faster-rcnn:基本概念【临时】

1. Region Proposals: SS (selective search)

合并相似区域，生成候选区

2. mAP

平均准确率

3. SPP

spatial pyramid pooling,空间金字塔池化，池化到固定大小

4. ROI

region of interest

5. bbox regressors

bounding-box regressors 边框回归

6. RPN

region proposal network

7. IOU