School of Materials Science and Engineering;
University of Science and Technology Beijing;
Beijing 100083;
China;
School of Information and Electronics;
Beijing Institute of Technology;
Beijing 100081;
China;
Collaborative Innovation Center of Steel Technology;
University of Science and Technology Beijing;
Beijing 100083;
China;
School of Materials Science and Engineering;
Liaoning Technical University;
Fuxin 123099;
China;
polycrystalline; iron; three-dimensional; structure; grain; boundaries; image; processing; digitizers;