diff --git a/scripts/colmap2nerf.py b/scripts/colmap2nerf.py
index d61b67208f00f30fc2fb774471c771a94bc6e598..5656eee5ac1820143564dddc005a50d36a4c4a82 100755
--- a/scripts/colmap2nerf.py
+++ b/scripts/colmap2nerf.py
@@ -43,6 +43,7 @@ def parse_args():
 	parser.add_argument("--out", default="transforms.json", help="Output path.")
 	parser.add_argument("--vocab_path", default="", help="Vocabulary tree path.")
 	parser.add_argument("--overwrite", action="store_true", help="Do not ask for confirmation for overwriting existing images and COLMAP data.")
+	parser.add_argument("--mask_categories", nargs="*", type=int, default=[], help="Object categories that should be masked out from the training images. See the category-to-id mapping here: https://gist.github.com/yenchenlin/75931e87cedad3d23868a79046fc97c2")
 	args = parser.parse_args()
 	return args
 
@@ -389,3 +390,40 @@ if __name__ == "__main__":
 	print(f"writing {OUT_PATH}")
 	with open(OUT_PATH, "w") as outfile:
 		json.dump(out, outfile, indent=2)
+
+	if len(args.mask_categories) > 1:
+		# Check if detectron2 is installed. If not, install it.
+		import importlib.util
+		package_name = 'detectron2'
+		spec = importlib.util.find_spec(package_name)
+		if spec is None:
+			input("Detectron2 is not installed. Press enter to install it.")
+			os.system("python -m pip install 'git+https://github.com/facebookresearch/detectron2.git'")
+
+		import torch, detectron2
+		from pathlib import Path
+		from detectron2.config import get_cfg
+		from detectron2 import model_zoo
+		from detectron2.engine import DefaultPredictor
+
+		cfg = get_cfg()
+		# Add project-specific config (e.g., TensorMask) here if you're not running a model in detectron2's core library
+		cfg.merge_from_file(model_zoo.get_config_file("COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x.yaml"))
+		cfg.MODEL.ROI_HEADS.SCORE_THRESH_TEST = 0.5  # set threshold for this model
+		# Find a model from detectron2's model zoo.
+		cfg.MODEL.WEIGHTS = model_zoo.get_checkpoint_url("COCO-InstanceSegmentation/mask_rcnn_R_50_FPN_3x.yaml")
+		predictor = DefaultPredictor(cfg)
+
+		for frame in out['frames']:
+			img = cv2.imread(frame['file_path'])        
+			outputs = predictor(img)
+
+			output_mask = np.zeros((img.shape[0], img.shape[1]))
+			for i in range(len(outputs['instances'])):
+				if outputs['instances'][i].pred_classes.cpu().numpy()[0] in args.mask_categories:
+					pred_mask = outputs['instances'][i].pred_masks.cpu().numpy()[0]
+					output_mask = np.logical_or(output_mask, pred_mask)
+			
+			rgb_path = Path(frame['file_path'])
+			mask_name = str(rgb_path.parents[0] / Path('dynamic_mask_' + rgb_path.name.replace('.jpg', '.png')))
+			cv2.imwrite(mask_name, (output_mask*255).astype(np.uint8))