Unveiling the unconventional optical signatures of regular black holes within accretion disk Sen Guo, Yu-Xiang Huang, Yu-Hao Cui, Yan Han, Qing-Quan Jiang, En-Wei Liang and Kai Lin Eur. Phys. J. C, 83 11 (2023) 1059 Published online: 19 November 2023 DOI: 10.1140/epjc/s10052-023-12208-0