def gt_roidb(self):
        """
        Return the database of ground-truth regions of interest.

        This function loads/saves from/to a cache file to speed up future calls.
        """

        cache_file = os.path.join(self.cache_path, self.name + '_' + cfg.SUBCLS_NAME + '_gt_roidb.pkl')
        if os.path.exists(cache_file):
            with open(cache_file, 'rb') as fid:
                roidb = cPickle.load(fid)
            print '{} gt roidb loaded from {}'.format(self.name, cache_file)
            return roidb

        gt_roidb = [self._load_kitti_voxel_exemplar_annotation(index)
                    for index in self.image_index]

        if cfg.IS_RPN:
            # print out recall
            for i in xrange(1, self.num_classes):
                print '{}: Total number of boxes {:d}'.format(self.classes[i], self._num_boxes_all[i])
                print '{}: Number of boxes covered {:d}'.format(self.classes[i], self._num_boxes_covered[i])
                print '{}: Recall {:f}'.format(self.classes[i], float(self._num_boxes_covered[i]) / float(self._num_boxes_all[i]))

        with open(cache_file, 'wb') as fid:
            cPickle.dump(gt_roidb, fid, cPickle.HIGHEST_PROTOCOL)
        print 'wrote gt roidb to {}'.format(cache_file)

        return gt_roidb

        Return the database of ground-truth regions of interest.

        This function loads/saves from/to a cache file to speed up future calls.
        
lib/datasets/kitti.py