In this paper, digital stereoscopic imaging and reconstruction techniques have been developed for the tracking and velocity measurement of solid particles using a single camera. The variable shutter speeds of a digita...
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In this paper, digital stereoscopic imaging and reconstruction techniques have been developed for the tracking and velocity measurement of solid particles using a single camera. The variable shutter speeds of a digital camera are used to control the trajectory length of the tracked particles. A colour coding method has been developed to resolve the ambiguity of particle flow direction and avoid the confusion in manually matching particle pairs. The method could be applied to validate the automated particle matching algorithms. Besides using points (particle centroids) a matching algorithm for a stereo reconstruction pixel to pixel matching algorithm has been applied. The latter is able to resolve not only the particle position but also the shape and orientation of a non-spherical particle. This is of importance since non-spherical particle or bubble geometry is common in a practical system and the non-spherical geometry has a strong effect on the particle or bubble dynamics. The potential of using this system for the quantitative 3D measurement of multiphase flow has been demonstrated with several test cases. (c) 2005 Elsevier Ltd. All rights reserved.
The responsiveness of adult beech and spruce trees to chronic O-3 stress was studied at a free-air O-3 exposure experiment in Freising/Germany. Over three growing seasons, gas exchange characteristics, biochemical par...
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The responsiveness of adult beech and spruce trees to chronic O-3 stress was studied at a free-air O-3 exposure experiment in Freising/Germany. Over three growing seasons, gas exchange characteristics, biochemical parameters, macroscopic O-3 injury and the phenology of leaf organs were investigated, along with assessments of branch and stem growth as indications of tree performance. To assess response pattern to chronic O-3 stress in adult forest trees, we introduce a new evaluation approach, which provides a comprehensive, readily accomplishable overview across several tree-internal scaling levels, different canopy regions and growing seasons. This new approach, based on a three-grade colour coding, combines statistical analysis and the proficient ability of the "human eye" in pattern recognition. (c) 2005 Elsevier Ltd. All rights reserved.
Eighteen people participated in an experiment in which they were asked to search for targets on control room like displays which had been produced using three different coding methods. The monochrome coding method dis...
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Eighteen people participated in an experiment in which they were asked to search for targets on control room like displays which had been produced using three different coding methods. The monochrome coding method displayed the information in black and white only, the maximally discriminable method contained colours chosen for their high perceptual discriminability, the visual layers method contained colours developed from psychological and cartographic principles which grouped information into a perceptual hierarchy. The visual layers method produced significantly faster search times than the other two coding methods which did not differ significantly from each other. Search time also differed significantly for presentation order and for the method x order interaction. There was no significant difference between the methods in the number of errors made. Participants clearly preferred the visual layers coding method. Proposals are made for the design of experiments to further test and develop the visual layers colour coding methodology. (C) 2002 Published by Elsevier Science Ltd.
The honeybee, Apis mellifera L., is one of the living creatures that has its colour vision proven through behavioural tests. Previous studies of honeybee colour vision has emphasized the relationship between the spect...
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The honeybee, Apis mellifera L., is one of the living creatures that has its colour vision proven through behavioural tests. Previous studies of honeybee colour vision has emphasized the relationship between the spectral sensitivities of photoreceptors and colour discrimination behaviour. The current understanding of the neural mechanisms of bee colour vision is, however, rather limited. The present study surveyed the patterns of chromatic information processing of visual neurons in the lobula of the honeybee, using intracellular recording stimulated by three light-emitting diodes, whose emission spectra approximately match the spectral sensitivity peaks of the honeybee. The recorded visual neurons can be divided into two groups: non-colour opponent cells and colour opponent cells. The non-colour opponent cells comprise six types of broad-band neurons and four response types of narrow-band neurons. The former might detect brightness of the environment or function as chromatic input channels, and the latter might supply specific chromatic input. Amongst the colour opponent cells, the principal neural mechanism of colour vision, eight response types were recorded. The receptive fields of these neurons were not centre surround as observed in primates. Some recorded neurons with tonic post-stimulus responses were observed, however, suggesting temporal defined spectral opponency may be part of the colour-coding mechanisms. (C) 2004 Elsevier Ltd. All rights reserved.
We study the generalization of covering problems such as the set cover problem to partial covering problems. Here we only want to cover a given number k of elements rather than all elements. For instance, in the k-par...
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We study the generalization of covering problems such as the set cover problem to partial covering problems. Here we only want to cover a given number k of elements rather than all elements. For instance, in the k-partial (weighted) set cover problem, we wish to compute a minimum weight collection of sets that covers at least k elements. As a main result, we show that the k-partial set cover problem and its special cases like the k-partial vertex cover problem are all fixed parameter tractable (with parameter k). As a second example, we consider the minimum weight k-partial t-restricted cycle cover problem. (C) 2002 Elsevier Science B.V. All rights reserved.
In intensive care units (ICU) most of the drugs have to be administered by y-piece infusions or admixtures. Drug stability and compatibility are critical elements in the accurate and appropriate delivery of drug thera...
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In intensive care units (ICU) most of the drugs have to be administered by y-piece infusions or admixtures. Drug stability and compatibility are critical elements in the accurate and appropriate delivery of drug therapies to patients. Five years after the implementation of a simple "colour code system" in an attempt to minimize the number of incompatibilities, the situation has been re-examined. The clinical pharmacist collected 78 different medication regimes and the compatibility and incompatibilities were evaluated based on the available literature. Before initiating the "colour code system" in the ICU, 15% of the administered drugs were incompatible and afterwards the number decreased to 2%. This rate could be kept at 2%, even 5 years after the implementation of the system, without any further intervention. As a result of teamwork between nurses, doctors and clinical pharmacy a simple "colour system" was established to minimize incidences of drug incompatibility in the ICU The system is highly accepted because the degree of uncertainty has been considerably reduced.
A method is reported which enables designers to colour code computer displayed information into a perceptual hierarchy in much the same way as visual layering effects arc achieved in cartography. Principles of colour ...
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A method is reported which enables designers to colour code computer displayed information into a perceptual hierarchy in much the same way as visual layering effects arc achieved in cartography. Principles of colour perception and cartography are used to derive palettes of colours. The colours within these palettes are used to code screen based information such that elements of the display most relevant to the user's task appear more conspicuous and nearer than less task relevant information. The application of this method to a typical control room display is described and illustrated. (C) 2001 Elsevier Science B.V. All rights reserved.
Subjects sought a unique target shape in a display of distractor shapes under three colour coding conditions. In the no colour coding condition (NCC) all shapes shared the same colour. In the two colour-coded condit...
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Subjects sought a unique target shape in a display of distractor shapes
under three colour coding conditions. In the no colour coding condition (NCC) all
shapes shared the same colour. In the two colour-coded conditions, the target was
uniquely and redundantly colour coded with a colour whose CIE 1976 UCS chromaticity
coordinates were either linearly separable (LS) or not linearly separable (NLS) from
the set of distractor chromaticity coordinates. Performance was optimal under LS
coding, was reduced under NLS coding and was least efficient in the NCC condition.
We discuss the implications of these results for refining colour selection algorithms
and for colour coding in situations where the gamut of available colours is limited.
Crown Copyright. (Author abstract) 29 Refs.
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