CARLA single modality object detection model (#1160)

* rename to deconflict from carla multimodality object detection model

* remove duplicate file

Co-authored-by: Sterling Suggs <sterling.suggs@twosixtech.com>

armory/baseline_models/pytorch/carla_single_modality_object_detection_frcnn.py

@@ -0,0 +1,46 @@
+"""
+PyTorch Faster-RCNN Resnet50-FPN object detection model
+"""
+import logging
+from typing import Optional
+
+from art.estimators.object_detection import PyTorchFasterRCNN
+import torch
+from torchvision import models
+
+logger = logging.getLogger(__name__)
+
+DEVICE = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+
+
+# NOTE: PyTorchFasterRCNN expects numpy input, not torch.Tensor input
+def get_art_model(
+    model_kwargs: dict, wrapper_kwargs: dict, weights_path: Optional[str] = None
+) -> PyTorchFasterRCNN:
+
+    if weights_path:
+        assert (
+            model_kwargs.get("num_classes", None) == 4
+        ), "model trained on CARLA data outputs predictions for 4 classes"
+        assert not model_kwargs.get(
+            "pretrained", False
+        ), "model trained on CARLA data should not use COCO-pretrained weights"
+    else:
+        assert (
+            model_kwargs.get("num_classes", None) == 91
+        ), "model without predefined weights should use COCO classes"
+        assert model_kwargs.get(
+            "pretrained", False
+        ), "model without predefined weights should use COCO-pretrained weights"
+
+    model = models.detection.fasterrcnn_resnet50_fpn(**model_kwargs)
+    model.to(DEVICE)
+
+    if weights_path:
+        checkpoint = torch.load(weights_path, map_location=DEVICE)
+        model.load_state_dict(checkpoint)
+
+    wrapped_model = PyTorchFasterRCNN(
+        model, clip_values=(0.0, 1.0), channels_first=False, **wrapper_kwargs,
+    )
+    return wrapped_model