SegNet


在结构上，SegNet和U-net其实大同小异，都是编码-解码的结果。

 区别在于：SegNet没有直接融合不同尺度层的信息，为了解决位置信息丢失的问题，SegNet使用了带有坐标index的池化。

 如图所示，在maxpooling时，选择最大像素的同时，记录下该像素在Feature Map的位置。在反池化的时候，根据记录的坐标，把最大值复原到原来对应的位置，其他位置补0。后面的卷积可以把0的元素给填上。这样就解决了由于多次池化造成的位置信息的丢失。

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