class_docstr: This class assigns labels to anchors via `SSD matching process <https://arxiv.org/abs/1512.02325>`_
  
  Args:
      opts: command line arguments
      bg_class_id: Background class index
  
  Shape:
      - Input:
          - gt_boxes: Ground-truth boxes in corner form (xyxy format). Shape is :math:`(N, 4)` where :math:`N` is the number of boxes
          - gt_labels: Ground-truth box labels. Shape is :math:`(N)`
          - anchors: Anchor boxes in center form (c_x, c_y, w, h). Shape is :math:`(M, 4)` where :math:`M` is the number of anchors
  
      - Output:
          - matched_boxes of shape :math:`(M, 4)`
          - matched_box_labels of shape :math:`(M)`
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docstr: Add SSD Matcher specific arguments
docstr_tok: ["Add","SSD","Matcher","specific","arguments"]
code: def add_arguments(
      cls, parser: argparse.ArgumentParser
  ) -> argparse.ArgumentParser:
      """
      Add SSD Matcher specific arguments
      """
      group = parser.add_argument_group(title=cls.__name__)
      group.add_argument(
          "--matcher.ssd.center-variance",
          type=float,
          default=0.1,
          help="Center variance for matching",
      )
      group.add_argument(
          "--matcher.ssd.size-variance",
          type=float,
          default=0.2,
          help="Size variance.",
      )
      group.add_argument(
          "--matcher.ssd.iou-threshold",
          type=float,
          default=0.45,
          help="IOU Threshold.",
      )
  
      return parser
  
file_path: ml-cvnets/cvnets/matcher_det/ssd_matcher.py
imports: import argparse
  from typing import Optional, Tuple, Union
  import numpy
  import torch
  from torch import Tensor
  from cvnets.matcher_det import MATCHER_REGISTRY, BaseMatcher
  from cvnets.misc.box_utils import center_form_to_corner_form, convert_boxes_to_locations, convert_locations_to_boxes, corner_form_to_center_form
  from cvnets.misc.third_party.ssd_utils import assign_priors
  from utils import logger
label_desc: Use image node_id 3 for calling the SSDMatcher obj's underlying member method code with example usage: obj.add_arguments(cls, parser) and returns: parser