University of Ljubljana

About: University of Ljubljana is a education organization based out in Ljubljana, Slovenia. It is known for research contribution in the topics: Population & Liquid crystal. The organization has 17210 authors who have published 47013 publications receiving 1082684 citations. The organization is also known as: Univerza v Ljubljani.

Combined Object Categorization and Segmentation With an Implicit Shape Model

Abstract: We present a method for object categorization in real-world scenes. Following a common consensus in the field, we do not assume that a figure- ground segmentation is available prior to recognition. However, in contrast to most standard approaches for object class recognition, our approach automati- cally segments the object as a result of the categorization. This combination of recognition and segmentation into one process is made pos- sible by our use of an Implicit Shape Model, which integrates both into a common probabilistic framework. In addition to the recognition and segmentation result, it also generates a per-pixel confidence measure specifying the area that supports a hypothesis and how much it can be trusted. We use this confidence to derive a nat- ural extension of the approach to handle multiple objects in a scene and resolve ambiguities between overlapping hypotheses with a novel MDL-based criterion. In addition, we present an extensive evaluation of our method on a standard dataset for car detection and compare its performance to existing methods from the literature. Our results show that the proposed method significantly outper- forms previously published methods while needing one order of magnitude less training examples. Finally, we present results for articulated objects, which show that the proposed method can categorize and segment unfamiliar objects in differ- ent articulations and with widely varying texture patterns, even under significant partial occlusion.

Dermoscopy of pigmented skin lesions: results of a consensus meeting via the Internet

Abstract: Background: There is a need for better standardization of the dermoscopic terminology in assessing pigmented skin lesions. Objective: The virtual Consensus Net Meeting on Dermoscopy was organized to investigate reproducibility and validity of the various features and diagnostic algorithms. Methods: Dermoscopic images of 108 lesions were evaluated via the Internet by 40 experienced dermoscopists using a 2-step diagnostic procedure. The first-step algorithm distinguished melanocytic versus nonmelanocytic lesions. The second step in the diagnostic procedure used 4 algorithms (pattern analysis, ABCD rule, Menzies method, and 7-point checklist) to distinguish melanoma versus benign melanocytic lesions. κ Values, log odds ratios, sensitivity, specificity, and positive likelihood ratios were estimated for all diagnostic algorithms and dermoscopic features. Results: Interobserver agreement was fair to good for all diagnostic methods, but it was poor for the majority of dermoscopic criteria. Intraobserver agreement was good to excellent for all algorithms and features considered. Pattern analysis allowed the best diagnostic performance (positive likelihood ratio: 5.1), whereas alternative algorithms revealed comparable sensitivity but less specificity. Interobserver agreement on management decisions made by dermoscopy was fairly good (mean κ value: 0.53). Conclusion: The virtual Consensus Net Meeting on Dermoscopy represents a valid tool for better standardization of the dermoscopic terminology and, moreover, opens up a new territory for diagnosing and managing pigmented skin lesions. (J Am Acad Dermatol 2003;48:679-93.) J Am Acad Dermatol 2003;48:679-93.

A Nonlinear Analysis Method for Performance‐Based Seismic Design

Abstract: A relatively simple nonlinear method for the seismic analysis of structures (the N2 method) is presented. It combines the pushover analysis of a multi‐degree‐of‐freedom (MDOF) model with the response spectrum analysis of an equivalent single‐degree‐of‐freedom (SDOF) system. The method is formulated in the acceleration‐displacement format, which enables the visual interpretation of the procedure and of the relations between the basic quantities controlling the seismic response. Inelastic spectra, rather than elastic spectra with equivalent damping and period, are applied. This feature represents the major difference with respect to the capacity spectrum method. Moreover, demand quantities can be obtained without iteration. Generally, the results of the N2 method are reasonably accurate, provided that the structure oscillates predominantly in the first mode. Some additional limitations apply. In the paper, the method is described and discussed, and it basic derivations are given. The similarities a...

Web Surveys versus other Survey Modes: A Meta-Analysis Comparing Response Rates:

Abstract: One question that arises when discussing the usefulness of web-based surveys is whether they gain the same response rates compared to other modes of collecting survey data. A common perception exists that, in general, web survey response rates are considerably lower. However, such unsystematic anecdotal evidence could be misleading and does not provide any useful quantitative estimate. Metaanalytic procedures synthesising controlled experimental mode comparisons could give accurate answers but, to the best of the authors' knowledge, such research syntheses have so far not been conducted. To overcome this gap, the authors have conducted a meta-analysis of 45 published and unpublished experimental comparisons between web and other survey modes. On average, web surveys yield an 11% lower response rate compared to other modes (the 95% confidence interval is confined by 15% and 6% to the disadvantage of the web mode). This response rate difference to the disadvantage of the web mode is systematically influenced by the sample recruitment base (a smaller difference for panel members as compared to one-time respondents), the solicitation mode chosen for web surveys (a greater difference for postal mail solicitation compared to email) and the number of contacts (the more contacts, the larger the difference in response rates between modes). No significant influence on response rate differences can be revealed for the type of mode web surveys are compared to, the type of target population, the type of sponsorship, whether or not incentives were offered, and the year the studies were conducted. Practical implications are discussed.

Discriminative Correlation Filter with Channel and Spatial Reliability

Abstract: Short-term tracking is an open and challenging problem for which discriminative correlation filters (DCF) have shown excellent performance. We introduce the channel and spatial reliability concepts to DCF tracking and provide a novel learning algorithm for its efficient and seamless integration in the filter update and the tracking process. The spatial reliability map adjusts the filter support to the part of the object suitable for tracking. This allows tracking of non-rectangular objects as well as extending the search region. Channel reliability reflects the quality of the learned filter and it is used as a feature weighting coefficient in localization. Experimentally, with only two simple standard features, HOGs and Colornames, the novel CSR-DCF method – DCF with Channel and Spatial Reliability – achieves state-of-the-art results on VOT 2016, VOT 2015 and OTB. The CSR-DCF runs in real-time on a CPU.