1,722,109 research outputs found
Trust on Instagram (Gottschlich & Winkelmann, Jan. 2021)
No full textBachelor thesis from Jens Gottschlich & Max Winkelmann
Directional global three-part image decomposition
No full textWe consider the task of image decomposition, and we introduce a new model coined directional global three-part decomposition (DG3PD) for solving it. As key ingredients of the DG3PD model, we introduce a discrete multi-directional total variation norm and a discrete multi-directional G-norm. Using these novel norms, the proposed discrete DG3PD model can decompose an image into two or three parts. Existing models for image decomposition by Vese and Osher (J. Sci. Comput. 19(1–3):553–572, 2003), by Aujol and Chambolle (Int. J. Comput. Vis. 63(1):85–104, 2005), by Starck et al. (IEEE Trans. Image Process. 14(10):1570–1582, 2005), and by Thai and Gottschlich are included as special cases in the new model. Decomposition of an image by DG3PD results in a cartoon image, a texture image, and a residual image. Advantages of the DG3PD model over existing ones lie in the properties enforced on the cartoon and texture images. The geometric objects in the cartoon image have a very smooth surface and sharp edges. The texture image yields oscillating patterns on a defined scale which are both smooth and sparse. Moreover, the DG3PD method achieves the goal of perfect reconstruction by summation of all components better than the other considered methods. Relevant applications of DG3PD are a novel way of image compression as well as feature extraction for applications such as latent fingerprint processing and optical character recognition
Hieracium moravense Gottschlich & Selvi 2023, spec. nov.
No full textHieracium moravense Gottschl. & Selvi, spec. nov. („waldsteinii – bifidum“) (figs. 1+2) Type:— ALBANIA. Korcë, Mt. Moravë, gola rocciosa che parte da Drenovë, rocce e rupi ultramafiche (serpentino), 40.5780°N, 20.7966°E, 980–1100 m, 14.07.2022, F. Selvi, A. Coppi, I. Colzi, E. Bianchi s. n. (holotype: FI068417; isotype: Hb. Gottschlich 81174). Diagnosis:— Planta inter Hieracium waldsteinii subsp. plumulosum et H. bifidum intermedia, ab Hieracio waldsteinii foliis rosulariis veris et supra minus hirsutis vel glabrescentibus, foliis caulinis minus numerosis, ab Hieracio bifido indumento plumoso differt. Perennial, hemicryptophyte. Rhizome stout, vertical. Stem erect, vertical, cylindrical, stout (2 mm in diam.), 25–40 cm tall, light green, brownish-purple at base, slightly striated, phyllopodous, in lower part with dense plumose whitish, soft, simple hairs and sparse minute (up to 0.1 mm long) yellowish glandular hairs, above glabrous. Basal leaves 3–4, ovate to elliptical, blade 4–8 × 3–4 cm, greyish-green, at base rounded to shortly attenuate, entire or denticulate only in the lower part, petiole 1–3 cm long, like the lower surface of leaves densely covered with 1–1.5 mm long plumose whitish soft simple hairs, upper surface becoming glabrous or only covered with moderate to sparse plumose hairs, glandular and stellate hairs absent. Cauline leaves 2–3, lanceolate, entire, the lower one long attenuate in a short, 1 cm long petiole, the one or two others attenuate-sessile, pubescence like on the basal leaves. Synflorescence racemose, peduncles 2–3, 3–7 cm long, sparsely covered with stellate hairs, in the upper part with 1–2 filiform bracts 3–4 mm long. Involucre almost ovoid, 8–9 mm long. Involucral bracts in a few rows, dark green, linear-lanceolate, 1 mm wide, acute, with dense stellate and few 0.3 mm long glandular hairs, simple hairs lacking. Corolla limb ligulate, yellow, glabrous. Styles yellow. Margins of alveoli with short broad teeth. Achenes not seen. Phenology: —Flowering in June and July. Fruiting in July. Distribution and ecology:— Hieracium moravense is currently known from only the type locality in the massif of Mt. Moravë in the region of Korcë. This locality is found in the narrow rocky valley ending at the south-eastern border of the village of Drenovë. The few plants that we could observe were growing at 1030–1050 m a.s.l. in fissures of steep, nearly vertical serpentine rocks on the hydrographic right of the gorge, mainly facing to the south-west (Fig. 3). Due to the difficult access to the site, only two specimens could be collected. This new hawkweed can be categorized as a metallophyte, and is also likely an obligate serpentinophyte, being able to tolerate the several chemical and physical anomalies of ultramafic soils, especially the elevated concentrations of trace metals such as Ni, Cr and Co. Taxonomic affinities:—As given in the diagnosis, Hieracium moravense is quite intermediate between H. waldsteinii subsp. plumulosum and H. bifidum. Such species with intermediate characters between a species of Hieracium sect. Pannosa and a species of Hieracium sect. Hieracium or H. sect. Bifida (Arvet-Touvet) A.R.Clapham in Clapham et al. (1952: 1135) are well known from the Balkan Peninsula. They may have evolved by hybridisation. Examples are Hieracium eriobasis Freyn & Sintenis in Freyn (1897: 787) („pannosum – murorum“), H. megalothecum Zahn (1921: 587) („gymnocephalum – murorum“), H. mattfeldianum Zahn (1928: 383) („pannosum – bifidum“) and H. wettsteinianum Zahn (1921: 586) („gymnocephalum – bifidum“). In the habit they all are characterised in being intermediate between the aphyllopodous Pannosa species and the phyllopodous H. murorum Linnaeus (1753: 802) or H. bifidum Kitaibel ex Hornemann (1815: 761). Differences are easy to recognize by the different pubescence of the putative parents. Final remarks:—The discovery of Hieracium moravense underlies the phytogeographical importance of Mount Moravë as a centre of plant diversity in Albania, especially for the serpentine flora. This area is home of local endemics such as Odontarrhena moravensis (F.K.Meyer) L. Cecchi & Selvi (2018: 18) and Centaurea drenovensis Pils (2016: 9), as well as of Albanian endemics like Acantholimon albanicum O.Schwarz & F.K.Meyer in Meyer (1987: 31), and others.Published as part of Gottschlich, Günter & Selvi, Federico, 2023, Hieracium moravense (Asteraceae), a new hawkweed from Albania, pp. 73-78 in Phytotaxa 592 (1) on pages 73-75, DOI: 10.11646/phytotaxa.592.1.7, http://zenodo.org/record/783571
Curved-Region-Based Ridge Frequency Estimation and Curved Gabor Filters for Fingerprint Image Enhancement
No full textGabor filters (GFs) play an important role in many application areas for the enhancement of various types of images and the extraction of Gabor features. For the purpose of enhancing curved structures in noisy images, we introduce curved GFs that locally adapt their shape to the direction of flow. These curved GFs enable the choice of filter parameters that increase the smoothing power without creating artifacts in the enhanced image. In this paper, curved GFs are applied to the curved ridge and valley structures of low-quality fingerprint images. First, we combine two orientation-field estimation methods in order to obtain a more robust estimation for very noisy images. Next, curved regions are constructed by following the respective local orientation. Subsequently, these curved regions are used for estimating the local ridge frequency. Finally, curved GFs are defined based on curved regions, and they apply the previously estimated orientations and ridge frequencies for the enhancement of low-quality fingerprint images. Experimental results on the FVC2004 databases show improvements of this approach in comparison with state-of-the-art enhancement methods.DFG RTG [1023
Convolution Comparison Pattern: An Efficient Local Image Descriptor for Fingerprint Liveness Detection.
No full textWe present a new type of local image descriptor which yields binary patterns from small image patches. For the application to fingerprint liveness detection, we achieve rotation invariant image patches by taking the fingerprint segmentation and orientation field into account. We compute the discrete cosine transform (DCT) for these rotation invariant patches and attain binary patterns by comparing pairs of two DCT coefficients. These patterns are summarized into one or more histograms per image. Each histogram comprises the relative frequencies of pattern occurrences. Multiple histograms are concatenated and the resulting feature vector is used for image classification. We name this novel type of descriptor convolution comparison pattern (CCP). Experimental results show the usefulness of the proposed CCP descriptor for fingerprint liveness detection. CCP outperforms other local image descriptors such as LBP, LPQ and WLD on the LivDet 2013 benchmark. The CCP descriptor is a general type of local image descriptor which we expect to prove useful in areas beyond fingerprint liveness detection such as biological and medical image processing, texture recognition, face recognition and iris recognition, liveness detection for face and iris images, and machine vision for surface inspection and material classification
FIGURE 2 in New taxa of Hieracium (Asteraceae) from Mount Lesima and adjacent regions (Northern Apennine, Italy)
No full textFIGURE 2. Hieracium lesimanum (isotype, Hb. Gottschlich-75892).Published as part of Gottschlich, Günter & Orsenigo, Simone, 2021, New taxa of Hieracium (Asteraceae) from Mount Lesima and adjacent regions (Northern Apennine, Italy), pp. 39-55 in Phytotaxa 505 (1) on page 44, DOI: 10.11646/phytotaxa.505.1.2, http://zenodo.org/record/542516
Hieracium murorum subsp. cophogonium Bornm. & Zahn
No full textHieracium murorum subsp. cophogonium Bornm. & Zahn in Zahn (1925: 161). Ind. loc.: “Frontière bâloise-badoise: Hohr[sic!] M i hr près Zell (A. Krafft). Trouvé aussi par Bornmüller à Tr i bsdorf, près Weimar, dans la Thuringe.” Lectotype (designated here by Gottschlich): — GERMANY. Baden-Wuerttemberg: Hohe M i hr, 11 June 1923, A. Krafft (BREG!). — Remaining syntype: GERMANY. Thuringia: Weimar, Tr i bsdorf, westl. bei d. Bahnbrücke, 8 June 1923, J. Bornmüller (B barcode B 10 0460350!). Remarks: —Although Bornmüller is co-author of the taxon, in the protologue the collection of Krafft is cited first and is here selected as lectotype.Published as part of Vogt, Robert & Gottschlich, Günter, 2023, Type material in the Hieracium (Compositae: Cichorieae) collection of Joseph Bornmüller, pp. 81-126 in Phytotaxa 613 (2) on page 102, DOI: 10.11646/phytotaxa.613.2.1, http://zenodo.org/record/834553
Statistical analyses of fingerprint growth
No full textWe study the effect of growth on the fingerprints of adolescents, based on which we suggest a simple method to adjust for growth when trying to retrieve an adolescent's fingerprint in a database years later. Here, we focus on the statistical analyses used to determine how fingerprints grow: Procrustes analysis allows us to establish that fingerprints grow isotropically, an appropriate mixed effects model shows that fingerprints essentially grow proportionally to body height. The resulting growth model is validated by showing that it brings points of interest as close as if both fingerprints were taken from an adult. Further details on this study, in particular results when applying our growth model in verification and identification tests, can be found in C. Gottschlich, T. Hotz, R. Lorenz, S. Bernhardt, M. Hantschel and A. Munk: Modeling the Growth of Fingerprints Improves Matching for Adolescents, IEEE Transations on Information Forensics and Security, 201
Statistical analyses of fingerprint growth
No full textWe study the effect of growth on the fingerprints of adolescents, based on which we suggest a simple method to adjust for growth when trying to retrieve an adolescent's fingerprint in a database years later. Here, we focus on the statistical analyses used to determine how fingerprints grow: Procrustes analysis allows us to establish that fingerprints grow isotropically, an appropriate mixed effects model shows that fingerprints essentially grow proportionally to body height. The resulting growth model is validated by showing that it brings points of interest as close as if both fingerprints were taken from an adult. Further details on this study, in particular results when applying our growth model in verification and identification tests, can be found in C. Gottschlich, T. Hotz, R. Lorenz, S. Bernhardt, M. Hantschel and A. Munk: Modeling the Growth of Fingerprints Improves Matching for Adolescents, IEEE Transations on Information Forensics and Security, 201
The Shortlist Method for fast computation of the Earth Mover's Distance and finding optimal solutions to transportation problems.
No full textFinding solutions to the classical transportation problem is of great importance, since this optimization problem arises in many engineering and computer science applications. Especially the Earth Mover's Distance is used in a plethora of applications ranging from content-based image retrieval, shape matching, fingerprint recognition, object tracking and phishing web page detection to computing color differences in linguistics and biology. Our starting point is the well-known revised simplex algorithm, which iteratively improves a feasible solution to optimality. The Shortlist Method that we propose substantially reduces the number of candidates inspected for improving the solution, while at the same time balancing the number of pivots required. Tests on simulated benchmarks demonstrate a considerable reduction in computation time for the new method as compared to the usual revised simplex algorithm implemented with state-of-the-art initialization and pivot strategies. As a consequence, the Shortlist Method facilitates the computation of large scale transportation problems in viable time. In addition we describe a novel method for finding an initial feasible solution which we coin Modified Russell's Method
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