982 resultados para camera motion
Resumo:
Laughter is a frequently occurring social signal and an important part of human non-verbal communication. However it is often overlooked as a serious topic of scientific study. While the lack of research in this area is mostly due to laughter’s non-serious nature, it is also a particularly difficult social signal to produce on demand in a convincing manner; thus making it a difficult topic for study in laboratory settings. In this paper we provide some techniques and guidance for inducing both hilarious laughter and conversational laughter. These techniques were devised with the goal of capturing mo- tion information related to laughter while the person laughing was either standing or seated. Comments on the value of each of the techniques and general guidance as to the importance of atmosphere, environment and social setting are provided.
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We address the problem of multi-target tracking in realistic crowded conditions by introducing a novel dual-stage online tracking algorithm. The problem of data-association between tracks and detections, based on appearance, is often complicated by partial occlusion. In the first stage, we address the issue of occlusion with a novel method of robust data-association, that can be used to compute the appearance similarity between tracks and detections without the need for explicit knowledge of the occluded regions. In the second stage, broken tracks are linked based on motion and appearance, using an online-learned linking model. The online-learned motion-model for track linking uses the confident tracks from the first stage tracker as training examples. The new approach has been tested on the town centre dataset and has performance comparable with the present state-of-the-art
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Manipulator motion planning is a task which relies heavily on the construction of a configuration space prior to path planning. However when fast real-time motion is needed, the full construction of the manipulator's high-dimensional configu-ration space can be too slow and expensive. Alternative planning methods, which avoid this full construction of the manipulator's configuration space are needed to solve this problem. Here, one such existing local planning method for manipulators based on configuration-sampling and subgoal-selection has been extended. Using a modified Artificial Potential Fields (APF) function, goal-configuration sampling and a novel subgoal selection method, it provides faster, more optimal paths than the previously proposed work. Simulation results show a decrease in both runtime and path lengths, along with a decrease in unexpected local minimum and crashing issues.
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In this paper, an improved video encryption method for encrypting the sign bit of motion vectors is proposed based on H.264/AVC, which belongs to selective encryption. This method improves upon previous work involving the sign bit encryption of motion vectors by ensuring the four candidates for the encrypted motion vectors are always located in two orthogonal lines. The improved method can provide a much more effective scrambling effect while keeping the encrypted stream format-compliant and the compression ratio unchanged. The combination of the proposed method with encryption of intra prediction modes can further enhance the scrambling effect, especially for the first few frames which are left clear when only the motion vectors are encrypted.
Resumo:
Paradoxical kinesia describes the motor improvement in Parkinson's disease (PD) triggered by the presence of external sensory information relevant for the movement. This phenomenon has been puzzling scientists for over 60 years, both in neurological and motor control research, with the underpinning mechanism still being the subject of fierce debate. In this paper we present novel evidence supporting the idea that the key to understanding paradoxical kinesia lies in both spatial and temporal information conveyed by the cues and the coupling between perception and action. We tested a group of 7 idiopathic PD patients in an upper limb mediolateral movement task. Movements were performed with and without a visual point light display, travelling at 3 different speeds. The dynamic information presented in the visual point light display depicted three different movement speeds of the same amplitude performed by a healthy adult. The displays were tested and validated on a group of neurologically healthy participants before being tested on the PD group. Our data show that the temporal aspects of the movement (kinematics) in PD can be moderated by the prescribed temporal information presented in a dynamic environmental cue. Patients demonstrated a significant improvement in terms of movement time and peak velocity when executing movement in accordance with the information afforded by the point light display, compared to when the movement of the same amplitude and direction was performed without the display. In all patients we observed the effect of paradoxical kinesia, with a strong relationship between the perceptual information prescribed by the biological motion display and the observed motor performance of the patients. © 2013 Elsevier B.V. All rights reserved.
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We present the results of an extensive high-resolution imaging survey of M-dwarf multiplicity using the Lucky Imaging technique. The survey made use of the AstraLux Norte camera at the Calar Alto 2.2m telescope and the AstraLux Sur camera at the ESO New Technology Telescope in order to cover nearly the full sky. In total, 761 stars were observed (701M-type and 60 late K-type), among which 182 new and 37 previously known companions were detected in 205 systems. Most of the targets have been observed during two or more epochs, and could be confirmed as physical companions through common proper motion, often with orbital motion being confirmed in addition. After accounting for various bias effects, we find a total M-dwarf multiplicity fraction of 27% ± 3% within the AstraLux detection range of 008-6? (semimajor axes of ~3-227 AU at a median distance of 30pc). We examine various statistical multiplicity properties within the sample, such as the trend of multiplicity fraction with stellar mass and the semimajor axis distribution. The results indicate that M-dwarfs are largely consistent with constituting an intermediate step in a continuous distribution from higher-mass stars down to brown dwarfs. Along with other observational results in the literature, this provides further indications that stars and brown dwarfs may share a common formation mechanism, rather than being distinct populations. © 2012. The American Astronomical Society. All rights reserved.
E-motion: tutors’ experiences of the transition to e-portfolio use in pre-service teacher education.
Resumo:
ULTRACAM is a high-speed three-colour CCD camera designed to provide imaging photometry at high temporal resolutions. The instrument is highly portable and will be used at a number of large telescopes around the world. ULTRACAM was successfully commissioned on the 4.2-m William Herschel Telescope on La Palma on 16 May 2002 over 3 months ahead of schedule and within budget. The instrument was funded by PPARC and designed and built by a consortium involving the Universities of Sheffield Southampton and the UKATC Edinburgh. We present an overview of the design and performance characteristics of ULTRACAM and highlight some of its most recent scientific results.
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Respiratory motion introduces complex spatio-temporal variations in the dosimetry of radiotherapy and may contribute towards uncertainties in radiotherapy planning. This study investigates the potential radiobiological implications occurring due to tumour motion in areas of geometric miss in lung cancer radiotherapy. A bespoke phantom and motor-driven platform to replicate respiratory motion and study the consequences on tumour cell survival in vitro was constructed. Human non-small-cell lung cancer cell lines H460 and H1299 were irradiated in modulated radiotherapy configurations in the presence and absence of respiratory motion. Clonogenic survival was calculated for irradiated and shielded regions. Direction of motion, replication of dosimetry by multi-leaf collimator (MLC) manipulation and oscillating lead shielding were investigated to confirm differences in cell survival. Respiratory motion was shown to significantly increase survival for out-of-field regions for H460/H1299 cell lines when compared with static irradiation (p <0.001). Significantly higher survival was found in the in-field region for the H460 cell line (p <0.030). Oscillating lead shielding also produced these significant differences. Respiratory motion and oscillatory delivery of radiation dose to human tumour cells has a significant impact on in- and out-of-field survival in the presence of non-uniform irradiation in this in vitro set-up. This may have important radiobiological consequences for modulated radiotherapy in lung cancer.