title: Image preprocessing improves Fourier-based texture analysis of nuclear chromatin.
abstract: OBJECTIVE
  To investigate whether preprocessing of digitized images can improve the image analysis of chromatin of cytologic preparations using Fast Fourier Transformation (FFT).
  
  
  METHODS
  In a preprocessing step the nuclear borders of the segmented nuclei were smoothed, thus avoiding the Airy ring artifact. We tested this method, comparing the inertia values of digitalized cardiomyocyte nuclei of rats of different ages. Furthermore, we created in silicio nuclear images with chromatin alterations at or nearby the nuclear edge in order to investigate the robustness of our method.
  
  
  RESULTS
  After preprocessing, the FFT-derived variable inertia discriminated significantly better the chromatin structure of the nuclei at different ages in every frequency range. The investigation on simulated nuclei revealed that within the frequency ranges from 1.8 microm to 0.72 microm smoothing of the borders does not interfere with the detection of chromatin changes at the nuclear border.
  
  
  CONCLUSIONS
  Smoothing of borders in segmented images can improve the analysis of Fourier-derived variables of the chromatin texture.
authors.affiliation: Institute of Computing, Brazil.
authors.forename: Randall L
authors.initials: RL
authors.lastname: Adam
authors.forename: Neucimar J
authors.initials: NJ
authors.lastname: Leite
authors.forename: Konradin
authors.initials: K
authors.lastname: Metze
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000737:chemistry*; D002843:Chromatin / Q000737:chemistry*; D005583:Fourier Analysis; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D032383:Myocytes, Cardiac / Q000737:chemistry* / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002843:Chromatin