Proposal Generator creating same proposal boxes for any input image

[siddbane10]

I'm trying to run the detectron 2 model partially to visualize proposal boxes on test images.

image = ImageList.from_tensors([image])
features = model.backbone(image.tensor)
proposals, _ = model.proposal_generator(image, features)

The gives me 1000 instances of proposal boxes:

proposals[0][i].get_fields()['proposal_boxes']

But these 1000 proposal boxes remain the same regardless of the input image. Why is this happening?

This is weird because if I run the entire model through the DefaultPredictor object

predictor = DefaultPredictor(cfg)
outputs = predictor(im)
outputs["instances"].pred_boxes

it gives me perfect results with accurate masks and bounding boxes. How is this possible?