title: Scale-sensitive fractal analysis using the patchwork method for the assessment of skin roughness.
abstract: OBJECTIVE
  As skin roughness and wrinkles are easily perceived by the consumer, quantifying skin surface structures is a vital parameter for cosmetic product development. As more tools are available for measuring three-dimensional (3-D) surface data, instead of two-dimensional (2-D) profile lines, new algorithms are desirable, to take advantage of the information gathered.
  
  
  METHODS
  The patchwork method tiles topographic data sets virtually and analyzes the change in apparent area as a function of tile scale. The patchwork method and conventional 2-D profilometric analysis were applied to 24 topographic skin data sets. The data sets were derived before and after application of 15% glycerol solution on the skin of eight volunteers.
  
  
  RESULTS
  One hour after application, skin roughness decreased by 20.8%, as measured by conventional analysis, and by 23.3%, as measured by the patchwork method. For both methods, the differences were not significant.
  
  
  CONCLUSIONS
  The patchwork method can be applied to skin data and renders results similar in intensity and direction to conventional 2-D analysis. It is advantageous over conventional 2-D analysis in three ways: it makes use of the full topologic information, it requires no high-pass or low-pass filtering, and it is independent of the anisotropy of the skin.
authors.affiliation: proDERM Institute for Applied Dermatological Research, Schenefeld/Hamburg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Articus
authors.forename: C A
authors.initials: CA
authors.lastname: Brown
authors.forename: K P
authors.initials: KP
authors.lastname: Wilhelm
mesh_terms: D000465:Algorithms; D017709:Fractals; D006801:Humans; D008953:Models, Anatomic; D008954:Models, Biological; D012828:Silicones; D012867:Skin / Q000648:ultrastructure*; D012984:Software
chemical_list: D012828:Silicones