I have a MaskRCNN model for instance segmentation with Resnet 50 - FPN backbone trained in detectron2. And I want to extract the embedding/feature vectors for visualizing input and hopefully detecting outliers. Which place would be the best to extract the embedding vector? I tried p5 of FPN whose shape is (1,256,51,68), but it's a tensor should I flatten this and feed it into the visualizer?