title: Colour texture analysis for quantitative laryngoscopy.
abstract: OBJECTIVE
  Whilst considerable progress has been made in enhancing the quality of indirect laryngoscopy and image processing, the evaluation of clinical findings is still based on the clinician's judgement. The aim of this paper was to examine the feasibility of an objective computer-based method for evaluating laryngeal disease.
  
  
  METHODS
  Digitally recorded images obtained by 90 degree- and 70 degree-angled indirect rod laryngoscopy using standardized white balance values were made of 16 patients and 19 healthy subjects. The digital images were evaluated manually by the clinician based on a standardized questionnaire, and suspect lesions were marked and classified on the image. Following colour separation, normal vocal cord areas as well as suspect lesions were analyzed automatically using co-occurrence matrices, which compare colour differences between neighbouring pixels over a predefined distance.
  
  
  RESULTS
  Whilst colour histograms did not provide sufficient information for distinguishing between healthy and diseased tissues, consideration of the blue content of neighbouring pixels enabled a correct classification in 81.4% of cases. If all colour channels (red, green and blue) were regarded simultaneously, the best classification correctness obtained was 77.1%.
  
  
  CONCLUSIONS
  Although only a very basic classification differentiating between healthy and diseased tissue was attempted, the results showed progress compared to grey-scale histograms, which have been evaluated before. The results document a first step towards an objective, machine-based classification of laryngeal images, which could provide the basis for further development of an expert system for use in indirect laryngoscopy.
authors.affiliation: Department of Otorhinolaryngology, Plastic Head and Neck Surgery, University Hospital Aachen, Aachen, Germany. jilgner@ukaachen.de
authors.forename: Justus F R
authors.initials: JF
authors.lastname: Ilgner
authors.forename: Christoph
authors.initials: C
authors.lastname: Palm
authors.forename: Andreas G
authors.initials: AG
authors.lastname: Schütz
authors.forename: Klaus
authors.initials: K
authors.lastname: Spitzer
authors.forename: Martin
authors.initials: M
authors.lastname: Westhofen
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Lehmann
mesh_terms: D003116:Color; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007818:Laryngeal Diseases / Q000175:diagnosis*; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000379:methods*