title: HIDDEN INFORMATION IN COLOR FUNDUS PHOTOGRAPHS IS REVEALED BY THE DECORRELATION STRETCHING METHOD.
abstract: OBJECTIVE
  To investigate whether the decorrelation stretching method can be used to reveal hidden information in color fundus photographs.
  
  
  METHODS
  Five healthy subjects and 16 patients diagnosed with various eye diseases (five eyes with an epiretinal membrane, five eyes with geographic atrophy, five eyes with glaucoma, and one eye with pit-macular syndrome). Fundus photographs, obtained using a TRC-NW8F Plus Mydriatic/Non-Mydriatic Retinal Camera, were used for analyses, and the corresponding lesions were confirmed by other imaging modalities. Decorrelation stretching was performed using ImageJ.
  
  
  RESULTS
  The decorrelation stretching method successfully enhanced color fundus photographs. In eyes with epiretinal membrane, retinal folds, and the irregular reflex of the macula were markedly enhanced. In eyes with geographic atrophy, the area of the retinal pigment epithelium atrophy was clearly delineated after decorrelation stretching. Images of a laminar defect and nerve fiber layer defect were emphasized in glaucoma. In pit-macular syndrome, the pit was enhanced as minor color changes in the disk rim.
  
  
  CONCLUSIONS
  The decorrelation stretching method has the potential to reveal hidden information in a color fundus photograph. Decorrelation stretching can be a powerful tool in a clinical setting in which only color fundus photography is available.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Uji
authors.forename: Yuki
authors.initials: Y
authors.lastname: Muraoka
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D003941:Diagnostic Techniques, Ophthalmological; D005654:Fundus Oculi; D005901:Glaucoma / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D010781:Photography / Q000379:methods*; D012164:Retinal Diseases / Q000000981:diagnostic imaging*; D012189:Retrospective Studies