Add RetinaNet Object detection with Backbones (#529)

* refactor frcnn
* start adding retina
* complete Retinanet
* update requirments
* Apply suggestions from code review
* Set pytorch-lightning>=1.4.0
* Use LightningCLI

Co-authored-by: Akihiro Nitta <nitta@akihironitta.com>
Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Jirka <jirka.borovec@seznam.cz>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Nicki Skafte <skaftenicki@gmail.com>
Co-authored-by: praecipue <43908213+praecipue@users.noreply.github.com>

CHANGELOG.md

@@ -17,6 +17,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added nn.Module support for FasterRCNN backbone ([#661](https://github.com/PyTorchLightning/lightning-bolts/pull/661))
 
 
+- Added `RetinaNet` with torchvision backbones ([#529](https://github.com/PyTorchLightning/lightning-bolts/pull/529))
+
+
 - Added Python 3.9 support ([#786](https://github.com/PyTorchLightning/lightning-bolts/pull/786))
 
 

docs/source/deprecated/models/object_detection.rst

@@ -13,6 +13,14 @@ Faster R-CNN
 
 -------------
 
+RetinaNet
+---------
+
+.. autoclass:: pl_bolts.models.detection.retinanet.retinanet_module.RetinaNet
+    :noindex:
+
+-------------
+
 YOLO
 ----
 

pl_bolts/models/detection/__init__.py

@@ -1,5 +1,6 @@
 from pl_bolts.models.detection import components
 from pl_bolts.models.detection.faster_rcnn import FasterRCNN
+from pl_bolts.models.detection.retinanet import RetinaNet
 from pl_bolts.models.detection.yolo.yolo_config import YOLOConfiguration
 from pl_bolts.models.detection.yolo.yolo_module import YOLO
 
@@ -8,4 +9,5 @@
     "FasterRCNN",
     "YOLOConfiguration",
     "YOLO",
+    "RetinaNet",
 ]

pl_bolts/models/detection/faster_rcnn/faster_rcnn_module.py

@@ -43,7 +43,7 @@ class FasterRCNN(LightningModule):
     CLI command::
 
         # PascalVOC
-        python faster_rcnn.py --gpus 1 --pretrained True
+        python faster_rcnn_module.py --gpus 1 --pretrained True
     """
 
     def __init__(

pl_bolts/models/detection/retinanet/__init__.py

@@ -0,0 +1,4 @@
+from pl_bolts.models.detection.retinanet.backbones import create_retinanet_backbone
+from pl_bolts.models.detection.retinanet.retinanet_module import RetinaNet
+
+__all__ = ["create_retinanet_backbone", "RetinaNet"]

pl_bolts/models/detection/retinanet/backbones.py

@@ -0,0 +1,37 @@
+from typing import Any, Optional
+
+import torch.nn as nn
+
+from pl_bolts.models.detection.components import create_torchvision_backbone
+from pl_bolts.utils import _TORCHVISION_AVAILABLE
+from pl_bolts.utils.warnings import warn_missing_pkg
+
+if _TORCHVISION_AVAILABLE:
+    from torchvision.models.detection.backbone_utils import resnet_fpn_backbone
+else:  # pragma: no cover
+    warn_missing_pkg("torchvision")
+
+
+def create_retinanet_backbone(
+    backbone: str, fpn: bool = True, pretrained: Optional[str] = None, trainable_backbone_layers: int = 3, **kwargs: Any
+) -> nn.Module:
+    """
+    Args:
+        backbone:
+            Supported backones are: "resnet18", "resnet34","resnet50", "resnet101", "resnet152",
+            "resnext50_32x4d", "resnext101_32x8d", "wide_resnet50_2", "wide_resnet101_2",
+            as resnets with fpn backbones.
+            Without fpn backbones supported are: "resnet18", "resnet34", "resnet50","resnet101",
+            "resnet152", "resnext101_32x8d", "mobilenet_v2", "vgg11", "vgg13", "vgg16", "vgg19",
+        fpn: If True then constructs fpn as well.
+        pretrained: If None creates imagenet weights backbone.
+        trainable_backbone_layers: number of trainable resnet layers starting from final block.
+    """
+
+    if fpn:
+        # Creates a torchvision resnet model with fpn added.
+        backbone = resnet_fpn_backbone(backbone, pretrained=True, trainable_layers=trainable_backbone_layers, **kwargs)
+    else:
+        # This does not create fpn backbone, it is supported for all models
+        backbone, _ = create_torchvision_backbone(backbone, pretrained)
+    return backbone

pl_bolts/models/detection/retinanet/retinanet_module.py

@@ -0,0 +1,131 @@
+from typing import Any, Optional
+
+import torch
+from pytorch_lightning import LightningModule
+
+from pl_bolts.models.detection.retinanet import create_retinanet_backbone
+from pl_bolts.utils import _TORCHVISION_AVAILABLE
+from pl_bolts.utils.warnings import warn_missing_pkg
+
+if _TORCHVISION_AVAILABLE:
+    from torchvision.models.detection.retinanet import RetinaNet as torchvision_RetinaNet
+    from torchvision.models.detection.retinanet import RetinaNetHead, retinanet_resnet50_fpn
+    from torchvision.ops import box_iou
+else:  # pragma: no cover
+    warn_missing_pkg("torchvision")
+
+
+class RetinaNet(LightningModule):
+    """PyTorch Lightning implementation of RetinaNet.
+
+    Paper: `Focal Loss for Dense Object Detection <https://arxiv.org/abs/1708.02002>`_.
+
+    Paper authors: Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, Piotr Dollár
+
+    Model implemented by:
+        - `Aditya Oke <https://github.com/oke-aditya>`
+
+    During training, the model expects both the input tensors, as well as targets (list of dictionary), containing:
+        - boxes (`FloatTensor[N, 4]`): the ground truth boxes in `[x1, y1, x2, y2]` format.
+        - labels (`Int64Tensor[N]`): the class label for each ground truh box
+
+    CLI command::
+
+        # PascalVOC using LightningCLI
+        python retinanet_module.py --trainer.gpus 1 --model.pretrained True
+    """
+
+    def __init__(
+        self,
+        learning_rate: float = 0.0001,
+        num_classes: int = 91,
+        backbone: Optional[str] = None,
+        fpn: bool = True,
+        pretrained: bool = False,
+        pretrained_backbone: bool = True,
+        trainable_backbone_layers: int = 3,
+        **kwargs: Any,
+    ):
+        """
+        Args:
+            learning_rate: the learning rate
+            num_classes: number of detection classes (including background)
+            backbone: Pretained backbone CNN architecture.
+            fpn: If True, creates a Feature Pyramind Network on top of Resnet based CNNs.
+            pretrained: if true, returns a model pre-trained on COCO train2017
+            pretrained_backbone: if true, returns a model with backbone pre-trained on Imagenet
+            trainable_backbone_layers: number of trainable resnet layers starting from final block
+        """
+        super().__init__()
+        self.learning_rate = learning_rate
+        self.num_classes = num_classes
+        self.backbone = backbone
+        if backbone is None:
+            self.model = retinanet_resnet50_fpn(pretrained=pretrained, **kwargs)
+
+            self.model.head = RetinaNetHead(
+                in_channels=self.model.backbone.out_channels,
+                num_anchors=self.model.head.classification_head.num_anchors,
+                num_classes=num_classes,
+                **kwargs,
+            )
+
+        else:
+            backbone_model = create_retinanet_backbone(
+                self.backbone, fpn, pretrained_backbone, trainable_backbone_layers, **kwargs
+            )
+            self.model = torchvision_RetinaNet(backbone_model, num_classes=num_classes, **kwargs)
+
+    def forward(self, x):
+        self.model.eval()
+        return self.model(x)
+
+    def training_step(self, batch, batch_idx):
+
+        images, targets = batch
+        targets = [{k: v for k, v in t.items()} for t in targets]
+
+        # fasterrcnn takes both images and targets for training, returns
+        loss_dict = self.model(images, targets)
+        loss = sum(loss for loss in loss_dict.values())
+        self.log("loss", loss, prog_bar=True)
+        return loss
+
+    def validation_step(self, batch, batch_idx):
+        images, targets = batch
+        # fasterrcnn takes only images for eval() mode
+        preds = self.model(images)
+        iou = torch.stack([self._evaluate_iou(p, t) for p, t in zip(preds, targets)]).mean()
+        self.log("val_iou", iou, prog_bar=True)
+        return {"val_iou": iou}
+
+    def validation_epoch_end(self, outs):
+        avg_iou = torch.stack([o["val_iou"] for o in outs]).mean()
+        self.log("val_avg_iou", avg_iou)
+
+    def _evaluate_iou(self, preds, targets):
+        """Evaluate intersection over union (IOU) for target from dataset and output prediction from model."""
+        # no box detected, 0 IOU
+        if preds["boxes"].shape[0] == 0:
+            return torch.tensor(0.0, device=preds["boxes"].device)
+        return box_iou(preds["boxes"], targets["boxes"]).diag().mean()
+
+    def configure_optimizers(self):
+        return torch.optim.SGD(
+            self.model.parameters(),
+            lr=self.learning_rate,
+            momentum=0.9,
+            weight_decay=0.005,
+        )
+
+
+def cli_main():
+    from pytorch_lightning.utilities.cli import LightningCLI
+
+    from pl_bolts.datamodules import VOCDetectionDataModule
+
+    LightningCLI(RetinaNet, VOCDetectionDataModule, seed_everything_default=42)
+
+
+if __name__ == "__main__":
+    cli_main()

requirements.txt

@@ -1,4 +1,4 @@
-torch>=1.7.*
+torch>=1.7.1
 torchmetrics>=0.4.1
-pytorch-lightning>=1.3.0
+pytorch-lightning>=1.4.0
 packaging

requirements/models.txt

@@ -1,4 +1,4 @@
-torchvision>=0.8.*
+torchvision>=0.8.2
 scikit-learn>=0.23
 Pillow
 opencv-python-headless

requirements/test.txt

@@ -14,3 +14,4 @@ atari-py==0.2.6  # needed for RL
 scikit-learn>=0.23
 sparseml
 ale-py>=0.7
+jsonargparse[signatures]  # for LightningCLI

tests/models/test_detection.py

@@ -6,7 +6,7 @@
 from torch.utils.data import DataLoader
 
 from pl_bolts.datasets import DummyDetectionDataset
-from pl_bolts.models.detection import YOLO, FasterRCNN, YOLOConfiguration
+from pl_bolts.models.detection import YOLO, FasterRCNN, RetinaNet, YOLOConfiguration
 from pl_bolts.models.detection.faster_rcnn import create_fasterrcnn_backbone
 from pl_bolts.models.detection.yolo.yolo_layers import _aligned_iou
 from tests import TEST_ROOT
@@ -30,16 +30,46 @@ def test_fasterrcnn_train(tmpdir):
     train_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
     valid_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
 
-    trainer = Trainer(fast_dev_run=True, default_root_dir=tmpdir)
+    trainer = Trainer(fast_dev_run=True, logger=False, checkpoint_callback=False, default_root_dir=tmpdir)
     trainer.fit(model, train_dataloader=train_dl, val_dataloaders=valid_dl)
 
 
 def test_fasterrcnn_bbone_train(tmpdir):
-    model = FasterRCNN(backbone="resnet18", fpn=True, pretrained_backbone=False, pretrained=False)
+    model = FasterRCNN(backbone="resnet18", fpn=True, pretrained_backbone=False)
     train_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
     valid_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
 
-    trainer = Trainer(fast_dev_run=True, default_root_dir=tmpdir)
+    trainer = Trainer(fast_dev_run=True, logger=False, checkpoint_callback=False, default_root_dir=tmpdir)
+    trainer.fit(model, train_dl, valid_dl)
+
+
+@torch.no_grad()
+def test_retinanet():
+    model = RetinaNet(pretrained=False)
+
+    image = torch.rand(1, 3, 400, 400)
+    model(image)
+
+
+def test_retinanet_train(tmpdir):
+    model = RetinaNet(pretrained=False)
+
+    train_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
+    valid_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
+
+    trainer = Trainer(fast_dev_run=True, logger=False, checkpoint_callback=False, default_root_dir=tmpdir)
+    trainer.fit(model, train_dataloader=train_dl, val_dataloaders=valid_dl)
+
+
+def test_retinanet_backbone_train(tmpdir):
+    model = RetinaNet(backbone="resnet18", fpn=True, pretrained_backbone=False)
+    train_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
+    valid_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
+
+    trainer = Trainer(fast_dev_run=True, logger=False, checkpoint_callback=False, default_root_dir=tmpdir)
+    model = FasterRCNN(backbone="resnet18", fpn=True, pretrained_backbone=False, pretrained=False)
+    train_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
+    valid_dl = DataLoader(DummyDetectionDataset(), collate_fn=_collate_fn)
     trainer.fit(model, train_dl, valid_dl)
 
 

tests/models/test_scripts.py

@@ -5,6 +5,9 @@
 from tests import _MARK_REQUIRE_GPU, DATASETS_PATH
 
 _DEFAULT_ARGS = f" --data_dir {DATASETS_PATH} --max_epochs 1 --max_steps 2 --batch_size 4"
+_DEFAULT_LIGHTNING_CLI_ARGS = (
+    f" fit --data.data_dir {DATASETS_PATH} --data.batch_size 4 --trainer.max_epochs 1 --trainer.max_steps 2"
+)
 
 
 @pytest.mark.parametrize("dataset_name", ["mnist", "cifar10"])
@@ -105,3 +108,14 @@ def test_cli_run_vision_image_gpt(cli_args):
     cli_args = cli_args.strip().split(" ") if cli_args else []
     with mock.patch("argparse._sys.argv", ["any.py"] + cli_args):
         cli_main()
+
+
+@pytest.mark.parametrize("cli_args", [_DEFAULT_LIGHTNING_CLI_ARGS + " --trainer.gpus 1"])
+@pytest.mark.skipif(**_MARK_REQUIRE_GPU)
+def test_cli_run_retinanet(cli_args):
+    """Test running CLI for an example with default params."""
+    from pl_bolts.models.detection.retinanet.retinanet_module import cli_main
+
+    cli_args = cli_args.strip().split(" ") if cli_args else []
+    with mock.patch("argparse._sys.argv", ["any.py"] + cli_args):
+        cli_main()