class_docstr: A meta architecture that only predicts object proposals.
class_docstr_tok: ["A","meta","architecture","that","only","predicts","object","proposals","."]
docstr: Args:
      backbone: a backbone module, must follow detectron2's backbone interface
      proposal_generator: a module that generates proposals using backbone features
      pixel_mean, pixel_std: list or tuple with #channels element, representing
          the per-channel mean and std to be used to normalize the input image
docstr_tok: ["Args",":","backbone",":","a","backbone","module",",","must","follow","detectron2","'s","backbone","interface","proposal_generator",":","a","module","that","generates","proposals","using","backbone","features","pixel_mean",",","pixel_std",":","list","or","tuple","with","#","channels","element",",","representing","the","per-channel","mean","and","std","to","be","used","to","normalize","the","input","image"]
code: def __init__(
      self,
      *,
      backbone: Backbone,
      proposal_generator: nn.Module,
      pixel_mean: Tuple[float],
      pixel_std: Tuple[float],
  ):
      """
      Args:
          backbone: a backbone module, must follow detectron2's backbone interface
          proposal_generator: a module that generates proposals using backbone features
          pixel_mean, pixel_std: list or tuple with #channels element, representing
              the per-channel mean and std to be used to normalize the input image
      """
      super().__init__()
      self.backbone = backbone
      self.proposal_generator = proposal_generator
      self.register_buffer(
          "pixel_mean", torch.tensor(pixel_mean).view(-1, 1, 1), False
      )
      self.register_buffer(
          "pixel_std", torch.tensor(pixel_std).view(-1, 1, 1), False
      )
  
imports: import logging
  import numpy
  from typing import Dict, List, Optional, Tuple
  import torch
  from torch import nn
  from detectron2.config import configurable
  from detectron2.data.detection_utils import convert_image_to_rgb
  from detectron2.layers import move_device_like
  from detectron2.structures import ImageList, Instances
  from detectron2.utils.events import get_event_storage
  from detectron2.utils.logger import log_first_n
  from ..backbone import Backbone, build_backbone
  from ..postprocessing import detector_postprocess
  from ..proposal_generator import build_proposal_generator
  from ..roi_heads import build_roi_heads
  from .build import META_ARCH_REGISTRY
label_desc: Use image node_id 1 to create a new ProposalNetwork object from inherited base classes: nn with example: obj = ProposalNetwork()