PASCAL VOC & MS COCO简介

https://arleyzhang.github.io/articles/1dc20586/
https://arleyzhang.github.io/articles/e5b86f16/
https://www.cnblogs.com/q735613050/p/8969452.html
ms coco下载：https://blog.csdn.net/u014734886/article/details/78830713