Multi-scale deep learning for estimating horizontal velocity fields on the solar surface Ryohtaroh T. Ishikawa, Motoki Nakata, Yukio Katsukawa, Youhei Masada and Tino L. Riethmüller A&A, 658 (2022) A142 Published online: 16 February 2022 DOI: 10.1051/0004-6361/202141743