def load_rpn_roidb(self, gt_roidb):
        """
        turn rpn detection boxes into roidb
        :param gt_roidb: [image_index]['boxes', 'gt_classes', 'gt_overlaps', 'flipped']
        :return: roidb: [image_index]['boxes', 'gt_classes', 'gt_overlaps', 'flipped']
        """
        box_list = self.load_rpn_data()
        return self.create_roidb_from_box_list(box_list, gt_roidb)

        turn rpn detection boxes into roidb
        :param gt_roidb: [image_index]['boxes', 'gt_classes', 'gt_overlaps', 'flipped']
        :return: roidb: [image_index]['boxes', 'gt_classes', 'gt_overlaps', 'flipped']
        
lib/dataset/imdb.py