class_docstr: Base class of Single Shot Multibox Detector.
  
  This is a base class of Single Shot Multibox Detector [#]_.
  
  .. [#] Wei Liu, Dragomir Anguelov, Dumitru Erhan, Christian Szegedy,
     Scott Reed, Cheng-Yang Fu, Alexander C. Berg.
     SSD: Single Shot MultiBox Detector. ECCV 2016.
  
  Args:
      extractor: A link which extracts feature maps.
          This link must have :obj:`insize`, :obj:`grids` and
          :meth:`forward`.
  
          * :obj:`insize`: An integer which indicates             the size of input images. Images are resized to this size before             feature extraction.
          * :obj:`grids`: An iterable of integer. Each integer indicates             the size of feature map. This value is used by             :class:`~chainercv.links.model.ssd.MultiBboxCoder`.
          * :meth:`__call_`: A method which computes feature maps.             It must take a batched images and return batched feature maps.
      multibox: A link which computes :obj:`mb_locs` and :obj:`mb_confs`
          from feature maps.
          This link must have :obj:`n_class`, :obj:`aspect_ratios` and
          :meth:`forward`.
  
          * :obj:`n_class`: An integer which indicates the number of             classes.             This value should include the background class.
          * :obj:`aspect_ratios`: An iterable of tuple of integer.             Each tuple indicates the aspect ratios of default bounding boxes             at each feature maps. This value is used by             :class:`~chainercv.links.model.ssd.MultiboxCoder`.
          * :meth:`forward`: A method which computes             :obj:`mb_locs` and :obj:`mb_confs`.             It must take a batched feature maps and             return :obj:`mb_locs` and :obj:`mb_confs`.
      steps (iterable of float): The step size for each feature map.
          This value is used by
          :class:`~chainercv.links.model.ssd.MultiboxCoder`.
      sizes (iterable of float): The base size of default bounding boxes
          for each feature map. This value is used by
          :class:`~chainercv.links.model.ssd.MultiboxCoder`.
      variance (tuple of floats): Two coefficients for decoding
          the locations of bounding boxes.
          This value is used by
          :class:`~chainercv.links.model.ssd.MultiboxCoder`.
          The default value is :obj:`(0.1, 0.2)`.
  
  Parameters:
      nms_thresh (float): The threshold value
          for :func:`~chainercv.utils.non_maximum_suppression`.
          The default value is :obj:`0.45`.
          This value can be changed directly or by using :meth:`use_preset`.
      score_thresh (float): The threshold value for confidence score.
          If a bounding box whose confidence score is lower than this value,
          the bounding box will be suppressed.
          The default value is :obj:`0.6`.
          This value can be changed directly or by using :meth:`use_preset`.
code: def to_gpu(self, device=None):
      super(SSD, self).to_gpu(device)
      self.coder.to_gpu(device=device)
  
file_path: chainercv/chainercv/links/model/ssd/ssd.py
imports: from __future__ import division
  import numpy
  import chainer
  from chainercv.links.model.ssd import MultiboxCoder
  from chainercv import transforms
label_desc: Use image node_id 5 for calling the SSD obj's underlying member method code with example usage: obj.to_gpu(device) without return types