title: Offset-sparsity decomposition for automated enhancement of color microscopic image of stained specimen in histopathology.
abstract: We propose an offset-sparsity decomposition method for the enhancement of a color microscopic image of a stained specimen. The method decomposes vectorized spectral images into offset terms and sparse terms. A sparse term represents an enhanced image, and an offset term represents a "shadow." The related optimization problem is solved by computational improvement of the accelerated proximal gradient method used initially to solve the related rank-sparsity decomposition problem. Removal of an image-adapted color offset yields an enhanced image with improved colorimetric differences among the histological structures. This is verified by a no-reference colorfulness measure estimated from 35 specimens of the human liver, 1 specimen of the mouse liver stained with hematoxylin and eosin, 6 specimens of the mouse liver stained with Sudan III, and 3 specimens of the human liver stained with the anti-CD34 monoclonal antibody. The colorimetric difference improves on average by 43.86% with a 99% confidence interval (CI) of [35.35%, 51.62%]. Furthermore, according to the mean opinion score, estimated on the basis of the evaluations of five pathologists, images enhanced by the proposed method exhibit an average quality improvement of 16.60% with a 99% CI of [10.46%, 22.73%].
authors.affiliation: Ruder Boškovic Institute, Division of Laser and Atomic R&D, Bijenicka cesta 54, Zagreb 10002, Croatia.
authors.forename: Ivica
authors.initials: I
authors.lastname: Kopriva
authors.affiliation: Ruder Boškovic Institute, Division of Molecular Medicine, Bijenicka cesta 54, Zagreb 10002, Croatia.
authors.forename: Marijana Popovic
authors.initials: MP
authors.lastname: Hadžija
authors.affiliation: Ruder Boškovic Institute, Division of Molecular Medicine, Bijenicka cesta 54, Zagreb 10002, Croatia.
authors.forename: Mirko
authors.initials: M
authors.lastname: Hadžija
authors.affiliation: Clinical Hospital Dubrava, Department of Pathology and Cytology, Avenija Gojka Šuška 6, Zagreb 10000, CroatiadUniversity of Zagreb, School of Medicine, Šalata 3, Zagreb 10000, Croatia.
authors.forename: Gorana
authors.initials: G
authors.lastname: Aralica
mesh_terms: D000465:Algorithms; D000818:Animals; D004396:Coloring Agents / Q000737:chemistry*; D006651:Histocytochemistry / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000737:chemistry; D008113:Liver Neoplasms / Q000737:chemistry; D008297:Male; D051379:Mice; D008853:Microscopy / Q000379:methods*
chemical_list: D004396:Coloring Agents