“…It is worth noting that image-level fusion, or image fusion, is closely related to signal-level fusion since an image can be considered a two-dimensional signal. In recent years, image fusion has been attracting a large amount of attention in a wide variety of applications such as concealed weapon detection [6][7][8], remote sensing [9][10][11], intelligent robots [12,13], 1566 [14,15], defect inspection [16,17], and military surveillance [18][19][20].…”