Fig. 9

Illustration of MIND and macMIND descriptor. a The dotted box illustrates the supporting window, the red box illustrates the central patch of the supporting window, its 6-neighborhood patches are colored in blue. L and R symbolize the patch distance and size, respectively. b The 3D structure of 6-connectivities (3-orientation) in MIND. c The single scale 3D structure layout of 18-connectivities (9-orientation) in macMIND. The black (shown as black solid lines and black dotted lines) 12-connectivities are introduced by macMIND, while the gray 6-connectivities (3-orientation) attached to MIND. d The supporting window of macMIND similar with MIND. Light blue and dark blue patches indicate the dual sampling scales, and black and gray connections indicate the multi sampling orientation