title: Unsupervised segmentation of low-contrast multichannel images: discrimination of tissue components in microscopic images of unstained specimens.
abstract: Low-contrast images, such as color microscopic images of unstained histological specimens, are composed of objects with highly correlated spectral profiles. Such images are very hard to segment. Here, we present a method that nonlinearly maps low-contrast color image into an image with an increased number of non-physical channels and a decreased correlation between spectral profiles. The method is a proof-of-concept validated on the unsupervised segmentation of color images of unstained specimens, in which case the tissue components appear colorless when viewed under the light microscope. Specimens of human hepatocellular carcinoma, human liver with metastasis from colon and gastric cancer and mouse fatty liver were used for validation. The average correlation between the spectral profiles of the tissue components was greater than 0.9985, and the worst case correlation was greater than 0.9997. The proposed method can potentially be applied to the segmentation of low-contrast multichannel images with high spatial resolution that arise in other imaging modalities.
authors.affiliation: Division of Laser and Atomic Research and Development, Ruđer Bošković Institute, Bijenička cesta 54, 10002 Zagreb, Croatia.
authors.forename: Ivica
authors.initials: I
authors.lastname: Kopriva
authors.affiliation: Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička cesta 54, 10002 Zagreb, Croatia.
authors.forename: Marijana
authors.initials: M
authors.lastname: Popović Hadžija
authors.affiliation: Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička cesta 54, 10002 Zagreb, Croatia.
authors.forename: Mirko
authors.initials: M
authors.lastname: Hadžija
authors.affiliation: 1] Department of Pathology and Cytology, Clinical Hospital Dubrava, Avenija Gojka Šuška 6, 10000 Zagreb, Croatia [2] School of Medicine, University of Zagreb, Šalata 3, 10000 Zagreb, Croatia.
authors.forename: Gorana
authors.initials: G
authors.lastname: Aralica
mesh_terms: D000465:Algorithms; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000473:pathology; D003110:Colonic Neoplasms / Q000556:secondary; D003116:Color; D016616:Cryoultramicrotomy; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000473:pathology; D051379:Mice; D008853:Microscopy / Q000379:methods*; D059629:Signal-To-Noise Ratio; D013194:Staining and Labeling; D013274:Stomach Neoplasms / Q000556:secondary