Faster-rcnn数据准备过程

Faster-rcnn数据出来流程：
数据读取流程

__main__
----------------combined_roidb
                                                           ------------get_imdb(factory.py)-------------coco(imdb)----------
                                                           ------------set_proposal_method--------------gt_roidb(coco.py)--------_load_coco_annotation---------getAnnIds(pycocotools)
                                                                                                                                                                                                                                               |---------loadAnns(pycocotools)

                                                           ------------get_training_roidb-----------prepare_roidb(roi_data_layer/roidb.py)--------gt_overlaps
                                                                                                                                                                                                                       --------max_classes


----------------train_net
                         ---------SolverWrapper---------add_bbox_regression_targets(roi_data_layer/roidb.py)计算boundingbox的均值与方差，进行loss计算时需要对box进行归一化
                         ---------train_model


数据输入层：
RoIDataLayer---------------------
                                                               forward-----------------
                                                                                                              _get_next_minibatch-------------------_get_next_minibatch_inds
                                                                                                                                                     -------------------get_minibatch
                                                                                                                                                                                                                     -------------------_get_image_blob，读图像并放入blob中