_loss", aux_loss, True) elif num_classes is None: num_classes = 21 backbone = resnet101(weights=weights_backbone, replace_stride_with_dilation=[False, True, True]) model = _deeplabv3_resnet(backbone, num_classes, aux_loss) if weights is not None: model.load_state_dict(weights.get_state_dict(progress=progress)) return model
[docs]@register_model() @handle_legacy_interface( weights=("pretrained", DeepLabV3_MobileNet_V3_Large_Weights.COCO_WITH_VOC_LABELS_V1), weights_backbone=("pretrained_backbone", MobileNet_V3_Large_Weights.IMAGENET1K_V1), ) def deeplabv3_mobilenet_v3_large( *, weights: Optional[DeepLabV3_MobileNet_V3_Large_Weights] = None, progress: bool = True, num_classes: Optional[int] = None, aux_loss: Optional[bool] = None, weights_backbone: Optional[MobileNet_V3_Large_Weights] = MobileNet_V3_Large_Weights.IMAGENET1K_V1, **kwargs: Any, ) -> DeepLabV3: """Constructs a DeepLabV3 model with a MobileNetV3-Large backbone. Reference: `Rethinking Atrous Convolution for Semantic Image Segmentation <https://arxiv.org/abs/1706.05587>`__. Args: weights (:class:`~torchvision.models.segmentation.DeepLabV3_MobileNet_V3_Large_Weights`, optional): The pretrained weights to use. See :class:`~torchvision.models.segmentation.DeepLabV3_MobileNet_V3_Large_Weights` below for more details, and possible values. By default, no pre-trained weights are used. progress (bool, optional): If True, displays a progress bar of the download to stderr. Default is True. num_classes (int, optional): number of output classes of the model (including the background) aux_loss (bool, optional): If True, it uses an auxiliary loss weights_backbone (:class:`~torchvision.models.MobileNet_V3_Large_Weights`, optional): The pretrained weights for the backbone **kwargs: unused .. autoclass:: torchvision.models.segmentation.DeepLabV3_MobileNet_V3_Large_Weights :members: """ weights = DeepLabV3_MobileNet_V3_Large_Weights.verify(weights) weights_backbone = MobileNet_V3_Large_Weights.verify(weights_backbone) if weights is not None: weights_backbone = None num_classes = _ovewrite_value_param("num_classes", num_classes, len(weights.meta["categories"])) aux_loss = _ovewrite_value_param("aux_loss", aux_loss, True) elif num_classes is None: num_classes = 21 backbone = mobilenet_v3_large(weights=weights_backbone, dilated=True) model = _deeplabv3_mobilenetv3(backbone, num_classes, aux_loss) if weights is not None: model.load_state_dict(weights.get_state_dict(progress=progress)) return model

Docs

Access comprehensive developer documentation for PyTorch

View Docs

Tutorials

Get in-depth tutorials for beginners and advanced developers

View Tutorials

Resources

Find development resources and get your questions answered

View Resources