“…Traditional sparse representation fusion method usually processes the color channels separately, which easily destroys the correlation between image channels and results in loss of color in the fused image. Geometric algebra (GA) has been considered as one of the most powerful tools in multi-dimensional signal processing and has witnessed great success in a wide range of applications, such as physics, quantum computing, electromagnetism, satellite navigation, neural computing, camera geometry, image processing, robotics, and computer vision, et al ( da Rocha and Vaz, 2006 ; Wang et al, 2019a ; Wang et al, 2021a ). Inspired by the paper ( Wang et al, 2019b ), the geometric algebra-based sparse representation (GA-SR) is introduced for multi-modal medical image fusion in this paper.…”