Paper: A Geometry-Aware Multi-Coordinate Transformation Fusion Network for Optic Disc and Cup Segmentation

core modules:

1. Sector Association Layer (SAL)
   1. ConvRNN
   2. ConvGRU
   3. ConvLSTM
2. Multi-Coordinate Transformation Fusion Network (MCTF)
   1. Polar Transformation in feature map level
   2. Inverse Polar Transformation in feature map level