source image example: img_data/man/
reference image example: ref_data/hat/

train source image: exp_scripts/train_img.sh
test source image: exp_scripts/inference_img.py

train reference image: exp_scripts/train_ref.sh
test reference image: exp_scripts/inference_ref.sh

train fusion: exp_scripts/train_merge_patchall.sh
test fusion: exp_scripts/learn_merge_patchall.sh