Contrastive_seg based on https://github.com/dewenzeng/positional_cl.git ref: @article{zeng2021positional, title={Positional Contrastive Learning for VolumetricMedical Image Segmentation}, author={Zeng, Dewen and Wu, Yawen and Hu, Xinrong and Xu, Xiaowei and Yuan, Haiyun and Huang, Meiping and Zhuang, Jian and Hu, Jingtong and Shi, Yiyu}, journal={arXiv preprint arXiv:2106.09157}, year={2021} }