title: Qualification of a new and precise automatic tool for the assessment of hair diameters in phototrichograms.
abstract: OBJECTIVE
  To automatically assess hair growth during cosmetic trials, incorporating parameters such as anagen-to-telogen rate, growth rate, and especially hair diameter.
  
  
  METHODS
  We designed and qualified a new and automatic phototrichogram system based on a high-resolution DSLR camera system (theoretical resolution of 2.557 μm/pixel) and modular macrolens system with fixed focus, combined with a trainable pattern recognition software for automated analysis.
  
  
  RESULTS
  We improved the standard routine for dermatological phototrichogram technique to overcome inaccuracy in thickness measurements due to hair swelling by using an alternative immersion fluid, and increased the effective resolution for hair size and thickness measurement to <4 μm. After having qualified manual measurements as gold standard for the determination of hair diameters, we established a new trainable automatic picture analysis software able to locate and measure individual hairs in length and thickness even in picture series taken from the same skin area at different time points. Comparisons between manual and automatic measurements of the same hairs showed a >90% correlation, and by comparing the automatic results with manual measurements of the same images without individual hair annotation, we could find a correlation of at least 80%.
  
  
  CONCLUSIONS
  According to the results and findings generated in this qualification study, we have a reliable tool now that enables us to test cosmetic products for hair treatment in a highly automated way with a sufficient degree of precision and accuracy to detect even small changes in hair diameter during cosmetic trials.
authors.affiliation: Beiersdorf AG, R&D Cosmed-Biophysics II, Beiersdorf AG, Hamburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Scheede
authors.forename: Andreas
authors.initials: A
authors.lastname: Herpens
authors.forename: Frank
authors.initials: F
authors.lastname: Burmeister
authors.forename: Bernhard
authors.initials: B
authors.lastname: Oltrogge
authors.forename: K
authors.initials: K
authors.lastname: Saenger
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmidt-Rose
authors.forename: Volker
authors.initials: V
authors.lastname: Schreiner
authors.forename: Horst
authors.initials: H
authors.lastname: Wenck
authors.forename: Torsten
authors.initials: T
authors.lastname: Knieps
authors.forename: Thomas
authors.initials: T
authors.lastname: Berlage
mesh_terms: D000505:Alopecia / Q000473:pathology*; D003880:Dermatology / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D005260:Female; D006197:Hair / Q000033:anatomy & histology*; D006203:Hair Preparations; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D008297:Male; D010781:Photography / Q000295:instrumentation / Q000379:methods*; D012984:Software
chemical_list: D006203:Hair Preparations