where c pq is a complex moment of the image. The one from GHIs has a similar form V h = d 11 , d 21 d 12 , Re(d 20 d 2 12), Im(d 20 d 2 12), Re(d 30 d 3 12), Im(d 30 d 3 12), d 22 , Re(d 31 d 2 12), Im(d 31 d 2 12), Re(d 40 d 4 12), Im(d 40 d 4 12), d 32 d 23 , Re(d 32 d 12), Im(d 32 d 12), Re(d 41 d 3 12), Im(d 41 d 3 12), Re(d 50 d 5 12), Im(d 50 d 5 12) .