Pipelines of the extraction of the gyral skeleton and 3-hinge patterns. (a) Cortical surface of the white matter/gray matter boundaries. (b) and (d) Gyral crest segmentation and skeletonization on an enlarged region. (b) Presentation of gyral altitudes. Red regions have positive altitude values, while blue regions have negative altitude values. (c) The cortical surface is segmented into gyral crests (black dots). (d) Gyral crest skeleton extraction (black curves). (e) The gyral crest skeleton on a brain. (f) The presentation of 3-hinge patterns’ centers (red dots).