text: # --------------------------------------------------------
  # Fast R-CNN
  # Copyright (c) 2015 Microsoft
  # Licensed under The MIT License [see LICENSE for details]
  # Written by Ross Girshick and Xinlei Chen
  # --------------------------------------------------------
  from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  
  import os
  import os.path as osp
  import PIL
  #from model.utils.cython_bbox import bbox_overlaps
  import numpy as np
  import scipy.sparse
  from model.utils.config import cfg
  import pdb
  
  ROOT_DIR = osp.join(osp.dirname(__file__), '..', '..')
  
  class imdb(object):
    """Image database."""
  
    def __init__(self, name, classes=None):
      self._name = name
      self._num_classes = 0
      if not classes:
        self._classes = []
      else:
        self._classes = classes
      self._image_index = []
      self._obj_proposer = 'gt'
      self._roidb = None
      self._roidb_handler = self.default_roidb
      # Use this dict for storing dataset specific config options
      self.config = {}
  
    @property
    def name(self):
      return self._name
  
    @property
    def num_classes(self):
      return len(self._classes)
  
    @property
    def classes(self):
      return self._classes
  
    @property
    def image_index(self):
      return self._image_index
  
    @property
    def roidb_handler(self):
      return self._roidb_handler
  
    @roidb_handler.setter
    def roidb_handler(self, val):
      self._roidb_handler = val
  
    def set_proposal_method(self, method):
      method = eval('self.' + method + '_roidb')
      self.roidb_handler = method
  
    @property
    def roidb(self):
      # A roidb is a list of dictionaries, each with the following keys:
      #   boxes
      #   gt_overlaps
      #   gt_classes
      #   flipped
      if self._roidb is not None:
        return self._roidb
      self._roidb = self.roidb_handler()
      return self._roidb
  
    @property
    def cache_path(self):
      cache_path = osp.abspath(osp.join(cfg.DATA_DIR, 'cache'))
      if not os.path.exists(cache_path):
        os.makedirs(cache_path)
      return cache_path
  
    @property
    def num_images(self):
      return len(self.image_index)
  
    def image_path_at(self, i):
      raise NotImplementedError
  
    def image_id_at(self, i):
      raise NotImplementedError
  
    def default_roidb(self):
      raise NotImplementedError
  
    def evaluate_detections(self, all_boxes, output_dir=None):
      """
      all_boxes is a list of length number-of-classes.
      Each list element is a list of length number-of-images.
      Each of those list elements is either an empty list []
      or a numpy array of detection.
  
      all_boxes[class][image] = [] or np.array of shape #dets x 5
      """
      raise NotImplementedError
  
    def _get_widths(self):
      return [PIL.Image.open(self.image_path_at(i)).size[0]
              for i in range(self.num_images)]
  
    def append_flipped_images(self):
      num_images = self.num_images
      widths = self._get_widths()
      for i in range(num_images):
        boxes = self.roidb[i]['boxes'].copy()
        oldx1 = boxes[:, 0].copy()
        oldx2 = boxes[:, 2].copy()
        boxes[:, 0] = widths[i] - oldx2 - 1
        boxes[:, 2] = widths[i] - oldx1 - 1
        assert (boxes[:, 2] >= boxes[:, 0]).all()
        entry = {'boxes': boxes,
                 'gt_overlaps': self.roidb[i]['gt_overlaps'],
                 'gt_classes': self.roidb[i]['gt_classes'],
                 'flipped': True}
        self.roidb.append(entry)
      self._image_index = self._image_index * 2
  
    # def evaluate_recall(self, candidate_boxes=None, thresholds=None,
    #                     area='all', limit=None):
    #   """Evaluate detection proposal recall metrics.
    #
    #   Returns:
    #       results: dictionary of results with keys
    #           'ar': average recall
    #           'recalls': vector recalls at each IoU overlap threshold
    #           'thresholds': vector of IoU overlap thresholds
    #           'gt_overlaps': vector of all ground-truth overlaps
    #   """
    #   # Record max overlap value for each gt box
    #   # Return vector of overlap values
    #   areas = {'all': 0, 'small': 1, 'medium': 2, 'large': 3,
    #            '96-128': 4, '128-256': 5, '256-512': 6, '512-inf': 7}
    #   area_ranges = [[0 ** 2, 1e5 ** 2],  # all
    #                  [0 ** 2, 32 ** 2],  # small
    #                  [32 ** 2, 96 ** 2],  # medium
    #                  [96 ** 2, 1e5 ** 2],  # large
    #                  [96 ** 2, 128 ** 2],  # 96-128
    #                  [128 ** 2, 256 ** 2],  # 128-256
    #                  [256 ** 2, 512 ** 2],  # 256-512
    #                  [512 ** 2, 1e5 ** 2],  # 512-inf
    #                  ]
    #   assert area in areas, 'unknown area range: {}'.format(area)
    #   area_range = area_ranges[areas[area]]
    #   gt_overlaps = np.zeros(0)
    #   num_pos = 0
    #   for i in range(self.num_images):
    #     # Checking for max_overlaps == 1 avoids including crowd annotations
    #     # (...pretty hacking :/)
    #     max_gt_overlaps = self.roidb[i]['gt_overlaps'].toarray().max(axis=1)
    #     gt_inds = np.where((self.roidb[i]['gt_classes'] > 0) &
    #                        (max_gt_overlaps == 1))[0]
    #     gt_boxes = self.roidb[i]['boxes'][gt_inds, :]
    #     gt_areas = self.roidb[i]['seg_areas'][gt_inds]
    #     valid_gt_inds = np.where((gt_areas >= area_range[0]) &
    #                              (gt_areas <= area_range[1]))[0]
    #     gt_boxes = gt_boxes[valid_gt_inds, :]
    #     num_pos += len(valid_gt_inds)
    #
    #     if candidate_boxes is None:
    #       # If candidate_boxes is not supplied, the default is to use the
    #       # non-ground-truth boxes from this roidb
    #       non_gt_inds = np.where(self.roidb[i]['gt_classes'] == 0)[0]
    #       boxes = self.roidb[i]['boxes'][non_gt_inds, :]
    #     else:
    #       boxes = candidate_boxes[i]
    #     if boxes.shape[0] == 0:
    #       continue
    #     if limit is not None and boxes.shape[0] > limit:
    #       boxes = boxes[:limit, :]
    #
    #     overlaps = bbox_overlaps(boxes.astype(np.float),
    #                              gt_boxes.astype(np.float))
    #
    #     _gt_overlaps = np.zeros((gt_boxes.shape[0]))
    #     for j in range(gt_boxes.shape[0]):
    #       # find which proposal box maximally covers each gt box
    #       argmax_overlaps = overlaps.argmax(axis=0)
    #       # and get the iou amount of coverage for each gt box
    #       max_overlaps = overlaps.max(axis=0)
    #       # find which gt box is 'best' covered (i.e. 'best' = most iou)
    #       gt_ind = max_overlaps.argmax()
    #       gt_ovr = max_overlaps.max()
    #       assert (gt_ovr >= 0)
    #       # find the proposal box that covers the best covered gt box
    #       box_ind = argmax_overlaps[gt_ind]
    #       # record the iou coverage of this gt box
    #       _gt_overlaps[j] = overlaps[box_ind, gt_ind]
    #       assert (_gt_overlaps[j] == gt_ovr)
    #       # mark the proposal box and the gt box as used
    #       overlaps[box_ind, :] = -1
    #       overlaps[:, gt_ind] = -1
    #     # append recorded iou coverage level
    #     gt_overlaps = np.hstack((gt_overlaps, _gt_overlaps))
    #
    #   gt_overlaps = np.sort(gt_overlaps)
    #   if thresholds is None:
    #     step = 0.05
    #     thresholds = np.arange(0.5, 0.95 + 1e-5, step)
    #   recalls = np.zeros_like(thresholds)
    #   # compute recall for each iou threshold
    #   for i, t in enumerate(thresholds):
    #     recalls[i] = (gt_overlaps >= t).sum() / float(num_pos)
    #   # ar = 2 * np.trapz(recalls, thresholds)
    #   ar = recalls.mean()
    #   return {'ar': ar, 'recalls': recalls, 'thresholds': thresholds,
    #           'gt_overlaps': gt_overlaps}
  
    def create_roidb_from_box_list(self, box_list, gt_roidb):
      assert len(box_list) == self.num_images, \
        'Number of boxes must match number of ground-truth images'
      roidb = []
      for i in range(self.num_images):
        boxes = box_list[i]
        num_boxes = boxes.shape[0]
        overlaps = np.zeros((num_boxes, self.num_classes), dtype=np.float32)
  
        if gt_roidb is not None and gt_roidb[i]['boxes'].size > 0:
          gt_boxes = gt_roidb[i]['boxes']
          gt_classes = gt_roidb[i]['gt_classes']
          gt_overlaps = bbox_overlaps(boxes.astype(np.float),
                                      gt_boxes.astype(np.float))
          argmaxes = gt_overlaps.argmax(axis=1)
          maxes = gt_overlaps.max(axis=1)
          I = np.where(maxes > 0)[0]
          overlaps[I, gt_classes[argmaxes[I]]] = maxes[I]
  
        overlaps = scipy.sparse.csr_matrix(overlaps)
        roidb.append({
          'boxes': boxes,
          'gt_classes': np.zeros((num_boxes,), dtype=np.int32),
          'gt_overlaps': overlaps,
          'flipped': False,
          'seg_areas': np.zeros((num_boxes,), dtype=np.float32),
        })
      return roidb
  
    @staticmethod
    def merge_roidbs(a, b):
      assert len(a) == len(b)
      for i in range(len(a)):
        a[i]['boxes'] = np.vstack((a[i]['boxes'], b[i]['boxes']))
        a[i]['gt_classes'] = np.hstack((a[i]['gt_classes'],
                                        b[i]['gt_classes']))
        a[i]['gt_overlaps'] = scipy.sparse.vstack([a[i]['gt_overlaps'],
                                                   b[i]['gt_overlaps']])
        a[i]['seg_areas'] = np.hstack((a[i]['seg_areas'],
                                       b[i]['seg_areas']))
      return a
  
    def competition_mode(self, on):
      """Turn competition mode on or off."""
      pass
  