https://medium.com/@penolove15/%E5%BF%83%E5%BE%97-objects-as-points-e6f3cca92190
https://www.jianshu.com/p/d5d7cd7ad200
https://zhuanlan.zhihu.com/p/72373052
https://blog.csdn.net/c20081052/article/details/89358658