class_docstr: Base class for YOLOv2 and YOLOv2Tiny.
  
  A subclass of this class should have :obj:`_extractor`,
  :obj:`_models`, and :obj:`_anchors`.
class_docstr_tok: ["Base","class","for","YOLOv2","and","YOLOv2Tiny",".","A","subclass","of","this","class","should","have",":","obj",":","`","_extractor","`",",",":","obj",":","`","_models","`",",","and",":","obj",":","`","_anchors","`","."]
code: def _decode(self, loc, obj, conf):
      raw_bbox = self._default_bbox.copy()
      raw_bbox[:, :2] += 1 / (1 + self.xp.exp(-loc[:, :2]))
      raw_bbox[:, 2:] *= self.xp.exp(loc[:, 2:])
      raw_bbox[:, :2] -= raw_bbox[:, 2:] / 2
      raw_bbox[:, 2:] += raw_bbox[:, :2]
      raw_bbox *= self.insize / self.extractor.grid
  
      obj = 1 / (1 + self.xp.exp(-obj))
      conf = self.xp.exp(conf)
      conf /= conf.sum(axis=1, keepdims=True)
      raw_score = obj[:, None] * conf
  
      bbox = []
      label = []
      score = []
      for l in range(self.n_fg_class):
          bbox_l = raw_bbox
          score_l = raw_score[:, l]
  
          mask = score_l >= self.score_thresh
          bbox_l = bbox_l[mask]
          score_l = score_l[mask]
  
          indices = utils.non_maximum_suppression(
              bbox_l, self.nms_thresh, score_l
          )
          bbox_l = bbox_l[indices]
          score_l = score_l[indices]
  
          bbox.append(bbox_l)
          label.append(self.xp.array((l,) * len(bbox_l)))
          score.append(score_l)
  
      bbox = self.xp.vstack(bbox).astype(np.float32)
      label = self.xp.hstack(label).astype(np.int32)
      score = self.xp.hstack(score).astype(np.float32)
  
      return bbox, label, score
  
imports: from __future__ import division
  import itertools
  import numpy
  import chainer
  from chainer.backends import cuda
  import chainer.functions
  from chainer.links import Convolution2D
  from chainercv.links import Conv2DBNActiv
  from chainercv import utils
  from chainercv.links.model.yolo.yolo_base import YOLOBase
label_desc: Use image node_id 5 for calling the YOLOv2Base obj's underlying member method code with example usage: obj._decode(loc, obj, conf) and returns: bbox,  label,  score