title: Local fractal dimension based approaches for colonic polyp classification.
abstract: This work introduces texture analysis methods that are based on computing the local fractal dimension (LFD; or also called the local density function) and applies them for colonic polyp classification. The methods are tested on 8 HD-endoscopic image databases, where each database is acquired using different imaging modalities (Pentax's i-Scan technology combined with or without staining the mucosa) and on a zoom-endoscopic image database using narrow band imaging. In this paper, we present three novel extensions to a LFD based approach. These extensions additionally extract shape and/or gradient information of the image to enhance the discriminativity of the original approach. To compare the results of the LFD based approaches with the results of other approaches, five state of the art approaches for colonic polyp classification are applied to the employed databases. Experiments show that LFD based approaches are well suited for colonic polyp classification, especially the three proposed extensions. The three proposed extensions are the best performing methods or at least among the best performing methods for each of the employed databases. The methods are additionally tested by means of a public texture image database, the UIUCtex database. With this database, the viewpoint invariance of the methods is assessed, an important features for the employed endoscopic image databases. Results imply that most of the LFD based methods are more viewpoint invariant than the other methods. However, the shape, size and orientation adapted LFD approaches (which are especially designed to enhance the viewpoint invariance) are in general not more viewpoint invariant than the other LFD based approaches.
authors.affiliation: St. Elisabeth Hospital, Landstraßer Hauptstraße 4a, Vienna A-1030, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Häfner
authors.affiliation: Department of Information Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-hiroshima, Hiroshima 739-8527, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Tamaki
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Computer Sciences, Jakob Haringerstrasse 2, University of Salzburg, Salzburg 5020, Austria. Electronic address: uhl@cosy.sbg.ac.at.
authors.forename: Andreas
authors.initials: A
authors.lastname: Uhl
authors.affiliation: Department of Computer Sciences, Jakob Haringerstrasse 2, University of Salzburg, Salzburg 5020, Austria. Electronic address: gwimmer@cosy.sbg.ac.at.
authors.forename: Georg
authors.initials: G
authors.lastname: Wimmer
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Shigeto
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D000465:Algorithms; D003111:Colonic Polyps / Q000473:pathology*; D003113:Colonoscopy / Q000379:methods*; D017709:Fractals; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D000069550:Machine Learning; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Local fractal dimension; Polyp classification; Texture recognition; Viewpoint invariance