完善line_net的结构

models/base/base_detection_net.py

@@ -0,0 +1,118 @@
+"""
+Implements the Generalized R-CNN framework
+"""
+
+import warnings
+from collections import OrderedDict
+from typing import Dict, List, Optional, Tuple, Union
+
+import torch
+from torch import nn, Tensor
+
+from libs.vision_libs.utils import _log_api_usage_once
+
+
+class BaseDetectionNet(nn.Module):
+    """
+    Main class for Generalized R-CNN.
+
+    Args:
+        backbone (nn.Module):
+        rpn (nn.Module):
+        roi_heads (nn.Module): takes the features + the proposals from the RPN and computes
+            detections / masks from it.
+        transform (nn.Module): performs the data transformation from the inputs to feed into
+            the model
+    """
+
+    def __init__(self, backbone: nn.Module, rpn: nn.Module, roi_heads: nn.Module, transform: nn.Module) -> None:
+        super().__init__()
+        _log_api_usage_once(self)
+        self.transform = transform
+        self.backbone = backbone
+        self.rpn = rpn
+        self.roi_heads = roi_heads
+        # used only on torchscript mode
+        self._has_warned = False
+
+    @torch.jit.unused
+    def eager_outputs(self, losses, detections):
+        # type: (Dict[str, Tensor], List[Dict[str, Tensor]]) -> Union[Dict[str, Tensor], List[Dict[str, Tensor]]]
+        if self.training:
+            return losses
+
+        return detections
+
+    def forward(self, images, targets=None):
+        # type: (List[Tensor], Optional[List[Dict[str, Tensor]]]) -> Tuple[Dict[str, Tensor], List[Dict[str, Tensor]]]
+        """
+        Args:
+            images (list[Tensor]): images to be processed
+            targets (list[Dict[str, Tensor]]): ground-truth boxes present in the image (optional)
+
+        Returns:
+            result (list[BoxList] or dict[Tensor]): the output from the model.
+                During training, it returns a dict[Tensor] which contains the losses.
+                During testing, it returns list[BoxList] contains additional fields
+                like `scores`, `labels` and `mask` (for Mask R-CNN models).
+
+        """
+        if self.training:
+            if targets is None:
+                torch._assert(False, "targets should not be none when in training mode")
+            else:
+                for target in targets:
+                    boxes = target["boxes"]
+                    if isinstance(boxes, torch.Tensor):
+                        torch._assert(
+                            len(boxes.shape) == 2 and boxes.shape[-1] == 4,
+                            f"Expected target boxes to be a tensor of shape [N, 4], got {boxes.shape}.",
+                        )
+                    else:
+                        torch._assert(False, f"Expected target boxes to be of type Tensor, got {type(boxes)}.")
+
+        original_image_sizes: List[Tuple[int, int]] = []
+        for img in images:
+            val = img.shape[-2:]
+            torch._assert(
+                len(val) == 2,
+                f"expecting the last two dimensions of the Tensor to be H and W instead got {img.shape[-2:]}",
+            )
+            original_image_sizes.append((val[0], val[1]))
+
+        images, targets = self.transform(images, targets)
+
+        # Check for degenerate boxes
+        # TODO: Move this to a function
+        if targets is not None:
+            for target_idx, target in enumerate(targets):
+                boxes = target["boxes"]
+                degenerate_boxes = boxes[:, 2:] <= boxes[:, :2]
+                if degenerate_boxes.any():
+                    # print the first degenerate box
+                    bb_idx = torch.where(degenerate_boxes.any(dim=1))[0][0]
+                    degen_bb: List[float] = boxes[bb_idx].tolist()
+                    torch._assert(
+                        False,
+                        "All bounding boxes should have positive height and width."
+                        f" Found invalid box {degen_bb} for target at index {target_idx}.",
+                    )
+
+        features = self.backbone(images.tensors)
+        if isinstance(features, torch.Tensor):
+            features = OrderedDict([("0", features)])
+        proposals, proposal_losses = self.rpn(images, features, targets)
+        detections, detector_losses = self.roi_heads(features, proposals, images.image_sizes, targets)
+        detections = self.transform.postprocess(detections, images.image_sizes, original_image_sizes)  # type: ignore[operator]
+
+        losses = {}
+        losses.update(detector_losses)
+        losses.update(proposal_losses)
+
+        if torch.jit.is_scripting():
+            if not self._has_warned:
+                warnings.warn("RCNN always returns a (Losses, Detections) tuple in scripting")
+                self._has_warned = True
+            return losses, detections
+        else:
+            return self.eager_outputs(losses, detections)

models/line_net/LineNet.py

@@ -0,0 +1,843 @@
+from typing import Any, Callable, List, Optional, Tuple, Union
+
+import torch
+import torch.nn.functional as F
+from torch import nn
+from torchvision.ops import MultiScaleRoIAlign
+
+from  libs.vision_libs.ops import misc as misc_nn_ops
+from libs.vision_libs.transforms._presets import ObjectDetection
+from .._api import register_model, Weights, WeightsEnum
+from .._meta import _COCO_CATEGORIES
+from .._utils import _ovewrite_value_param, handle_legacy_interface
+from ..mobilenetv3 import mobilenet_v3_large, MobileNet_V3_Large_Weights
+from ..resnet import resnet50, ResNet50_Weights
+from ._utils import overwrite_eps
+from .anchor_utils import AnchorGenerator
+from .backbone_utils import _mobilenet_extractor, _resnet_fpn_extractor, _validate_trainable_layers
+from .generalized_rcnn import GeneralizedRCNN
+from .roi_heads import RoIHeads
+from .rpn import RegionProposalNetwork, RPNHead
+from .transform import GeneralizedRCNNTransform
+
+
+__all__ = [
+    "FasterRCNN",
+    "FasterRCNN_ResNet50_FPN_Weights",
+    "FasterRCNN_ResNet50_FPN_V2_Weights",
+    "FasterRCNN_MobileNet_V3_Large_FPN_Weights",
+    "FasterRCNN_MobileNet_V3_Large_320_FPN_Weights",
+    "fasterrcnn_resnet50_fpn",
+    "fasterrcnn_resnet50_fpn_v2",
+    "fasterrcnn_mobilenet_v3_large_fpn",
+    "fasterrcnn_mobilenet_v3_large_320_fpn",
+]
+
+
+def _default_anchorgen():
+    anchor_sizes = ((32,), (64,), (128,), (256,), (512,))
+    aspect_ratios = ((0.5, 1.0, 2.0),) * len(anchor_sizes)
+    return AnchorGenerator(anchor_sizes, aspect_ratios)
+
+
+class FasterRCNN(GeneralizedRCNN):
+    """
+    Implements Faster R-CNN.
+
+    The input to the model is expected to be a list of tensors, each of shape [C, H, W], one for each
+    image, and should be in 0-1 range. Different images can have different sizes.
+
+    The behavior of the model changes depending on if it is in training or evaluation mode.
+
+    During training, the model expects both the input tensors and targets (list of dictionary),
+    containing:
+        - boxes (``FloatTensor[N, 4]``): the ground-truth boxes in ``[x1, y1, x2, y2]`` format, with
+          ``0 <= x1 < x2 <= W`` and ``0 <= y1 < y2 <= H``.
+        - labels (Int64Tensor[N]): the class label for each ground-truth box
+
+    The model returns a Dict[Tensor] during training, containing the classification and regression
+    losses for both the RPN and the R-CNN.
+
+    During inference, the model requires only the input tensors, and returns the post-processed
+    predictions as a List[Dict[Tensor]], one for each input image. The fields of the Dict are as
+    follows:
+        - boxes (``FloatTensor[N, 4]``): the predicted boxes in ``[x1, y1, x2, y2]`` format, with
+          ``0 <= x1 < x2 <= W`` and ``0 <= y1 < y2 <= H``.
+        - labels (Int64Tensor[N]): the predicted labels for each image
+        - scores (Tensor[N]): the scores or each prediction
+
+    Args:
+        backbone (nn.Module): the network used to compute the features for the model.
+            It should contain an out_channels attribute, which indicates the number of output
+            channels that each feature map has (and it should be the same for all feature maps).
+            The backbone should return a single Tensor or and OrderedDict[Tensor].
+        num_classes (int): number of output classes of the model (including the background).
+            If box_predictor is specified, num_classes should be None.
+        min_size (int): minimum size of the image to be rescaled before feeding it to the backbone
+        max_size (int): maximum size of the image to be rescaled before feeding it to the backbone
+        image_mean (Tuple[float, float, float]): mean values used for input normalization.
+            They are generally the mean values of the dataset on which the backbone has been trained
+            on
+        image_std (Tuple[float, float, float]): std values used for input normalization.
+            They are generally the std values of the dataset on which the backbone has been trained on
+        rpn_anchor_generator (AnchorGenerator): module that generates the anchors for a set of feature
+            maps.
+        rpn_head (nn.Module): module that computes the objectness and regression deltas from the RPN
+        rpn_pre_nms_top_n_train (int): number of proposals to keep before applying NMS during training
+        rpn_pre_nms_top_n_test (int): number of proposals to keep before applying NMS during testing
+        rpn_post_nms_top_n_train (int): number of proposals to keep after applying NMS during training
+        rpn_post_nms_top_n_test (int): number of proposals to keep after applying NMS during testing
+        rpn_nms_thresh (float): NMS threshold used for postprocessing the RPN proposals
+        rpn_fg_iou_thresh (float): minimum IoU between the anchor and the GT box so that they can be
+            considered as positive during training of the RPN.
+        rpn_bg_iou_thresh (float): maximum IoU between the anchor and the GT box so that they can be
+            considered as negative during training of the RPN.
+        rpn_batch_size_per_image (int): number of anchors that are sampled during training of the RPN
+            for computing the loss
+        rpn_positive_fraction (float): proportion of positive anchors in a mini-batch during training
+            of the RPN
+        rpn_score_thresh (float): during inference, only return proposals with a classification score
+            greater than rpn_score_thresh
+        box_roi_pool (MultiScaleRoIAlign): the module which crops and resizes the feature maps in
+            the locations indicated by the bounding boxes
+        box_head (nn.Module): module that takes the cropped feature maps as input
+        box_predictor (nn.Module): module that takes the output of box_head and returns the
+            classification logits and box regression deltas.
+        box_score_thresh (float): during inference, only return proposals with a classification score
+            greater than box_score_thresh
+        box_nms_thresh (float): NMS threshold for the prediction head. Used during inference
+        box_detections_per_img (int): maximum number of detections per image, for all classes.
+        box_fg_iou_thresh (float): minimum IoU between the proposals and the GT box so that they can be
+            considered as positive during training of the classification head
+        box_bg_iou_thresh (float): maximum IoU between the proposals and the GT box so that they can be
+            considered as negative during training of the classification head
+        box_batch_size_per_image (int): number of proposals that are sampled during training of the
+            classification head
+        box_positive_fraction (float): proportion of positive proposals in a mini-batch during training
+            of the classification head
+        bbox_reg_weights (Tuple[float, float, float, float]): weights for the encoding/decoding of the
+            bounding boxes
+
+    Example::
+
+        >>> import torch
+        >>> import torchvision
+        >>> from torchvision.models.detection import FasterRCNN
+        >>> from torchvision.models.detection.rpn import AnchorGenerator
+        >>> # load a pre-trained model for classification and return
+        >>> # only the features
+        >>> backbone = torchvision.models.mobilenet_v2(weights=MobileNet_V2_Weights.DEFAULT).features
+        >>> # FasterRCNN needs to know the number of
+        >>> # output channels in a backbone. For mobilenet_v2, it's 1280,
+        >>> # so we need to add it here
+        >>> backbone.out_channels = 1280
+        >>>
+        >>> # let's make the RPN generate 5 x 3 anchors per spatial
+        >>> # location, with 5 different sizes and 3 different aspect
+        >>> # ratios. We have a Tuple[Tuple[int]] because each feature
+        >>> # map could potentially have different sizes and
+        >>> # aspect ratios
+        >>> anchor_generator = AnchorGenerator(sizes=((32, 64, 128, 256, 512),),
+        >>>                                    aspect_ratios=((0.5, 1.0, 2.0),))
+        >>>
+        >>> # let's define what are the feature maps that we will
+        >>> # use to perform the region of interest cropping, as well as
+        >>> # the size of the crop after rescaling.
+        >>> # if your backbone returns a Tensor, featmap_names is expected to
+        >>> # be ['0']. More generally, the backbone should return an
+        >>> # OrderedDict[Tensor], and in featmap_names you can choose which
+        >>> # feature maps to use.
+        >>> roi_pooler = torchvision.ops.MultiScaleRoIAlign(featmap_names=['0'],
+        >>>                                                 output_size=7,
+        >>>                                                 sampling_ratio=2)
+        >>>
+        >>> # put the pieces together inside a FasterRCNN model
+        >>> model = FasterRCNN(backbone,
+        >>>                    num_classes=2,
+        >>>                    rpn_anchor_generator=anchor_generator,
+        >>>                    box_roi_pool=roi_pooler)
+        >>> model.eval()
+        >>> x = [torch.rand(3, 300, 400), torch.rand(3, 500, 400)]
+        >>> predictions = model(x)
+    """
+
+    def __init__(
+        self,
+        backbone,
+        num_classes=None,
+        # transform parameters
+        min_size=512,
+        max_size=1333,
+        image_mean=None,
+        image_std=None,
+        # RPN parameters
+        rpn_anchor_generator=None,
+        rpn_head=None,
+        rpn_pre_nms_top_n_train=2000,
+        rpn_pre_nms_top_n_test=1000,
+        rpn_post_nms_top_n_train=2000,
+        rpn_post_nms_top_n_test=1000,
+        rpn_nms_thresh=0.7,
+        rpn_fg_iou_thresh=0.7,
+        rpn_bg_iou_thresh=0.3,
+        rpn_batch_size_per_image=256,
+        rpn_positive_fraction=0.5,
+        rpn_score_thresh=0.0,
+        # Box parameters
+        box_roi_pool=None,
+        box_head=None,
+        box_predictor=None,
+        box_score_thresh=0.05,
+        box_nms_thresh=0.5,
+        box_detections_per_img=100,
+        box_fg_iou_thresh=0.5,
+        box_bg_iou_thresh=0.5,
+        box_batch_size_per_image=512,
+        box_positive_fraction=0.25,
+        bbox_reg_weights=None,
+        **kwargs,
+    ):
+
+        if not hasattr(backbone, "out_channels"):
+            raise ValueError(
+                "backbone should contain an attribute out_channels "
+                "specifying the number of output channels (assumed to be the "
+                "same for all the levels)"
+            )
+
+        if not isinstance(rpn_anchor_generator, (AnchorGenerator, type(None))):
+            raise TypeError(
+                f"rpn_anchor_generator should be of type AnchorGenerator or None instead of {type(rpn_anchor_generator)}"
+            )
+        if not isinstance(box_roi_pool, (MultiScaleRoIAlign, type(None))):
+            raise TypeError(
+                f"box_roi_pool should be of type MultiScaleRoIAlign or None instead of {type(box_roi_pool)}"
+            )
+
+        if num_classes is not None:
+            if box_predictor is not None:
+                raise ValueError("num_classes should be None when box_predictor is specified")
+        else:
+            if box_predictor is None:
+                raise ValueError("num_classes should not be None when box_predictor is not specified")
+
+        out_channels = backbone.out_channels
+
+        if rpn_anchor_generator is None:
+            rpn_anchor_generator = _default_anchorgen()
+        if rpn_head is None:
+            rpn_head = RPNHead(out_channels, rpn_anchor_generator.num_anchors_per_location()[0])
+
+        rpn_pre_nms_top_n = dict(training=rpn_pre_nms_top_n_train, testing=rpn_pre_nms_top_n_test)
+        rpn_post_nms_top_n = dict(training=rpn_post_nms_top_n_train, testing=rpn_post_nms_top_n_test)
+
+        rpn = RegionProposalNetwork(
+            rpn_anchor_generator,
+            rpn_head,
+            rpn_fg_iou_thresh,
+            rpn_bg_iou_thresh,
+            rpn_batch_size_per_image,
+            rpn_positive_fraction,
+            rpn_pre_nms_top_n,
+            rpn_post_nms_top_n,
+            rpn_nms_thresh,
+            score_thresh=rpn_score_thresh,
+        )
+
+        if box_roi_pool is None:
+            box_roi_pool = MultiScaleRoIAlign(featmap_names=["0", "1", "2", "3"], output_size=7, sampling_ratio=2)
+
+        if box_head is None:
+            resolution = box_roi_pool.output_size[0]
+            representation_size = 1024
+            box_head = TwoMLPHead(out_channels * resolution**2, representation_size)
+
+        if box_predictor is None:
+            representation_size = 1024
+            box_predictor = FastRCNNPredictor(representation_size, num_classes)
+
+        roi_heads = RoIHeads(
+            # Box
+            box_roi_pool,
+            box_head,
+            box_predictor,
+            box_fg_iou_thresh,
+            box_bg_iou_thresh,
+            box_batch_size_per_image,
+            box_positive_fraction,
+            bbox_reg_weights,
+            box_score_thresh,
+            box_nms_thresh,
+            box_detections_per_img,
+        )
+
+        if image_mean is None:
+            image_mean = [0.485, 0.456, 0.406]
+        if image_std is None:
+            image_std = [0.229, 0.224, 0.225]
+        transform = GeneralizedRCNNTransform(min_size, max_size, image_mean, image_std, **kwargs)
+
+        super().__init__(backbone, rpn, roi_heads, transform)
+
+
+class TwoMLPHead(nn.Module):
+    """
+    Standard heads for FPN-based models
+
+    Args:
+        in_channels (int): number of input channels
+        representation_size (int): size of the intermediate representation
+    """
+
+    def __init__(self, in_channels, representation_size):
+        super().__init__()
+
+        self.fc6 = nn.Linear(in_channels, representation_size)
+        self.fc7 = nn.Linear(representation_size, representation_size)
+
+    def forward(self, x):
+        x = x.flatten(start_dim=1)
+
+        x = F.relu(self.fc6(x))
+        x = F.relu(self.fc7(x))
+
+        return x
+
+
+class FastRCNNConvFCHead(nn.Sequential):
+    def __init__(
+        self,
+        input_size: Tuple[int, int, int],
+        conv_layers: List[int],
+        fc_layers: List[int],
+        norm_layer: Optional[Callable[..., nn.Module]] = None,
+    ):
+        """
+        Args:
+            input_size (Tuple[int, int, int]): the input size in CHW format.
+            conv_layers (list): feature dimensions of each Convolution layer
+            fc_layers (list): feature dimensions of each FCN layer
+            norm_layer (callable, optional): Module specifying the normalization layer to use. Default: None
+        """
+        in_channels, in_height, in_width = input_size
+
+        blocks = []
+        previous_channels = in_channels
+        for current_channels in conv_layers:
+            blocks.append(misc_nn_ops.Conv2dNormActivation(previous_channels, current_channels, norm_layer=norm_layer))
+            previous_channels = current_channels
+        blocks.append(nn.Flatten())
+        previous_channels = previous_channels * in_height * in_width
+        for current_channels in fc_layers:
+            blocks.append(nn.Linear(previous_channels, current_channels))
+            blocks.append(nn.ReLU(inplace=True))
+            previous_channels = current_channels
+
+        super().__init__(*blocks)
+        for layer in self.modules():
+            if isinstance(layer, nn.Conv2d):
+                nn.init.kaiming_normal_(layer.weight, mode="fan_out", nonlinearity="relu")
+                if layer.bias is not None:
+                    nn.init.zeros_(layer.bias)
+
+
+class FastRCNNPredictor(nn.Module):
+    """
+    Standard classification + bounding box regression layers
+    for Fast R-CNN.
+
+    Args:
+        in_channels (int): number of input channels
+        num_classes (int): number of output classes (including background)
+    """
+
+    def __init__(self, in_channels, num_classes):
+        super().__init__()
+        self.cls_score = nn.Linear(in_channels, num_classes)
+        self.bbox_pred = nn.Linear(in_channels, num_classes * 4)
+
+    def forward(self, x):
+        if x.dim() == 4:
+            torch._assert(
+                list(x.shape[2:]) == [1, 1],
+                f"x has the wrong shape, expecting the last two dimensions to be [1,1] instead of {list(x.shape[2:])}",
+            )
+        x = x.flatten(start_dim=1)
+        scores = self.cls_score(x)
+        bbox_deltas = self.bbox_pred(x)
+
+        return scores, bbox_deltas
+
+
+_COMMON_META = {
+    "categories": _COCO_CATEGORIES,
+    "min_size": (1, 1),
+}
+
+
+class FasterRCNN_ResNet50_FPN_Weights(WeightsEnum):
+    COCO_V1 = Weights(
+        url="https://download.pytorch.org/models/fasterrcnn_resnet50_fpn_coco-258fb6c6.pth",
+        transforms=ObjectDetection,
+        meta={
+            **_COMMON_META,
+            "num_params": 41755286,
+            "recipe": "https://github.com/pytorch/vision/tree/main/references/detection#faster-r-cnn-resnet-50-fpn",
+            "_metrics": {
+                "COCO-val2017": {
+                    "box_map": 37.0,
+                }
+            },
+            "_ops": 134.38,
+            "_file_size": 159.743,
+            "_docs": """These weights were produced by following a similar training recipe as on the paper.""",
+        },
+    )
+    DEFAULT = COCO_V1
+
+
+class FasterRCNN_ResNet50_FPN_V2_Weights(WeightsEnum):
+    COCO_V1 = Weights(
+        url="https://download.pytorch.org/models/fasterrcnn_resnet50_fpn_v2_coco-dd69338a.pth",
+        transforms=ObjectDetection,
+        meta={
+            **_COMMON_META,
+            "num_params": 43712278,
+            "recipe": "https://github.com/pytorch/vision/pull/5763",
+            "_metrics": {
+                "COCO-val2017": {
+                    "box_map": 46.7,
+                }
+            },
+            "_ops": 280.371,
+            "_file_size": 167.104,
+            "_docs": """These weights were produced using an enhanced training recipe to boost the model accuracy.""",
+        },
+    )
+    DEFAULT = COCO_V1
+
+
+class FasterRCNN_MobileNet_V3_Large_FPN_Weights(WeightsEnum):
+    COCO_V1 = Weights(
+        url="https://download.pytorch.org/models/fasterrcnn_mobilenet_v3_large_fpn-fb6a3cc7.pth",
+        transforms=ObjectDetection,
+        meta={
+            **_COMMON_META,
+            "num_params": 19386354,
+            "recipe": "https://github.com/pytorch/vision/tree/main/references/detection#faster-r-cnn-mobilenetv3-large-fpn",
+            "_metrics": {
+                "COCO-val2017": {
+                    "box_map": 32.8,
+                }
+            },
+            "_ops": 4.494,
+            "_file_size": 74.239,
+            "_docs": """These weights were produced by following a similar training recipe as on the paper.""",
+        },
+    )
+    DEFAULT = COCO_V1
+
+
+class FasterRCNN_MobileNet_V3_Large_320_FPN_Weights(WeightsEnum):
+    COCO_V1 = Weights(
+        url="https://download.pytorch.org/models/fasterrcnn_mobilenet_v3_large_320_fpn-907ea3f9.pth",
+        transforms=ObjectDetection,
+        meta={
+            **_COMMON_META,
+            "num_params": 19386354,
+            "recipe": "https://github.com/pytorch/vision/tree/main/references/detection#faster-r-cnn-mobilenetv3-large-320-fpn",
+            "_metrics": {
+                "COCO-val2017": {
+                    "box_map": 22.8,
+                }
+            },
+            "_ops": 0.719,
+            "_file_size": 74.239,
+            "_docs": """These weights were produced by following a similar training recipe as on the paper.""",
+        },
+    )
+    DEFAULT = COCO_V1
+
+
+@register_model()
+@handle_legacy_interface(
+    weights=("pretrained", FasterRCNN_ResNet50_FPN_Weights.COCO_V1),
+    weights_backbone=("pretrained_backbone", ResNet50_Weights.IMAGENET1K_V1),
+)
+def fasterrcnn_resnet50_fpn(
+    *,
+    weights: Optional[FasterRCNN_ResNet50_FPN_Weights] = None,
+    progress: bool = True,
+    num_classes: Optional[int] = None,
+    weights_backbone: Optional[ResNet50_Weights] = ResNet50_Weights.IMAGENET1K_V1,
+    trainable_backbone_layers: Optional[int] = None,
+    **kwargs: Any,
+) -> FasterRCNN:
+    """
+    Faster R-CNN model with a ResNet-50-FPN backbone from the `Faster R-CNN: Towards Real-Time Object
+    Detection with Region Proposal Networks <https://arxiv.org/abs/1506.01497>`__
+    paper.
+
+    .. betastatus:: detection module
+
+    The input to the model is expected to be a list of tensors, each of shape ``[C, H, W]``, one for each
+    image, and should be in ``0-1`` range. Different images can have different sizes.
+
+    The behavior of the model changes depending on if it is in training or evaluation mode.
+
+    During training, the model expects both the input tensors and a targets (list of dictionary),
+    containing:
+
+        - boxes (``FloatTensor[N, 4]``): the ground-truth boxes in ``[x1, y1, x2, y2]`` format, with
+          ``0 <= x1 < x2 <= W`` and ``0 <= y1 < y2 <= H``.
+        - labels (``Int64Tensor[N]``): the class label for each ground-truth box
+
+    The model returns a ``Dict[Tensor]`` during training, containing the classification and regression
+    losses for both the RPN and the R-CNN.
+
+    During inference, the model requires only the input tensors, and returns the post-processed
+    predictions as a ``List[Dict[Tensor]]``, one for each input image. The fields of the ``Dict`` are as
+    follows, where ``N`` is the number of detections:
+
+        - boxes (``FloatTensor[N, 4]``): the predicted boxes in ``[x1, y1, x2, y2]`` format, with
+          ``0 <= x1 < x2 <= W`` and ``0 <= y1 < y2 <= H``.
+        - labels (``Int64Tensor[N]``): the predicted labels for each detection
+        - scores (``Tensor[N]``): the scores of each detection
+
+    For more details on the output, you may refer to :ref:`instance_seg_output`.
+
+    Faster R-CNN is exportable to ONNX for a fixed batch size with inputs images of fixed size.
+
+    Example::
+
+        >>> model = torchvision.models.detection.fasterrcnn_resnet50_fpn(weights=FasterRCNN_ResNet50_FPN_Weights.DEFAULT)
+        >>> # For training
+        >>> images, boxes = torch.rand(4, 3, 600, 1200), torch.rand(4, 11, 4)
+        >>> boxes[:, :, 2:4] = boxes[:, :, 0:2] + boxes[:, :, 2:4]
+        >>> labels = torch.randint(1, 91, (4, 11))
+        >>> images = list(image for image in images)
+        >>> targets = []
+        >>> for i in range(len(images)):
+        >>>     d = {}
+        >>>     d['boxes'] = boxes[i]
+        >>>     d['labels'] = labels[i]
+        >>>     targets.append(d)
+        >>> output = model(images, targets)
+        >>> # For inference
+        >>> model.eval()
+        >>> x = [torch.rand(3, 300, 400), torch.rand(3, 500, 400)]
+        >>> predictions = model(x)
+        >>>
+        >>> # optionally, if you want to export the model to ONNX:
+        >>> torch.onnx.export(model, x, "faster_rcnn.onnx", opset_version = 11)
+
+    Args:
+        weights (:class:`~torchvision.models.detection.FasterRCNN_ResNet50_FPN_Weights`, optional): The
+            pretrained weights to use. See
+            :class:`~torchvision.models.detection.FasterRCNN_ResNet50_FPN_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)
+        weights_backbone (:class:`~torchvision.models.ResNet50_Weights`, optional): The
+            pretrained weights for the backbone.
+        trainable_backbone_layers (int, optional): number of trainable (not frozen) layers starting from
+            final block. Valid values are between 0 and 5, with 5 meaning all backbone layers are
+            trainable. If ``None`` is passed (the default) this value is set to 3.
+        **kwargs: parameters passed to the ``torchvision.models.detection.faster_rcnn.FasterRCNN``
+            base class. Please refer to the `source code
+            <https://github.com/pytorch/vision/blob/main/torchvision/models/detection/faster_rcnn.py>`_
+            for more details about this class.
+
+    .. autoclass:: torchvision.models.detection.FasterRCNN_ResNet50_FPN_Weights
+        :members:
+    """
+    weights = FasterRCNN_ResNet50_FPN_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"]))
+    elif num_classes is None:
+        num_classes = 91
+
+    is_trained = weights is not None or weights_backbone is not None
+    trainable_backbone_layers = _validate_trainable_layers(is_trained, trainable_backbone_layers, 5, 3)
+    norm_layer = misc_nn_ops.FrozenBatchNorm2d if is_trained else nn.BatchNorm2d
+
+    backbone = resnet50(weights=weights_backbone, progress=progress, norm_layer=norm_layer)
+    backbone = _resnet_fpn_extractor(backbone, trainable_backbone_layers)
+    model = FasterRCNN(backbone, num_classes=num_classes, **kwargs)
+
+    if weights is not None:
+        model.load_state_dict(weights.get_state_dict(progress=progress, check_hash=True))
+        if weights == FasterRCNN_ResNet50_FPN_Weights.COCO_V1:
+            overwrite_eps(model, 0.0)
+
+    return model
+
+
+@register_model()
+@handle_legacy_interface(
+    weights=("pretrained", FasterRCNN_ResNet50_FPN_V2_Weights.COCO_V1),
+    weights_backbone=("pretrained_backbone", ResNet50_Weights.IMAGENET1K_V1),
+)
+def fasterrcnn_resnet50_fpn_v2(
+    *,
+    weights: Optional[FasterRCNN_ResNet50_FPN_V2_Weights] = None,
+    progress: bool = True,
+    num_classes: Optional[int] = None,
+    weights_backbone: Optional[ResNet50_Weights] = None,
+    trainable_backbone_layers: Optional[int] = None,
+    **kwargs: Any,
+) -> FasterRCNN:
+    """
+    Constructs an improved Faster R-CNN model with a ResNet-50-FPN backbone from `Benchmarking Detection
+    Transfer Learning with Vision Transformers <https://arxiv.org/abs/2111.11429>`__ paper.
+
+    .. betastatus:: detection module
+
+    It works similarly to Faster R-CNN with ResNet-50 FPN backbone. See
+    :func:`~torchvision.models.detection.fasterrcnn_resnet50_fpn` for more
+    details.
+
+    Args:
+        weights (:class:`~torchvision.models.detection.FasterRCNN_ResNet50_FPN_V2_Weights`, optional): The
+            pretrained weights to use. See
+            :class:`~torchvision.models.detection.FasterRCNN_ResNet50_FPN_V2_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)
+        weights_backbone (:class:`~torchvision.models.ResNet50_Weights`, optional): The
+            pretrained weights for the backbone.
+        trainable_backbone_layers (int, optional): number of trainable (not frozen) layers starting from
+            final block. Valid values are between 0 and 5, with 5 meaning all backbone layers are
+            trainable. If ``None`` is passed (the default) this value is set to 3.
+        **kwargs: parameters passed to the ``torchvision.models.detection.faster_rcnn.FasterRCNN``
+            base class. Please refer to the `source code
+            <https://github.com/pytorch/vision/blob/main/torchvision/models/detection/faster_rcnn.py>`_
+            for more details about this class.
+
+    .. autoclass:: torchvision.models.detection.FasterRCNN_ResNet50_FPN_V2_Weights
+        :members:
+    """
+    weights = FasterRCNN_ResNet50_FPN_V2_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"]))
+    elif num_classes is None:
+        num_classes = 91
+
+    is_trained = weights is not None or weights_backbone is not None
+    trainable_backbone_layers = _validate_trainable_layers(is_trained, trainable_backbone_layers, 5, 3)
+
+    backbone = resnet50(weights=weights_backbone, progress=progress)
+    backbone = _resnet_fpn_extractor(backbone, trainable_backbone_layers, norm_layer=nn.BatchNorm2d)
+    rpn_anchor_generator = _default_anchorgen()
+    rpn_head = RPNHead(backbone.out_channels, rpn_anchor_generator.num_anchors_per_location()[0], conv_depth=2)
+    box_head = FastRCNNConvFCHead(
+        (backbone.out_channels, 7, 7), [256, 256, 256, 256], [1024], norm_layer=nn.BatchNorm2d
+    )
+    model = FasterRCNN(
+        backbone,
+        num_classes=num_classes,
+        rpn_anchor_generator=rpn_anchor_generator,
+        rpn_head=rpn_head,
+        box_head=box_head,
+        **kwargs,
+    )
+
+    if weights is not None:
+        model.load_state_dict(weights.get_state_dict(progress=progress, check_hash=True))
+
+    return model
+
+
+def _fasterrcnn_mobilenet_v3_large_fpn(
+    *,
+    weights: Optional[Union[FasterRCNN_MobileNet_V3_Large_FPN_Weights, FasterRCNN_MobileNet_V3_Large_320_FPN_Weights]],
+    progress: bool,
+    num_classes: Optional[int],
+    weights_backbone: Optional[MobileNet_V3_Large_Weights],
+    trainable_backbone_layers: Optional[int],
+    **kwargs: Any,
+) -> FasterRCNN:
+    if weights is not None:
+        weights_backbone = None
+        num_classes = _ovewrite_value_param("num_classes", num_classes, len(weights.meta["categories"]))
+    elif num_classes is None:
+        num_classes = 91
+
+    is_trained = weights is not None or weights_backbone is not None
+    trainable_backbone_layers = _validate_trainable_layers(is_trained, trainable_backbone_layers, 6, 3)
+    norm_layer = misc_nn_ops.FrozenBatchNorm2d if is_trained else nn.BatchNorm2d
+
+    backbone = mobilenet_v3_large(weights=weights_backbone, progress=progress, norm_layer=norm_layer)
+    backbone = _mobilenet_extractor(backbone, True, trainable_backbone_layers)
+    anchor_sizes = (
+        (
+            32,
+            64,
+            128,
+            256,
+            512,
+        ),
+    ) * 3
+    aspect_ratios = ((0.5, 1.0, 2.0),) * len(anchor_sizes)
+    model = FasterRCNN(
+        backbone, num_classes, rpn_anchor_generator=AnchorGenerator(anchor_sizes, aspect_ratios), **kwargs
+    )
+
+    if weights is not None:
+        model.load_state_dict(weights.get_state_dict(progress=progress, check_hash=True))
+
+    return model
+
+
+@register_model()
+@handle_legacy_interface(
+    weights=("pretrained", FasterRCNN_MobileNet_V3_Large_320_FPN_Weights.COCO_V1),
+    weights_backbone=("pretrained_backbone", MobileNet_V3_Large_Weights.IMAGENET1K_V1),
+)
+def fasterrcnn_mobilenet_v3_large_320_fpn(
+    *,
+    weights: Optional[FasterRCNN_MobileNet_V3_Large_320_FPN_Weights] = None,
+    progress: bool = True,
+    num_classes: Optional[int] = None,
+    weights_backbone: Optional[MobileNet_V3_Large_Weights] = MobileNet_V3_Large_Weights.IMAGENET1K_V1,
+    trainable_backbone_layers: Optional[int] = None,
+    **kwargs: Any,
+) -> FasterRCNN:
+    """
+    Low resolution Faster R-CNN model with a MobileNetV3-Large backbone tuned for mobile use cases.
+
+    .. betastatus:: detection module
+
+    It works similarly to Faster R-CNN with ResNet-50 FPN backbone. See
+    :func:`~torchvision.models.detection.fasterrcnn_resnet50_fpn` for more
+    details.
+
+    Example::
+
+        >>> model = torchvision.models.detection.fasterrcnn_mobilenet_v3_large_320_fpn(weights=FasterRCNN_MobileNet_V3_Large_320_FPN_Weights.DEFAULT)
+        >>> model.eval()
+        >>> x = [torch.rand(3, 300, 400), torch.rand(3, 500, 400)]
+        >>> predictions = model(x)
+
+    Args:
+        weights (:class:`~torchvision.models.detection.FasterRCNN_MobileNet_V3_Large_320_FPN_Weights`, optional): The
+            pretrained weights to use. See
+            :class:`~torchvision.models.detection.FasterRCNN_MobileNet_V3_Large_320_FPN_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)
+        weights_backbone (:class:`~torchvision.models.MobileNet_V3_Large_Weights`, optional): The
+            pretrained weights for the backbone.
+        trainable_backbone_layers (int, optional): number of trainable (not frozen) layers starting from
+            final block. Valid values are between 0 and 6, with 6 meaning all backbone layers are
+            trainable. If ``None`` is passed (the default) this value is set to 3.
+        **kwargs: parameters passed to the ``torchvision.models.detection.faster_rcnn.FasterRCNN``
+            base class. Please refer to the `source code
+            <https://github.com/pytorch/vision/blob/main/torchvision/models/detection/faster_rcnn.py>`_
+            for more details about this class.
+
+    .. autoclass:: torchvision.models.detection.FasterRCNN_MobileNet_V3_Large_320_FPN_Weights
+        :members:
+    """
+    weights = FasterRCNN_MobileNet_V3_Large_320_FPN_Weights.verify(weights)
+    weights_backbone = MobileNet_V3_Large_Weights.verify(weights_backbone)
+
+    defaults = {
+        "min_size": 320,
+        "max_size": 640,
+        "rpn_pre_nms_top_n_test": 150,
+        "rpn_post_nms_top_n_test": 150,
+        "rpn_score_thresh": 0.05,
+    }
+
+    kwargs = {**defaults, **kwargs}
+    return _fasterrcnn_mobilenet_v3_large_fpn(
+        weights=weights,
+        progress=progress,
+        num_classes=num_classes,
+        weights_backbone=weights_backbone,
+        trainable_backbone_layers=trainable_backbone_layers,
+        **kwargs,
+    )
+
+
+@register_model()
+@handle_legacy_interface(
+    weights=("pretrained", FasterRCNN_MobileNet_V3_Large_FPN_Weights.COCO_V1),
+    weights_backbone=("pretrained_backbone", MobileNet_V3_Large_Weights.IMAGENET1K_V1),
+)
+def fasterrcnn_mobilenet_v3_large_fpn(
+    *,
+    weights: Optional[FasterRCNN_MobileNet_V3_Large_FPN_Weights] = None,
+    progress: bool = True,
+    num_classes: Optional[int] = None,
+    weights_backbone: Optional[MobileNet_V3_Large_Weights] = MobileNet_V3_Large_Weights.IMAGENET1K_V1,
+    trainable_backbone_layers: Optional[int] = None,
+    **kwargs: Any,
+) -> FasterRCNN:
+    """
+    Constructs a high resolution Faster R-CNN model with a MobileNetV3-Large FPN backbone.
+
+    .. betastatus:: detection module
+
+    It works similarly to Faster R-CNN with ResNet-50 FPN backbone. See
+    :func:`~torchvision.models.detection.fasterrcnn_resnet50_fpn` for more
+    details.
+
+    Example::
+
+        >>> model = torchvision.models.detection.fasterrcnn_mobilenet_v3_large_fpn(weights=FasterRCNN_MobileNet_V3_Large_FPN_Weights.DEFAULT)
+        >>> model.eval()
+        >>> x = [torch.rand(3, 300, 400), torch.rand(3, 500, 400)]
+        >>> predictions = model(x)
+
+    Args:
+        weights (:class:`~torchvision.models.detection.FasterRCNN_MobileNet_V3_Large_FPN_Weights`, optional): The
+            pretrained weights to use. See
+            :class:`~torchvision.models.detection.FasterRCNN_MobileNet_V3_Large_FPN_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)
+        weights_backbone (:class:`~torchvision.models.MobileNet_V3_Large_Weights`, optional): The
+            pretrained weights for the backbone.
+        trainable_backbone_layers (int, optional): number of trainable (not frozen) layers starting from
+            final block. Valid values are between 0 and 6, with 6 meaning all backbone layers are
+            trainable. If ``None`` is passed (the default) this value is set to 3.
+        **kwargs: parameters passed to the ``torchvision.models.detection.faster_rcnn.FasterRCNN``
+            base class. Please refer to the `source code
+            <https://github.com/pytorch/vision/blob/main/torchvision/models/detection/faster_rcnn.py>`_
+            for more details about this class.
+
+    .. autoclass:: torchvision.models.detection.FasterRCNN_MobileNet_V3_Large_FPN_Weights
+        :members:
+    """
+    weights = FasterRCNN_MobileNet_V3_Large_FPN_Weights.verify(weights)
+    weights_backbone = MobileNet_V3_Large_Weights.verify(weights_backbone)
+
+    defaults = {
+        "rpn_score_thresh": 0.05,
+    }
+
+    kwargs = {**defaults, **kwargs}
+    return _fasterrcnn_mobilenet_v3_large_fpn(
+        weights=weights,
+        progress=progress,
+        num_classes=num_classes,
+        weights_backbone=weights_backbone,
+        trainable_backbone_layers=trainable_backbone_layers,
+        **kwargs,
+    )