8 resultados para Video Analysis

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Pós-graduação em Engenharia Elétrica - FEIS

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A target tracking algorithm able to identify the position and to pursuit moving targets in video digital sequences is proposed in this paper. The proposed approach aims to track moving targets inside the vision field of a digital camera. The position and trajectory of the target are identified by using a neural network presenting competitive learning technique. The winning neuron is trained to approximate to the target and, then, pursuit it. A digital camera provides a sequence of images and the algorithm process those frames in real time tracking the moving target. The algorithm is performed both with black and white and multi-colored images to simulate real world situations. Results show the effectiveness of the proposed algorithm, since the neurons tracked the moving targets even if there is no pre-processing image analysis. Single and multiple moving targets are followed in real time.

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Understanding the biological activity profile of the snake venom components is fundamental for improving the treatment of snakebite envenomings and may also contribute for the development of new potential therapeutic agents. In this work, we tested the effects of BthTX-I, a Lys49 PLA2 homologue from the Bothrops jararacussu snake venom. While this toxin induces conspicuous myonecrosis by a catalytically independent mechanism, a series of in vitro studies support the hypothesis that BthTX-I might also exert a neuromuscular blocking activity due to its ability to alter the integrity of muscle cell membranes. To gain insight into the mechanisms of this inhibitory neuromuscular effect, for the first time, the influence of BthTX-I on nerve-evoked ACh release was directly quantified by radiochemical and real-time video-microscopy methods. Our results show that the neuromuscular blockade produced by in vitro exposure to BthTX-I (1 μM) results from the summation of both pre- and postsynaptic effects. Modifications affecting the presynaptic apparatus were revealed by the significant reduction of nerve-evoked [3H]-ACh release; real-time measurements of transmitter exocytosis using the FM4-64 fluorescent dye fully supported radiochemical data. The postsynaptic effect of BthTX-I was characterized by typical histological alterations in the architecture of skeletal muscle fibers, increase in the outflow of the intracellular lactate dehydrogenase enzyme and progressive depolarization of the muscle resting membrane potential. In conclusion, these findings suggest that the neuromuscular blockade produced by BthTX-I results from transient depolarization of skeletal muscle fibers, consequent to its general membrane-destabilizing effect, and subsequent decrease of evoked ACh release from motor nerve terminals. © 2012 Elsevier Ltd.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This paper introduces the Optimum-Path Forest (OPF) classifier for static video summarization, being its results comparable to the ones obtained by some state-of-the-art video summarization techniques. The experimental section has been conducted using several image descriptors in two public datasets, followed by an analysis of OPF robustness regarding one ad-hoc parameter. Future works are guided to improve OPF effectiveness on each distinct video category.

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To evaluate the volumetric changes due to polymerization and thermocycling on different resin-composites. Methods: Thirteen A2 Universal Dentin shade resin-composites (n = 10) from eight manufacturers were evaluated (4Seasons, Grandio, Venus, Amelogen Plus, P90, Z350, Esthet-X, Amaris, Vita-l-escence, Natural-Look, Charisma, Z250 and Opallis). The polymerization shrinkage percentage (PS) was calculated using an image measurement device (ACUVOL - Bisco Dental). Equal volumes of material, standardized by a semisphere polyurethane matrix (d = 3mm) were used and, after 5 minutes of relaxation, the baseline volume measurements were obtained with 18 J of energy dose from the LED light-curing unit. Measurements were obtained after 5 minutes and PS values calculated. Specimens were stored in a drydark environment for 24 hours and re-measured. Specimens were then thermocycled in distilled water between 5oC and 55oC for 20,000 cycles, subjected to another volume measurement at 5,000 cycle intervals. Specimens were gently dried prior to each measurement. Results: Repeated measurements were made using ANOVA (α = 0.05) showed that all resin-composite volumes were influenced by the number of cycles. Volumes at 5 minutes post-polymerization (12.47 ± 0.08) were significantly lower than those at baseline (12.80 ± 0.09). Volumes at 24 hours (12.43 ± 0.19) were insignificantly lower than those at 5 minutes postpolymerization. With regards to the impact of thermocycling, all specimens showed statistically significant increases in volume after 5,000 cycles (13.04 ± 0.22). Although statistically different from those after 5,000 cycles, there was no statistically significant difference between volumes measured at 10,000 (12.87±0.21), 15,000 (12.92±0.24), and 20,000 (12.84±0.23) cycles. Conclusion: According to the video-imaging analysis, thermocycling caused a significant expansion in resin-composites tested, the volume increase was not able to...