代码实现了超分辨率重建时用到的n倍下采样，程序较简单，原理也很简单，所以一般没人特别指出怎么做，但是初学者往往很头疼，特地实现下-N times down-sampling used in the code to achieve super-resolution reconstruction, the procedure is relatively simple, the principle is very simple, it is generally not particularly pointed out how, but beginners often a headache, specifically to achieve the next