title: [Selection of Chinese visual targets by fourier frequency spectrum analysis].
abstract: OBJECTIVE
  To select Chinese characters for Chinese visual acuity chart by using the method of Fourier frequency spectrum analysis.
  
  
  METHODS
  BMP images were made for 1062 Chinese characters with small or medium number of strokes. The images were processed to derive frequency spectrum at the frequency domain by using a MatLab program. Euclidean distance from Cluster analysis was then used to classify and select the Chinese characters for optotypes of the visual acuity chart, based on their mean frequency spectrum from all the characters analyzed.
  
  
  RESULTS
  Fifty and forty Chinese characters were selected from the groups of the small and the middle number of strokes respectively.
  
  
  CONCLUSIONS
  It is important and interesting to select Chinese characters by using Fourier analysis method for designing Chinese visual acuity chart that is consisting with the property of the visual system of the eye.
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical College, Wenzhou, China.
authors.forename: Chen-Xiao
authors.initials: CX
authors.lastname: Wang
authors.forename: Xiang-Jun
authors.initials: XJ
authors.lastname: Chen
authors.forename: Ji-Cang
authors.initials: JC
authors.lastname: He
authors.forename: Cheng-Peng
authors.initials: CP
authors.lastname: Jin
authors.forename: Jia
authors.initials: J
authors.lastname: Qu
authors.forename: Fan
authors.initials: F
authors.lastname: Lü
mesh_terms: D005583:Fourier Analysis; D009907:Optometry / Q000379:methods*; D014792:Visual Acuity