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Object Detection (object + detection)
Selected AbstractsObject detection using straight line matching in ,-, spaceELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 3 2010Taisei Okuzono Abstract The contours of many industrial parts contain straight lines and the positions of the lines are therefore useful information for object detection. This paper presents a matching technique for straight lines. The method consists of ,-matching, ,-matching, and pose estimation. Any lines in 2D space are represented with parameters , and , by the Hough transform. In order to find the corresponding lines in a model and a scene, the , and , values are evaluated in ,-matching and ,-matching. When an object is translated and rotated, the contour lines of the object are also transferred and the , values of the lines are merely shifted by the rotation angle in the ,-, space. Thus, the relative positions of the , values are invariant. In ,-matching, the corresponding lines of the model and the scene are selected so that the relative , values of the corresponding lines are nearly equal. In ,-matching, the corresponding lines are evaluated further by computing the deviations of their , values. Finally, the transfer parameters of the selected pairs are estimated in pose estimation. The experiments show that this technique is robust to rotation, occlusion, and scaling of the objects. We also discuss the computation time, in which the preprocess such as edge detection and the Hough transform takes much of the time. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(3): 34,41, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10176 [source] Differentiation of morphology, genetics and electric signals in a region of sympatry between sister species of African electric fish (Mormyridae)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2008S. LAVOUÉ Abstract Mormyrid fishes produce and sense weak electric organ discharges (EODs) for object detection and communication, and they have been increasingly recognized as useful model organisms for studying signal evolution and speciation. EOD waveform variation can provide important clues to sympatric species boundaries between otherwise similar or morphologically cryptic forms. Endemic to the watersheds of Gabon (Central Africa), Ivindomyrus marchei and Ivindomyrus opdenboschi are morphologically similar to one another. Using morphometric, electrophysiological and molecular characters [cytochrome b sequences and amplified fragment length polymorphism (AFLP) genotypes], we investigated to what extent these nominal mormyrid species have diverged into biological species. Our sampling covered the known distribution of each species with a focus on the Ivindo River, where the two taxa co-occur. An overall pattern of congruence among datasets suggests that I. opdenboschi and I. marchei are mostly distinct. Electric signal analysis showed that EODs of I. opdenboschi tend to have a smaller initial head-positive peak than those of I. marchei, and they often possess a small third waveform peak that is typically absent in EODs of I. marchei. Analysis of sympatric I. opdenboschi and I. marchei populations revealed slight, but significant, genetic partitioning between populations based on AFLP data (FST , 0.04). Taken separately, however, none of the characters we evaluated allowed us to discriminate two completely distinct or monophyletic groups. Lack of robust separation on the basis of any single character set may be a consequence of incomplete lineage sorting due to recent ancestry and/or introgressive hybridization. Incongruence between genetic datasets in one individual, which exhibited a mitochondrial haplotype characteristic of I. marchei but nevertheless fell within a genetic cluster of I. opdenboschi based on AFLP genotypes, suggests that a low level of recent hybridization may also be contributing to patterns of character variation in sympatry. Nevertheless, despite less than perfect separability based on any one dataset and inconclusive evidence for complete reproductive isolation between them in the Ivindo River, we find sufficient evidence to support the existence of two distinctive species, I. opdenboschi and I. marchei, even if not ,biological species' in the Mayrian sense. [source] Vasilius: The design of an autonomous ground robotic vehicleJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 9 2004Jarrod M. Snider This paper presents the design and provides a partial analysis of the performance of an autonomous ground robotic vehicle called Vasilius. Applications for Vasilius include autonomous navigation on a somewhat marked path with obstacles, leader following, and waypoint navigation. The paper focuses on three aspects of Vasilius: the design, the performance, and a technique for filtering, mapping, and learning. The design of Vasilius embodies a novel idea of modeling an autonomous vehicle after human senses and the human decision-making process. For instance, Vasilius integrates information from seven types of independent sensors, and categorizes them into either short-range reaction sensors and/or long-range planning sensors, analogous to what the human brain does. The paper also analyzes the performance of Vasilius, relating theoretical predictions to actual behavior. Some of these analyses, especially for the filtering, mapping, and learning, are still in progress. Performance measures that have been measured include speed, ramp climbing, turn reaction time, battery life, stop reaction time, object detection, and waypoint accuracy. Finally, the paper discusses Vasilius' use of a new approach to filtering, mapping, and learning to enhance its performance. © 2004 Wiley Periodicals, Inc. [source] Visual object recognition in early Alzheimer's disease: deficits in semantic processingACTA NEUROLOGICA SCANDINAVICA, Issue 2 2003S. Laatu Objectives , The purpose of the present study was to divide visual object recognition into different stages and to reveal which of these stages are impaired in early Alzheimer's disease (AD). Methods , Performance in object detection, familiarity detection, semantic name and word categorization, and identification with naming were studied by using two-choice reaction-time tasks. Ten patients with newly diagnosed AD and 14 healthy subjects were studied. Results , Patients with early AD had impairments in several stages of the object recognition process. After controlling for the basic visuomotor slowness, they were as fast and as accurate as the controls in object detection, but had difficulties in all stages that required semantic processing. Conclusions , Semantic memory impairments contribute to the deficits in visual object recognition in early AD. Thus, the semantic memory deficit may be manifested in several ways in the difficulties that AD patients experience in everyday life. [source] Mindfulness-based stress reduction and attentional controlCLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 6 2007Nicole D. Anderson This study was designed to test the hypothesis that mindfulness involves sustained attention, attention switching, inhibition of elaborative processing and non-directed attention. Healthy adults were tested before and after random assignment to an 8-week Mindfulness-Based Stress Reduction (MBSR) course (n = 39) or a wait-list control (n = 33). Testing included measures of sustained attention, attention switching, Stroop interference (as a measure of inhibition of elaborative processing), detection of objects in consistent or inconsistent scenes (as a measure of non-directed attention), as well as self-report measures of emotional well-being and mindfulness. Participation in the MBSR course was associated with significantly greater improvements in emotional well-being and mindfulness, but no improvements in attentional control relative to the control group. However, improvements in mindfulness after MBSR were correlated with improvements in object detection. We discuss the implications of these results as they relate to the role of attention in mindfulness.,Copyright © 2007 John Wiley & Sons, Ltd. [source] | ||||||||||