8,438 research outputs found

    A fast method for computing the output of rank order filters within arbitrarily shaped windows

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    Rank order filters are used in a multitude of image processing tasks. Their application can range from simple preprocessing tasks which aim to reduce/remove noise, to more complex problems where such filters can be used to detect and segment image features. There is, therefore, a need to develop fast algorithms to compute the output of this class of filter. A number of methods for efficiently computing the output of specific rank order filters have been proposed [1]. For example, numerous fast algorithms exist that can be used for calculating the output of the median filter. Fast algorithms for calculating morphological erosions and dilations - which are also a special case of the more general rank order filter - have also been proposed. In this paper we present an extension of a recently introduced method for computing fast morphological operators to the more general case of rank order filters. Using our method, we are able to efficiently compute any rank, using any arbitrarily shaped window, such that it is possible to quickly compute the output of any rank order filter. We demonstrate the usefulness and efficiency of our technique by implementing a fast method for computing a recent generalisation of the morphological Hit-or-Miss Transform which makes it more robust in the presence of noise. We also compare the speed and efficiency of this routine with similar techniques that have been proposed in the literature

    Physiological cost of walking in those with chronic fatigue syndrome

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    <b>Purpose:</b> To examine the physiological cost of walking in subjects with chronic fatigue syndrome (CFS) and a matched control group, walking at their preferred and at matched walking speeds. <b>Methods:</b> Seventeen people with CFS and 17 matched-controls participated in this observational study of physiological cost during over-ground gait. Each subject walked for 5 min at their preferred walking speed (PWS). Controls then walked for 5 min at the same pace of their matched CFS subject. Gait speed and oxygen uptake, gross and net were measured and oxygen uptake was expressed per unit distance ambulated. CFS subjects completed the CFS-Activities and Participation Questionnaire (CFS-APQ). <b>Results:</b> At PWS the CFS group walked at a slower velocity of 0.84 ± 0.21 m s<sup>-1</sup> compared to controls with a velocity of 1.19 ± 0.13 m s<sup>-1</sup> (p < 0.001). At PWS both gross and net oxygen uptake of CFS subjects was significantly less than controls (p = 0.023 and p = 0.025 respectively). At matched-velocity both gross and net physiological cost of gait was greater for CFS subjects than controls (p = 0.048 and p = 0.001, respectively). <b>Conclusion:</b> The physiological cost of walking was significantly greater for people with CFS compared with healthy subjects. The reasons for these higher energy demands for walking in those with CFS have yet to be fully elucidated

    Low-fi skin vision: A case study in rapid prototyping a sensory substitution system

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    We describe the design process we have used to develop a minimal, twenty vibration motor Tactile Vision Sensory Substitution (TVSS) system which enables blind-folded subjects to successfully track and bat a rolling ball and thereby experience 'skin vision'. We have employed a low-fi rapid prototyping approach to build this system and argue that this methodology is particularly effective for building embedded interactive systems. We support this argument in two ways. First, by drawing on theoretical insights from robotics, a discipline that also has to deal with the challenge of building complex embedded systems that interact with their environments; second, by using the development of our TVSS as a case study: describing the series of prototypes that led to our successful design and highlighting what we learnt at each stage

    Measuring environments for public displays: a Space Syntax approach

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    This paper reports on an on-going project, which is investigating the role that location plays in the visibility of information presented on a public display. Spatial measures are presented, derived from the architectural theory of Space Syntax. These are shown to relate to the memorability of words and images presented on different displays. Results show a complex pattern of interactions between the size and shape of spaces in which displays are situated and the memorability of different types of representations depicted. This approach offers a new way to consider the role of space in guiding and constraining interaction in real settings: a growing concern within HCI and Ubicomp

    A near-infrared study of the luminous merging galaxies NGC 2623 and ARP 148

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    As part of an investigation of the physical mechanisms which produce large infrared luminosities in interacting systems, multicolor near-infrared maps were obtained of the long tailed galaxy NGC 2623 and the ring galaxy Arp 148. The near-infrared broadband spectrum was decomposed to obtain the contribution of four processes: emission from evolved stars, nebular continuum emission, thermal reradiation, and extinction. This multicolor analysis, along with 2 micrometer maps and 10 micrometer measurements, is used to determine the structure of these interacting galaxies and to delineate regions of star formation

    Red deer habitat management in the Highlands: Consequences for invertebrates

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    In Scotland, the well documented increase in the red deer population is widely regarded as a cause for concern, due to potentially detrimental impacts of grazing. This has lead to conflicting objectives between conservation and deer managers, despite the extent of the increase and the resulting impact both being hotly debated issues. Upland heather moorland is of international conservation importance while woodland habitats are some of the most stable ecosystems in anthropogenic landscapes. In the UK oak woodland plays a crucial role in the maintenance of biodiversity, and both heather moorland and oak woodland may be subject to degradation or decline due to grazing. This study is based in north-west Scotland, and investigates the consequences of two deer management strategies, in two habitat types, for invertebrates. An observational study of heather moorland under two extremes of grazing pressure provided little evidence for negative impacts of grazing on invertebrates on the more heavily grazed Letterewe Estate, suggesting that the deer population is not a cause for concern in terms of invertebrate biodiversity. An experimental study of grazed and un-grazed oak woodland found some positive effects, and no instances of negative grazing impacts on invertebrate biodiversity, and no effect on guild structure. This work highlights the need for science to inform land management policy that must often seek to balance conservation objectives with economic interests, and supports the notion that a red deer herd of a size consistent with viable stalking interests can be integral to the maintenance of biodiversity and the natural heritage