code: def _compute_targets(ex_rois, gt_rois):
      """Compute bounding-box regression targets for an image."""
  
      assert ex_rois.shape[0] == gt_rois.shape[0]
      assert ex_rois.shape[1] == 4
      assert gt_rois.shape[1] == 5
  
      return bbox_transform(ex_rois, gt_rois[:, :4]).astype(
          np.float32, copy=False
      )
  
file_path: CNTK/Examples/Image/Detection/utils/rpn/anchor_target_layer.py
imports: import os
  from cntk import output_variable
  from cntk.ops.functions import UserFunction
  import yaml
  import numpy
  import numpy.random
  from utils.rpn.generate_anchors import generate_anchors
  from utils.rpn.bbox_transform import bbox_transform
  from utils.cython_modules.cython_bbox import bbox_overlaps
label_desc: Use image node_id 2 for calling a global function with example usage: _compute_targets(ex_rois, gt_rois) and returns: bbox_transform