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1

Automated image analysis as a tool to quantify the colour and composition of rainbow trout  

E-print Network

Automated image analysis as a tool to quantify the colour and composition of rainbow trout cutlets in rainbow trout. The proposed automated image analysis methods were tested on a total of 983 of trout cutlets. © 2006 Elsevier B.V. All rights reserved. Keywords: Image analysis; Rainbow trout; Cutlet

Manne, Fredrik

2

Colour Guided Colour Image Steganography  

E-print Network

Information security has become a cause of concern because of the electronic eavesdropping. Capacity, robustness and invisibility are important parameters in information hiding and are quite difficult to achieve in a single algorithm. This paper proposes a novel steganography technique for digital color image which achieves the purported targets. The professed methodology employs a complete random scheme for pixel selection and embedding of data. Of the three colour channels (Red, Green, Blue) in a given colour image, the least two significant bits of any one of the channels of the color image is used to channelize the embedding capacity of the remaining two channels. We have devised three approaches to achieve various levels of our desired targets. In the first approach, Red is the default guide but it results in localization of MSE in the remaining two channels, which makes it slightly vulnerable. In the second approach, user gets the liberty to select the guiding channel (Red, Green or Blue) to guide the r...

Amirtharajan, R; Swarup, Motamarri Abhilash; K, Mohamed Ashfaaq; Rayappan, John Bosco Balaguru

2010-01-01

3

Ultrasonic colour Doppler imaging  

PubMed Central

Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been found to be of great value in assessing blood flow in many clinical conditions. Although the method for obtaining the velocity information is in many ways similar to the method for obtaining the anatomical information, it is technically more demanding for a number of reasons. It also has a number of weaknesses, perhaps the greatest being that in conventional systems, the velocities measured and thus displayed are the components of the flow velocity directly towards or away from the transducer, while ideally the method would give information about the magnitude and direction of the three-dimensional flow vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new techniques that seek to overcome the vector problem mentioned above are described. Finally, some examples of vector velocity images are presented. PMID:22866227

Evans, David H.; Jensen, J?rgen Arendt; Nielsen, Michael Bachmann

2011-01-01

4

Colour Parametrization in a Multiparametric Image Interface  

E-print Network

) and HSV (hue, saturation, lightness), are linked to human colour perception: the former to cone cell types is an image. It, too, uses colour to depict its appearance. Thus, the smallest elements of an image

Oldford, R.W.

5

Feature Extraction and Simplification from colour images based on Colour Image Segmentation and Skeletonization  

E-print Network

application for completely automated or semi-automated processing of (satellite) imagery and scanned maps, as well as heating or pollution monitoring and dense forest mapping among others. Keywords: colour imageFeature Extraction and Simplification from colour images based on Colour Image Segmentation

6

Colour television image analysis of carious lesions  

Microsoft Academic Search

The new technique of colour television image analysis has been used to produce seven-colour contour maps of the radiodensity\\u000a of micro-radiographs of enamel caries. This method permits the detailed measurement of the mineral content of enamel carious\\u000a lesions to a sensitivity of ±3% of the level of complete mineralisation. By selection of appropriate aluminium step-wedges,\\u000a exposed simultaneously with the tooth

J. C. Rodda; K. V. Mortimer; E. D. Williams

1975-01-01

7

Visual pattern based colour image compression G. Schaefer+  

E-print Network

& Imaging Institute ++ School of Computing & Mathematics University of Derby, UK ABSTRACT A novel colour of predefined, universal visual patterns in a uniform colour space. Source coding and colour quantisation per pixel) needed to represent a digital image whilst trying to maintain high perceptual image quality

Aickelin, Uwe

8

Towards more adequate colour histograms for in-body images  

Microsoft Academic Search

Although there is a growing number of scientific papers describing classification of in-body images, most of it is based on traditional colour histograms. In this paper we explain why these might not be the most adequate visual features for in-body image classification. Based on a colour dynamic range maximization criterion, we propose a methodology for creating more adequate colour histograms,

A. Sousa; M. Dinis-Ribeiro; M. Areia; M. Correia; M. Coimbra

2008-01-01

9

Assessment of fire damaged concrete using colour image analysis  

Microsoft Academic Search

Assessment of fire damaged concrete structures usually starts with visual observation of colour change, cracking and spalling. On heating, a change in colour from normal to a pink\\/red is often observed and this is useful since it coincides with the onset of significant loss of concrete strength. Optical microscopy combined with colour image analysis has been used to quantify changes

N. R Short; J. A Purkiss; S. E Guise

2001-01-01

10

Physics-based Segmentation of Colour Images in Spherical Coordinates  

Microsoft Academic Search

We present image segmentation and highlight detection algorithms based on the dichromatic re- flection model. For image segmentation, we use the model prediction that objects of a certain colour produce lines (the matte lines) radiating away from the origin of the RGB colour space. These lines therefore show up as peaks in a 2-dimensional histogram of the angular coordinates of

Allan Hanbury

2004-01-01

11

Ratio rule and homomorphic filter for enhancement of digital colour image  

Microsoft Academic Search

Digital colour image enhancement using a homomorphic filter provides good dynamic range compression, but it fails in colour rendition. In this letter, we propose to perform natural colour rendition in a digital colour image that is enhanced by a homomorphic filter. A novel neural network learning algorithm, named Ratio rule, is used to carry out the natural colour rendition process.

Ming-jung Seow; Vijayan K. Asari

2006-01-01

12

Colour Stability in Live Image Capturing Guy K. Kloss, Napoleon H. Reyes and Ken A. Hawick  

E-print Network

with a window (no artificial light) and an overcast sky (quite "neutral" daylight illumination). The weather vision; computer vision; digital video imaging; artificial intelligence; colour con- stancy; colour

Hawick, Ken

13

Fuzzy Homogeneity Measures for Path-based Colour Image Segmentation  

E-print Network

Fuzzy Homogeneity Measures for Path-based Colour Image Segmentation J. Chamorro-Martínez, D,daniel,belenps,elena}@decsai.ugr.es Abstract-- In this paper we study different measures of path homogeneity for fuzzy path-based image segmentation. We pro- vide fuzzy semantics for the concept of homogeneity in two steps: first, we introduce

Granada, Universidad de

14

Colour Doppler imaging of intracranial vasculopathy in severe infantile sialidosis  

Microsoft Academic Search

Neonatal ascites is usually attributed to prenatal infections, lysosomal storage disease and anomalies of the genitourinary tract, gastrointestinal tract or cardiovascular system. We report one case of neonatal ascites associated with infantile sialidosis. Cerebral sonography showed stripe-like intracerebral echogenicities in the region of the basal ganglia. Colour Doppler imaging demonstrated blood flow within the echogenicities confirming the suspected diagnosis of

M. Ries; K.-H. Deeg; D. Wölfel; H. Ibel; B. Maier; G. Buheitel

1992-01-01

15

Colour Stability of Veneering Composites after Accelerated Aging  

PubMed Central

Objectives: To investigate the colour stability of four indirect composite restorative materials after accelerated aging. Methods: Four indirect composites (Gradia, Signum+, HFO and Adoro) were used. For each material, six specimens were prepared and subjected to accelerated aging (Suntest CPS+, Atlas, Chicago, IL, USA) according to ISO 7491. A Dr. Lange Microcolor Data Station colorimeter (Braive Instruments, Liege, Belgium) was used to measure specimen colour before and after aging. Measurements were performed according to the CIE L*a*b* system, and the mean L*, a* and b* values for each material were calculated. The equation ?E = [(?L*)2 + (?a*)2 + (?b*)2]1/2 was used to measure the total colour change (?E), where ?L*, ?a* and ?b* are the differences in the respective values before and after aging. One-way ANOVA were used to determine statistically significant differences in ?L*, ?a*, ?b* and ?E. Results: No statistically significant differences were found in ?L*, ?a*, ?b* and ?E among the materials tested (P?L*=.063; P?a*=.521; P?b*=.984 and P?E=.408). After aging, Gradia specimens showed an increase in lightness (?L*=0.36) and a green-yellow shift (?a*=?1.18, ?b*=0.6), while Signum+ specimens exhibited an increase in lightness (?L*=0.5) and a green-blue shift (?a*=?0.9, ?b*=?0.45). HFO specimens exhibited an increase in lightness (?L*=0.75) and a green-yellow shift (?a*=?1.3, ?b*=0.06), and Adoro specimens exhibited an increase in lightness (?L*=2.07) and a green-yellow shift (?a*=?1.3, ?b*=0.68). Conclusions: Colour changes were found to be within accepted values of perceptibility and clinical acceptance after accelerated aging, and no statistically significant differences were found in ?L*, ?a*, ?b* and ?E among the materials tested. PMID:20396443

Papadopoulos, Triantafillos; Sarafianou, Aspasia; Hatzikyriakos, Andreas

2010-01-01

16

Superhigh Quality Colour Image TV System Telan  

Microsoft Academic Search

Among the shortcomings of TV system of high sharpness is that fact that the problem of increasing of noise suppression is not solved jet. In the digital TV the problem of increasing image sharpness is not solved. Their common shortcoming is their bad compatibility with existing systems of standard TV and very high complicativeness and cost. The perspective alternative to

Alexander A. Antonov

1998-01-01

17

Canvas: An Intelligent Colour Selection Tool For VDU Images  

Microsoft Academic Search

CANVAS is a palette-driven system for colour selection in the density slicing of single-band imagery. By incorporating intelligence on the visual distinction and ordering of colours, the system can operate in several modes. Colours can be selected individually from the palettes or by the system, which maximises the apparent distinction between them. Colour series with unipolar, repeating unipolar and bipolar

G. A. Gill; A. D. Trigg

1988-01-01

18

Using Colour for Image Indexing Graham D. Finlayson Bernt Schiele James L. Crowley  

E-print Network

. For example, because images of `beach scenes' typically comprise sea (deep blue), sky (light blue) and sand (beige) a tripartite colour query of Find(light blue, sky blue and beige) should suffice in finding] (a beach viewed under a red dusk sky will result in an image where all the colours are redder than

19

Automatic Detection of Blue-White Veil by Discrete Colour Matching in Dermoscopy Images  

E-print Network

Automatic Detection of Blue-White Veil by Discrete Colour Matching in Dermoscopy Images Ali Madooei common colours under dermoscopy, blue-grey (blue-white veil) is a strong in- dicator of malignant, to automatically detect and segment blue-white veil areas in dermoscopy images. The proposed method is an attempt

Drew, Mark S.

20

Effect of fining on the colour and pigment composition of young red wines.  

PubMed

This work aimed to evaluate the effect of four fining agents on the colour and pigment composition of red wines of Tannat. The wines were analysed 15 days after fining and immediately after separation of sediments and bottling. Colour was evaluated by spectrophotometry and polyphenols were analysed by spectrophotometry and HPLC-DAD. The colour intensity of wine was significantly decreased by bentonite and egg albumin. The most remarkable effects on wine phenolic composition were produced by bentonite and gelatin, which significantly decreased anthocyanin and tannin concentrations, respectively. Results show that each fining agent has very different impact on the wine attributes, and their effects depended as well on the composition of the clarified wine. The use of non-traditional agents of fining, as vegetable proteins, may have less impact on the colour and anthocyanin content of red wines. PMID:24679795

González-Neves, Gustavo; Favre, Guzmán; Gil, Graciela

2014-08-15

21

Composition of pigments and colour changes in green table olives related to processing type.  

PubMed

Brownish colourations in Natural green table olives (non-treated with alkali) make this product less attractive to consumers than Spanish-style green table olives (treated with alkali), which develop a more appreciated bright golden-yellow colour. These colour differences were studied in relation to changes in the composition of chlorophyll and carotenoid pigments, as well as polyphenolic compounds and polyphenol oxidase enzyme (PPO) activity. Natural green olives showed a different chlorophyll profile than Spanish-style. However, all the chlorophyll pigments formed in both processing types were Mg-free derivatives (mostly pheophytins) with similar colourations, ranging from grey to green brownish. In the carotenoid fraction no appreciable differences were found between both processing types. The fruit's brownish colour was mainly due to polymeric substances with a size of >1000 daltons and polyphenolic nature, resulting from an enzymatic oxidation by PPO of the o-diphenolic compounds present in the fresh fruits. PMID:25053036

Ramírez, Eva; Gandul-Rojas, Beatriz; Romero, Concepción; Brenes, Manuel; Gallardo-Guerrero, Lourdes

2015-01-01

22

A novel framework for low-light colour image enhancement and denoising  

Microsoft Academic Search

This article describes a novel framework for low-light colour image enhancement and denoising. To avoid influences from different colour channels, noise reduction and brightness\\/contrast enhancement are performed in different colour spaces. In the HSI space, the Bilateral filter is used for illumination- and reflection-component separation, and is effective for edge-preservation, halo removal and noise suppression. Brightness\\/contrast are extrapolated by using

Wenshuai Yin; Xiangbo Lin; Yi Sun

2011-01-01

23

Dynamic application of digital image and colour processing in characterizing flame radiation features  

NASA Astrophysics Data System (ADS)

In this work, the experimental investigation of the dynamic flame properties of flame flickering and equivalence ratio sensing of a combustion process was done. In particular, the time-varied flame properties were examined using a novel digital image and colour processing methodology. This technique makes use of the observed correlation between a digital image colour signal and physical flame radiation characteristics in the visible wavelength domain. Aspects of RGB and HSV colour modelling principles were applied to show that the addition of colour identification in the image processing of high-speed flame image data could yield three useful parameters which are related to the dynamic behaviour of different flame emanating components. First, the validity of the colour identities for tracking the yellowish-red diffusion and greenish-blue premixed flame colourations were examined by comparing their respective flickering frequency profiles. Then, the usefulness of the extracted Rdiffusion, Gpremixed and Bpremixed colour signals to abstractly represent the behaviour of soot, C2* and CH* emission characteristics in a dynamic flame transition from diffusion to stoichiometric premixed condition was demonstrated. In particular, the colour signal ratio Bpremixed/Gpremixed was correlated to exemplify the approximate time-varied state of the equivalence ratio from the imaged combustion phenomenon.

Huang, Hua Wei; Zhang, Yang

2010-08-01

24

Feeding efficiency of planktivores under disturbance, the effect of water colour, predation threat and shoal composition.  

PubMed

The consumption of phantom midge Chaoborus flavicans larvae by Perca fluviatilis showed clear response to water colour, predation threat and shoal composition with the most significant negative effect for water colour. In the case of Rutilus rutilus, no similar combined response was observed and the total prey consumption was significantly negatively affected by predation threat of Esox lucius. The results suggest that differences in life-history traits may result in disparity in species-specific responses to disturbance. PMID:24689675

Nurminen, L; Estlander, S; Olin, M; Lehtonen, H

2014-04-01

25

Analysis of the ignition process using a digital image and colour processing technique  

NASA Astrophysics Data System (ADS)

An experimental investigation of flame emission properties in the ignition-to-flame propagation process has been conducted. In particular, the phenomenon of ignition delay was analysed through digital image processing and colour analysis. This processing methodology makes use of the observed correlation between a digital colour signal and physical flame emission characteristics in the visible spectrum. Aspects of red, green, blue and hue, saturation, value colour modelling principles were combined to turn a high-speed digital colour camera into an abstract multi-spectral system. Experiments were carried out on both a laboratory-based atmospheric burner and an industrial gas-turbine combustor. In both cases, results have shown that the commonly observed flame colour feature from the soot radiation does not signify the start of combustion reaction but rather a later stage of flame development. Additional weak colour quantities were identified via digital colour image processing in the ignition delay time interval where there were no previous definitive signals to designate the presence of combustion. This colour entity was found to match with the typical digital colour signal output from the stimulation of CH* and C2* radical chemiluminescence emissions.

Huang, Hua Wei; Zhang, Yang

2011-07-01

26

Colour analysis and verification of CCTV images under different lighting conditions  

NASA Astrophysics Data System (ADS)

Colour information is not faithfully maintained by a CCTV imaging chain. Since colour can play an important role in identifying objects it is beneficial to be able to account accurately for changes to colour introduced by components in the chain. With this information it will be possible for law enforcement agencies and others to work back along the imaging chain to extract accurate colour information from CCTV recordings. A typical CCTV system has an imaging chain that may consist of scene, camera, compression, recording media and display. The response of each of these stages to colour scene information was characterised by measuring its response to a known input. The main variables that affect colour within a scene are illumination and the colour, orientation and texture of objects. The effects of illumination on the appearance of colour of a variety of test targets were tested using laboratory-based lighting, street lighting, car headlights and artificial daylight. A range of typical cameras used in CCTV applications, common compression schemes and representative displays were also characterised.

Smith, R. A.; MacLennan-Brown, K.; Tighe, J. F.; Cohen, N.; Triantaphillidou, S.; MacDonald, L. W.

2008-01-01

27

Influence of bottle storage time on colour, phenolic composition and sensory properties of sweet red wines.  

PubMed

Changes in colour and phenolic composition in sweet red wines made from Merlot, Syrah and Tempranillo grapes were studied in order to assess the influence of bottle storage over a period of 12months. For this purpose, wine colour parameters, sensory analysis and concentrations of monomeric anthocyanins, pyranoanthocyanins, methylmethine-mediated condensation adducts, flavan3-ol derivatives and flavonols were measured. Hue increased and red colours decreased with the storage time, particularly over the first 3months. The concentrations of low molecular weight flavan-3-ol derivatives decreased with time due to the effect of their conversion into tannins of high molecular weight. In addition, the glycosylated flavonols decreased through hydrolysis to give the corresponding aglycones. Overall, the concentration of phenolic compounds decreased markedly with storage time, whereas the antioxidant activity in the wines remained constant throughout. A panel of expert tasters judged the colour, aroma and flavour of all initial and final wines to be acceptable. PMID:24176375

Marquez, Ana; Serratosa, Maria P; Merida, Julieta

2014-03-01

28

Hundred metre virtual telescope captures unique detailed colour image  

NASA Astrophysics Data System (ADS)

A team of French astronomers has captured one of the sharpest colour images ever made. They observed the star T Leporis, which appears, on the sky, as small as a two-storey house on the Moon [1]. The image was taken with ESO's Very Large Telescope Interferometer (VLTI), emulating a virtual telescope about 100 metres across and reveals a spherical molecular shell around an aged star. ESO PR Photo 06a/09 The star T Leporis as seen with VLTI ESO PR Photo 06b/09 The star T Leporis to scale ESO PR Photo 06c/09 A virtual 100-metre telescope ESO PR Photo 06d/09 The orbit of Theta1 Orionis C ESO PR Video 06a/09 Zoom-in onto T Leporis "This is one of the first images made using near-infrared interferometry," says lead author Jean-Baptiste Le Bouquin. Interferometry is a technique that combines the light from several telescopes, resulting in a vision as sharp as that of a giant telescope with a diameter equal to the largest separation between the telescopes used. Achieving this requires the VLTI system components to be positioned to an accuracy of a fraction of a micrometre over about 100 metres and maintained so throughout the observations -- a formidable technical challenge. When doing interferometry, astronomers must often content themselves with fringes, the characteristic pattern of dark and bright lines produced when two beams of light combine, from which they can model the physical properties of the object studied. But, if an object is observed on several runs with different combinations and configurations of telescopes, it is possible to put these results together to reconstruct an image of the object. This is what has now been done with ESO's VLTI, using the 1.8-metre Auxiliary Telescopes. "We were able to construct an amazing image, and reveal the onion-like structure of the atmosphere of a giant star at a late stage of its life for the first time," says Antoine Mérand, member of the team. "Numerical models and indirect data have allowed us to imagine the appearance of the star before, but it is quite astounding that we can now see it, and in colour." Although it is only 15 by 15 pixel across, the reconstructed image shows an extreme close-up of a star 100 times larger than the Sun, a diameter corresponding roughly to the distance between the Earth and the Sun. This star is, in turn, surrounded by a sphere of molecular gas, which is about three times as large again. T Leporis, in the constellation of Lepus (the Hare), is located 500 light-years away. It belongs to the family of Mira stars, well known to amateur astronomers. These are giant variable stars that have almost extinguished their nuclear fuel and are losing mass. They are nearing the end of their lives as stars, and will soon die, becoming white dwarfs. The Sun will become a Mira star in a few billion years, engulfing the Earth in the dust and gas expelled in its final throes. Mira stars are among the biggest factories of molecules and dust in the Universe, and T Leporis is no exception. It pulsates with a period of 380 days and loses the equivalent of the Earth's mass every year. Since the molecules and dust are formed in the layers of atmosphere surrounding the central star, astronomers would like to be able to see these layers. But this is no easy task, given that the stars themselves are so far away -- despite their huge intrinsic size, their apparent radius on the sky can be just half a millionth that of the Sun. "T Leporis looks so small from the Earth that only an interferometric facility, such as the VLTI at Paranal, can take an image of it. VLTI can resolve stars 15 times smaller than those resolved by the Hubble Space Telescope," says Le Bouquin. To create this image with the VLTI astronomers had to observe the star for several consecutive nights, using all the four movable 1.8-metre VLT Auxiliary Telescopes (ATs). The ATs were combined in different groups of three, and were also moved to different positions, creating more new interferometric configurations, so that astronomers could emulate a virtual telescope

2009-02-01

29

Gender differences in colour naming performance for gender specific body shape images.  

PubMed

Males are increasingly subjected to pressures to conform to aesthetic body stereotypes. There is, however, comparatively little published research on the aetiology of male body shape concerns. Two experiments are presented, which investigate the relationship between gender specific body shape concerns and colour-naming performance. Each study comprised a between subject design, in which each subject was tested on a single occasion. A pictorial version of a modified Stroop task was used in both studies. Subjects colour-named gender specific obese and thin body shape images and semantically homogeneous neutral images (birds) presented in a blocked format. The first experiment investigated female subjects (N = 68) and the second investigated males (N = 56). Subjects also completed a self-report measure of eating behaviour. Currently dieting female subjects exhibited significant colour-naming differences between obese and neutral images. A similar pattern of colour-naming performance was found to be related to external eating in the male subjects. PMID:11234250

Elliman, N A; Green, M W; Wan, W K

1998-03-01

30

White-light full-field OCT resolution improvement by image sensor colour balance adjustment: numerical simulation  

NASA Astrophysics Data System (ADS)

The possibility of improving white-light full-field optical coherence tomography (OCT) resolution by image sensor colour balance tuning is shown numerically. We calculated the full-width at half-maximum (FWHM) of a coherence pulse registered by a silicon colour image sensor under various colour balance settings. The calculations were made for both a halogen lamp and white LED sources. The results show that the interference pulse width can be reduced by the proper choice of colour balance coefficients. The reduction is up to 18%, as compared with a colour image sensor with regular settings, and up to 20%, as compared with a monochrome sensor.

Kalyanov, A. L.; Lychagov, V. V.; Ryabukho, V. P.; Smirnov, I. V.

2012-12-01

31

Temperature Profiling of Pulverised Coal Flames Using MultiColour Pyrometric and Digital Imaging Techniques  

Microsoft Academic Search

This paper presents an imaging based multi-colour pyrometric system for the monitoring of temperature and its distribution in a coal-fired flame. An optical splitting\\/filtering device is designed and used to split the light of flame into three beams at three selected wavelengths as required in the multi-colour principle. A high-resolution CCD camera is employed to collect the three beams of

Gang Lu; Yong Yan; Steve Cornwell; Gerry Riley

2005-01-01

32

Image size scalable full-parallax coloured three-dimensional video by electronic holography.  

PubMed

In electronic holography, various methods have been considered for using multiple spatial light modulators (SLM) to increase the image size. In a previous work, we used a monochrome light source for a method that located an optical system containing lens arrays and other components in front of multiple SLMs. This paper proposes a colourization technique for that system based on time division multiplexing using laser light sources of three colours (red, green, and blue). The experimental device we constructed was able to perform video playback (20?fps) in colour of full parallax holographic three-dimensional (3D) images with an image size of 63?mm and a viewing-zone angle of 5.6 degrees without losing any part of the 3D image. PMID:24499811

Sasaki, Hisayuki; Yamamoto, Kenji; Ichihashi, Yasuyuki; Senoh, Takanori

2014-01-01

33

Image Size Scalable Full-parallax Coloured Three-dimensional Video by Electronic Holography  

PubMed Central

In electronic holography, various methods have been considered for using multiple spatial light modulators (SLM) to increase the image size. In a previous work, we used a monochrome light source for a method that located an optical system containing lens arrays and other components in front of multiple SLMs. This paper proposes a colourization technique for that system based on time division multiplexing using laser light sources of three colours (red, green, and blue). The experimental device we constructed was able to perform video playback (20?fps) in colour of full parallax holographic three-dimensional (3D) images with an image size of 63?mm and a viewing-zone angle of 5.6 degrees without losing any part of the 3D image. PMID:24499811

Sasaki, Hisayuki; Yamamoto, Kenji; Ichihashi, Yasuyuki; Senoh, Takanori

2014-01-01

34

A new colour image energy for active contours in natural scenes  

Microsoft Academic Search

A new colour image energy for active contours is proposed to segment objects of unknown topologies automatically in the natural scene. An important contribution is the formulation of an analytical expression for thresholding that enables our active contour to handle the effects of uneven illumination and image blur in complex natural scenes.

Kian Peng Ngoi; Jiancheng Jia

1996-01-01

35

Colour flow imaging in the diagnosis of multiple ventricular septal defects.  

PubMed Central

Thirty one patients with multiple ventricular septal defects were studied by cross sectional echocardiography, conventional pulsed and continuous wave Doppler, colour flow imaging, and left ventriculography to determine the relative diagnostic benefits and pitfalls of each technique. The patients studied had a wide range of congenital heart defects with 19 patients having isolated multiple ventricular septal defects, three with associated tetralogy of Fallot, five with double outlet right ventricle, three with complete transposition and ventricular septal defect, and one with a complete atrioventricular septal defect. In 23 patients the defects were inspected at operation. Cross sectional imaging with integrated pulsed and continuous wave Doppler correctly identified multiple defects in only 12 (39%) patients. In contrast, colour flow imaging was accurate in 24 (77%) patients and left ventriculography in 20 (65%) patients. When patients were subdivided on the basis of relative peak systolic ventricular pressures into restrictive defects (18 patients) and non-restrictive defects (13 patients) the diagnostic value of colour flow imaging was different for each group. Colour flow mapping correctly identified multiple ventricular septal defects in 16/18 (89%) patients with restrictive defects but only 8/13 (62%) with non-restrictive defects. The comparative diagnostic accuracy of left ventriculography was 15/18 (83%) in the restrictive group and 5/13 (38%) in the non-restrictive group. Colour flow imaging was the single investigative technique with the greatest diagnostic accuracy in the diagnosis of multiple ventricular septal defects. It failed to be consistently accurate in defined subgroups with non-restrictive defects as did left ventriculography. The greatest overall diagnostic accuracy in this series was obtained when both colour flow imaging and ventriculography techniques were used in combination in a complementary fashion. Images Fig 2 Fig 3 Fig 1 PMID:2757873

Sutherland, G R; Smyllie, J H; Ogilvie, B C; Keeton, B R

1989-01-01

36

Compositing digital images  

Microsoft Academic Search

Most computer graphics pictures have been computed all at once, so that the rendering program takes care of all computations relating to the overlap of objects. There are several applications, however, where elements must be rendered separately, relying on compositing techniques for the anti-aliased accumulation of the full image. This paper presents the case for four-channel pictures, demonstrating that a

Thomas Porter; Tom Duff

1984-01-01

37

A Basin Morphology Approach to Colour Image Segmentation by Region Merging  

E-print Network

A Basin Morphology Approach to Colour Image Segmentation by Region Merging Erchan Aptoula and S by region merging, with the procedure being formalized as a basin morphology, where regions are "eroded" in order to form greater catchment basins. The result is a fully automated processing chain, with multiple

Lefèvre, Sébastien

38

Novel and adaptive contribution of the red channel in pre-processing of colour fundus images  

Microsoft Academic Search

A new pre-processing method for colour fundus images with adaptive contribution of the red channel is proposed. Based on a condition that is developed in this paper, this method utilises the intensity information from both red and green channels instead of using only the green channel as in the usual practice. The histogram matching is used to modify the histogram

Nancy M. Salem; Asoke K. Nandi

2006-01-01

39

Screening for early familial ovarian cancer with transvaginal ultrasonography and colour blood flow imaging  

Microsoft Academic Search

OBJECTIVE--To assess the value of transvaginal ultrasonography with colour blood flow imaging in detecting early ovarian cancer in women with a family history of the disease. DESIGN--Study of self referred symptomless women with a close relative who had developed the disease. Each woman was screened to detect persistent lesions and defined changes in ovarian volume. Morphological score and pulsatility index

T H Bourne; S Campbell; K M Reynolds; M I Whitehead; J Hampson; P Royston; T J Crayford; W P Collins

1993-01-01

40

Phylogeographic structure, demographic history and morph composition in a colour polymorphic lizard.  

PubMed

In polymorphic species, population divergence in morph composition and frequency has the potential to promote speciation. We assessed the relationship between geographic variation in male throat colour polymorphism and phylogeographic structure in the tawny dragon lizard, Ctenophorus decresii. We identified four genetically distinct lineages, corresponding to two polymorphic lineages in the Northern Flinders Ranges and Southern Flinders Ranges/Olary Ranges regions respectively, and a monomorphic lineage in the Mt Lofty Ranges/Kangaroo Island region. The degree of divergence between these three lineages was consistent with isolation to multiple refugia during Pleistocene glacial cycles, whereas a fourth, deeply divergent (at the interspecific level) and monomorphic lineage was restricted to western New South Wales. The same four morphs occurred in both polymorphic lineages, although populations exhibited considerable variation in the frequency of morphs. By contrast, male throat coloration in the monomorphic lineages differed from each other and from the polymorphic lineages. Our results suggest that colour polymorphism has evolved once in the C. decresii species complex, with subsequent loss of polymorphism in the Mt Lofty Ranges/Kangaroo Island lineage. However, an equally parsimonious scenario, that polymorphism arose independently twice within C. decresii, could not be ruled out. We also detected evidence of a narrow contact zone with limited genotypic admixture between the polymorphic Olary Ranges and monomorphic Mt Lofty Ranges regions, yet no individuals of intermediate colour phenotype. Such genetic divergence and evidence for barriers to gene flow between lineages suggest incipient speciation between populations that differ in morph composition. PMID:25146412

McLean, C A; Stuart-Fox, D; Moussalli, A

2014-10-01

41

Colour measurement of colostrum for estimation of colostral IgG and colostrum composition in dairy cows.  

PubMed

Instruments for on-farm determination of colostrum quality such as refractometers and densimeters are increasingly used in dairy farms. The colour of colostrum is also supposed to reflect its quality. A paler or mature milk-like colour is associated with a lower colostrum value in terms of its general composition compared with a more yellowish and darker colour. The objective of this study was to investigate the relationships between colour measurement of colostrum using the CIELAB colour space (CIE L*=from white to black, a*=from red to green, b*=from yellow to blue, chroma value G=visual perceived colourfulness) and its composition. Dairy cow colostrum samples (n=117) obtained at 4·7±1·5 h after parturition were analysed for immunoglobulin G (IgG) by ELISA and for fat, protein and lactose by infrared spectroscopy. For colour measurements, a calibrated spectrophotometer was used. At a cut-off value of 50 mg IgG/ml, colour measurement had a sensitivity of 50·0%, a specificity of 49·5%, and a negative predictive value of 87·9%. Colostral IgG concentration was not correlated with the chroma value G, but with relative lightness L*. While milk fat content showed a relationship to the parameters L*, a*, b* and G from the colour measurement, milk protein content was not correlated with a*, but with L*, b*, and G. Lactose concentration in colostrum showed only a relationship with b* and G. In conclusion, parameters of the colour measurement showed clear relationships to colostral IgG, fat, protein and lactose concentration in dairy cows. Implementation of colour measuring devices in automatic milking systems and milking parlours might be a potential instrument to access colostrum quality as well as detecting abnormal milk. PMID:25226021

Gross, Josef J; Kessler, Evelyne C; Bruckmaier, Rupert M

2014-11-01

42

Independent component analysis applied to feature extraction from colour and stereo images.  

PubMed

Previous work has shown that independent component analysis (ICA) applied to feature extraction from natural image data yields features resembling Gabor functions and simple-cell receptive fields. This article considers the effects of including chromatic and stereo information. The inclusion of colour leads to features divided into separate red/green, blue/yellow, and bright/dark channels. Stereo image data, on the other hand, leads to binocular receptive fields which are tuned to various disparities. The similarities between these results and the observed properties of simple cells in the primary visual cortex are further evidence for the hypothesis that visual cortical neurons perform some type of redundancy reduction, which was one of the original motivations for ICA in the first place. In addition, ICA provides a principled method for feature extraction from colour and stereo images; such features could be used in image processing operations such as denoising and compression, as well as in pattern recognition. PMID:11014668

Hoyer, P O; Hyvärinen, A

2000-08-01

43

Minimally invasive use of coloured composite resin in aesthetic restoration of periodontially involved teeth: Case report  

PubMed Central

Gingival recession causes not only aesthetic problems, but problems with oral hygiene, plaque accumulation, speech, and tooth sensitivity. Replacing the missing gingival tissue with composite resin, when indicated, can be a time- and cost-effective solution. Here we report the case of a 25-year-old female who presented with generalized gingival recession. Black triangles were present between the maxillary and mandibular anterior teeth due to loss of interdental tissues, caused by recent periodontal surgery. She also had slightly malposed maxillary anterior teeth. The patient elected to replace gingival tissue with pink composite resin and to alter the midline with composite resin veneers. The first treatment phase involved placement of pink gingival composite to restore the appearance of interdental papilla to her upper (16, 15, 14, 13, 12, 11, 21, 22, 23, and 24) and lower (34, 33, 32, 31, 41, 42, 43, and 44) teeth. Phase two was to place direct composite resin bonded veneers on her upper (16, 15, 14, 13, 12, 11, 21, 22, 23, and 24) teeth to alter the midline and achieve desired colour. The third treatment phase was to level the lower incisal edge shape by enameloplasty (31, 32, 41, and 42) to produce a more youthful and attractive smile. This case report and brief review attempt to describe the clinical obstacles and the current treatment options along with a suggested protocol. Use of contemporary materials such as gingival coloured composite to restore lost gingival tissue and improve aesthetics can be a simple and cost-effective way to manage patients affected by generalized aggressive periodontitis (AgP). PMID:23960560

Wahbi, M.A.; Al Sharief, H.S.; Tayeb, H.; Bokhari, A.

2013-01-01

44

Digital image processing versus visual assessment of chewed two-colour wax in mixing ability tests.  

PubMed

Two-colour chewing gum and wax have been widely used as test foods to evaluate the ability to mix and knead a food bolus. The mixing of the colours has been assessed by computer analysis or by visual inspection. Reports contradict each other about whether computer analysis and visual assessment could equally well discriminate between the masticatory performances of groups of participants with different dental status. This study compares the results of computer analysis of digital images of chewed two-colour wax with the results of visual assessment of these images. Sixty healthy subjects participated and chewed on red-blue wax for 5, 10, 15 and 20 chewing strokes. The subjects were divided into three groups of 20, matched for age and gender, according to their dental status: natural dentition, full dentures and maxillary denture plus implant-supported mandibular overdenture. Mixing of the chewed wax was determined by computer analysis of images of the wax and by visual assessment of the images by five examiners. Both the computer method and the observers were able to distinguish the mixing abilities of the dentate subjects from the two denture wearer groups. Computer analysis could also discriminate the mixing abilities of the two denture groups. However, observers were not able to distinguish the mixing abilities of the two denture groups after 5, 10 and 15 chewing strokes. Only after 20 chewing strokes, they could detect a significant difference in mixing ability. PMID:21707695

van der Bilt, A; Speksnijder, C M; de Liz Pocztaruk, R; Abbink, J H

2012-01-01

45

Colour atlas of first pass functional imaging of the heart  

SciTech Connect

This book contains 21 chapters. Some of the titles are: Functional imaging; Fist pass radionuclide studies in evaluation of mitral valve replacement in chronic insufficiency using Bjork-Shiley tilting disc valves; First pass radionuclide studies in evaluation of left and right ventricular function in patients with bioprosthetic mitral valve replacement after 9-11 years; and First pass radionuclide studies in the evaluation of long term (up to about 15 years) follow up of aortic valve replacement using Starr-Edwards ball prosthesis.

Schad, N.; Andrews, E.J.; Fleming, J.W.

1985-01-01

46

NON-MELANOMA SKIN LESION CLASSIFICATION USING COLOUR IMAGE DATA IN A HIERARCHICAL K-NN CLASSIFIER  

E-print Network

NON-MELANOMA SKIN LESION CLASSIFICATION USING COLOUR IMAGE DATA IN A HIERARCHICAL K-NN CLASSIFIER lesions, including two non-melanoma cancer types. This is the most extensive published result on non-melanoma

Fisher, Bob

47

Identification and localization of fovea on colour fundus images using blur scales.  

PubMed

Identification of retinal landmarks is an important step in the extraction of anomalies in retinal fundus images. In the current study, we propose a technique to identify and localize the position of macula and hence the fovea avascular zone, in colour fundus images. The proposed method, based on varying blur scales in images, is independent of the location of other anatomical landmarks present in the fundus images. Experimental results have been provided using the open database MESSIDOR by validating our segmented regions using the dice coefficient, with ground truth segmentation provided by a human expert. Apart from testing the images on the entire MESSIDOR database, the proposed technique was also validated using 50 normal and 50 diabetic retinopathy chosen digital fundus images from the same database. A maximum overlap accuracy of 89.6%-93.8% and locational accuracy of 94.7%-98.9% was obtained for identification and localization of the fovea. PMID:25234036

Ganesan, Karthikeyan; Acharya, Rajendra U; Chua, Chua Kuang; Laude, Augustinus

2014-09-01

48

The colour preference control based on two-colour combinations  

NASA Astrophysics Data System (ADS)

This paper proposes a framework of colour preference control to satisfy the consumer's colour related emotion. A colour harmony algorithm based on two-colour combinations is developed for displaying the images with several complementary colour pairs as the relationship of two-colour combination. The colours of pixels belonging to complementary colour areas in HSV colour space are shifted toward the target hue colours and there is no colour change for the other pixels. According to the developed technique, dynamic emotions by the proposed hue conversion can be improved and the controlled output image shows improved colour emotions in the preference of the human viewer. The psychophysical experiments are conducted to investigate the optimal model parameters to produce the most pleasant image to the users in the respect of colour emotions.

Hong, Ji Young; Kwak, Youngshin; Park, Du-Sik; Kim, Chang Yeong

2008-02-01

49

Independent sources of condition dependency and multiple pathways determine a composite trait: lessons from carotenoid-based plumage colouration.  

PubMed

Many colour ornaments are composite traits consisting of at least four components, which themselves may be more complex, determined by independent evolutionary pathways, and potentially being under different environmental control. To date, little evidence exists that several different components of colour elaboration are condition dependent and no direct evidence exists that different ornamental components are affected by different sources of variation. For example, in carotenoid-based plumage colouration, one of the best-known condition-dependent ornaments, colour elaboration stems from both condition-dependent pigment concentration and structural components. Some environmental flexibility of these components has been suggested, but specifically which and how they are affected remains unknown. Here, we tested whether multiple colour components may be condition dependent, by using a comprehensive 3 × 2 experimental design, in which we carotenoid supplemented and immune challenged great tit nestlings (Parus major) and quantified effects on different components of colouration. Plumage colouration was affected by an interaction between carotenoid availability and immune challenge. Path analyses showed that carotenoid supplementation increased plumage saturation via feather carotenoid concentration and via mechanisms unrelated to carotenoid deposition, while immune challenge affected feather length, but not carotenoid concentration. Thus, independent condition-dependent pathways, affected by different sources of variation, determine colour elaboration. This provides opportunities for the evolution of multiple signals within components of ornamental traits. This finding indicates that the selective forces shaping the evolution of different components of a composite trait and the trait's signal content may be more complex than believed so far, and that holistic approaches are required for drawing comprehensive evolutionary conclusions. PMID:23331336

Romero-Diaz, C; Richner, H; Granado-Lorencio, F; Tschirren, B; Fitze, P S

2013-03-01

50

UV durable colour pigment doped SmA liquid crystal composites for outdoor trans-reflective bi-stable displays  

NASA Astrophysics Data System (ADS)

High brightness trans-reflective bi-stable displays based on smectic A (SmA) liquid crystals (LCs) can have nearly perfect transparency in the clear state and very high reflection in the scattered state. Because the LC material in use is stable under UV radiation, this kind of displays can stand for strong day-light and therefore be ideal for outdoor applications from e-books to public signage and advertisement. However, the colour application has been limited because the traditional colourants in use are conventional dyes which are lack of UV stability and that their colours are easily photo bleached. Here we present a colour SmA display demonstrator using pigments as colourant. Mixing pigments with SmA LCs and maintain the desirable optical switching performance is not straightforward. We show here how it can be done, including how to obtain fine sized pigment nano-particles, the effects of particle size and size distribution on the display performance. Our optimized pigments/SmA compositions can be driven by a low frequency waveform (~101Hz) to a scattered state to exhibit colour while by a high frequency waveform (~103Hz) to a cleared state showing no colour. Finally, we will present its excellent UV life-time (at least <7.2 years) in comparison with that of dye composition (~2.4 years). The complex interaction of pigment nano-particles with LC molecules and the resulting effects on the LC electro-optical performances are still to be fully understood. We hope this work will not only demonstrate a new and practical approach for outdoor reflective colour displays but also provide a new material system for fundamental liquid crystal colloid research work.

Xu, H.; Davey, A. B.; Crossland, W. A.; Chu, D. P.

2012-10-01

51

Physics Based Medical Image Understanding of the Colouration of the Ocular Fundus with Application to Detection of Diabetic  

E-print Network

Physics Based Medical Image Understanding of the Colouration of the Ocular Fundus with Application abnormalities from digital images. This approach to medical image understanding has also been employed by Cotton with the structures and pigments of the human ocular fundus a model has been developed capable of predicting

Claridge, Ela

52

Effect of tree types of light-curing units on 5-year colour changes of light-cured composite  

Microsoft Academic Search

The purpose of this study was to determine colour changes in a composite cured with tungsten-halogen, light-emitting diode (LED) or a plasma arc after 5 years. Five specimens 10 mm in diameter and 2 mm in height were prepared\\u000a using Hybrid (Clearfil AP-X) composite for each test group. The corresponding specimens were cured with a tungsten-halogen\\u000a curing light, a LED unit or with

Onjen Tak; Subutay Han Altintas; Nilgun Ozturk; Aslihan Usumez

2009-01-01

53

Hard shell gas-filled contrast enhancement particles for colour Doppler ultrasound imaging of tumors†  

PubMed Central

Hollow hard shell particles of 200 nm and 2 micron diameter with a 10 nm thick porous silica shell have been synthesized using polystyrene templates and a sol–gel process. The template ensures than the hollow particles are monodispersed, while the charged silica surface ensures that they remain suspended in solution for weeks. When filled with perfluorocarbon gas, the particles behave as an efficient contrast agent for colour Doppler ultrasound imaging in human breast tissue. The silica shell provides unique properties compared to conventional soft shell particles employed as ultrasound contrast agents: uniform size control, strong adsorption to tissue and cells immobilizing particles at the tissue injection site, a long imaging lifetime, and a silica surface that can be easily modified with biotargeting ligands or small molecules to adjust the surface charge and polarity. PMID:21841967

Martinez, H. Paul; Kono, Yuko; Blair, Sarah L.; Sandoval, Sergio; Wang-Rodriguez, Jessica

2011-01-01

54

Practical colour management  

NASA Astrophysics Data System (ADS)

Spectrophotometers have been successfully used for colour measurement. This paper addresses digital imaging as a complementary and alternative method of colour measurement and appearance and an effective communication tool as part of a practical colour management programme within the supply chain of a textile retailer. The specific needs—to measure and communicate textured dyed material and printed fabric—are discussed, as well as the colour specification and quality control (QC) of currently un-measurable fabrics and accessories. A unique method of using digital imaging for the assessment of colour fastness will also be discussed.

Williams, Susan

2006-06-01

55

Automated localisation of the optic disc, fovea, and retinal blood vessels from digital colour fundus images  

PubMed Central

AIM—To recognise automatically the main components of the fundus on digital colour images.?METHODS—The main features of a fundus retinal image were defined as the optic disc, fovea, and blood vessels. Methods are described for their automatic recognition and location. 112 retinal images were preprocessed via adaptive, local, contrast enhancement. The optic discs were located by identifying the area with the highest variation in intensity of adjacent pixels. Blood vessels were identified by means of a multilayer perceptron neural net, for which the inputs were derived from a principal component analysis (PCA) of the image and edge detection of the first component of PCA. The foveas were identified using matching correlation together with characteristics typical of a fovea—for example, darkest area in the neighbourhood of the optic disc. The main components of the image were identified by an experienced ophthalmologist for comparison with computerised methods.?RESULTS—The sensitivity and specificity of the recognition of each retinal main component was as follows: 99.1% and 99.1% for the optic disc; 83.3% and 91.0% for blood vessels; 80.4% and 99.1% for the fovea.?CONCLUSIONS—In this study the optic disc, blood vessels, and fovea were accurately detected. The identification of the normal components of the retinal image will aid the future detection of diseases in these regions. In diabetic retinopathy, for example, an image could be analysed for retinopathy with reference to sight threatening complications such as disc neovascularisation, vascular changes, or foveal exudation.?? PMID:10413690

Sinthanayothin, C.; Boyce, J.; Cook, H.; Williamson, T.

1999-01-01

56

A SURVEY OF METHODS FOR COLOUR IMAGE INDEXING AND RETRIEVAL IN IMAGE DATABASES  

Microsoft Academic Search

Color is a feature of the great majority of content-based image retrieval systems. However the robustness, effectiveness, and efficiency of its use in image indexing are still open issues. This paper provides a comprehensive survey of the methods for color image indexing and retrieval described in the literature. In particular, image preprocessing, the features used to represent color information, and

Raimondo SCHETTINI; Gianluigi CIOCCA; Silvia ZUFFI

2001-01-01

57

Colour matching of composite resin cements with their corresponding try-in pastes.  

PubMed

Two shades of four resin cements (Calibra, Clearfil Esthetic, Insure, Variolink II), in light- and dual-curing modes, were tested for colour matching with their corresponding try-in pastes, immediately after photopolymerization and after 24-hour dry and dark storage. Colour measurements were performed for 0.8 mm-thick specimens through a 0.8mm-thick ceramic plate. For each resin cement, colour differences (deltaE) were calculated between the two curing modes, and between the corresponding try-in paste, at baseline and after 24h. deltaE>0 values were detected between all resin cements and their try-in pastes, which were brand/shade/curing mode depended. The try-in pastes of the Variolink II system demonstrated the best colour matching (deltaE<2). Try-in pastes of Calibra and Insure, at both curing modes, did not match at an acceptable value, the shade of their corresponding resin cements (deltaE>3.3). Calibra presented the highest colour differences. deltaE values of the Clearfil Esthetic system immediately after photo-activation ranged between 2 and 3 units. A ceramic restoration may fail aesthetically as a result of not acceptable colour match (deltaE>3.3) between the shade of certain resin cements and their relevant try-in pastes. PMID:25134367

Kampouropoulos, D; Gaintantzopoulou, M; Papazoglou, E; Kakaboura, A

2014-06-01

58

Influence of choice of yeasts on volatile fermentation-derived compounds, colour and phenolics composition in Cabernet Sauvignon wine.  

PubMed

Wine colour, phenolics and volatile fermentation-derived composition are the quintessential elements of a red wine. Many viticultural and winemaking factors contribute to wine aroma and colour with choice of yeast strain being a crucial factor. Besides the traditional Saccharomyces species S. cerevisiae, S. bayanus and several Saccharomyces interspecific hybrids are able to ferment grape juice to completion. This study examined the diversity in chemical composition, including phenolics and fermentation-derived volatile compounds, of an Australian Cabernet Sauvignon due to the use of different Saccharomyces strains. Eleven commercially available Saccharomyces strains were used in this study; S. cerevisiae (7), S. bayanus (2) and interspecific Saccharomyces hybrids (2). The eleven Cabernet Sauvignon wines varied greatly in their chemical composition. Nine yeast strains completed alcoholic fermentation in 19 days; S. bayanus AWRI 1375 in 26 days, and S. cerevisiae AWRI 1554 required 32 days. Ethanol concentrations varied in the final wines (12.7-14.2 %). The two S. bayanus strains produced the most distinct wines, with the ability to metabolise malic acid, generate high glycerol concentrations and distinctive phenolic composition. Saccharomyces hybrid AWRI 1501 and S. cerevisiae AWRI 1554 and AWRI 1493 also generated distinctive wines. This work demonstrates that the style of a Cabernet Sauvignon can be clearly modulated by choice of commercially available wine yeast. PMID:22878903

Blazquez Rojas, Inmaculada; Smith, Paul A; Bartowsky, Eveline J

2012-12-01

59

Is colour cognitive?  

NASA Astrophysics Data System (ADS)

In recent years, colour-vision abilities have been rather generously ascribed to various invertebrates and even bacteria. This uncertainty of when to diagnose colour vision stems in part from confusing what colour vision can do with what it is. What colour vision can do is discriminate wavelength independent of intensity. However, if we take this as a definition of what colour vision is, then we might be obliged to conclude that some plants and bacteria have colour vision. Moreover, there is a similar confusion of what are necessary and what are sufficient mechanisms and behavioural abilities for colour vision. To humans, seeing in colour means seeing an image in which objects/lights have chromatic attributes—in contrast to the sensation that we have when viewing monochrome movies, or our experience in dim light when only rod vision is possible. The necessary basic equipment for this is to have at least two types of photoreceptors that differ in spectral sensitivity, and at least one type of spectrally opponent cell to compare the signals from the photoreceptors. Clearly, however, a necessary additional prerequisite for colour vision is to have vision, which entails the identification of shapes, sizes and locations of objects in the world. Thus, if an animal has colour vision, it should see an image in which distinct objects/lights have colour attributes. This distinguishes colour vision from wavelength discrimination, but also from what has historically been called wavelength-specific behaviour: a type of behaviour triggered by fixed configurations of spectral receptor signals; however, we discuss difficulties in diagnosing wavelength-specific behaviour as an indicator of the absence of colour vision. Finally, we discuss whether colour vision, by definition, contains a cognitive dimension for ordering and classifying perceptual experience.

Skorupski, Peter; Chittka, Lars

2011-03-01

60

A prominent colour front in False Bay, South Africa: Cross-frontal structure, composition and origin  

Microsoft Academic Search

Colour fronts are a frequent occurrence in False Bay, South Africa, and their occurrence has been the subject of previous study and anecdotal conjecture. The opportunity arose to make a cross-frontal study of this feature in November 2005. Photographs were taken and, subsequently, satellite imagery was obtained. Measurements were made of temperature, salinity, turbidity, dissolved oxygen, suspended solids, plant nutrients

H. N. Waldron; C. K. Wainman; M. E. Waldron; C. Whittle; G. B. Brundrit

2008-01-01

61

Storage at low temperature differentially affects the colour and carotenoid composition of two cultivars of banana.  

PubMed

Different storage conditions can induce changes in the colour and carotenoid profiles and levels in some fruits. The goal of this work was to evaluate the influence of low temperature storage on the colour and carotenoid synthesis in two banana cultivars: Prata and Nanicão. For this purpose, the carotenoids from the banana pulp were determined by HPLC-DAD-MS/MS, and the colour of the banana skin was determined by a colorimeter method. Ten carotenoids were identified, of which the major carotenoids were all-trans-lutein, all-trans-?-carotene and all-trans-?-carotene in both cultivars. The effect of the low temperatures was subjected to linear regression analysis. In cv. Prata, all-trans-?-carotene and all-trans-?-carotene were significantly affected by low temperature (p<0.01), with negative estimated values (? coefficients) indicating that during cold storage conditions, the concentrations of these carotenoids tended to decrease. In cv. Nanicão, no carotenoid was significantly affected by cold storage (p>0.05). The accumulation of carotenoids in this group may be because the metabolic pathways using these carotenoids were affected by storage at low temperatures. The colour of the fruits was not negatively affected by the low temperatures (p>0.05). PMID:25306323

Facundo, Heliofabia Virginia De Vasconcelos; Gurak, Poliana Deyse; Mercadante, Adriana Zerlotti; Lajolo, Franco Maria; Cordenunsi, Beatriz Rosana

2015-03-01

62

Measurement of ocular blood flow velocity using colour Doppler imaging in low tension glaucoma.  

PubMed

The purpose of this study was to compare the velocity of blood flow and vascular resistance measured by colour Doppler imaging in the ophthalmic and central retinal arteries in 34 eyes of 34 patients (mean age 68.1 years) with low tension glaucoma (LTG) and 17 eyes of 17 age-matched normal controls (mean age 65.2 years). The Acuson 128 machine (using a 7.5 MHz probe) was used to measure peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistive index (RI). The EDV of the ophthalmic artery (OA) in the LTG was significantly (p = 0.04) less than in the normal control group. There was a significant (p = 0.02) increase in the vascular RI of both the OA and central retinal artery in the LTG group compared with the normal controls. The OA RI increased with age (r = 0.61, p = 0.0001), and the OA EDV decreased with age (r = -0.50, p = 0.003), in the LTG group but not in the normal control group. The results suggest an increased resistance to blood flow in the ophthalmic and central retinal arteries of LTG patients. PMID:7713247

Butt, Z; McKillop, G; O'Brien, C; Allan, P; Aspinall, P

1995-01-01

63

Analysis of foveal avascular zone in colour fundus images for grading of diabetic retinopathy severity.  

PubMed

Diabetic retinopathy (DR) is a sight threatening complication due to diabetes mellitus that affects the retina. At present, the classification of DR is based on the International Clinical Diabetic Retinopathy Disease Severity. In this paper, FAZ enlargement with DR progression is investigated to enable a new and an effective grading protocol DR severity in an observational clinical study. The performance of a computerised DR monitoring and grading system that digitally analyses colour fundus image to measure the enlargement of FAZ and grade DR is evaluated. The range of FAZ area is optimised to accurately determine DR severity stage and progression stages using a Gaussian Bayes classifier. The system achieves high accuracies of above 96%, sensitivities higher than 88% and specificities higher than 96%, in grading of DR severity. In particular, high sensitivity (100%), specificity (>98%) and accuracy (99%) values are obtained for No DR (normal) and Severe NPDR/PDR stages. The system performance indicates that the DR system is suitable for early detection of DR and for effective treatment of severe cases. PMID:21097305

Ahmad Fadzil, M; Ngah, Nor Fariza; George, Tara M; Izhar, Lila I; Nugroho, Hermawan; Adi Nugroho, Hanung

2010-01-01

64

Composite ultrasound imaging apparatus and method  

DOEpatents

An imaging apparatus and method for use in presenting composite two dimensional and three dimensional images from individual ultrasonic frames. A cross-sectional reconstruction is applied by using digital ultrasound frames, transducer orientation and a known center. Motion compensation, rank value filtering, noise suppression and tissue classification are utilized to optimize the composite image.

Morimoto, Alan K. (Albuquerque, NM); Bow, Jr., Wallace J. (Albuquerque, NM); Strong, David Scott (Albuquerque, NM); Dickey, Fred M. (Albuquerque, NM)

1998-01-01

65

Forest cover type and landuse mapping using landsat Thematic Mapper False colour Composite a case study for chakrata in western himalayas U.P  

Microsoft Academic Search

In the present study authors have attempted to prepare a forest composition cover type map using landsat Thematic Mapper (T.M.)\\u000a False colour Composite (F.C.C.) on 1:3n250,000 scale synthesized by combining band 2, 3 & 4 pertaining to study area. Landsat\\u000a T.M.F.C.C. have been visually interpreted for delineation of forest cover type identified on the basis of tone\\/colour, texture,\\u000a pattern &

M. C. Porwal; D. N. Pant

1989-01-01

66

A new algorithm for automatic Rumex obtusifolius detection in digital images using colour and texture features and the influence of image resolution  

Microsoft Academic Search

In Gebhardt et al. (2006) an object-oriented image classification algorithm was introduced for detecting Rumex obtusifolius (RUMOB) and other weeds in mixed grassland swards, based on shape, colour and texture features. This paper describes a new\\u000a algorithm that improves classification accuracy. The leaves of the typical grassland weeds (RUMOB, Taraxacum officinale, Plantago major) and other homogeneous regions were segmented automatically in

Steffen Gebhardt; Walter Kühbauch

2007-01-01

67

Salivary gland tumours: is colour Doppler imaging of added value in their preoperative assessment?  

PubMed

Using a Toshiba SSA-270A Colour Duplex Scanner, 15 patients with suspected parotid and submandibular gland tumours had preoperative duplex scanning done. Peak systolic doppler shifts (fmax) were recorded and their vascularity was also subjectively scored. There were no arteries identified within the substance of contralateral normal glands. All recordings were analysed retrospectively and an independent histological assessment of tumours was made. Pleomorphic adenomas (n = 9) had a median peak systolic frequency (fmax) of 0.8 kHz, while adenolymphomas (n = 4) had a fmax of 1.65 and the two malignant tumours had fmax of 4.5 (P = 0.007 Kruskal-Wallis test). There appears to be a strong correlation between the fmax and the subjective vascular score (Corr 0.92). Colour duplex scanning is a non-invasive procedure which may be of help in the preoperative assessment of salivary gland tumours. PMID:1330705

Ajayi, B A; Pugh, N D; Carolan, G; Woodcock, J P

1992-10-01

68

A novel illumination-invariant colour constancy algorithm  

NASA Astrophysics Data System (ADS)

The human brain is able to extract the colour of objects no matter the existing illumination conditions which may affect the appearance of their colour. For a person, an object that is red, it will be red regardless of the type of illumination source. However, for a computer algorithm to achieve the same task is not as simple. For vision and robotics applications were feature extraction is essential having such an algorithm is crucial. It is well known from the literature that the colour of an object does not only depend on the chemical composition and shape of its surface but also on the illumination conditions, the intensity, number, location and colour of the sources of illumination as well as the intrinsic and extrinsic characteristics of the sensor used. Based on that knowledge, we propose a simple colour constancy algorithm that uses the quaternion representation of each pixel in the image instead of the commonly used RGB model. We assume linearity in the reception of the luminance spectrum of the charge-coupled device of the camera before variations in the illumination. We have tested our colour constancy algorithm in a variety of images containing different colour objects under different illumination conditions. Our experimental results show the feasibility of the proposed method.

Torres-Méndez, L. A.; Quiñones Muñoz, M. L.; Olaya-Benítez, E. J.

2011-08-01

69

Colour Doppler Imaging of Ophthalmic Artery and Central Retinal Artery in Glaucoma Patients with and without Diabetes Mellitus  

PubMed Central

Purpose: To assess the ocular blood flow in Diabetic and non-Diabetic Primary Open Angle Glaucoma (POAG) patients. Design: Prospective comparitive study. Material and Methods: A total 100 eyes of 50 POAG patients was included in the study and divided into two groups, Group 1 (25 POAG patients without Diabetes mellitus) and Group 2 (25 POAG patients with Diabetes mellitus). Colour Doppler Imaging (CDI) of Ophthalmic artery and Central retinal artery were studied and peak systolic velocity (V max), End diastolic velocity (V min) and Resistivity Index (RI) were assessed. Results: Ocular blood flow in Group 2 showed a reduction in V max, V min and increased RI compared to Group I with a statistically significant reduction in the central retinal artery flow (V max (p=0.01), V min (p=0.07) and RI (p=0.03). Conclusion: CDI showed a significant reduction in the ocular blood flow of POAG patients with Diabetes mellitus. PMID:24959497

Kumar, M. Ashok; Selvasundari, S.; Prakash, M. L.

2014-01-01

70

Pre-bottling use of dehydrated waste grape skins to improve colour, phenolic and aroma composition of red wines.  

PubMed

Different dehydrated waste grape skins from the juice industry were added into aged and young red wines as an innovative way of compensating for colour loss before bottling. After addition of grape skins, colour intensity of wines increased a mean 11% and a maximum of 31% with predominance of the red component. Total polyphenols mean increase was 10% with a maximum value of 20%. Analysis of low molecular weight phenolic compounds by HPLC-DAD showed a significant (p<0.05) content increase of the bioactive compounds gallic acid, (+)-catechin, (-)-epicatechin, and (E)-resveratrol. Anthocyanins content also increased at an average of 50mg/l. The volatile profile of wines analysed by SBSE-GC-MS was only moderately influenced by the treatments. Mixtures of dehydrated waste grape skins were useful to improve the colour and polyphenol profile of red wines, considering them a useful tool for correcting colour loss before bottling. PMID:23017417

Pedroza, Miguel Angel; Carmona, Manuel; Alonso, Gonzalo Luis; Salinas, Maria Rosario; Zalacain, Amaya

2013-01-01

71

Making Art and Understanding Images Utilizing sketchbooks, collage, colour exercises and cre-  

E-print Network

2NEW ART COURSES OPEN to ALL McMaster Students ART 1UI3 Making Art and Understanding Images, 2014-15 Thursday evenings 7 pm � 10pm 3 hours per week in a continuous block ART 1TI3 Making Art and Understanding Images & Technology Creating art utilizing a range of media, including digital tools and creative

Haykin, Simon

72

Composite model of a 3-D image  

NASA Technical Reports Server (NTRS)

This paper presents a composite model of a moving (3-D) image especially useful for the sequential image processing and encoding. A non-linear predictor based on the composite model is described. The performance of this predictor is used as a measure of the validity of the model for a real image source. The minimization of a total mean square prediction error provides an inequality which determines a condition for the profitable use of the composite model and can serve as a decision device for the selection of the number of subsources within the model. The paper also describes statistical properties of the prediction error and contains results of computer simulation of two non-linear predictors in the case of perfect classification between subsources.

Dukhovich, I. J.

1980-01-01

73

Colour detection thresholds in faces and colour patches.  

PubMed

Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior 32 216-227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology 30 845-857). Here, we examine Malaysian Chinese participants' detection thresholds for CIELab L* (lightness), a* (redness), and b* (yellowness) colour changes in Asian, African, and Caucasian faces and skin coloured patches. Twelve face photos and three skin coloured patches were transformed to produce four pairs of images of each individual face and colour patch with different amounts of red, yellow, or lightness, from very subtle (deltaE = 1.2) to quite large differences (deltaE = 9.6). Participants were asked to decide which of sequentially displayed, paired same-face images or colour patches were lighter, redder, or yellower. Changes in facial redness, followed by changes in yellowness, were more easily discriminated than changes in luminance. However, visual sensitivity was not greater for redness and yellowness in nonface stimuli, suggesting red facial skin colour special salience. Participants were also significantly better at recognizing colour differences in own-race (Asian) and Caucasian faces than in African faces, suggesting the existence of cross-race effect in discriminating facial colours. Humans' colour vision may have been selected for skin colour signalling (Changizi et al 2006 Biology Letters 2 217-221), enabling individuals to perceive subtle changes in skin colour, reflecting health and emotional status. PMID:24344549

Tan, Kok Wei; Stephen, Ian D

2013-01-01

74

A Markov Random Field Framework for Finding Shadows in a Single Colour Image  

E-print Network

. Drew School of Computing Science, Simon Fraser University, Vancouver (CANADA) Corresponding author of the scene illuminant. For the purpose of producing an invariant image, we start by representing a daylight

Drew, Mark S.

75

Changes in texture, colour and fatty acid composition of male and female pig shoulder fat due to different dietary fat sources.  

PubMed

Two experiments with 72 slaughter pigs in each were conducted. Entire males and females were individually fed restricted. Palm kernel-, soybean- and fish-oil were used in varying combinations, giving different dietary fat levels (29-80g/kg) and iodine values ranging from 50 to 131. Shoulder fat was analysed for fatty acid composition (inner and outer layer), firmness and colour. A clear dose-response relationship was seen between fatty acids in diets and in shoulder fat. Interestingly, the very long chain n-3 fatty acids seemed to be deposited more efficiently when additional fat was included in the diet. Both high and low dietary iodine values changed towards less extreme iodine values in fat. Low-fat diets enhanced de novo synthesis of fatty acids. Males revealed a higher percentage of PUFA and a lower percentage of C18:1 and MUFA. Fat firmness, but not colour, was influenced by sex and dietary fat source. PMID:22112523

Hallenstvedt, E; Kjos, N P; Overland, M; Thomassen, M

2012-03-01

76

A comparative analysis of pre-processing techniques in colour retinal images  

NASA Astrophysics Data System (ADS)

Diabetic retinopathy (DR) is a chronic disease of the ocular retina, which most of the times is only discovered when the disease is on an advanced stage and most of the damage is irreversible. For that reason, early diagnosis is paramount for avoiding the most severe consequences of the DR, of which complete blindness is not uncommon. Unsupervised or supervised image processing of retinal images emerges as a feasible tool for this diagnosis. The preprocessing stages are the key for any further assessment, since these images exhibit several defects, including non uniform illumination, sampling noise, uneven contrast due to pigmentation loss during sampling, and many others. Any feasible diagnosis system should work with images where these defects were compensated. In this work we analyze and test several correction techniques. Non uniform illumination is compensated using morphology and homomorphic filtering; uneven contrast is compensated using morphology and local enhancement. We tested our processing stages using Fuzzy C-Means, and local Hurst (self correlation) coefficient for unsupervised segmentation of the abnormal blood vessels. The results over a standard set of DR images are more than promising.

Salvatelli, A.; Bizai, G.; Barbosa, G.; Drozdowicz, B.; Delrieux, C.

2007-11-01

77

Generalized satellite image processing: eight years of ocean colour data for any region on earth  

Microsoft Academic Search

During the past decade, the world's oceans have been systematically observed by orbiting spectroradiometers such as MODIS and MERIS. These sensors have generated a huge amount of data with unprecedented temporal and spatial coverage. The data is freely available, but not always accessible for marine researchers with no image processing experience. In order to provide historical and current oceanographic parameters

Quinten Vanhellemont; Kevin Ruddick

2011-01-01

78

Colour Spaces for Colour Transfer Erik Reinhard and Tania Pouli  

E-print Network

, Correlation 1 Introduction Colour is one of the main image attributes used in art, photography and visuali of the L, M and S cones in the human retina (the letters stand for Long, Medium and Short wavelength

Reinhard, Erik

79

The use of digital imaging for colour matching and communication in restorative dentistry  

Microsoft Academic Search

Objective To develop a shade matching method based on digital imaging and to compare observers' ability using this method with the conventional one set against a spectrophotometric 'gold standard'.Methods Two Vita Lumin shade guides were used in this study, nine shades being selected from the first Vita Lumin shade guide, A2, A3, A3.5, B2, B3, B4, C1, C2 and C3.

M D Russell; B W Moss; F D Jarad

2005-01-01

80

Automatic Segmentation of Blood Vessels in Colour Retinal Images using Spatial Gabor Filter and Multiscale Analysis  

Microsoft Academic Search

Retinal blood vessels are significant anatomical structures in ophthalmic images. Automatic segmentation of blood vessels\\u000a is one of the important steps in computer aided diagnosis system for the detection of diseases such as Diabetic Retinopathy\\u000a that affect human retina. We propose a method for the segmentation of retinal blood vessels using Spatial Gabor filters as\\u000a they can be tuned to

P. C. Siddalingaswamy; K. Gopalakrishna Prabhu

81

Automatic extraction of retinal features from colour retinal images for glaucoma diagnosis: a review.  

PubMed

Glaucoma is a group of eye diseases that have common traits such as, high eye pressure, damage to the Optic Nerve Head and gradual vision loss. It affects peripheral vision and eventually leads to blindness if left untreated. The current common methods of pre-diagnosis of Glaucoma include measurement of Intra-Ocular Pressure (IOP) using Tonometer, Pachymetry, Gonioscopy; which are performed manually by the clinicians. These tests are usually followed by Optic Nerve Head (ONH) Appearance examination for the confirmed diagnosis of Glaucoma. The diagnoses require regular monitoring, which is costly and time consuming. The accuracy and reliability of diagnosis is limited by the domain knowledge of different ophthalmologists. Therefore automatic diagnosis of Glaucoma attracts a lot of attention. This paper surveys the state-of-the-art of automatic extraction of anatomical features from retinal images to assist early diagnosis of the Glaucoma. We have conducted critical evaluation of the existing automatic extraction methods based on features including Optic Cup to Disc Ratio (CDR), Retinal Nerve Fibre Layer (RNFL), Peripapillary Atrophy (PPA), Neuroretinal Rim Notching, Vasculature Shift, etc., which adds value on efficient feature extraction related to Glaucoma diagnosis. PMID:24139134

Haleem, Muhammad Salman; Han, Liangxiu; van Hemert, Jano; Li, Baihua

2013-01-01

82

Magnetic Resonance Imaging with Composite (Dual) Gradients  

PubMed Central

The tradeoff between gradient performance factors, size of the imaging region, and physiological factors such as nerve stimulation typically leads to compromises in gradient design and ultimately suboptimal imaging performance. Local gradient systems can add some performance flexibility, but are cumbersome to set up and remove. In nearly all conventional MRI systems, the use of local gradients precludes the use of the more homogeneous whole body gradients. This paper presents the concept of dynamically selectable composite gradient systems where local gradients and whole body gradients can be selected independently and simultaneously. The relative performance of whole body, insert, and composite gradients is predicted for echoplanar (EPI), turbo spin echo (TSE), and steady state free precession (SSFP). A realization of the concept is presented. PMID:20160925

Parker, Dennis L.; Goodrich, K. Craig; Hadley, J. Rock; Kim, Seong-Eun; Moon, Sung M.; Chronik, Blaine A.; Fontius, Ulrich; Schmitt, Franz

2009-01-01

83

Optical spectroscopy and imaging of colour centres in lithium fluoride crystals and thin films irradiated by 3 MeV proton beams  

NASA Astrophysics Data System (ADS)

Lithium fluoride is a well-known dosimeter material and it is currently under investigation also for high-resolution radiation imaging detectors based on colour centre photoluminescence. In order to extend their applications, proton beams of 3 MeV energy, produced by a linear accelerator, were used to irradiate LiF crystals and thin films in the fluence range of 1010-1015 protons/cm2. The irradiation induces the formation of colour centres, mainly the primary F centre and the aggregate F2 and F3+ defects, which are stable at room temperature. By optical pumping in the blue spectral region, the F2 and F3+ centres emit broad photoluminescence bands in the visible spectral range. By conventional fluorescence microscopy, the integrated photoluminescence intensity was carefully measured in LiF crystals and thin films as a function of the irradiation fluence: a linear optical response was obtained in a large range of fluence, which is dependent on the used LiF samples. Colour centres concentrations were estimated in LiF crystals by optical absorption spectroscopy. It was possible to record the transversal proton beam intensity profile by acquiring the photoluminescence image of the irradiated spots on LiF films.

Piccinini, M.; Ambrosini, F.; Ampollini, A.; Carpanese, M.; Picardi, L.; Ronsivalle, C.; Bonfigli, F.; Libera, S.; Vincenti, M. A.; Montereali, R. M.

2014-05-01

84

Printing colour at the optical diffraction limit.  

PubMed

The highest possible resolution for printed colour images is determined by the diffraction limit of visible light. To achieve this limit, individual colour elements (or pixels) with a pitch of 250 nm are required, translating into printed images at a resolution of ?100,000 dots per inch (d.p.i.). However, methods for dispensing multiple colourants or fabricating structural colour through plasmonic structures have insufficient resolution and limited scalability. Here, we present a non-colourant method that achieves bright-field colour prints with resolutions up to the optical diffraction limit. Colour information is encoded in the dimensional parameters of metal nanostructures, so that tuning their plasmon resonance determines the colours of the individual pixels. Our colour-mapping strategy produces images with both sharp colour changes and fine tonal variations, is amenable to large-volume colour printing via nanoimprint lithography, and could be useful in making microimages for security, steganography, nanoscale optical filters and high-density spectrally encoded optical data storage. PMID:22886173

Kumar, Karthik; Duan, Huigao; Hegde, Ravi S; Koh, Samuel C W; Wei, Jennifer N; Yang, Joel K W

2012-09-01

85

Upper Extremity Composite Tissue Allotransplantation Imaging  

PubMed Central

Objective: Upper extremity (UE) transplantation is the most commonly performed composite tissue allotransplantation worldwide. However, there is a lack of imaging standards for pre- and posttransplant evaluation. This study highlights the protocols and findings of UE allotransplantation toward standardization and implementation for clinical trials. Methods: Multimodality imaging protocols for a unilateral hand transplant candidate and a bilateral mid-forearm level UE transplant recipient include radiography, computed tomography (CT), magnetic resonance (MR) imaging, catheter angiography, and vascular ultrasonography. Pre- and posttransplant findings, including dynamic CT and MR performed for assessment of motor activity of transplanted hands, are assessed, and image quality of vessels and bones on CT and MR evaluated. Results: Preoperative imaging demonstrates extensive skeletal deformity and variation in vascular anatomy and vessel patency. Posttransplant images confirm bony union in anatomical alignment and patency of vascular anastomoses. Mild differences in rate of vascular enhancement and extent of vascular networks are noted between the 2 transplanted limbs. Dynamic CT and MR demonstrate a 15° to 30° range of motion at metacarpophalangeal joints and 90° to 110° at proximal interphalangeal joints of both transplanted hands at 8 months posttransplant. Image quality was slightly better for CT than for MR in the first subject, while MR was slightly better in the second subject. Conclusion: Advanced vascular and musculoskeletal imaging play an important role in surgical planning and can provide novel posttransplantation data to monitor the success of the procedure. Implementation of more standardized protocols should enable a more comprehensive assessment to evaluate the efficacy in clinical trials. PMID:23943677

George, Elizabeth; Mitsouras, Dimitrios; Kumamaru, Kanako K.; Shah, Nehal; Smith, Stacy E.; Schultz, Kurt; Deaver, Pamela M.; Mullen, Katherine M.; Steigner, Michael L.; Gravereaux, Edwin C.; Demehri, Shadpour; Bueno, Ericka M.; Talbot, Simon G.; Pomahac, Bohdan; Rybicki, Frank J.

2013-01-01

86

The colour wheels of art, perception, science and physiology  

NASA Astrophysics Data System (ADS)

Colour is not the domain of any one discipline be it art, philosophy, psychology or science. Each discipline has its own colour wheel and this presentation examines the origins and philosophies behind the colour circles of Art, Perception, Science and Physiology (after image) with reference to Aristotle, Robert Boyle, Leonardo da Vinci, Goethe, Ewald Hering and Albert Munsell. The paper analyses and discusses the differences between the four colour wheels using the Natural Colour System® notation as the reference for hue (the position of colours within each of the colour wheels). Examination of the colour wheels shows the dominance of blue in the wheels of art, science and physiology particularly at the expense of green. This paper does not consider the three-dimensionality of colour space its goal was to review the hue of a colour with regard to its position on the respective colour wheels.

Harkness, Nick

2006-06-01

87

AMS Composite GOES Image Viewer and Data Lister  

NSDL National Science Digital Library

The American Meteorological Society (AMS) Composite Geostationary Operational Environmental Satellite (GOES) Image Viewer and Data Lister is a small Java applet composite infrared (IR) image viewer that uses a near real-time composite infrared satellite picture of the U.S. to interactively explore the temperature as seen from space. The images are created every three hours from GOES-east and GOES-west by the McIDAS system. The composite IR image allows you to move the mouse pointer over the image while the temperature (degrees C), latitude and longitude are listed.

Whittaker, Tom

88

Automatic thermographic image defect detection of composites  

NASA Astrophysics Data System (ADS)

Detecting defects, and especially reliably measuring defect sizes, are critical objectives in automatic NDT defect detection applications. In this work, the Sentence software is proposed for the analysis of pulsed thermography and near IR images of composite materials. Furthermore, the Sentence software delivers an end-to-end, user friendly platform for engineers to perform complete manual inspections, as well as tools that allow senior engineers to develop inspection templates and profiles, reducing the requisite thermographic skill level of the operating engineer. Finally, the Sentence software can also offer complete independence of operator decisions by the fully automated "Beep on Defect" detection functionality. The end-to-end automatic inspection system includes sub-systems for defining a panel profile, generating an inspection plan, controlling a robot-arm and capturing thermographic images to detect defects. A statistical model has been built to analyze the entire image, evaluate grey-scale ranges, import sentencing criteria and automatically detect impact damage defects. A full width half maximum algorithm has been used to quantify the flaw sizes. The identified defects are imported into the sentencing engine which then sentences (automatically compares analysis results against acceptance criteria) the inspection by comparing the most significant defect or group of defects against the inspection standards.

Luo, Bin; Liebenberg, Bjorn; Raymont, Jeff; Santospirito, SP

2011-05-01

89

Frugal Colouring of Graphs  

Microsoft Academic Search

A k-frugal colouring of a graph G is a proper colouring of the vertices of G such that no colour appears more than k times in the neighbourhood of a vertex. This type of colouring was introduced by Hind, Molloy and Reed in 1997. In this paper, we study the frugal chromatic number of planar graphs, planar graphs with large

Omid Amini; Louis Esperet; Jan Van Den Heuvel

2007-01-01

90

Colloidal approach to prepare colour blends from colourants with different solubility profiles.  

PubMed

Food colouring plays a vital and a determining role in the processing and the manufacturing of food products because the appearance of products is critical for attracting consumers and influencing their food choices. However, factors such as legislative restrictions, limited number of approved colourants and the processing, formulation and stability issues of the natural colourants severely limits the application of food colouring in actual product formats. Hence, finding alternatives to the currently utilised formulation practises, represents an important area of research. Here, we report a simple colloidal approach to prepare colour blends by co-incorporating colourants with contrasting aqueous solubility profiles in composite colloidal particles. Curcumin and indigocarmine were selected as water insoluble and water soluble food-grade colourants respectively and incorporated in the colloidal particles prepared from food protein-zein. Composite particles obtained by loading of curcumin and indigocarmine (at different ratios) had mean particle size ranging from 76 to 300nm. The spherical shape of the colloidal particles was confirmed using transmission electron microscopy and the colloidal dispersions were further characterised using UV-Vis and fluorescence spectroscopy. The incorporation of colourants in colloidal particles led to the generation of different shade of colour in yellow-green-blue range. The encapsulation also led to the stabilization of individual pigments against photodegradation. Such composite colloidal particles could potentially serve as an approach for developing tuneable colouring system for food and nutraceutical applications. PMID:23790940

Patel, A R; Heussen, P C M; Dorst, E; Hazekamp, J; Velikov, K P

2013-11-15

91

Single shot white light interference microscopy with colour fringe analysis for quantitative phase imaging of biological cells  

NASA Astrophysics Data System (ADS)

To quantitatively obtain the phase map of Onion and human red blood cell (RBC) from white light interferogram we used Hilbert transform color fringe analysis technique. The three Red, Blue and Green color components are decomposed from single white light interferogram and Refractive index profile for Red, Blue and Green colour were computed in a completely non-invasive manner for Onion and human RBC. The present technique might be useful for non-invasive determination of the refractive index variation within cells and tissues and morphological features of sample with ease of operation and low cost.

Srivastava, Vishal; Mehta, D. S.

2013-02-01

92

[Studies on the metabolism of ketocarotenoids in species of Adonis : I. Composition of pigments in abnormally coloured petals].  

PubMed

The composition of carotenoids in yellow flowers of Adonis aestivalis, A. annua, and A. flammeus has been determined (see Table). In contrast to the pattern of pigments in normally red flowers, these petals are free of ketocarotenoids but rich in oxipolyenes. The role of these compounds as precursors of the ketocarotenoids has been discussed and summarized in a hypothetical scheme (Fig. 1). PMID:24515554

Czygan, F C

1969-03-01

93

Across light: through colour  

NASA Astrophysics Data System (ADS)

The speed at which our world is changing is reflected in the shifting way artistic images are created and produced. Holography can be used as a medium to express the perception of space with light and colour and to make the material and the immaterial experiments with optical and digital holography. This paper intends to be a reflection on the final product of that process surrounding a debate of ideas for new experimental methodologies applied to holographic images. Holography is a time-based medium and the irretrievable linear flow of time is responsible for a drama, unique to traditional cinematography. If the viewers move to left or right, they see glimpses of the next scene or the previous one perceived a second ago. This interaction of synthetic space arises questions such as: can we see, in "reality", two forms in the same space? Trying to answer this question, a series of works has been created. These concepts are embryonic to a series of digital art holograms and lenticulars technique's titled "Across Light: Through Colour". They required some technical research and comparison between effects from different camera types, using Canon IS3 and Sony HDR CX105.

Azevedo, Isabel; Richardson, Martin; Bernardo, Luis Miguel

2012-03-01

94

Proposal, verification and comparison of three computer image analysis methods for detection and evaluation of colour glaucomatous changes within the optic disc of a human eye retina  

NASA Astrophysics Data System (ADS)

The typical symptom of the human eye glaucoma is a rise and a progression of the bright area (named pallor area) within the retina blind spot. The image analysis manner proposed by the authors detects and suitably numerically describes the relative size of the representative pallor area in the colour digital image of the retina obtained by a suitable fundus camera connected with the computer. Three new different computer image analysis statistical methods for experimental diagnostic evaluation of the obtained characteristic data are proposed in this article: the quantile curves method, the neural net method and the probability density curves method. The quantile curves method is based on the graphical comparison of a relative representative pallor area size with its determined normal value. The neural net and probability density curves methods can automatically and objectively classify the investigated eyes in exactly defined glaucoma risk classes and diagnosed glaucoma with the rated probabilities of incorrect diagnosis determination. All mentioned methods are verified and mutually compared by their application to the large statistical sets of human retina images of various healthy and glaucomatous subjects.

Pluhacek, Frantisek; Pospisil, Jaroslav

2005-04-01

95

Colourful Simplicial Depth  

Microsoft Academic Search

Inspired by Barany's Colourful Caratheodory Theorem (4), we introduce a colourful generalization of Liu's simplicial depth (13). We prove a parity property and con- jecture that the minimum colourful simplicial depth of any core point in any d-dimensional configuration is d 2 + 1 and that the maximum is d d+1 + 1. We exhibit configurations attain- ing each of

Antoine Deza; Sui Huang; Tamon Stephen; Tamás Terlaky

2006-01-01

96

Does Colour Preference Have a Role in Colour Term Acquisition?  

ERIC Educational Resources Information Center

A developmental association exists between colour preference and emerging colour term acquisition in young children. Colour preference might influence colour term acquisition by directing attention towards or away from a particular colour, making it more or less memorable. To investigate the role that colour preference may have in the acquisition…

Pitchford, Nicola J.; Davis, Emma E.; Scerif, Gaia

2009-01-01

97

Understanding and Improving the Realism of Image Composites Yale University  

E-print Network

can automatically adjust the appearance of a foreground region to better match the background. A realistic composite requires adjusting the appearance of the foreground and background so that they appear perception experiments to study the realism of image composites. First, we evaluate a num- ber of standard 2D

98

LASER ULTRASONIC IMAGING FOR IMPACT DAMAGE VISUALIZATION IN COMPOSITE STRUCTURE  

E-print Network

evalutaion. INTRODUCTION In recent decades, composite materials such as carbon fibre reinforced polymer (CFRPLASER ULTRASONIC IMAGING FOR IMPACT DAMAGE VISUALIZATION IN COMPOSITE STRUCTURE Chao Zhang1, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China qiu@nuaa.edu.cn ABSTRACT Laser

Boyer, Edmond

99

Colours experienced in dreams.  

PubMed

Colours seen in dreams by six observers were recorded from memory and plotted on a CIE u, v, chromaticity diagram. Only about half the dreams recorded contained colour, and in those in which colour appeared the more saturated purples, blues and blue greens were absent. It is suggested that during achromatic dreams the areas of the visual cortex which seem to respond only to colour may be inoperative. The paucity of blue in dreams could be anatomically related to the small population of blue units in the colour areas of the cortex. PMID:165850

Padgham, C A

1975-02-01

100

Automatic Composition of Color Ocular Fundus Images  

Microsoft Academic Search

This paper describes a PC-based system that is able to automatically combine color ocular fundus images captured from different angles by a digital retinal camera. The system matches the locations of retinal vascular nodes (crossing points or branches) in the different images by comparing the correlation values of all nodes in a particular rectangular area with all other nodes in

K. Tanabe; T. Tsubouchi; H. Okuda; M. Oku

2006-01-01

101

Colour Measurements and Modeling  

NASA Astrophysics Data System (ADS)

The most common property to measure quality of any material is its appearance. Appearance includes colour, shape, size and surface conditions. The analysis of colour is especially an important consideration when determining the efficacy of variety of postharvest treatments. Consumers can easily be influenced by preconceived ideas of how a particular fruit or vegetable or a processed food should appear, and marketers often attempt to improve upon what nature has painted. Recently colour measurements have also been used as quality parameters and indicator of some inner constituents of the material. In spite of the significance of colour in food industries, many continue to analyze it inadequately. This chapter deals with theory of colour, colour scales and its measurement, sampling techniques, and modeling of colour values for correlating them with some internal quality parameters of selected fruits.

Jha, Shyam N.

102

Compositional breast imaging using a dual-energy mammography protocol  

SciTech Connect

Purpose: Mammography has a low sensitivity in dense breasts due to low contrast between malignant and normal tissue confounded by the predominant water density of the breast. Water is found in both adipose and fibroglandular tissue and constitutes most of the mass of a breast. However, significant protein mass is mainly found in the fibroglandular tissue where most cancers originate. If the protein compartment in a mammogram could be imaged without the influence of water, the sensitivity and specificity of the mammogram may be improved. This article describes a novel approach to dual-energy mammography, full-field digital compositional mammography (FFDCM), which can independently image the three compositional components of breast tissue: water, lipid, and protein. Methods: Dual-energy attenuation and breast shape measures are used together to solve for the three compositional thicknesses. Dual-energy measurements were performed on breast-mimicking phantoms using a full-field digital mammography unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the compositional compartments. They were made of two main stacks of thicknesses around 2 and 4 cm. Twenty-six thickness and composition combinations were used to derive the compositional calibration using a least-squares fitting approach. Results: Very high accuracy was achieved with a simple cubic fitting function with root mean square errors of 0.023, 0.011, and 0.012 cm for the water, lipid, and protein thicknesses, respectively. The repeatability (percent coefficient of variation) of these measures was tested using sequential images and was found to be 0.5%, 0.5%, and 3.3% for water, lipid, and protein, respectively. However, swapping the location of the two stacks of the phantom on the imaging plate introduced further errors showing the need for more complete system uniformity corrections. Finally, a preliminary breast image is presented of each of the compositional compartments separately. Conclusions: FFDCM has been derived and exhibited good compositional thickness accuracy on phantoms. Preliminary breast images demonstrated the feasibility of creating individual compositional diagnostic images in a clinical environment.

Laidevant, Aurelie D.; Malkov, Serghei; Flowers, Chris I.; Kerlikowske, Karla; Shepherd, John A. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94143 (United States); Department of Medicine and Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143 (United States); Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94143 (United States)

2010-01-15

103

Pitfalls in colour photography of choroidal tumours.  

PubMed

Colour imaging of fundus tumours has been transformed by the development of digital and confocal scanning laser photography. These advances provide numerous benefits, such as panoramic images, increased contrast, non-contact wide-angle imaging, non-mydriatic photography, and simultaneous angiography. False tumour colour representation can, however, cause serious diagnostic errors. Large choroidal tumours can be totally invisible on angiography. Pseudogrowth can occur because of artefacts caused by different methods of fundus illumination, movement of reference blood vessels, and flattening of Bruch's membrane and sclera when tumour regression occurs. Awareness of these pitfalls should prevent the clinician from misdiagnosing tumours and wrongfully concluding that a tumour has grown. PMID:23238442

Schalenbourg, A; Zografos, L

2013-02-01

104

Colour doppler valvar and subvalvar flow diameter imaging versus echo score in mitral stenosis: comparison with type of surgery.  

PubMed Central

OBJECTIVE: To compare the value of echo score with that of Doppler subvalvar flow broadening in deciding the type of mitral stenosis surgery. PATIENTS: 30 patients, mean age 47 years, with severe stenosis undergoing surgery were divided into two groups according to type of surgery: open heart commissurotomy (group 1, n = 12), or prosthesis (group 2, n = 18). A control group of 10 patients with prosthesis served as reference, representing mild stenosis without subvalvar connection. METHODS: For echo, the score proposed by Wilkins for cross sectional imaging was used. For Doppler, the flow diameters were measured in cm by an independent examiner from the long axis view in early diastole at two levels: (1) at the level of the stenosis (origin flow diameter), and (2) 1.5 cm downstream from the stenosis in the left ventricle (subvalvar flow diameter) with calculation of a Doppler ratio relating these two measurements, expressed as a percentage of broadening. Diagnostic value was compared for both procedures. RESULTS: There was no significant difference in age, mitral valve areas, or haemodynamics for the two groups. Mean values (SD) were: echo score: group 1, 9.83 (1.26) v group 2, 10.8 (8.1), NS; Doppler ratio %: group 1, 44 (24) v group 2, 12 (21) (P < 0.001); control group: 69 (15). The per cent diagnostic value for an open heart commissurotomy of respective cut off points was: Doppler ratio > 25% (range 71% to 87%); echo score < 10 (range 50% to 75%). CONCLUSIONS: The new Doppler ratio diagnostic value agreed better with surgical management, repair or prosthesis, in this study. Thus, it appears to better reflect the subvalvar involvement and changes in kinetics than the echo score alone. This easy Doppler method might become a routine examination for follow up of patients with open heart commissurotomy, to avoid performing repeated transoesophageal echocardiography. Images PMID:8665342

Veyrat, C.; Pellerin, D.; Sainte Beuve, D.; Larrazet, F.; Kalmanson, D.; Witchitz, S.

1996-01-01

105

Colouring planar graphs  

Microsoft Academic Search

There is no known polynomial time 4-colouring algorithm for planar graphs, except the algorithms that can be derived from\\u000a the proofs of Appel et al. and Robertson et al. An alternative way to colour planar graphs is to investigate the problem of finding nowhere-zero k-flows in graphs.

Paulette Lieby

106

Floral colour diversity in plant communities, bee colour space and a null model  

PubMed Central

Evolutionary biologists have long hypothesized that the diversity of flower colours we see is in part a strategy to promote memorization by pollinators, pollinator constancy, and therefore, a directed and efficient pollen transfer between plants. However, this hypothesis has never been tested against a biologically realistic null model, nor were colours assessed in the way pollinators see them. Our intent here is to fill these gaps. Throughout one year, we sampled floral species compositions at five ecologically distinct sites near Berlin, Germany. Bee-subjective colours were quantified for all 168 species. A model of colour vision was used to predict how similar the colours of sympatric and simultaneously blooming flowers were for bees. We then compared flower colour differences in the real habitats with those of random plant communities. We did not find pronounced deviations from chance when we considered common plants. When we examined rare plants, however, we found significant divergence in two of the five plant communities. At one site, similarly coloured species were found to be more frequent than expected, and at the other two locations, flower colours were indistinguishable from a random distribution. These results fit theoretical considerations that rare plants are under stronger selective pressure to secure pollination than common plants. Our study illustrates the power of linking such distinct biological traditions as community ecology and the neuroethology of bee vision.

Gumbert, A.; Kunze, J.; Chittka, L.

1999-01-01

107

A Method for Compositing MODIS Satellite Images to Remove Cloud Cover  

Microsoft Academic Search

Techniques are presented for generating thermal infrared and visible composite images from cloud-free portions of MODIS (MODerate resolution Imaging Spectroradiometer) images closely spaced in time, with a focus on studies of landfast sea ice along the East Antarctic coast. Composite image inclusion criteria are based on modified MODIS EOS cloud mask product results. The compositing process places emphasis on retaining

Alexander D. Fraser; Robert A. Massom; Kelvin J. Michael

2009-01-01

108

Object knowledge modulates colour appearance  

PubMed Central

We investigated the memory colour effect for colour diagnostic artificial objects. Since knowledge about these objects and their colours has been learned in everyday life, these stimuli allow the investigation of the influence of acquired object knowledge on colour appearance. These investigations are relevant for questions about how object and colour information in high-level vision interact as well as for research about the influence of learning and experience on perception in general. In order to identify suitable artificial objects, we developed a reaction time paradigm that measures (subjective) colour diagnosticity. In the main experiment, participants adjusted sixteen such objects to their typical colour as well as to grey. If the achromatic object appears in its typical colour, then participants should adjust it to the opponent colour in order to subjectively perceive it as grey. We found that knowledge about the typical colour influences the colour appearance of artificial objects. This effect was particularly strong along the daylight axis. PMID:23145224

Witzel, Christoph; Valkova, Hanna; Hansen, Thorsten; Gegenfurtner, Karl R

2011-01-01

109

The connotations of colour terms: colour based X-phemisms  

Microsoft Academic Search

This paper investigates the connotations of colour terms with particular attention to figurative uses of black, white, grey, brown, yellow, red, green, blue and a few miscellaneous colours. The connotations are judged on the basis of whether the phrases in which the colour terms occur are typically orthophemistic, euphemistic, or dysphemistic. All the colours surveyed have some, often many, orthophemistic

Keith Allan

110

HUMAN COLOUR VISION: 2. COLOUR APPEARANCE AND CORTICAL TRANSFORMATIONS  

E-print Network

HUMAN COLOUR VISION: 2. COLOUR APPEARANCE AND CORTICAL TRANSFORMATIONS JOHN S. WERNER Department in area V1 vary much more in their colour tuning than in LGN, and they have significantly more S is a "colour centre" in the monkey brain, and it is equally unlikely to be homologous with those regions

Olshausen, Bruno

111

Principal components colour display of ERTS imagery  

NASA Technical Reports Server (NTRS)

In the technique presented, colours are not derived from single bands, but rather from independent linear combinations of the bands. Using a simple model of the processing done by the visual system, three informationally independent linear combinations of the four ERTS bands are mapped onto the three visual colour dimensions of brightness, redness-greenness and blueness-yellowness. The technique permits user-specific transformations which enhance particular features, but this is not usually needed, since a single transformation provides a picture which conveys much of the information implicit in the ERTS data. Examples of experimental vector images with matched individual band images are shown.

Taylor, M. M.

1974-01-01

112

False-color composite image of Prince Albert, Canada  

NASA Technical Reports Server (NTRS)

This is a false color composite of Prince Albert, Canada, centered at 53.91 north latitude and 104.69 west longitude. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on the 20th orbit of the Shuttle Endeavour. The area is located 40 km north and 30 km east of the town of Prince Albert in the Saskatchewan province of Canada. The image covers the area east of the Candle Lake, between gravel surface highways 120 and 106 and west of 106. The area in the middle of the image covers the entire Nipawin (Narrow Hills) provincial park. The look angle of the radar is 30 degrees and the size of the image is approximately 20 kilometers by 50 kilometers (12 by 30 miles). Most of the dark areas in the image are the ice-covered lakes in the region. The dark area on the top right corner of the image is the White Gull Lake north of the intersection of Highway 120 and 913. The right middle part of the image shows Lake Ispuchaw and Lower Fishing Lake

1994-01-01

113

Optimality of the basic colour categories for classification  

PubMed Central

Categorization of colour has been widely studied as a window into human language and cognition, and quite separately has been used pragmatically in image-database retrieval systems. This suggests the hypothesis that the best category system for pragmatic purposes coincides with human categories (i.e. the basic colours). We have tested this hypothesis by assessing the performance of different category systems in a machine-vision task. The task was the identification of the odd-one-out from triples of images obtained using a web-based image-search service. In each triple, two of the images had been retrieved using the same search term, the other a different term. The terms were simple concrete nouns. The results were as follows: (i) the odd-one-out task can be performed better than chance using colour alone; (ii) basic colour categorization performs better than random systems of categories; (iii) a category system that performs better than the basic colours could not be found; and (iv) it is not just the general layout of the basic colours that is important, but also the detail. We conclude that (i) the results support the plausibility of an explanation for the basic colours as a result of a pressure-to-optimality and (ii) the basic colours are good categories for machine vision image-retrieval systems. PMID:16849219

Griffin, Lewis D

2005-01-01

114

Rockpool gobies change colour for camouflage.  

PubMed

Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

Stevens, Martin; Lown, Alice E; Denton, Alexander M

2014-01-01

115

Rockpool Gobies Change Colour for Camouflage  

PubMed Central

Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

Stevens, Martin; Lown, Alice E.; Denton, Alexander M.

2014-01-01

116

Quantitative Luminance And Colour Representation With CRT Displays  

NASA Astrophysics Data System (ADS)

Colour displays in image processing admit grey scales as well as colour scales for the visual representation of image information. Pseudocolours can be used to enhance the discriminability of different parts of the image. Luminance scales, on the other hand, are preferred for representing fine detail as human colour vision is limited to relatively low spatial frequencies. In the present paper, the generation of quantitative luminance and colour scales with CRT displays is discussed. This includes the colour characteristics of CRTs as well as a recapitulation of the CIE 1931 (X, Y, Z) tristimulus colorimetry system. The CIE 1976 UCS diagram (u', v') is used as an approximation to a perceptually uniform representation of chromaticity. On this basis, it is shown how, for each pixel, luminance and colour (hue) can be chosen independently. In order to add colour as a further visual dimension to greyscale images, a set of equiluminant hues is proposed for each luminance level. The hues are chosen from equidistant steps around a circle in the (u', v') chromaticity diagram. This choice of colours is particularly suitable for the visual representation of a cyclic quantity like phase angle.

Brettel, Hans

1989-03-01

117

Combination of colour and thermal sensors for enhanced object detection  

Microsoft Academic Search

In uncontrolled environments, with dynamic background and lighting changes, performing efficient and real-time foreground - background segmentation is very challenging. This work is based on the hypothesis that the combination of long wave infrared (LWIR) (8-12 mum) and colour cameras can significantly improve the robustness of moving objects extraction. Pros and cons of colour and thermal imagers in outdoor video

Louis St-Laurent; Xavier Maldague; Donald Prévost

2007-01-01

118

Imaging strategies for assessing cartilage composition in osteoarthritis.  

PubMed

Efforts to reduce the ever-increasing rates of osteoarthritis (OA) in the developed world require the ability to non-invasively detect the degradation of joint tissues before advanced damage has occurred. This is particularly relevant for damage to articular cartilage because this soft tissue lacks the capacity to repair itself following major damage and is essential to proper joint function. While conventional magnetic resonance imaging (MRI) provides sufficient contrast to visualize articular cartilage morphology, more advanced imaging strategies are necessary for understanding the underlying biochemical composition of cartilage that begins to break down in the earliest stages of OA. This review discusses the biochemical basis and the advantages and disadvantages associated with each of these techniques. Recent implementations for these techniques are touched upon, and future considerations for improving the research and clinical power of these imaging technologies are also discussed. PMID:25218737

Matzat, Stephen J; Kogan, Feliks; Fong, Grant W; Gold, Garry E

2014-11-01

119

The colour of fitness: plumage coloration and lifetime reproductive success in the tawny owl  

PubMed Central

We studied variation in plumage colour and life history in a population of tawny owls (Strix aluco) in southern Finland, using 26 years of data on individually marked male and female owls. Colour was scored on a semi-continuous scale from pale grey to reddish brown. Colour scoring was repeatable and showed a bimodal distribution (grey and brown morph) in both sexes. During the study period, colour composition was stable in the study population in both sexes. The sexes did not mate assortatively with respect to their colour. Colour was a highly heritable trait and was under selection. Grey-coloured male and female owls had a higher lifetime production of fledglings, and grey-coloured male (but not female) owls produced more recruits during their lifetime than brown individuals. Selection on colour was mediated through viability selection and not through fecundity selection. Our results reveal remarkably strong selection on a genetically determined phenotypic trait. PMID:16024349

Brommer, Jon E; Ahola, Kari; Karstinen, Teuvo

2005-01-01

120

Colour in flux: describing and printing colour in art  

NASA Astrophysics Data System (ADS)

This presentation will describe artists, practitioners and scientists, who were interested in developing a deeper psychological, emotional and practical understanding of the human visual system who were working with wavelength, paint and other materials. From a selection of prints at The Prints and Drawings Department at Tate London, the presentation will refer to artists who were motivated by issues relating to how colour pigment was mixed and printed, to interrogate and explain colour perception and colour science, and in art, how artists have used colour to challenge the viewer and how a viewer might describe their experience of colour. The title Colour in Flux refers, not only to the perceptual effect of the juxtaposition of one colour pigment with another, but also to the changes and challenges for the print industry. In the light of screenprinted examples from the 60s and 70s, the presentation will discuss 21 st century ideas on colour and how these notions have informed the Centre for Fine Print Research's (CFPR) practical research in colour printing. The latter part of this presentation will discuss the implications for the need to change methods in mixing inks that moves away from existing colour spaces, from non intuitive colour mixing to bespoke ink sets, colour mixing approaches and colour mixing methods that are not reliant on RGB or CMYK.

Parraman, Carinna

2008-01-01

121

Genetic analyses of the human eye colours using a novel objective method for eye colour classification.  

PubMed

In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE-score ranged from -1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE-score and the human perception of eye colour was observed. The correlations between the PIE-scores and the six IrisPlex SNPs (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, TYR rs1393350, SLC45A2 rs16891982 and IRF4 rs12203592) were analyzed in 570 individuals. Significant differences (p<10(-6)) in the PIE-scores of the individuals typed as HERC2 rs12913832 G (PIE=0.99) and rs12913832 GA (PIE=-0.71) or A (PIE=-0.87) were observed. We adjusted for the effect of HERC2 rs12913832 and showed that the quantitative PIE-scores were significantly associated with SNPs with minor effects (OCA2 rs1800407, SLC24A4 rs12896399 and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had difficulties in categorizing individuals typed as HERC2 rs12913832 GA because of the large variation in eye colour in HERC2 rs12913832 GA individuals. With the use of the DIAT software and the PIE-score, it will be possible to automatically compare the iris colour of large numbers of iris images obtained by different studies and to perform large meta-studies that may reveal loci with small effects on the eye colour. PMID:23948321

Andersen, Jeppe D; Johansen, Peter; Harder, Stine; Christoffersen, Susanne R; Delgado, Mikaela C; Henriksen, Sarah T; Nielsen, Mette M; Sørensen, Erik; Ullum, Henrik; Hansen, Thomas; Dahl, Anders L; Paulsen, Rasmus R; Børsting, Claus; Morling, Niels

2013-09-01

122

Composite delamination depth profiling in sonic-IR imaging  

NASA Astrophysics Data System (ADS)

Impact damage remains a major issue for aerospace composite structures. Considerable internal damage can occur in laminated composites from external impact loads in service with only minimal visual detectability from the surface of the structure. Damage can occur at any ply depth without visual indications on the front surface. Accurate depth measurements can aid repair assessments. This method is focused on investigating depth profiling of composite delamination by using Sonic-IR, which is a nondestructive evaluation method (NDE) technique that makes images of defects using an infrared camera with an ultrasonic transducer as a stimulation source. The depth profiling relies on the time delays of the temperature increases at the surface from the different defect depths. To process the time vs. temperature data captured from the camera, polynomial curve fitting was used. A mathematical model has been built to calculated time vs. second derivative of temperature curves for depth measurements. The samples used to calibrate the mathematical model data are carbon fiber composite panels with ply thickness variance and inserts with known depths.

Zhao, Selina X.; Han, Xiaoyan; Favro, Lawrence D.; Newaz, Golam; Thomas, Robert L.

2012-05-01

123

Colouring as a special list-colouring problem  

Microsoft Academic Search

Colouring of planar graphs can be treated as a special list-colouring problem\\u000awith selected lists for near-triangulations. The new idea is to use sublists of\\u000aa common list of four colours, to enforce a common colour in all lists, and to\\u000aadmit on the bounding cycle at most one vertex with a list of at least two\\u000acolours. By these

Peter Doerre

2004-01-01

124

"GenotypeColour™": colour visualisation of SNPs and CNVs  

PubMed Central

Background The volume of data available on genetic variations has increased considerably with the recent development of high-density, single-nucleotide polymorphism (SNP) arrays. Several software programs have been developed to assist researchers in the analysis of this huge amount of data, but few can rely upon a whole genome variability visualisation system that could help data interpretation. Results We have developed GenotypeColour™ as a rapid user-friendly tool able to upload, visualise and compare the huge amounts of data produced by Affymetrix Human Mapping GeneChips without losing the overall view of the data. Some features of GenotypeColour™ include visualising the entire genome variability in a single screenshot for one or more samples, the simultaneous display of the genotype and Copy Number state for thousands of SNPs, and the comparison of large amounts of samples by producing "consensus" images displaying regions of complete or partial identity. The software is also useful for genotype analysis of trios and to show regions of potential uniparental disomy (UPD). All information can then be exported in a tabular format for analysis with dedicated software. At present, the software can handle data from 10 K, 100 K, 250 K, 5.0 and 6.0 Affymetrix chips. Conclusion We have created a software that offers a new way of displaying and comparing SNP and CNV genomic data. The software is available free at and is especially useful for the analysis of multiple samples. PMID:19193232

Barlati, Sergio; Chiesa, Sergio; Magri, Chiara

2009-01-01

125

Why birds eat colourful grit: colour preferences revealed by the colour of gizzard stones.  

PubMed

Colour preferences from sexual or social contexts are assumed to have arisen owing to preferences for specific kinds of food, representing a sensory bias, but once colour preferences have evolved in a sexual context, they may also be expressed during foraging. We tested whether preferences for specific body colours (i.e. plumage and soft parts) were related to colour preferences for grit ingested by birds. Birds eat grit to facilitate break down of food by the gizzard, and this function is independent of the colour of grit, but depends on the physical properties of stones. Bird species were significantly consistent in colour of grit, and grit of different colours varied in prevalence among species, even when analyses were restricted to a sample from a single locality. There were positive correlations between presence of lilac and red grit in the gizzard and presence of sexually dichromatic lilac and red colour on the body. There was a positive correlation between red grit colour and red sexually monochromatic body colour. Bird species with many different sexual colours, but not sexually monochromatic colours on their body had many different colours of grit. Males had more lilac and red grit than females, with this effect differing among species, whereas that was not the case for grit of other colours. These findings are consistent with the sensory bias hypothesis that birds express preferences for grit of specific colours and a high diversity of colours related to sexual colouration of the body, even when the colour of such grit is only visible to the individual at the moment of ingestion. PMID:20050966

Møller, A P; Erritzøe, J

2010-03-01

126

Spatio-temporal colour correction of strongly degraded movies  

NASA Astrophysics Data System (ADS)

The archives of motion pictures represent an important part of precious cultural heritage. Unfortunately, these cinematography collections are vulnerable to different distortions such as colour fading which is beyond the capability of photochemical restoration process. Spatial colour algorithms-Retinex and ACE provide helpful tool in restoring strongly degraded colour films but, there are some challenges associated with these algorithms. We present an automatic colour correction technique for digital colour restoration of strongly degraded movie material. The method is based upon the existing STRESS algorithm. In order to cope with the problem of highly correlated colour channels, we implemented a preprocessing step in which saturation enhancement is performed in a PCA space. Spatial colour algorithms tend to emphasize all details in the images, including dust and scratches. Surprisingly, we found that the presence of these defects does not affect the behaviour of the colour correction algorithm. Although the STRESS algorithm is already in itself more efficient than traditional spatial colour algorithms, it is still computationally expensive. To speed it up further, we went beyond the spatial domain of the frames and extended the algorithm to the temporal domain. This way, we were able to achieve an 80 percent reduction of the computational time compared to processing every single frame individually. We performed two user experiments and found that the visual quality of the resulting frames was significantly better than with existing methods. Thus, our method outperforms the existing ones in terms of both visual quality and computational efficiency.

Islam, A. B. M. Tariqul; Farup, Ivar

2011-01-01

127

Damage Assessment of Composite Structures Using Digital Image Correlation  

NASA Astrophysics Data System (ADS)

The steady increase of Carbon-Fiber Reinforced Polymer (CFRP) Structures in modern aircraft will reach a new dimension with the entry into service of the Boeing 787 and Airbus 350. Replacement of damaged parts will not be a preferable solution due to the high level of integration and the large size of the components involved. Consequently the need to develop repair techniques and processes for composite components is readily apparent. Bonded patch repair technologies provide an alternative to mechanically fastened repairs with significantly higher performance, especially for relatively thin skins. Carefully designed adhesively bonded patches can lead to cost effective and highly efficient repairs in comparison with conventional riveted patch repairs that cut fibers and introduce highly strained regions. In this work, the assessment of the damage process taking place in notched (open-hole) specimens under uniaxial tensile loading was studied. Two-dimensional (2D) and three-dimensional (3D) Digital Image Correlation (DIC) techniques were employed to obtain full-field surface strain measurements in carbon-fiber/epoxy T700/M21 composite plates with different stacking sequences in the presence of an open circular hole. Penetrant enhanced X-ray radiographs were taken to identify damage location and extent after loading around the hole. DIC strain fields were compared to finite element predictions. In addition, DIC techniques were used to characterise damage and performance of adhesively bonded patch repairs in composite panels under tensile loading. This part of work relates to strength/stiffness restoration of damaged composite aircraft that becomes more important as composites are used more extensively in the construction of modern jet airliners. The behaviour of bonded patches under loading was monitored using DIC full-field strain measurements. Location and extent of damage identified by X-ray radiography correlates well with DIC strain results giving confidence to the technique for structural health monitoring of bonded patches.

Caminero, M. A.; Lopez-Pedrosa, M.; Pinna, C.; Soutis, C.

2014-02-01

128

The Four-Colour Theorem  

Microsoft Academic Search

The four-colour theorem, that every loopless planar graph admits a vertex-colouring with at most four different colours, was proved in 1976 by Appel and Haken, using a computer. Here we give another proof, still using a computer, but simpler than Appel and Haken's in several respects.

Neil Robertson; Daniel P. Sanders; Paul D. Seymour; Robin Thomas

1997-01-01

129

Specifying colour and maintaining colour accuracy for 3D printing  

NASA Astrophysics Data System (ADS)

Advances in rapid prototyping technologies have led to the emergence of three-dimensional printers which can fabricate physical artefacts, including the application of surface colours. In light of these developments, this paper asserts that the need to print colour accurately is just as important for designers using three-dimensional colour printing as it is for two-dimensional inkjet printing. Parallels can be made with two-dimensional digital Inkjet printing and 2D common problems include: on screen previsualisation, colour management methods, colour gamut and maintaining colour accuracy. However, for three dimensional colour printed objects, there are more variables that will affect the finished colour. These are: the powder and process inks, unevenness of the surface, wax post-processing and other infiltration media and procedures. Furthermore, in some 3D printers, the K channel is replaced by the binder and so the printer is only using the cyan, magenta and yellow channels. The paper will suggest methods for improving pre-visualisation and accurate pre-viewing of the colours through the manufacture of three-dimensional colour charts as a reference guide for designers so that they can make accurate coloured artefacts. A series of case studies will be demonstrated.

Parraman, Carinna; Walters, Peter; Reid, Brendan; Huson, David

2008-02-01

130

Measuring the colour of rendering mortars  

NASA Astrophysics Data System (ADS)

When restoring decorative mortar layers on historic façades, professionals need to determine the colour of these finishes in order to select an appropriate repair mortar. Currently, the appearance of these renders is only assessed from a subjective point of view. To match with the aesthetic aspects of the façade, contractors must constantly adjust their repair mortar composition to avoid a patchwork of different colours, which is detrimental for heritage. This time-consuming (trial-and-error) methodology can be excluded by evaluating `colour' with an objective numerical approach. The challenge of the research was to define and evaluate optimal material dependent boundary conditions for measuring the colour of nonhomogeneous mortars. Four samples with different scale of heterogeneity were measured by two spectrocolorimeters, both with a diffuse illumination geometry. The results were plotted in CIE-L*a*b* colour space. By calculating the colour difference (?E*), the influence of measuring with or without specular component was evaluated. We discovered the minimal number of measuring points depends on the scale of heterogeneity and the aperture area. The less homogeneous the mortar sample is and the smaller the aperture area, the more unique measuring points are required. Therefore, it is recommended to choose an aperture head of 25 mm or more to reduce the number of measurements, making your work time-efficient. However, in order to obtain accurate measurements on site, a portable optical spectrum analyser can be used with a 6 mm-diameter aperture, a viewing angle of 10°, SCI mode, illumination source D65, considering a minimum of 15 unique measuring points.

Govaerts, Yves; Meulebroeck, Wendy; Verdonck, Ann; de Bouw, Michael

2014-05-01

131

Algorithms for Moderate Resolution Imaging Spectroradiometer cloud-free image compositing  

NASA Astrophysics Data System (ADS)

The presence of clouds is the biggest obstacle in the investigation of land cover, and many techniques have been developed to detect clouds. However, few indicators have been proposed for the detection of cloud-free conditions. To address this, we propose two indicators for use in compositing 8-day cloud-free images: the B ratio is the ratio of the band 1 reflectance to the band 7 reflectance of Terra surface reflectance images (MOD09GA), and saturation refers to the color saturation of these images. Here, we describe the principles underlying these two indicators and analyze their characteristics for vegetation, water, urban, and nonvegetation pixels under cloud-free, cloud shadow, and cloudy conditions using MOD09GA from October 16 to 23, 2007, in North China (sample A) and using data published by the U.S. Geological Survey (USGS). We found that the B ratio and saturation are suitable for extracting cloud-free pixels over land and water, respectively; therefore, we combined these two indicators to develop a single-unified model. In particular, our results demonstrate that the pixels exhibiting the lowest B ratios should be adopted as cloud-free pixels over land when the value of B for land surfaces is between 0 and 1, and the surface reflectance of Moderate Resolution Imaging Spectroradiometer band 1 is less than 0.3. Otherwise, the pixels exhibiting the greatest saturation values should be adopted. We used our model to composite cloud-free images for two additional regions in China: the Tarim basin (sample B) from October 2 to 9, 2012, and the coastal areas of southeastern China (sample C) from April 15 to 23, 2013. We compared the cloud-free images of these regions with the 8-day surface reflectance product (MOD09A1) with respect to clouds, cloud shadow, and cirrus clouds, and we found that our proposed cloud-free image compositing approach can accurately eliminate both clouds and cirrus clouds. Specifically, the percentage of residual cloud pixels in sample C was found to be less than that in MOD09A1. Moreover, in the cloud-free images obtained using our newly developed method, cloud-free pixels are typically associated with greater sensor zenith angles and smaller scatter angles than those in MOD09A1. However, our method retains some limitations. In particular, 9.68, 33.22, and 33.00% of cloud-shadow pixels remain in the cloud-free images for samples A, B, and C, respectively.

Xiang, Hai-bing; Liu, Jin-song; Cao, Chun-xiang; Xu, Min

2013-01-01

132

Road Sign Detection and Recognition using Colour Segmentation, Shape Analysis and Template Matching  

Microsoft Academic Search

The paper presents a system for detection and recognition of road signs with red boundaries and black symbols inside. The detection is invariant to varying lighting conditions and shadows. The algorithm is tested on RGB images taken from camera. These images are converted to HSV colour space. Colour segmentation for red regions is applied on the whole image. All red

RABIA MALIK; JAVAID KHURSHID; SANA NAZIR AHMAD

2007-01-01

133

Hyperbolic geometry for colour metrics.  

PubMed

It is well established from both colour difference and colour order perpectives that the colour space cannot be Euclidean. In spite of this, most colour spaces still in use today are Euclidean, and the best Euclidean colour metrics are performing comparably to state-of-the-art non-Euclidean metrics. In this paper, it is shown that a transformation from Euclidean to hyperbolic geometry (i.e., constant negative curvature) for the chromatic plane can significantly improve the performance of Euclidean colour metrics to the point where they are statistically significantly better than state-of-the-art non-Euclidean metrics on standard data sets. The resulting hyperbolic geometry nicely models both qualitatively and quantitatively the hue super-importance phenomenon observed in colour order systems. PMID:24921355

Farup, Ivar

2014-05-19

134

Compositional maps of Saturn's moon Phoebe from imaging spectroscopy.  

PubMed

The origin of Phoebe, which is the outermost large satellite of Saturn, is of particular interest because its inclined, retrograde orbit suggests that it was gravitationally captured by Saturn, having accreted outside the region of the solar nebula in which Saturn formed. By contrast, Saturn's regular satellites (with prograde, low-inclination, circular orbits) probably accreted within the sub-nebula in which Saturn itself formed. Here we report imaging spectroscopy of Phoebe resulting from the Cassini-Huygens spacecraft encounter on 11 June 2004. We mapped ferrous-iron-bearing minerals, bound water, trapped CO2, probable phyllosilicates, organics, nitriles and cyanide compounds. Detection of these compounds on Phoebe makes it one of the most compositionally diverse objects yet observed in our Solar System. It is likely that Phoebe's surface contains primitive materials from the outer Solar System, indicating a surface of cometary origin. PMID:15875014

Clark, Roger N; Brown, Robert H; Jaumann, Ralf; Cruikshank, Dale P; Nelson, Robert M; Buratti, Bonnie J; McCord, Thomas B; Lunine, J; Baines, K H; Bellucci, G; Bibring, J-P; Capaccioni, F; Cerroni, P; Coradini, A; Formisano, V; Langevin, Y; Matson, D L; Mennella, V; Nicholson, P D; Sicardy, B; Sotin, C; Hoefen, Todd M; Curchin, John M; Hansen, Gary; Hibbits, Karl; Matz, K-D

2005-05-01

135

Digital Compositing Techniques for Coronal Imaging (Invited review)  

NASA Astrophysics Data System (ADS)

The solar corona exhibits a huge range in brightness which cannot be captured in any single photographic exposure. Short exposures show the bright inner corona and prominences, while long exposures reveal faint details in equatorial streamers and polar brushes. For many years, radial gradient filters and other analog techniques have been used to compress the corona's dynamic range in order to study its morphology. Such techniques demand perfect pointing and tracking during the eclipse, and can be difficult to calibrate. In the past decade, the speed, memory and hard disk capacity of personal computers have rapidly increased as prices continue to drop. It is now possible to perform sophisticated image processing of eclipse photographs on commercially available CPU's. Software programs such as Adobe Photoshop permit combining multiple eclipse photographs into a composite image which compresses the corona's dynamic range and can reveal subtle features and structures. Algorithms and digital techniques used for processing 1998 eclipse photographs will be discussed which are equally applicable to the recent eclipse of 1999 August 11.

Espenak, F.

2000-04-01

136

Colour vision requirements of firefighters.  

PubMed

To perform their job safely firefighters must be able to identify colours on industrial gas cylinders, portable fire extinguishers, road traffic signals and several pieces of firefighting equipment. Although good colour vision is necessary we believe that the existing colour vision standard, which bars entry to the fire service to applicants who fail more than two plates of the Ishihara test, is unnecessarily stringent. We have identified and quantified the colour coded information encountered by firefighters. Colours were plotted on the CIE chromaticity diagram (1931) and isochromatic zones, which document the colour confusions of colour deficient observers, superimposed. This novel technique established possible colour confusions in different types of colour deficiency. Analysis of the results showed that red/green dichromats (protanopes and deuteranopes), severe deuteranomalous trichromats who fail the Farnsworth D15 test, and protanomalous trichromats are unsuitable for firefighting work. However, people with slight deuteranomalous trichromatism who pass the D15 test, are not disadvantaged and can be employed safely as firefighters. A new colour vision standard and a new testing procedure is recommended. PMID:8776247

Margrain, T H; Birch, J; Owen, C G

1996-04-01

137

Specifying colour and maintaining colour accuracy for 3D printing  

Microsoft Academic Search

Advances in rapid prototyping technologies have led to the emergence of three-dimensional printers which can fabricate physical artefacts, including the application of surface colours. In light of these developments, this paper asserts that the need to print colour accurately is just as important for designers using three-dimensional colour printing as it is for two-dimensional inkjet printing. Parallels can be made

Carinna Parraman; Peter Walters; Brendan Reid; David Huson

2008-01-01

138

The colours of the Sun  

NASA Astrophysics Data System (ADS)

We compile a sample of Sun-like stars with accurate effective temperatures, metallicities and colours (from the ultraviolet to the near-infrared). A crucial improvement is that the effective temperature scale of the stars has recently been established as both accurate and precise through direct measurement of angular diameters obtained with stellar interferometers. We fit the colours as a function of effective temperature and metallicity, and derive colour estimates for the Sun in the Johnson-Cousins, Tycho, Strömgren, 2MASS and SDSS photometric systems. For (B-V)solar, we favour the `red' colour 0.64 versus the `blue' colour 0.62 of other recent papers, but both values are consistent within the errors; we ascribe the difference to the selection of Sun-like stars versus interpolation of wider colour-Teff-metallicity relations.

Holmberg, Johan; Flynn, Chris; Portinari, Laura

2006-04-01

139

The colours of the Sun  

E-print Network

We compile a sample of Sun-like stars with accurate effective temperatures, metallicities and colours (from the UV to the near-IR). A crucial improvement is that the effective temperature scale of the stars has recently been established as both accurate and precise through direct measurement of angular diameters obtained with stellar interferometers. We fit the colours as a function of effective temperature and metallicity, and derive colour estimates for the Sun in the Johnson/Cousins, Tycho, Stromgren, 2MASS and SDSS photometric systems. For (B-V)_Sun, we favour the ``red'' colour 0.64 versus the ``blue'' colour 0.62 of other recent papers, but both values are consistent within the errors; we ascribe the difference to the selection of Sun-like stars versus interpolation of wider colour-Teff-metallicity relations.

Johan Holmberg; Chris Flynn; Laura Portinari

2005-11-06

140

Novel coloured flowers.  

PubMed

The floricultural industry has focused its attention primarily on the development of novel coloured and longer living cut flowers. The basis for this was laid down some years ago through the isolation of 'blue' genes and ethylene biosynthesis genes. Recently, a novel 'blue' gene has been discovered and yellow pigments were produced in petunias by addition of a new branch to the phenylpropanoid pathway. More insight was obtained into the sequestration of anthocyanin pigments into storage vacuoles. Significant progress has been achieved in the commercialisation of genetically modified flower varieties. PMID:10209139

Mol, J; Cornish, E; Mason, J; Koes, R

1999-04-01

141

The colour of bubbles  

NASA Astrophysics Data System (ADS)

Students of General Physics often complain that the course is too abstract and remote from daily life. As teachers, we emphasize that the abstract concepts of physics are indispensable for understanding our daily experiences, and we try to give the impression that quantitative descriptions can be achieved by adopting concrete mathematical expressions. Thus the abstract formulation is not to make physics more difficult, but to make it easier to grasp. We expect the students to learn to describe phenomena qualitatively using the concepts of physics, and to provide a quantitative description by manipulating the mathematical formulation. Here we supply one such example to calculate the colour of bubble films.

Huang, Ding-wei; Huang, Wei-neng; Tseng, Hsiang-chi

2005-11-01

142

A Method for Compositing Polar MODIS Satellite Images to Remove Cloud Cover for Landfast Sea-Ice Detection  

Microsoft Academic Search

This paper presents details of techniques for generating thermal infrared and visible composite images from the cloud-free portions of temporally closely spaced MODerate resolution Imaging Spectroradiometer (MODIS) images, with a focus on studies of landfast sea ice along the East Antarctic coast. Composite image inclusion criteria are based on modified MODIS Earth Observing System cloud mask product results. The compositing

Alexander D. Fraser; Robert A. Massom; Kelvin J. Michael

2009-01-01

143

A METHOD FOR COLOR NAMING AND DESCRIPTION OF COLOR COMPOSITION IN IMAGES  

E-print Network

, regions labeled as light blue and strong green may represent sky and grass, vivid colors are typically. Finally, we extend the method and develop a scheme for extracting the color composition of a complex imageA METHOD FOR COLOR NAMING AND DESCRIPTION OF COLOR COMPOSITION IN IMAGES Aleksandra Mojsilovic IBM

Mojsilovic, Aleksandra

144

Measuring colour rivalry suppression in amblyopia  

PubMed Central

AIMS—To determine if the colour rivalry suppression is an index of the visual impairment in amblyopia and if the stereopsis and fusion evaluator (SAFE) instrument is a reliable indicator of the difference in visual input from the two eyes.?METHODS—To test the accuracy of the SAFE instrument for measuring the visual input from the two eyes, colour rivalry suppression was measured in six normal subjects. A test neutral density filter (NDF) was placed before one eye to induce a temporary relative afferent defect and the subject selected the NDF before the fellow eye to neutralise the test NDF. In a non-paediatric private practice, 24 consecutive patients diagnosed with unilateral amblyopia were tested with the SAFE. Of the 24 amblyopes, 14 qualified for the study because they were able to fuse images and had no comorbid disease. The relation between depth of colour rivalry suppression, stereoacuity, and interocular difference in logMAR acuity was analysed.?RESULTS—In normal subjects, the SAFE instrument reversed temporary defects of 0.3 to 1.8 log units to within 0.6 log units. In amblyopes, the NDF to reverse colour rivalry suppression was positively related to interocular difference in logMAR acuity (?=1.21, p<0.0001), and negatively related to stereoacuity (?=?0.16, p=0.019). The interocular difference in logMAR acuity was negatively related to stereoacuity (?=?0.13, p=0.009).?CONCLUSIONS—Colour rivalry suppression as measured with the SAFE was found to agree closely with the degree of visual acuity impairment in non-paediatric patients with amblyopia.?? PMID:10535858

Hofeldt, T.; Hofeldt, A.

1999-01-01

145

Characterizing Weave Geometry in Textile Ceramic Composites Using Digital Image Correlation  

E-print Network

or thermal loads.1­3 In the context of fiber-reinforced ceramic composites (CMCs), DIC has been used to probeCharacterizing Weave Geometry in Textile Ceramic Composites Using Digital Image Correlation Michael ceramic composites are required for generating high-fidel- ity geometric models and subsequently probing

Ritchie, Robert

146

Computational Production of Colour Harmony. Part 1: A Prototype Colour  

E-print Network

with the human expression of personal taste. Our Colour Harmoniser is a research tool that is meant to explore 5 July 2011; accepted 24 August 2011 Abstract: Although web page and computer interface devel- opers the possibility of automatically producing har- monious and usable user interface colour schemes by modeling

Marsland, Stephen

147

Rapid mixing for lattice colourings with fewer colours  

Microsoft Academic Search

We provide an optimally mixing Markov chain for 6-colourings of the square lattice on rectangular regions with free, fixed, or toroidal boundary conditions. This implies that the uniform distribution on the set of such colourings has strong spatial mixing, so the six-state Potts antiferromagnet has a finite correlation length and a unique Gibbs measure at zero temperature. Four and five

Dimitris Achlioptas; Mike Molloy; Cristopher Moore; Frank Van Bussel

2005-01-01

148

Improper Colourings of Unit Disk Graphs  

Microsoft Academic Search

Abstract: Motivated by a satellite communications problem, we consider a generalised colouring problem on unit disk graphs. A colouring is k-improper if no vertex receives the same colour as k+1 of its neighbours. The k-improper chromatic number ´, for unit interval graphs. Key-words: improper colouring, defective colouring, unit disk graph, interval graph, triangular

Frédéric Havet; Ross J. Kang; Jean-sébastien Sereni

2005-01-01

149

Disruptive Colouration and Perceptual Grouping  

PubMed Central

Camouflage is the primary defence of many animals and includes multiple strategies that interfere with figure-ground segmentation and object recognition. While matching background colours and textures is widespread and conceptually straightforward, less well explored are the optical ‘tricks’, collectively called disruptive colouration, that exploit perceptual grouping mechanisms. Adjacent high contrast colours create false edges, but this is not sufficient for an object’s shape to be broken up; some colours must blend with the background. We test the novel hypothesis that this will be particularly effective when the colour patches on the animal appear to belong to, not merely different background colours, but different background objects. We used computer-based experiments where human participants had to find cryptic targets on artificial backgrounds. Creating what appeared to be bi-coloured foreground objects on bi-coloured backgrounds, we generated colour boundaries that had identical local contrast but either lay within or between (illusory) objects. As predicted, error rates for targets matching what appeared to be different background objects were higher than for targets which had otherwise identical local contrast to the background but appeared to belong to single background objects. This provides evidence for disruptive colouration interfering with higher-level feature integration in addition to previously demonstrated low-level effects involving contour detection. In addition, detection was impeded in treatments where targets were on or in close proximity to multiple background colour or tone boundaries. This is consistent with other studies which show a deleterious influence of visual ‘clutter’ or background complexity on search. PMID:24466337

Espinosa, Irene; Cuthill, Innes C.

2014-01-01

150

Published online 30 July 2002 The uses of colour vision: behavioural and  

E-print Network

that we learn from our experience of colour and greyscale images in photography, in the cinema and on television. However, this paper makes the case that the distinc- tiveness could arise naturally from signals or a by-product of our experience. In principle, colour images are qualitatively different from

Nottingham, University of

151

Development and Performance Characterization of Colour Star Trackers  

NASA Astrophysics Data System (ADS)

Star trackers provide an essential component to a satellite mission requiring high-precision and high-accuracy attitude measurements. A star tracker operates by taking pictures of the celestial sphere and attempting to identify the stars in the image using a combination of the geometric and brightness patterns. The star-positions in the image then determine the attitude of the sensor in the inertial frame. I propose extending the capability of star trackers by including the colour properties of the stars into the star identification process; hence, colour star tracking. Current generation star trackers exist in a variety of forms, with a variety of additional potential designs and operational algorithms proposed in the literature. However, they all share the common trait of using a combination of geometric and monochrome brightness derived patterns to identify stars. Including colour information with the geometric and brightness properties into the identification process represents a new branch in the field of star tracker design. The process of measuring colour also causes a reduction in the amount of light gathered by the sensor, decreasing the number of stars observed. The challenge in colour star tracking becomes establishing that the additional information provided by colour to star patterns is greater than the loss of observable stars due to the measurement process. While superficially brief, accomplishing it touches upon a wide range of topic areas. This includes most research developed for monochromatic star trackers including imaging hardware, optics, noise rejection, parameter estimation, signal detection, data mining, pattern matching, and astronomy. Additionally, using colour necessitates introducing the topics of stellar photometry, spectral filtering, and colour imaging. The approach to colour star tracker development, presented here, considers three aspects to the operation of the technology: colour measurement, star detection, and star pattern matching. In the measurement of colour analysis, a new set of estimation techniques are developed to estimate the colour and position of stars using colour-filter-array and trichroic prism cameras. Validation of the proposed techniques is achieved through a combination of laboratory and nigh-sky testing of hardware prototypes. The detection performance of the colour star tracker designs centres on a comparison with equivalent monochrome designs. By considering primitive detection algorithms, essentially raw thresholding, allows for a fair determination of the relative performance. Numerical simulations of potential designs examine the percentage of the celestial sphere where sufficient quantity of stars can be observed to yield an identification. Finally, extending the results of the detection analysis allows for a determination of the ambiguity within observed star scenes. While not explicitly pattern matching, this analysis establishes a baseline for the performance to be expected from practical pattern matching algorithms. Together, the combined results establish the overall expected increase in performance of colour star tracking over equivalent monochrome designs. A critical goal of any star tracker design is to maximize the region of sky where the star tracker can successfully return an attitude solution. Additionally, the reliability of achieving correct attitude solutions must also be a factor. The work presented demonstrates that, given the correct design circumstances, colour star trackers can supersede their monochrome counterparts in these two aspects. Specifically by resolving formerly ambiguous scenes and increasing the total number of scenes that can yield a solution. As a consequence, colour measurement should now become a viable and explicit consideration in future star tracker design processes.

McVittie, Geoffrey

152

Three-dimensional plasmonic stereoscopic prints in full colour.  

PubMed

Metal nanostructures can be designed to scatter different colours depending on the polarization of the incident light. Such spectral control is attractive for applications such as high-density optical storage, but challenges remain in creating microprints with a single-layer architecture that simultaneously enables full-spectral and polarization control of the scattered light. Here we demonstrate independently tunable biaxial colour pixels composed of isolated nanoellipses or nanosquare dimers that can exhibit a full range of colours in reflection mode with linear polarization dependence. Effective polarization-sensitive full-colour prints are realized. With this, we encoded two colour images within the same area and further use this to achieve depth perception by realizing three-dimensional stereoscopic colour microprint. Coupled with the low cost and durability of aluminium as the functional material in our pixel design, such polarization-sensitive encoding can realize a wide spectrum of applications in colour displays, data storage and anti-counterfeiting technologies. PMID:25369035

Goh, Xiao Ming; Zheng, Yihan; Tan, Shawn J; Zhang, Lei; Kumar, Karthik; Qiu, Cheng-Wei; Yang, Joel K W

2014-01-01

153

Discriminating colours under LED illumination  

Microsoft Academic Search

We measured the discrimination efficiency of three LED clusters (RGB, RGB + Amber, cool White + Amber) using the desaturated Lanthony-Panel D15 colour vision test. Compared with a continuous spectrum illumination, all LED clusters impair colour discrimination, with a severe impairment for RGB LED cluster. 1. PURPOSE LED technology offers light sources with narrow spectrum in the visible range. At

Françoise Viénot; Elodie Mahler; Lucile Serreault; Margalith Harrar; Jean-Jacques Ezrati; Pierre Pérignon; Alain Bricoune

154

Reversible colour change in Arthropoda.  

PubMed

The mechanisms and functions of reversible colour change in arthropods are highly diverse despite, or perhaps due to, the presence of an exoskeleton. Physiological colour changes, which have been recorded in 90 arthropod species, are rapid and are the result of changes in the positioning of microstructures or pigments, or in the refractive index of layers in the integument. By contrast, morphological colour changes, documented in 31 species, involve the anabolism or catabolism of components (e.g. pigments) directly related to the observable colour. In this review we highlight the diversity of mechanisms by which reversible colour change occurs and the evolutionary context and diversity of arthropod taxa in which it has been observed. Further, we discuss the functions of reversible colour change so far proposed, review the limited behavioural and ecological data, and argue that the field requires phylogenetically controlled approaches to understanding the evolution of reversible colour change. Finally, we encourage biologists to explore new model systems for colour change and to engage scientists from other disciplines; continued cross-disciplinary collaboration is the most promising approach to this nexus of biology, physics, and chemistry. PMID:24495279

Umbers, Kate D L; Fabricant, Scott A; Gawryszewski, Felipe M; Seago, Ainsley E; Herberstein, Marie E

2014-11-01

155

Light Filters of Coloured `Perspex'  

Microsoft Academic Search

LIGHT filters of coloured glass and gelatin are in common use for visual and photoelectric photometers. They are satisfactory, on the whole; but the glass filters are easily broken, and those of gelatin require to be mounted between glass to protect them from water. The transparent polymethyl methacrylate `Perspex' is now obtainable in several colours and in sheets. This material

E. J. King; S. Ventura

1951-01-01

156

Associating Colours with Musical Genres  

Microsoft Academic Search

To study visualizations for music, we arranged a set of online questionnaires on how people map various visual properties to certain musical attributes. This paper presents the results of a questionnaire that concentrated on how people map colours to musical genres. The participants were shown 12 colours one at a time, and asked which of listed 18 genres they associated

Jukka Holm; Antti Aaltonen; Harri Siirtola

2009-01-01

157

The Four-Colour Problem  

Microsoft Academic Search

THE correctness of the statement that any plane map may always be tinted with four colours in such a way that two areas meeting on the same boundary never have the same colour has always been admitted since Möbius mentioned it in 1840, although no mathematical proof of this theorem has yet been firmly established. I think I have found

S. M. de Backer

1944-01-01

158

Late Fusion of Compact Composite Descriptors for Retrieval from Heterogeneous Image Databases  

E-print Network

Late Fusion of Compact Composite Descriptors for Retrieval from Heterogeneous Image Databases, Theory Keywords: Image Retrieval, CCD, Fusion, Normalization, Com- bination 1. INTRODUCTION Fusion for the future of image retrieval research [3]. Two main approaches to fusion have been taken: early fusion

Arampatzis, Avi

159

Regional geological interpretation of a digital coloured residual Bouguer gravity image of eastern Australia with a wavelength cut?off of 250 km  

Microsoft Academic Search

A short wavelength (<250 km) residual Bouguer gravity image of eastern Australia emphasizes anomalies and anomaly patterns related to continental crustal structure in comparison with a total?field gravity image. Filtering removes the masking effect of long wavelength anomalies, whether they have a shallow origin (e.g. extensive platform cover) or a deep source (e.g. mantle). Short wavelength anomalies are mainly caused

C. G. Murray; E. Scheibner; R. N. Walker

1989-01-01

160

Classification of delaminated composites using neuro-fuzzy image analysis  

E-print Network

involves video imaging of a surface displacements illuminated by laser. A specially designed CCD camera produces two laterally sheared images of the surface. Shearography is based on the phenomenon that coherent examination, the test specimen is excited while illuminated by laser light. An image shearing CCD

Martin, Ralph R.

161

Introduction Colour-impaired vision, where certain colours cannot be  

E-print Network

these colours. Dark green, brown, orange, and dark red in the first row appear as almost indistinguishable olive, where he produces print graphics for daily publication and interactive web graphics. nvkelso

Jenny, Bernhard

162

Linguistic Determinants of Word Colouring in Grapheme-Colour Synaesthesia  

Microsoft Academic Search

Previous studies of grapheme-colour synaesthesia have suggested that words tend to be coloured by their initial letter or initial vowel (e.g., Baron-Cohen et al., 1993; Ward et al., 2005). We examine this assumption in two ways. First, we show that letter position and syllable stress have been confounded, such that the initial letters of a word are often in stressed

Julia Simner; Louise Glover; Alice Mowat

2006-01-01

163

Optimal colour quality of LED clusters based on memory colours.  

PubMed

The spectral power distributions of tri- and tetrachromatic clusters of Light-Emitting-Diodes, composed of simulated and commercially available LEDs, were optimized with a genetic algorithm to maximize the luminous efficacy of radiation and the colour quality as assessed by the memory colour quality metric developed by the authors. The trade-off of the colour quality as assessed by the memory colour metric and the luminous efficacy of radiation was investigated by calculating the Pareto optimal front using the NSGA-II genetic algorithm. Optimal peak wavelengths and spectral widths of the LEDs were derived, and over half of them were found to be close to Thornton's prime colours. The Pareto optimal fronts of real LED clusters were always found to be smaller than those of the simulated clusters. The effect of binning on designing a real LED cluster was investigated and was found to be quite large. Finally, a real LED cluster of commercially available AlGaInP, InGaN and phosphor white LEDs was optimized to obtain a higher score on memory colour quality scale than its corresponding CIE reference illuminant. PMID:21451716

Smet, Kevin; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

2011-03-28

164

Floral scent emitted by white and coloured morphs in orchids.  

PubMed

Polymorphism of floral signals, such as colour and odour, is widespread in flowering plants and often considered to be adaptive, reflecting various pollinator preferences for particular floral traits. Several authors have recently hypothesized that particular associations exist between floral colour and scent, which would result from shared biochemistry between these two floral traits. In this study, we compared the chemical composition of floral volatiles emitted by white- and purple-flowered morphs of three different orchid species, including two food-deceptive species (Orchis mascula and Orchis simia) and a food-rewarding species (Anacamptis coriophora fragrans). We found clear interspecific differences in floral odours. As expected from their pollination strategy, the two deceptive orchids showed high inter-individual variation of floral volatiles, whereas the food-rewarding A. c. fragrans showed low variation of floral scent. Floral volatiles did not differ overall between white- and coloured-flowered morphs in O. mascula and A. c. fragrans, while O. simia exhibited different volatile profiles between the two colour morphs. However, a detailed analysis restricted to benzenoid compounds (which are associated with the production of floral anthocyanin pigments) showed that white inflorescences emitted more volatiles of the shikimic pathway than coloured ones, both for O. mascula and O. simia. These results are consistent with the current hypothesis that shared biochemistry creates pleiotropic links between floral colour and scent. Whether intraspecific variation of floral signals actually affects pollinator attraction and influences the reproductive success of these orchids remains to be determined. PMID:24525191

Dormont, L; Delle-Vedove, R; Bessière, J-M; Schatz, B

2014-04-01

165

Artist: Ken Hodges Composite image explaining Objective and Motivation for Galileo Probe Heat Loads:  

NASA Technical Reports Server (NTRS)

Artist: Ken Hodges Composite image explaining Objective and Motivation for Galileo Probe Heat Loads: Galileo Probe descending into Jupiters Atmosphere shows heat shield separation with parachute deployed. (Ref. JPL P-19180)

1981-01-01

166

NONLINEAR ACOUSTIC IMAGING OF STRUCTURAL DAMAGES IN LAMINATED COMPOSITES  

E-print Network

and requires an ever increasing accuracy of detection. A good example is the inspection of composite materials are performed on a carbon fiber/epoxy laminated composite plate with barely visible impact damage others [1,2]. Recent years show, however, an increasing interest in novel nonlinear damage detection

Boyer, Edmond

167

On the material characterization of a composite using micro CT image based finite element modeling  

Microsoft Academic Search

Novel techniques for generating robust and accurate meshes based on 3-D imaging data have recently been developed which make the prediction of macro-structural properties of composite structures based on micro-structural composition straightforward. The accuracy of reconstructions is a particular strong point of these new techniques with geometric accuracy only contingent on image quality. Algorithms developed and used are topology preserving,

A. Abdul Aziz; C. Saury; V. Bui Xuan; P. Young

2006-01-01

168

Meaning-Making with Colour in Multimodal Texts: An 11-Year-Old Student's Purposeful "Doing"  

ERIC Educational Resources Information Center

Colour, a visual element of art and design, is a semiotic mode that is used strategically by sign-makers to communicate meaning. Understanding the meaning-making potential of colour can enhance students' understanding, appreciation, interpretation and composition of multimodal texts. This article features a case study of Anya, an 11-year-old…

Pantaleo, Sylvia

2012-01-01

169

Plants and colour: Flowers and pollination  

Microsoft Academic Search

While there is a range of colours found in plants the predominant colour is green. Pigments in plants have several roles e.g. photosynthesis and signalling. If colour is to be used as a signal then it must stand out from green. However, one should be aware that there are also coloured compounds where we have not yet fully investigated the

Renee Miller; Simon J. Owens; Bjørn Rørslett

2011-01-01

170

Coloured solutions of equations in finite groups  

Microsoft Academic Search

In this article, we consider the relations between colourings and some equations in finite groups. We will express relations linking the numbers of the differently coloured solutions of an equation that depend only on the cardinality of the colouring and not on the distribution of the colours. This gives a link between Ramsey theory that investigates the existence of monochromatic

Éric Balandraud

2007-01-01

171

Beyond a Dichotomic Approach, the Case of Colour Phenomena  

ERIC Educational Resources Information Center

This research documents the aims and the impact of a teaching experiment concerning colour phenomena. This teaching experiment is designed in order to make students consider not only the spectral composition of light but also its intensity, and to consider the absorption of light by a pigment as relative, instead of as total or zero. Eight…

Viennot, L.; de Hosson, C.

2012-01-01

172

Colouring as a special list-colouring problem with selected lists  

Microsoft Academic Search

Colouring of planar graphs can be treated as a special list-colouring problem with selected lists for near-triangulations. The new idea is to use sublists of a common list of four colours, to enforce a common colour in all lists, and to admit on the bounding cycle at most one vertex with a list of at least two colours. By these

Peter Dörre

173

Distortion-free single point imaging of multi-layered composite sandwich panel structures  

NASA Astrophysics Data System (ADS)

The results of a magnetic resonance imaging (MRI) investigation concerning the effects of an aluminum honeycomb sandwich panel on the B1 and B0 fields and on subsequent image quality are presented. Although the sandwich panel structure, representative of an aircraft composite material, distorts B0 and attenuates B1, distortion-free imaging is possible using single point (constant time) imaging techniques. A new expression is derived for the error caused by gradient field distortion due to the heterogeneous magnetic susceptibility within a sample and this error is shown not to cause geometric distortion in the image. The origin of the B0 distortion in the sample under investigation was also examined. The graphite-epoxy `skin' of the panel is the principal source of the B0 distortion. Successful imaging of these structures sets the stage for the development of methods for detecting moisture ingress and degradation within composite sandwich structures.

Marble, Andrew E.; Mastikhin, Igor V.; MacGregor, Rod P.; Akl, Mohamad; LaPlante, Gabriel; Colpitts, Bruce G.; Lee-Sullivan, Pearl; Balcom, Bruce J.

2004-05-01

174

Improper colouring of unit disk graphs  

Microsoft Academic Search

Motivated by a satellite communications problem, we consider a generalised colouring problem on unit disk graphs. A colouring is k-improper if no vertex receives the same colour as k+1 of its neighbours. The k-improper chromatic number k(G) the least number of colours needed in a k-improper colouring of a graph G. The main subject of this work is analysing the

Ross J. Kang; Jean-S ebastien Sereni

175

3-facial colouring of plane graphs  

Microsoft Academic Search

A plane graph is l-facially k-colourable if its vertices can be coloured with\\u000ak colours such that any two distinct vertices on a facial segment of length at\\u000amost l are coloured differently. We prove that every plane graph is 3-facially\\u000a11-colourable. As a consequence, we derive that every 2-connected plane graph\\u000awith maximum face-size at most 7 is cyclically

Frédéric Havet; Jean-Sébastien Sereni; Riste Skrekovski

2006-01-01

176

Neuronal correlates of colour-graphemic synaesthesia: a fMRI study.  

PubMed

Synaesthesia is a perceptual phenomenon in which specific events in one sensory modality induce experiences in another. In colour-graphemic synaesthesia, subjects report colour experiences induced by written letters. Our subjects displayed this type of synaesthesia, as verified by a test of the consistency of the perceptual associations over time, and had no history of neurological or psychiatric disorders. We investigated the hypothesis that the synaesthetic colour experience is accompanied by an activation of the human colour area (V4/V8) using functional magnetic resonance imaging (fMRI). With retinotopic and colour mapping we could confirm that colour stimuli specifically activate area V4/V8. For the study of colour-graphemic synaesthesia we used an AB boxcar design with blocks of letters that elicited a synaesthetic colour experience (condition A) alternating with blocks of letters that did not (condition B). In both hemispheres condition A led to a significantly higher activation of V4/V8 than condition B. These findings support the hypothesis that the grapheme-induced colour perception in synaesthesia is caused by an activation of the colour areas of the human visual cortex. PMID:16683504

Sperling, Julia M; Prvulovic, David; Linden, David E J; Singer, Wolf; Stirn, Aglaja

2006-02-01

177

Class Separation Improvements in Pixel Classification Using Colour Injection  

PubMed Central

This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS) sub-space. The authors propose to inject (add) a colour vector in the Red Green Blue (RGB) space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC1C2) space) is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required. PMID:22163628

Blanco, Edward; Mazo, Manuel; Bergasa, Luis; Palazuelos, Sira; Rodríguez, Jose; Losada, Cristina; Martín, Jose

2010-01-01

178

Class separation improvements in pixel classification using colour injection.  

PubMed

This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS) sub-space. The authors propose to inject (add) a colour vector in the Red Green Blue (RGB) space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC(1)C(2)) space) is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required. PMID:22163628

Blanco, Edward; Mazo, Manuel; Bergasa, Luis; Palazuelos, Sira; Rodríguez, Jose; Losada, Cristina; Martín, Jose

2010-01-01

179

Colour distributions in E-S0 galaxies . IV. Colour data and dust in E's from Nieto's B, R frames  

NASA Astrophysics Data System (ADS)

The B-R colours distributions (with R in Cousins's system) have been measured in 44 E classified galaxies in the Local Supercluster, from pairs of frames collected by Nieto and co-workers in 1989-91. These are nearly all from the CFHT, and of sub-arsec resolution. Great attention has been given to the effects of unequal PSF's in the B and R frames upon colour distributions near centre; such effects are illustrated from model calculations and from pseudo-colours obtained from pairs of frames taken in the same band but with different seeing conditions. Appropriate corrections were systematically applied in order to derive central colours and inner gradients, although still affected by the limited resolution of the frames. The radial colour distributions have been measured in more detail than usual, considering separately the near major axis and near minor axis regions of the isophotal contours. Azimuthal colour distributions, in rings limited by selected isophotes, were also obtained. Dust ``patterns", i.e. patches, lanes, arcs, ..., have been detected and mapped from the colour distributions. An ad hoc dust pattern importance index (or DPII) in a scale of 0 to 3, has been introduced to qualify their size and contrast. We have tried to find evidence of a diffuse dust concentration towards the disk, if one is apparent. Positive results (noted by the dd symbol) have been obtained for disky E's, whenever the inclination of their disk to the line of sight is large enough, and eventually also in the small isolated disks sometimes present in both boxy and disky galaxies. The red central peak occurring in many E-galaxies might be the signature of a central concentration of dust, also in cases where this peak is isolated rather than embedded in some extensive colour pattern. The properties of the near centre colour profiles have been related to a classification of nuclear photometric profiles into ``flat topped" and ``sharply peaked" (equivalent to ``core-like" and ``power-law" in the terminology of te[Faber et al. 1997).]{fab97} The published here data include the following: . Short descriptions and codes for the characters of the B-R distribution of each object, and comparison to the results of recent surveys. . A table of the mean B-R at the centre and at two selected isophotes, a ``core colour gradient" and the usual logarithmic gradient. . Maps of near core B-R isochromes and B isophotes for comparison. Images of the B-R colour distribution are made available in electronic form. Based on observations collected at the Canada-France-Hawaii Telescope and at the Observatoire du Pic du Midi.

Michard, R.

1999-06-01

180

Applications of Colour Processing In Optical Inspection  

NASA Astrophysics Data System (ADS)

Humans are endowed with the facility to perceive colour. This not only provides an additional aesthetic dimension but also helps perform visual tasks efficiently. There are many occupations, including inspection, not open to those with defective colour vision. Todays machine vision systems are virtually all colour-blind. Yet there are applications where colour is intrinsic. Consider for example the inspection and grading of fruit, vegetables, biscuits and other food products. Consider also the widespread use of colour coding for wiring and components in the electrical and electronic industries. Automatic optical inspection of such things cannot be done without relating to colour. There are other applications where colour is not directly relevant but the additional information provided can help simplify and speed up the processing task. This paper reviews the nature of colour, relating the psychophysical aspects of colour perception and the physical properties of available sensors to the needs of an automatic inspection system. The theory of colour perception is based on the tri-stimulus theory which says that any colour may be matched using appropriate proportions of three primary colours. Although later experiments have suggested human colour perception is more complex, most electronic video sensors employ a three colour system. Usually the red, green and blue primary components are derived and may be used directly as sensory inputs to a vision system. However the primary representation of colour is not the most efficient means of encoding nor is it the most useful basis for interpretive processing. The R,G and B primary signals may be simply transformed into a new coordinate system where one of the axes represents true object colour or hue. Using this new colour space simplifies processing. These ideas are illustrated by an inspection example. The colour coded wires of a European power cable are identified to ensure that a power plug is safely wired. For this application a straightforward and reliable inspection system can only be produced using colour information.

Thomas, W. V.; Connolly, C.

1986-11-01

181

Two-Dimensional Imaging of Selected Ply Orientations in Quasi-Isotropic Composite Laminates Using Polar Backscattering  

Microsoft Academic Search

The polar backscatter technique of Bar-Cohen and Crane offers the potential of selectively interrogating plies of a single orientation in composite material composed of lamina exhibiting multiple orientations. In this work we report an application of this novel measurement technique to quantitative two-dimensional imaging of impact and fatigue damage in graphite epoxy composite materials. For each composite investigated, 4 images

Eric I. Madaras; J. G. Miller

1982-01-01

182

Segmenting memory colours Clement Fredembach, Francisco Estrada, and Sabine Susstrunk  

E-print Network

colours: blue sky, green vegetation, and skin tones. Using a large database of real-world images, we: blue sky, green vegetation and skin tones [10]. It has been shown that human observers locate. The classes we consider here: blue sky, green vegetation, and skin tones generally fulfil, due to physics

Estrada, Francisco

183

Non-Photorealistic Rendering with Reduced Colour Palettes  

E-print Network

Abstract In contrast to photorealistic rendering, where richer colours are likely to be preferred, non algorithm [23] is applied to a grey level version of the image in Fig. 11.2(a) the result is unattractive, and moreover contains blotches, speckles, and has lost many significant details (Fig. 11.2(b)). In fact

Martin, Ralph R.

184

The colour of gender stereotyping.  

PubMed

Despite legislative attempts to eliminate gender stereotyping from society, the propensity to evaluate people on the basis of their sex remains a pernicious social problem. Noting the critical interplay between cultural and cognitive factors in the establishment of stereotypical beliefs, the current investigation explored the extent to which culturally transmitted colour-gender associations (i.e., pink is for girls, blue is for boys) set the stage for the automatic activation and expression of gender stereotypes. Across six experiments, the results demonstrated that (1) consumer choice for children's goods is dominated by gender-stereotyped colours (Experiment 1); (2) colour-based stereotypic associations guide young children's behaviour (Experiment 2); (3) colour-gender associations automatically activate associated stereotypes in adulthood (Experiments 3-5); and (4) colour-based stereotypic associations bias impressions of male and female targets (Experiment 6). These findings indicate that, despite prohibitions against stereotyping, seemingly innocuous societal practices may continue to promote this mode of thought. PMID:21752009

Cunningham, Sheila J; Macrae, C Neil

2011-08-01

185

Scanning thermal imaging microscopy using composite cantilever probes  

Microsoft Academic Search

We have developed a simple technique of measuring surface temperature contrast with submicron spatial resolution. The technique uses the atomic force microscope (AFM) to scan a composite cantilever probe made of a thin metal film (aluminum or gold) deposited on a regular silicon nitride AFM probe. During tip-surface contact, heat flow through the tip changes the cantilever temperature which bends

O. Nakabeppu; M. Chandrachood; Y. Wu; J. Lai; A. Majumdar

1995-01-01

186

Juvenile colour polymorphism in the red rock crab, Cancer productus: patterns, causes, and possible adaptive significance.  

PubMed

Juveniles of the common red rock crab of the Northeastern Pacific, Cancer productus, display a stunning diversity of colours and patterns, while adults all have the same drab colouration. Although this is widely known, key questions remain: (1) Does the frequency of different juvenile colours or patterns vary among collection sites or seasonally? (2) Does juvenile colour polymorphism reflect genetic heterogeneity or phenotypic plasticity in response to variable environmental conditions? (3) Do juveniles of different colours or patterns prefer substrata of different heterogeneity or brightness? We therefore: (i) described the variation in colour and pattern of juvenile C. productus; (ii) tested for associations between colour/pattern morphs and crab size, collection site, and season, in the field; (iii) conducted preliminary tests for habitat preferences (background colour, substratum type, light level) of different colour/pattern morphs in laboratory experiments, and (iv) tested the effect of diet (mussels versus shrimp) and feeding rate (high versus low) on juvenile colour/pattern. We describe 30 phenotypes that embrace a wide range of colour and pattern variants. The proportions of these phenotypes did not vary significantly among four collection sites, but they did vary significantly with season: over the summer and fall, juvenile colour and pattern variation was gradually replaced by the uniform adult colouration. The number of crabs displaying adult colouration also increased with crab size. Laboratory experiments suggest no significant preferences of different juvenile morphs for different backgrounds, substrata, or light levels. Diet (mussels versus shrimp) and feeding frequency had no effect on colour/pattern. Collectively, these results, although limited in scope, are not consistent with two likely hypotheses that could explain the extensive colour and pattern variation in juvenile C. productus: (i) selection for background matching by different cryptic forms and (ii) direct effects of diet or feeding rate on colour or pattern. Most probably, the large variety of different juvenile morphs is a result of frequency-dependent selection in which abundant variants are attacked disproportionately often and rarer forms are favoured. Juvenile colour polymorphism in C. productus may reduce the vulnerability to visual predators, impede the formation of a search image, and consequently decrease the risk of predation during the juvenile stages. PMID:20435453

Krause-Nehring, Jacqueline; Matthias Starck, J; Palmer, A Richard

2010-05-01

187

Multispectral near-infrared imaging of composite restorations in extracted teeth  

NASA Astrophysics Data System (ADS)

One major advantage of composite restoration materials is that they can be color matched to the tooth. However, this presents a challenge when composites fail and they need to be replaced. Dentists typically spend more time repairing and replacing composites than placing new restorations. Previous studies have shown that near-infrared imaging can be used to distinguish between sound enamel and decay due to the differences in light scattering. The purpose of this study was to use a similar approach and exploit differences in light scattering to attain high contrast between composite and tooth structure. Extracted human teeth with composites (n=16) were imaged in occlusal transmission mode at wavelengths of 1300-nm, 1460-nm and 1550-nm using an InGaAs image sensor with a tungsten halogen light source with spectral filters. All samples were also imaged in the visible range using a high definition 3D digital microscope. Our results indicate that NIR wavelengths at 1460-nm and 1550-nm, coincident with higher water absorption yield the highest contrast between dental composites and tooth structure.

Logan, Cooper M.; Co, Katrina U.; Fried, William A.; Simon, Jacob C.; Staninec, Michal; Fried, Daniel; Darling, Cynthia L.

2014-02-01

188

Multispectral Near-Infrared Imaging of Composite Restorations in Extracted Teeth  

PubMed Central

One major advantage of composite restoration materials is that they can be color matched to the tooth. However, this presents a challenge when composites fail and they need to be replaced. Dentists typically spend more time repairing and replacing composites than placing new restorations. Previous studies have shown that near-infrared imaging can be used to distinguish between sound enamel and decay due to the differences in light scattering. The purpose of this study was to use a similar approach and exploit differences in light scattering to attain high contrast between composite and tooth structure. Extracted human teeth with composites (n=16) were imaged in occlusal transmission mode at wavelengths of 1300-nm, 1460-nm and 1550-nm using an InGaAs image sensor with a tungsten halogen light source with spectral filters. All samples were also imaged in the visible range using a high definition 3D digital microscope. Our results indicate that NIR wavelengths at 1460-nm and 1550-nm, coincident with higher water absorption yield the highest contrast between dental composites and tooth structure.

Logan, Cooper M.; Co, Katrina U.; Fried, William A.; Simon, Jacob C.; Staninec, Michal; and, Daniel Fried; Darling, Cynthia L.

2014-01-01

189

Confocal time lapse imaging as an efficient method for the cytocompatibility evaluation of dental composites.  

PubMed

It is generally accepted that in vitro cell material interaction is a useful criterion in the evaluation of dental material biocompatibility. The objective of this study was to use 3D CLSM time lapse confocal imaging to assess the in vitro biocompatibility of dental composites. This method provides an accurate and sensitive indication of viable cell rate in contact with dental composite extracts. The ELS extra low shrinkage, a dental composite used for direct restoration, has been taken as example. In vitro assessment was performed on cultured primary human gingival fibroblast cells using Live/Dead staining. Images were obtained with the FV10i confocal biological inverted system and analyzed with the FV10-ASW 3.1 Software. Image analysis showed a very slight cytotoxicity in the presence of the tested composite after 5 hours of time lapse. A slight decrease of cell viability was shown in contact with the tested composite extracts compared to control cells. The findings highlighted the use of 3D CLSM time lapse imaging as a sensitive method to qualitatively and quantitatively evaluate the biocompatibility behavior of dental composites. PMID:25406737

Attik, Ghania Nina; Gritsch, Kerstin; Colon, Pierre; Grosgogeat, Brigitte

2014-01-01

190

The effect of stress and stress hormones on dynamic colour-change in a sexually dichromatic Australian frog.  

PubMed

Rapid colour changes in vertebrates have fascinated biologists for centuries, herein we demonstrate dynamic colour change in an anuran amphibian, the stony creek frog (Litoria wilcoxii), which turns from brown to bright (lemon) yellow during amplexus. We show this by comparing the colour of baseline (unpaired males) and amplecting (paired) males. We also investigate the possible role of stress and stress hormones on this colour change. Frogs were subjected to four different levels of stressors (handling, toe-clipping, saline injection and adrenocorticotropic hormone [ACTH] injection) and the colour change was measured using digital photography. A comparison of baseline colour and stress hormone (corticosterone) levels was also conducted to give further insight to this topic. From the images, the Red Blue Green (RGB) colour values were calculated, and a principal components analysis (PCA) was used to create a single colour metric (the major axis) as an index of colour in the visible spectrum. A moderate stressor (toe-clipping) led to a significant change in colour (within 10 min) similar to that of amplecting males. Surprisingly, neither a mild stressor (handling and saline injection) nor the maximum stressor (handling and ACTH injection) led to a lightening response. This study confirms that the dynamic male colour change in this species in response to medium stressors adds new knowledge to the understanding of the functional mechanisms of dynamic colour change in amphibians. PMID:23507571

Kindermann, Christina; Narayan, Edward J; Wild, Francis; Wild, Clyde H; Hero, Jean-Marc

2013-06-01

191

Ecological genomics in full colour.  

PubMed

Colour patterns in animals have long offered an opportunity to observe adaptive traits in natural populations. Colour plays myriad roles in interactions within and among species, from reproductive signalling to predator avoidance, leading to multiple targets of natural and sexual selection and opportunities for diversification. Understanding the genetic and developmental underpinnings of variation in colour promises a fuller understanding of these evolutionary processes, but the path to unravelling these connections can be arduous. The advent of genomic techniques suitable for nonmodel organisms is now beginning to light the way. Two new studies in this issue of Molecular Ecology use genomic sequencing of laboratory crosses to map colour traits in cichlid fishes, a remarkably diverse group in which coloration has played a major role in diversification. They illustrate how genomic approaches, specifically RAD sequencing, can rapidly identify both simple and more complex genetic variation underlying ecologically important traits. In the first, Henning et al. () detect a single locus that appears to control in a Mendelian fashion the presence of horizontal stripes, a trait that has evolved in numerous cichlid lineages. In the second, Albertson et al. () identify several genes and epistatic interactions affecting multiple colour traits, as well as a novel metric describing integration across colour traits. Albertson et al. () go further, by quantifying differential expression of parental alleles at a candidate locus and by relating differentiation among natural populations at mapped loci to trait divergence. Herein lies the promise of ecological genomics - efficiently integrating genetic mapping of phenotypes with population genomic data to both identify functional genes and unravel their evolutionary history. These studies offer guidance on how genomic techniques can be tailored to a research question or study system, and they also add to the growing body of empirical examples addressing basic questions about how ecologically important traits evolve in natural populations. PMID:25330852

Hohenlohe, Paul A

2014-11-01

192

Carotenoid-Based Colours Reflect the Stress Response in the Common Lizard  

PubMed Central

Under chronic stress, carotenoid-based colouration has often been shown to fade. However, the ecological and physiological mechanisms that govern colouration still remain largely unknown. Colour changes may be directly induced by the stressor (for example through reduced carotenoid intake) or due to the activation of the physiological stress response (PSR, e.g. due to increased blood corticosterone concentrations). Here, we tested whether blood corticosterone concentration affected carotenoid-based colouration, and whether a trade-off between colouration and PSR existed. Using the common lizard (Lacerta vivipara), we correlatively and experimentally showed that elevated blood corticosterone levels are associated with increased redness of the lizard's belly. In this study, the effects of corticosterone did not depend on carotenoid ingestion, indicating the absence of a trade-off between colouration and PSR for carotenoids. While carotenoid ingestion increased blood carotenoid concentration, colouration was not modified. This suggests that carotenoid-based colouration of common lizards is not severely limited by dietary carotenoid intake. Together with earlier studies, these findings suggest that the common lizard's carotenoid-based colouration may be a composite trait, consisting of fixed (e.g. genetic) and environmentally elements, the latter reflecting the lizard's PSR. PMID:19352507

Fitze, Patrick S.; Cote, Julien; San-Jose, Luis Martin; Meylan, Sandrine; Isaksson, Caroline; Andersson, Staffan; Rossi, Jean-Marc; Clobert, Jean

2009-01-01

193

Research of processing method for infrared image of sandwich structure composite  

NASA Astrophysics Data System (ADS)

Composite sandwich structure has been widely used in aerospace due to its lightweight, high stiffness and strength. Existence of delaminations in the structure reduce the performance of the composites significantly, such flaws can be detected effectively and non-destructively by non-contact pulsed infrared thermography, but the contrast of infrared images of the material is low due to complex structure, so delaminations and sound area are difficult to be differentiated. In this paper, sandwich structure composites with aluminum facesheet and aluminum honeycomb cores are chosen as study objectives, several round-shape and rectangle-shape Teflon inserts with different sizes embedded in specimen, which simulate delaminations in the structure, and the processing method of infrared image is developed. The thermal image is processed through image denoising, image enhancement and feature extraction, and then the sizes of the defects are determined. Refer to the designed sizes, the results show that the accuracy of sizes measured by image processing is more than 90% for the defects bigger than ?10mm , these results demonstrated that detecting accuracy of the structure is higher by infrared image processing.

Huo, Yan; Zhang, Cun-Lin; Hu, Chun-Yu; Li, Chun-Guang

2012-10-01

194

Rainbow Colouring of Split and Threshold Graphs  

E-print Network

A rainbow colouring of a connected graph is a colouring of the edges of the graph, such that every pair of vertices is connected by at least one path in which no two edges are coloured the same. Such a colouring using minimum possible number of colours is called an optimal rainbow colouring, and the minimum number of colours required is called the rainbow connection number of the graph. In this article, we show the following: 1. The problem of deciding whether a graph can be rainbow coloured using 3 colours remains NP-complete even when restricted to the class of split graphs. However, any split graph can be rainbow coloured in linear time using at most one more colour than the optimum. 2. For every integer k larger than 2, the problem of deciding whether a graph can be rainbow coloured using k colours remains NP-complete even when restricted to the class of chordal graphs. 3. For every positive integer k, threshold graphs with rainbow connection number k can be characterised based on their degree sequence al...

Chandran, L Sunil

2012-01-01

195

Preparation of AlB sub 4 C composites for image analysis  

SciTech Connect

Composites made by infiltrating B{sub 4}C networks with aluminium, or its alloys are of interest for lightweight armor applications. Image analysis plays an important part in correlating the microstructures of such composites with their mechanical properties. Accurate image analysis requires a high degree of perfection in the metallographic preparation, which is particularly difficult where the phases present have such disparate hardness and reactivities. Two preparation procedures have been developed that produce adequate contrast and definition for analysis of key microstructural features. 8 refs., 5 figs., 1 tab.

Kelly, A.M.; Reiswig, R.D.; Hill, M.A.; Blumenthal, W.R.

1990-01-01

196

Composition of a dewarped and enhanced document image from two view images.  

PubMed

In this paper, we propose an algorithm to compose a geometrically dewarped and visually enhanced image from two document images taken by a digital camera at different angles. Unlike the conventional works that require special equipment or assumptions on the contents of books or complicated image acquisition steps, we estimate the unfolded book or document surface from the corresponding points between two images. For this purpose, the surface and camera matrices are estimated using structure reconstruction, 3-D projection analysis, and random sample consensus-based curve fitting with the cylindrical surface model. Because we do not need any assumption on the contents of books, the proposed method can be applied not only to optical character recognition (OCR), but also to the high-quality digitization of pictures in documents. In addition to the dewarping for a structurally better image, image mosaic is also performed for further improving the visual quality. By finding better parts of images (with less out of focus blur and/or without specular reflections) from either of views, we compose a better image by stitching and blending them. These processes are formulated as energy minimization problems that can be solved using a graph cut method. Experiments on many kinds of book or document images show that the proposed algorithm robustly works and yields visually pleasing results. Also, the OCR rate of the resulting image is comparable to that of document images from a flatbed scanner. PMID:19447710

Koo, Hyung Il; Kim, Jinho; Cho, Nam Ik

2009-07-01

197

Dynamic holographic images using polyvinylcarbazole-based photorefractive composites  

NASA Astrophysics Data System (ADS)

We present here the optimized photorefractive polymeric composite (PPC) film based on simple materials of poly(N-vinylcarbazole) (PVCz)/4-azacycloheptylbenzylidenemalononitrile (7-DCST)/N-ethylcarbazole (ECz)/2,4,7-trinitro-9- fluorenone (TNF). The-simple-materials-based PPC was optimized from the photorefractive characteristics of PPCs with PVCz/7-DCST/ECz/TNF (the best ratio: 44/35/20/1 wt %) that changed molecular weights of PVCz: 23,000, 100,000, 290,000, 370,000, 520,000, 780,000, 860,000, and < 1,000,000 g mol-1. Diffraction efficiency and photorefractive response time of the PPC film with Mw: 860,000 of PVCz/7-DCST/ECz/TNF (44/35/20/1 wt %) showed an appropriate photorefractive performance, which was determined as the optimized PPC. It is notable that the optimized PPC could be easily obtained from relatively inexpensive materials; furthermore, the required nonlinear optical dye 7-DCST could be synthesized in high-yield. We believe that the PPCs based on PVCz or other polyvinylcarbazole derivatives will be the potential composite for creating holographic displays because of low fabrication costs, and be of benefit to developing technologies.

Kinashi, Kenji; Wang, Yu; Nonomura, Asato; Sakai, Wataru; Tsutsumi, Naoto

2012-10-01

198

A novel Bayesian imaging method for probabilistic delamination detection of composite materials  

NASA Astrophysics Data System (ADS)

A probabilistic framework for location and size determination for delamination in carbon-carbon composites is proposed in this paper. A probability image of delaminated area using Lamb wave-based damage detection features is constructed with the Bayesian updating technique. First, the algorithm for the probabilistic delamination detection framework using the proposed Bayesian imaging method (BIM) is presented. Next, a fatigue testing setup for carbon-carbon composite coupons is described. The Lamb wave-based diagnostic signal is then interpreted and processed. Next, the obtained signal features are incorporated in the Bayesian imaging method for delamination size and location detection, as well as the corresponding uncertainty bounds prediction. The damage detection results using the proposed methodology are compared with x-ray images for verification and validation. Finally, some conclusions are drawn and suggestions made for future works based on the study presented in this paper.

Peng, Tishun; Saxena, Abhinav; Goebel, Kai; Xiang, Yibing; Sankararaman, Shankar; Liu, Yongming

2013-12-01

199

Damage threshold study of sonic IR imaging on carbon-fiber reinforced laminated composite materials  

NASA Astrophysics Data System (ADS)

Sonic Infrared Imaging, as a young NDE technology, has drawn a lot of attentions due to it's fast, wide-area evaluation capability, and due to its broad applications in different materials such as metal/metal alloy, composites and detection of various types of defects: surface, subsurface, cracks, delaminations/disbonds. Sonic IR Imaging combines pulsed ultrasound excitation and infrared imaging to detect defects in materials. The sound pulse causes rubbing due to non-unison motion between faces of defects, and infrared sensors image the temperature map over the target to identify defects. However, concerns have also been brought up about possible damages which might occur at the contact spots between the ultrasound transducer from the external excitation source and the target materials. In this paper, we present our results from a series of systematically designed experiments on carbon-fiber reinforced laminated composite panels to address the concerns.

Han, Xiaoyan; He, Qi; Zhang, Ding; Ashbaugh, Mike; Favro, Lawrence D.; Newaz, Golam; Thomas, Robert L.

2013-01-01

200

Interference colours of soap bubbles  

Microsoft Academic Search

In this article, we present a new versatile method for calculating the interference colour of any configuration of thin, optically isotropic, dielectric films. This method is free from common weakness of previous methods, namely the poor accuracy for large angles of incidence of light. This method gives full control over the accuracy and speed of computations, and allows for adjustments

Dariusz Jaszkowski; Janusz Rzeszut

2003-01-01

201

The Colour of Butterflies' Wings  

Microsoft Academic Search

IN making some experiments a short time ago, I came across a fact of which I was hitherto ignorant. I wished to test the effect of acid on the colours of the wings of a butterfly or moth, and with this view applied muriatic acid to a dried and set specimen of the Six-spotted Burnet [Zygæna filipendulæ). The red parts

F. E. v

1870-01-01

202

The colours of the sun.  

NASA Astrophysics Data System (ADS)

In this paper, arguments are developed for treating (R-I)C as the most important colour to be derived for the Sun. The solar value of (R-I)C is then found to be 0.335±0.002 mag. This result updates a counterpart given by Taylor in 1992.

Taylor, B. J.

203

Roles of biologic breast tissue composition and quantitative image analysis of mammographic images in breast tumor characterization  

NASA Astrophysics Data System (ADS)

Purpose. Investigate whether knowledge of the biologic image composition of mammographic lesions provides imagebased biomarkers above and beyond those obtainable from quantitative image analysis (QIA) of X-ray mammography. Methods. The dataset consisted of 45 in vivo breast lesions imaged with the novel 3-component breast (3CB) imaging technique based on dual-energy mammography (15 malignant, 30 benign diagnoses). The 3CB composition measures of water, lipid, and protein thicknesses were assessed and mathematical descriptors, `3CB features', were obtained for the lesions and their periphery. The raw low-energy mammographic images were analyzed with an established in-house QIA method obtaining `QIA features' describing morphology and texture. We investigated the correlation within the `3CB features', within the `QIA features', and between the two. In addition, the merit of individual features in the distinction between malignant and benign lesions was assessed. Results. Whereas many descriptors within the `3CB features' and `QIA features' were, often by design, highly correlated, correlation between descriptors of the two feature groups was much weaker (maximum absolute correlation coefficient 0.58, p<0.001) indicating that 3CB and QIA-based biomarkers provided potentially complementary information. Single descriptors from 3CB and QIA appeared equally well-suited for the distinction between malignant and benign lesions, with maximum area under the ROC curve 0.71 for a protein feature (3CB) and 0.71 for a texture feature (QIA). Conclusions. In this pilot study analyzing the new 3CB imaging modality, knowledge of breast tissue composition appeared additive in combination with existing mammographic QIA methods for the distinction between benign and malignant lesions.

Drukker, Karen; Giger, Maryellen L.; Duewer, Fred; Malkov, Serghei; Flowers, Christopher I.; Joe, Bonnie; Kerlikowske, Karla; Drukteinis, Jennifer S.; Shepherd, John

2014-03-01

204

Image correlation nondestructive evaluation of impact damage in a glass fiber composite  

NASA Technical Reports Server (NTRS)

Presented in viewgraph format, digital image correlation, damage in fibrous composites, and damaged coupons (cross-ply scotchply GI-Ep laminate) are outlined. It was concluded that the image correlation accuracy was 0.03 percent; strains can be processed through Tsai-Hill failure criteria to qualify the damage; the statistical data base must be generated to evaluate certainty of the damage estimate; size effects need consideration; and better numerical techniques are needed.

Russell, Samuel S.

1990-01-01

205

Tomographic Imaging of Glass/Epoxy Composite with a Laser Based Ultrasonics Setup  

SciTech Connect

The present work is an attempt to augment the classical laser-based-ultrasonics setup for tomographic imaging purposes. A Glass/epoxy composite with steel insert is the test specimen and time-of-flight data has been used for tomographic reconstruction. Multiplicative algebraic reconstruction technique is used for this limited-view experiment. The resulting image is able to bring out the strong metal features.

Khanna, N.; Raghuram, V.; Munshi, P.; Kishore, N. N. [Department of Mechanical Engineering Indian Institute of Technology Kanpur 208016 (India); Arnold, W. [Fraunhofer Institute of Nondestructive Testing Saarbruecken 66123 (Germany)

2008-09-26

206

BOTANICAL BRIEFING Structural colour and iridescence in plants: the poorly studied relations of pigment colour  

Microsoft Academic Search

†Background Colour is a consequence of the optical properties of an object and the visual system of the animal perceiving it. Colour is produced through chemical and structural means, but structural colour has been relatively poorly studied in plants. †Scope This Botanical Briefing describes the mechanisms by which structures can produce colour. In plants, as in animals, the most common

Beverley J. Glover; Heather M. Whitney

207

The connotations of English colour terms: Colour-based X-phemisms  

Microsoft Academic Search

This paper investigates the connotations of English colour terms with particular attention to figurative uses of black, white, grey, brown, yellow, red, green, blue and a few miscellaneous colours. The connotations are judged on the basis of whether the phrases in which the colour terms occur are typically orthophemistic, euphemistic, or dysphemistic. All the colours surveyed have some, often many,

Keith Allan

2009-01-01

208

Biological Components of Colour Preference in Infancy  

ERIC Educational Resources Information Center

Adult colour preference has been summarized quantitatively in terms of weights on the two fundamental neural processes that underlie early colour encoding: the S-(L+M) ("blue-yellow") and L-M ("red-green") cone-opponent contrast channels ( Ling, Hurlbert & Robinson, 2006; Hurlbert & Ling, 2007). Here, we investigate whether colour preference in…

Franklin, Anna; Bevis, Laura; Ling, Yazhu; Hurlbert, Anya

2010-01-01

209

Ultraviolet Colour Vision and Ornamentation in Bluethroats  

Microsoft Academic Search

Many birds see in the ultraviolet (300-400 nm), but there is limited evidence for colour communication (signalling by spectral shape independently of brightness) in this 'hidden' waveband. Such data are critical for the understanding of extravagant plumage colours, some of which show considerable UV reflectance. We investigated UV colour vision in female social responses to the male UV\\/violet ornament in

Staffan Andersson; Trond Amundsen

1997-01-01

210

Colour space models for soil science  

Microsoft Academic Search

Soil colour is an important soil property. It is frequently used by soil scientists for the identification and classification of soil. It is also used as an indicator of field soil physical, chemical and biological properties as well as of the occurrence of soil processes. Measurements of soil colour are commonly made using the Munsell soil colour charts. A number

R. A. Viscarra Rossel; B. Minasny; P. Roudier; A. B. McBratney

2006-01-01

211

An RGB Approach to Prismatic Colours  

ERIC Educational Resources Information Center

Teaching prismatic colours usually boils down to establishing the take-home message that white light consists of "differently refrangible" coloured rays. This approach explains the classical spectrum of seven colours but has its limitations, e.g. in discussing spectra from setups with higher resolution or in understanding the well…

Theilmann, Florian; Grusche, Sascha

2013-01-01

212

Genetic and environmental effects influencing fruit colour and QTL analysis in raspberry.  

PubMed

Raspberry (Rubus idaeus) fruit colour was assessed in the Latham x Glen Moy mapping population using a colour meter and visual scores over three seasons and three environments. The colour measurements were found to be significantly associated with pigment content, have high heritability, and stable QTL were identified across environments and seasons. Anthocyanin content has previously been shown to be the major contributor to fruit colour in red raspberry. Major structural genes (F3'H, FLS, DFR, IFR, OMT and GST) and transcription factors (bZIP, bHLH and MYB) influencing flavonoid biosynthesis have been identified, mapped and shown to underlie QTL for quantitative and qualitative anthocyanin composition. Favourable alleles for the selected traits were identified for the aspects of fruit colour and partitioning of individual pigments. PMID:20419285

McCallum, Susan; Woodhead, Mary; Hackett, Christine A; Kassim, Angzzas; Paterson, Alistair; Graham, Julie

2010-08-01

213

Plexus structure imaging with thin slab MR neurography: rotating frames, fly-throughs, and composite projections  

NASA Astrophysics Data System (ADS)

We explored multiple image processing approaches by which to display the segmented adult brachial plexus in a three-dimensional manner. Magnetic resonance neurography (MRN) 1.5-Tesla scans with STIR sequences, which preferentially highlight nerves, were performed in adult volunteers to generate high-resolution raw images. Using multiple software programs, the raw MRN images were then manipulated so as to achieve segmentation of plexus neurovascular structures, which were incorporated into three different visualization schemes: rotating upper thoracic girdle skeletal frames, dynamic fly-throughs parallel to the clavicle, and thin slab volume-rendered composite projections.

Raphael, David T.; McIntee, Diane; Tsuruda, Jay S.; Colletti, Patrick; Tatevossian, Raymond; Frazier, James

2006-03-01

214

Can Imageability Help Us Draw the Line between Storage and Composition?  

ERIC Educational Resources Information Center

Language requires both storage and composition. However, exactly what is retrieved from memory and what is assembled remains controversial, especially for inflected words. Here, "imageability effects" is introduced as a new diagnostic of storage and a complement to frequency effects. In 2 studies of past-tense morphology, more reliable…

Prado, Elizabeth L.; Ullman, Michael T.

2009-01-01

215

Synthesize multi-level composite filter for synthetic-aperture radar image identification  

Microsoft Academic Search

A novel optical correlator system to identify the Synthetic-Aperture Radar (SAR) image based on multilevel composite function (MCF) filters, constructed in input domain, is presented. The MCFs are synthesized by the simulated annealing algorithm, which are suitable to current spatial light modulators because of their limited dynamic range requirement of the MCFs. In this paper, we focus our investigation on

Chun-Te Li; Jiang Li; Shizhuo Yin; Tracy D. Hudson; Deanna K. McMillen

1998-01-01

216

BOREAS RSS-7 Regional LAI and FPAR Images From 10-Day AVHRR-LAC Composites  

NASA Technical Reports Server (NTRS)

The BOReal Ecosystem-Atmosphere Study Remote Sensing Science (BOREAS RSS-7) team collected various data sets to develop and validate an algorithm to allow the retrieval of the spatial distribution of Leaf Area Index (LAI) from remotely sensed images. Advanced Very High Resolution Radiometer (AVHRR) level-4c 10-day composite Normalized Difference Vegetation Index (NDVI) images produced at CCRS were used to produce images of LAI and the Fraction of Photosynthetically Active Radiation (FPAR) absorbed by plant canopies for the three summer IFCs in 1994 across the BOREAS region. The algorithms were developed based on ground measurements and Landsat Thematic Mapper (TM) images. The data are stored in binary image format files.

Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Chen, Jing; Cihlar, Josef

2000-01-01

217

Colour vision in diurnal and nocturnal hawkmoths.  

PubMed

Diurnal and nocturnal hawkmoths (Sphingidae, Lepidoptera) have three spectral types of receptor sensitive to ultraviolet, blue and green light. As avid flower visitors and pollinators, they use olfactory and visual cues to find and recognise flowers. Moths of the diurnal species Macroglossum stellatarum and the nocturnal species Deilephila elpenor, Hyles lineata and Hyles gallii use and learn the colour of flowers. Nocturnal species can discriminate flowers at starlight intensities when humans and honeybees are colour-blind. M. stellatarum can use achromatic, intensity-related cues if colour cues are absent, and this is probably also true for D. elpenor. Both species can recognise colours even under a changed illumination colour. PMID:21680465

Kelber, Almut; Balkenius, Anna; Warrant, Eric J

2003-08-01

218

Bone-composition imaging using coherent-scatter computed tomography: Assessing bone health beyond bone mineral density  

E-print Network

Bone-composition imaging using coherent-scatter computed tomography: Assessing bone health beyond bone mineral density Deidre L. Batchelara and Melanie T. M. Davidson Imaging Research Laboratories analysis of bone composition is necessary for the accurate diagnosis and monitoring of metabolic bone

Cunningham, Ian

219

Carotenoids need structural colours to shine  

PubMed Central

The bright colours of feathers are among the most striking displays in nature and are frequently used as sexual signals. Feathers can be coloured by pigments or by ordered tissue, and these mechanisms have traditionally been treated as distinct modes of display. Here we show that some yellow plumage colour is created both by reflection of light from white structural tissue and absorption of light by carotenoids. Thus, structural components of feathers contribute substantially to yellow ‘carotenoid’ displays, but the effect of variation in structural components on variation in colour displays is, to our knowledge, unstudied. The presence of structural colour in some carotenoid-based colour displays will have to be considered in studies of colour signalling. PMID:17148144

Shawkey, Matthew D; Hill, Geoffrey E

2005-01-01

220

Colourings and preservatives in food.  

PubMed

Colours and preservatives are only two of the many classes of additives in food but they are of interest because many reported cases of sensitivity involve these two groups of substances. Preservatives present the greatest potential health hazard being, by definition, biologically active. Colours and other additives are required to perform a technological function whilst remaining as biologically inert as possible. Food additives are controlled by the Food and Drugs Act 1955 on the basis of advice from the Food Advisory Committee (FAC). Lists of the permitted preservatives and colourings are available, together with details of restrictions on their uses; this information is continually being updated. Food labelling regulations mean that some information about additives can be determined from the labelling--but even if an additive is not listed on the package, one cannot always assume that it is not present in the product, since additives coming through in the original ingredients need not always be listed. Other exemptions also exist, so there can be no absolute certainty about the presence, or absence, of a specific additive. That information can only be obtained by contacting the manufacturer. PMID:6526689

Denner, W H

1984-12-01

221

A composite six bp in-frame deletion in the melanocortin 1 receptor (MC1R) gene is associated with the Japanese brindling coat colour in rabbits (Oryctolagus cuniculus)  

PubMed Central

Background In the domestic rabbit (Oryctolagus cuniculus), classical genetic studies have identified five alleles at the Extension locus: ED (dominant black), ES (steel, weaker version of ED), E (wild type, normal extension of black), eJ(Japanese brindling, mosaic distribution of black and yellow) and e (non-extension of black, yellow/red with white belly). Sequencing almost the complete coding sequence (CDS) of the rabbit MC1R gene, we recently identified two in-frame deletions associated with dominant black (c.280_285del6; alleles ED or ES) and recessive red (c.304_333del30; allele e) coat colours. It remained to characterize the eJallele whose phenotypic effect is similar to the Orange and Sex-linked yellow loci of cat and Syrian hamster. Results We sequenced the whole CDS in 25 rabbits of different coat colours including 10 Japanese and 10 Rhinelander (tricolour) rabbits and identified another 6 bp-in frame deletion flanked by a G > A transition in 5' (c.[124G>A;125_130del6]) that was present in all animals with Japanese brindling coat colour and pattern. These mutations eliminate two amino acids in the first transmembrane domain and, in addition, cause an amino acid substitution at position 44 of the wild type sequence. Genotyping 371 rabbits of 31 breeds with different coat colour this allele (eJ) was present in homozygous state in Japanese, Rhinelander and Dutch tricolour rabbits only (except one albino rabbit). Rabbits with eJ/eJ genotype were non fixed at the non-agouti mutation we previously identified in the ASIP gene. Segregation in F1 and F2 families confirmed the order of dominance already determined by classical genetic experiments with a possible dose effect evident comparing eJ/eJ and eJ/e animals. MC1R mRNA was expressed in black hair skin regions only. Conclusions The c.[124A;125_130del6] allele may be responsible for a MC1R variant determining eumelanin production in the black areas. However, the mechanism determining the presence of both red and black hairs in the same animal seems more complex. Expression analyses of the c.[124A;125_130del6] allele suggest that MC1R transcription may be regulated epigenetically in rabbits with the Japanese brindling phenotype. Further studies are needed to clarify this issue. PMID:20594318

2010-01-01

222

Brilliant Star in a Colourful Neighbourhood  

NASA Astrophysics Data System (ADS)

A spectacular new image from ESO's Wide Field Imager at the La Silla Observatory in Chile shows the brilliant and unusual star WR 22 and its colourful surroundings. WR 22 is a very hot and bright star that is shedding its atmosphere into space at a rate many millions of times faster than the Sun. It lies in the outer part of the dramatic Carina Nebula from which it formed. Very massive stars live fast and die young. Some of these stellar beacons have such intense radiation passing through their thick atmospheres late in their lives that they shed material into space many millions of times more quickly than relatively sedate stars such as the Sun. These rare, very hot and massive objects are known as Wolf-Rayet stars [1], after the two French astronomers who first identified them in the mid-nineteenth century, and one of the most massive ones yet measured is known as WR 22. It appears at the centre of this picture, which was created from images taken through red, green and blue filters with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. WR 22 is a member of a double star system and has been measured to have a mass at least 70 times that of the Sun. WR 22 lies in the southern constellation of Carina, the keel of Jason's ship Argo in Greek mythology. Although the star lies over 5000 light-years from the Earth it is so bright that it can just be faintly seen with the unaided eye under good conditions. WR 22 is one of many exceptionally brilliant stars associated with the beautiful Carina Nebula (also known as NGC 3372) and the outer part of this huge region of star formation in the southern Milky Way forms the colourful backdrop to this image. The subtle colours of the rich background tapestry are a result of the interactions between the intense ultraviolet radiation coming from hot massive stars, including WR 22, and the vast gas clouds, mostly hydrogen, from which they formed. The central part of this enormous complex of gas and dust lies off the left side of this picture as can be seen in image eso1031b. This area includes the remarkable star Eta Carinae and was featured in an earlier press release (eso0905). Notes [1] More information about Wolf-Rayet stars More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

2010-07-01

223

Repeatability of digital image correlation for measurement of surface strains in composite long bones.  

PubMed

Digital image correlation (DIC) can measure full-field surface strains during mechanical testing of hard and soft tissues. When compared to traditional methods, such as strain gauges, DIC offers larger validation data (?50,000 points) for, e.g., finite element models. Our main aim was to evaluate the repeatability of surface strain measurements with DIC during compressive testing of composite femurs mimicking human bones. We also studied the similarity of the composite femur samples using CT. Composite femurs were chosen as test material to minimize the uncertainties associated with the use of cadaveric tissues and to understand the variability of the DIC measurement itself. Six medium-sized fourth generation composite human proximal femora (Sawbones) were CT imaged and mechanically tested in stance configuration. The force-displacement curves were recorded and the 3D surface strains were measured with DIC on the anterior surface of the femurs. Five femurs fractured at the neck-trochanter junction and one at the site below the minor trochanter. CT image of this bone showed an air cavity at the initial fracture site. All femurs fractured through a sudden brittle crack. The fracture force for the composite bones was 5751±650N (mean±SD). The maximum von Mises strain during the fractures was 2.4±0.8%. Noise in one experiment was 5-30µ?. When applied loads were equalized the variation in strains between the bones was 20-25%, and when the maximum strains were equalized, variation in the other regions was 5-10%. DIC showed that the ability of nominally identical composite bones to bear high strains and loads before fracturing may vary between the samples. PMID:23791085

Väänänen, Sami P; Amin Yavari, Saber; Weinans, Harrie; Zadpoor, Amir Abbas; Jurvelin, Jukka S; Isaksson, Hanna

2013-07-26

224

The original colours of fossil beetles  

PubMed Central

Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group. PMID:21957131

McNamara, Maria E.; Briggs, Derek E. G.; Orr, Patrick J.; Noh, Heeso; Cao, Hui

2012-01-01

225

Color composite C-band and L-band image of Kilauea volcanoe on Hawaii  

NASA Technical Reports Server (NTRS)

This color composite C-band and L-band image of the Kilauea volcano on the Big Island of Hawaii was acuired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperature Radar (SIR-C/X-SAR) flying on the Space Shuttle Endeavour. The city of Hilo can be seen at the top. The image shows the different types of lava flows around the crater Pu'u O'o. Ash deposits which erupted in 1790 from the summit of Kilauea volcano show up as dark in this image, and fine details associated with lava flows which erupted in 1919 and 1974 can be seen to the south of the summit in an area called the Ka'u Desert. Other historic lava flows can also be seen. Highway 11 is the linear feature running from Hilo to the Kilauea volcano. The Jet Propulsion Laboratory alternative photo number is P-43918.

1994-01-01

226

Opening up a Colourful Cosmic Jewel Box  

NASA Astrophysics Data System (ADS)

The combination of images taken by three exceptional telescopes, the ESO Very Large Telescope on Cerro Paranal , the MPG/ESO 2.2-metre telescope at ESO's La Silla observatory and the NASA/ESA Hubble Space Telescope, has allowed the stunning Jewel Box star cluster to be seen in a whole new light. Star clusters are among the most visually alluring and astrophysically fascinating objects in the sky. One of the most spectacular nestles deep in the southern skies near the Southern Cross in the constellation of Crux. The Kappa Crucis Cluster, also known as NGC 4755 or simply the "Jewel Box" is just bright enough to be seen with the unaided eye. It was given its nickname by the English astronomer John Herschel in the 1830s because the striking colour contrasts of its pale blue and orange stars seen through a telescope reminded Herschel of a piece of exotic jewellery. Open clusters [1] such as NGC 4755 typically contain anything from a few to thousands of stars that are loosely bound together by gravity. Because the stars all formed together from the same cloud of gas and dust their ages and chemical makeup are similar, which makes them ideal laboratories for studying how stars evolve. The position of the cluster amongst the rich star fields and dust clouds of the southern Milky Way is shown in the very wide field view generated from the Digitized Sky Survey 2 data. This image also includes one of the stars of the Southern Cross as well as part of the huge dark cloud of the Coal Sack [2]. A new image taken with the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile shows the cluster and its rich surroundings in all their multicoloured glory. The large field of view of the WFI shows a vast number of stars. Many are located behind the dusty clouds of the Milky Way and therefore appear red [3]. The FORS1 instrument on the ESO Very Large Telescope (VLT) allows a much closer look at the cluster itself. The telescope's huge mirror and exquisite image quality have resulted in a brand-new, very sharp view despite a total exposure time of just 5 seconds. This new image is one of the best ever taken of this cluster from the ground. The Jewel Box may be visually colourful in images taken on Earth, but observing from space allows the NASA/ESA Hubble Space Telescope to capture light of shorter wavelengths than can not be seen by telescopes on the ground. This new Hubble image of the core of the cluster represents the first comprehensive far ultraviolet to near-infrared image of an open galactic cluster. It was created from images taken through seven filters, allowing viewers to see details never seen before. It was taken near the end of the long life of the Wide Field Planetary Camera 2 ? Hubble's workhorse camera up until the recent Servicing Mission, when it was removed and brought back to Earth. Several very bright, pale blue supergiant stars, a solitary ruby-red supergiant and a variety of other brilliantly coloured stars are visible in the Hubble image, as well as many much fainter ones. The intriguing colours of many of the stars result from their differing intensities at different ultraviolet wavelengths. The huge variety in brightness of the stars in the cluster exists because the brighter stars are 15 to 20 times the mass of the Sun, while the dimmest stars in the Hubble image are less than half the mass of the Sun. More massive stars shine much more brilliantly. They also age faster and make the transition to giant stars much more quickly than their faint, less-massive siblings. The Jewel Box cluster is about 6400 light-years away and is approximately 16 million years old. Notes [1] Open, or galactic, star clusters are not to be confused with globular clusters ? huge balls of tens of thousands of ancient stars in orbit around our galaxy and others. It seems that most stars, including our Sun, formed in open clusters. [2] The Coal Sack is a dark nebula in the Southern Hemisphere, near the Southern Cross, that can be seen with the unaided eye. A dark nebula is not the compl

2009-10-01

227

Capability of Thermographic Imaging Defined for Detection in High-Temperature Composite Materials  

NASA Technical Reports Server (NTRS)

Significant effort and resources are being expended to develop ceramic matrix (CMC), metal matrix (MMC), and polymer matrix (PMC) composites for high-temperature engine components and other parts in advanced aircraft. The objective of this NASA Lewis Research Center study was to evaluate the ability of a thermographic imaging technique for detecting artificially created defects (flat-bottom holes) of various diameters and depths in four composite systems (two CMC's, one MMC, and one PMC) of interest as high-temperature structural materials.

Roth, Don J.

1997-01-01

228

Geometric and Colour Data Fusion for Outdoor 3D Models  

PubMed Central

This paper deals with the generation of accurate, dense and coloured 3D models of outdoor scenarios from scanners. This is a challenging research field in which several problems still remain unsolved. In particular, the process of 3D model creation in outdoor scenes may be inefficient if the scene is digitalized under unsuitable technical (specific scanner on-board camera) and environmental (rain, dampness, changing illumination) conditions. We address our research towards the integration of images and range data to produce photorealistic models. Our proposal is based on decoupling the colour integration and geometry reconstruction stages, making them independent and controlled processes. This issue is approached from two different viewpoints. On the one hand, given a complete model (geometry plus texture), we propose a method to modify the original texture provided by the scanner on-board camera with the colour information extracted from external images taken at given moments and under specific environmental conditions. On the other hand, we propose an algorithm to directly assign external images onto the complete geometric model, thus avoiding tedious on-line calibration processes. We present the work conducted on two large Roman archaeological sites dating from the first century A.D., namely, the Theatre of Segobriga and the Fori Porticus of Emerita Augusta, both in Spain. The results obtained demonstrate that our approach could be useful in the digitalization and 3D modelling fields. PMID:22969327

Merchan, Pilar; Adan, Antonio; Salamanca, Santiago; Dominguez, Vicente; Chacon, Ricardo

2012-01-01

229

On the colour of the dark side of the Moon  

E-print Network

Aims. 'Earthshine' is the dim light seen on the otherwise dark side of the Moon, particularly when it is close to new. 'Earthlight', or reflected sunlight from the Earth, is the source of Earthshine. Using B and V band CCD images of both the dark and bright side of the Moon, we aim to estimate the Johnson photometry B-V colour of the Earthshine for the first time since the late 1960s. From these measurements we are also able to quantify the colour of Earthlight. Methods. We present images of the Moon taken with a small refractor in Hawaii, in B and V bands and taken under favourable conditions so that scattered light in both bands almost completely cancels, yielding a map of the surface in B-V colour. Co-addition of 100 such images taken in rapid succession substantially improves the signal to noise ratio, and several sources of photometric bias are eliminated by use of relative methods. Results. The earthlit dark side of the Moon is observed to be 0.150 +/- 0.005 mag bluer in B-V than the sunlit bright side,...

Thejll, Peter; Gleisner, Hans; Andersen, Torben; Ulla, Ana; Owner-Petersen, Mette; Darudi, Ahmad; Schwarz, Henriette

2014-01-01

230

Volume and tissue composition preserving deformation of breast CT images to simulate breast compression in mammographic imaging  

NASA Astrophysics Data System (ADS)

Images of mastectomy breast specimens have been acquired with a bench top experimental Cone beam CT (CBCT) system. The resulting images have been segmented to model an uncompressed breast for simulation of various CBCT techniques. To further simulate conventional or tomosynthesis mammographic imaging for comparison with the CBCT technique, a deformation technique was developed to convert the CT data for an uncompressed breast to a compressed breast without altering the breast volume or regional breast density. With this technique, 3D breast deformation is separated into two 2D deformations in coronal and axial views. To preserve the total breast volume and regional tissue composition, each 2D deformation step was achieved by altering the square pixels into rectangular ones with the pixel areas unchanged and resampling with the original square pixels using bilinear interpolation. The compression was modeled by first stretching the breast in the superior-inferior direction in the coronal view. The image data were first deformed by distorting the voxels with a uniform distortion ratio. These deformed data were then deformed again using distortion ratios varying with the breast thickness and re-sampled. The deformation procedures were applied in the axial view to stretch the breast in the chest wall to nipple direction while shrinking it in the mediolateral to lateral direction re-sampled and converted into data for uniform cubic voxels. Threshold segmentation was applied to the final deformed image data to obtain the 3D compressed breast model. Our results show that the original segmented CBCT image data were successfully converted into those for a compressed breast with the same volume and regional density preserved. Using this compressed breast model, conventional and tomosynthesis mammograms were simulated for comparison with CBCT.

Han, Tao; Chen, Lingyun; Lai, Chao-Jen; Liu, Xinming; Shen, Youtao; Zhong, Yuncheng; Ge, Shuaiping; Yi, Ying; Wang, Tianpeng; Shaw, Chris C.

2009-02-01

231

BOREAS Level-4b AVHRR-LAC Ten-Day Composite Images: At-sensor Radiance  

NASA Technical Reports Server (NTRS)

The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science Satellite Data Acquisition Program focused on providing the research teams with the remotely sensed satellite data products they needed to compare and spatially extend point results. Manitoba Remote Sensing Center (MRSC) and BOREAS Information System (BORIS) personnel acquired, processed, and archived data from the Advanced Very High Resolution Radiometer (AVHRR) instruments on the National Oceanic and Atmospheric Administration (NOAA-11) and -14 satellites. The AVHRR data were acquired by CCRS and were provided to BORIS for use by BOREAS researchers. These AVHRR level-4b data are gridded, 10-day composites of at-sensor radiance values produced from sets of single-day images. Temporally, the 10- day compositing periods begin 11-Apr-1994 and end 10-Sep-1994. Spatially, the data cover the entire BOREAS region. The data are stored in binary image format files.

Cihlar, Josef; Chen, Jing; Nickerson, Jaime; Newcomer, Jeffrey A.; Huang, Feng-Ting; Hall, Forrest G. (Editor)

2000-01-01

232

Simultaneously measuring 3D shape and colour texture of moving objects using IR and colour fringe projection techniques  

NASA Astrophysics Data System (ADS)

Simultaneously measuring the three-dimensional (3D) shape and colour texture of moving objects in real time is becoming increasingly important in many application fields. The existing methods of measuring moving objects have certain disadvantages, such as complicated procedures to build the coordinate transformation between cameras, inaccurate 3D shape data because of the longer capturing time of fringe pattern images, and sensitivity to environmental light due to the projected visible fringe patterns. This paper presents a novel method to capture 3D shape and colour texture information of moving objects simultaneously by combining the infrared (IR) channel and visible channel together. Shape data are calculated from IR fringe patterns to avoid the effect of environmental light on the measured objects. Shape data and colour texture information are simultaneously captured by IR and visible channels of a 2-CCD camera; therefore, these parameters have pixel-to-pixel correspondence without needing any registration. The experimental results on two moving objects indicate that the proposed method can simultaneously obtain 3D shape and colour texture information in a reliable way.

Xu, Y. J.; Chen, C.; Huang, S. J.; Zhang, Z. H.

2014-10-01

233

Field-emission SEM imaging of compositional and doping layer semiconductor superlattices  

Microsoft Academic Search

Field-emission scanning electron microscopy (FE-SEM) has been used to study several semiconductor multilayer heterostructures. Compositional superlattices based on GexSi1?xSi and AlxGa1?xAsGaAs have been studied in both cross-sectional and oblique plan-views after indentation. Secondary and backscattered electron images reveal strong atomic number contrast which is primarily structural in origin. Secondly, for the first time, heterostructures containing n and p doping have

D. D. Perovic; M. R. Castell; A. Howie; C. Lavoie; T. Tiedje; J. S. W. Cole

1995-01-01

234

Adapted list colouring of planar graphs  

Microsoft Academic Search

Given a (possibly improper) edge-colouring F of a graph G, a vertex colour- ing of G is adapted to F if no colour appears at the same time on an edge and on its two endpoints. If for some integer k, a graph G is such that given any list assignment L to the vertices of G, with jL(v)j ‚

Louis Esperet; Mickael Montassiery Xuding Zhuz

235

Comparison of spread spectrum and pulse signal excitation for split spectrum techniques composite imaging  

NASA Astrophysics Data System (ADS)

Ultrasonic imaging of composites was investigated. Glass and carbon fiber reinforced plastic produced by resin transfer molding and prepreg forming were analyzed. In some of the samples air bubbles were trapped during RTM (resin transfer molding) process and interlayer gaps were present in prepreg technology samples. One of the most expected techniques to apply in such case is the Split Spectrum processing. On the other hand such signals require specific processing to reliably reconstruct the temporal position of the defect reflection. Correlation processing can be used for signal compression or Wiener filtering can be applied for spectral content equalisation. Pulse signals are simple to generate, but lack the possibility to alter the signal's spectrum shape. Spread spectrum signals offer a powerful tool for signal energy over frequency band increase and resolution enhancement. CW (continuous wave) burst has high energy but lacks the bandwidth needed for SSP (spread spectrum processing). The aim of the investigation was to compare the performance of the above signals in case of composite imaging, when various Split Spectrum Processing techniques are used with preceding Wiener processing for spectral content compensation. Resulting composite signals and images obtained are presented. Structural noise removal performance was evaluated as Receiver Operating Characteristics (ROC).

Svilainis, L.; Kitov, S.; Rodríguez, A.; Vergara, L.; Dumbrava, V.; Chaziachmetovas, A.

2012-12-01

236

Multi-scale 3D image-based modelling of a carbon/carbon composite  

NASA Astrophysics Data System (ADS)

Detailed thermal and mechanical finite element analyses of woven composites are computationally challenging due to the heterogeneous nature and the geometrical complexity of the composite. In this paper two finite element three-dimensional image-based models at different length scales are used to evaluate the thermal diffusivity and stiffness of a 2D carbon/carbon composite. The micro-scale model was developed from SEM micrographs of the carbon tow whereas the macro-scale model was derived from high resolution x-ray tomographic images of the composite. The micro-scale model predicts thermal conductivities and Young's modulus at the tow scale in the three orthogonal directions (x, y and z). The output results from the micro-scale model are then incorporated in the macro-scale model to obtain through-thickness thermal diffusivity and in-plane Young's modulus. The modelling results are in excellent agreement with the experimental results obtained from the laser flash and tensile tests and the deviations are within the bounds of numerical error of 5%.

Alghamdi, A.; Mummery, P.; Sheikh, M. A.

2013-12-01

237

Myopia and iris colour: a possible connection?  

PubMed

Myopia is a common ocular disease in the world. Its prevalence has increased rapidly worldwide, especially in some East-Asian countries. Genetic factors and environmental factors both affect myopia's onset and its progress. Iris colour is an important characteristic of a person. It is a possible risk factor for myopia by affecting the amount and the colour of light entering eyes. The study of iris colour may contribute to the understanding of myopia mechanism and provide good suggestive evidence for studies on other eye diseases. In this article, the possible connection between myopia and iris colour is proposed. Approaches to dissect any link are suggested. PMID:22465466

Meng, Weihua; Butterworth, Jacqueline; Calvas, Patrick; Malecaze, Francois

2012-06-01

238

Strain measurements and imaging of metal matrix composites using high-energy X-rays  

NASA Astrophysics Data System (ADS)

Metal matrix composites (MMCs) are of technological importance for a variety of applications [1, 2]. One important aspect of MMCs is their unique mechanical behavior, which is controlled by the load transfer occurring between matrix and reinforcement. Load transfer is affected by the mismatch in stiffness between matrix and reinforcement, by plastic deformation of the metallic matrix and by damage of the ceramic reinforcement or its interface with the matrix. The goal of this thesis is to study the micromechanics of load transfer in MMC by a combination of x-ray diffraction and imaging, using high-energy synchrotron x-rays in conjunction with in-situ mechanical loading. Diffraction was used for direct measurements of internal elastic strains of all phases within the bulk (rather than near surface) of MMCs during in-situ mechanical loading. Imaging was done using an edge-enhanced, phase-contrast technique providing high spatial resolution radiographic images providing insight into the macro- and micro-mechanical evolution of damage. Three MMC systems with widely different architectures, composition, and end-use were studied: ultrahigh-carbon steels, superconducting fiber composites, and co-continuous composites. First, ultrahigh-carbon steels exhibiting spherical Fe3C particles in a Fe matrix are characterized by no load transfer in the elastic range, followed by marked load transfer in the plastic range of the matrix. Second, superconducting composites consisting of continuous MgB2 fibers in a Mg matrix show mostly elastic (and somewhat plastic) load transfer from matrix to reinforcement, which is complicated by the presence of cracks and a WB4 core in the fibers. Finally, a complex three-dimensional (3-D) Al2O3 preform infiltrated with an Al matrix, like the superconducting composites, show mostly elastic load transfer from matrix to reinforcement. For the latter two composites, differences were found between average bulk measurements and spatially-resolved measurements. Predictions from analytical models (based on rule-of-mixture) and numerical models (based on the finite-element method) are compared with experimental strain measurements.

Young, Marcus L.

239

Occupational colour vision requirements for police officers.  

PubMed

Inclusion of public service professions in the UK Disability Discrimination Act in 2004 prompted a review of occupational colour vision requirements for police officers. Changes in the regulations which existed prior to 2003 were proposed. The aim of this study was to obtain the views of serving police officers in Northern Ireland on the importance of good colour discrimination in everyday police work and on the recruitment regulations for patrol constables introduced in 2003 in mainland UK. These views were obtained by means of a questionnaire and informal discussions. More than 65% of police officers who responded to the questionnaire considered that good colour vision was very important for effective policing. Fewer than 2% considered that colour vision was unimportant. Experienced police officers agreed that the employment of colour-deficient patrol constables, as permitted in the new regulations, would lead to reduced efficiency and organisational difficulties at the local level. A number of everyday activities were described which showed the need for accurate colour discrimination. The change in recruitment policy and the lack of clarity in the new regulations show inadequate appreciation of the needs of the occupation, of different types of colour vision anomalies and of the diagnostic function of colour vision tests. Failure to provide guidance on appropriate colour vision tests, examination procedures and counselling services is likely to result in inconsistent employment policies in different police forces. It is recommended that the colour vision standard in place prior to 2003 is reinstated at the recruitment stage. The Ishihara test should be used for screening, and colour-deficient applicants further examined with the Farnsworth D15 test as a replacement for the City University Test 2nd edition. PMID:19076554

Birch, Jennifer; Chisholm, Catharine M

2008-11-01

240

Combining 3D optical imaging and dual energy absorptiometry to measure three compositional components  

PubMed Central

We report on the design of the technique combining 3D optical imaging and dual-energy absorptiometry body scanning to estimate local body area compositions of three compartments. Dual-energy attenuation and body shape measures are used together to solve for the three compositional tissue thicknesses: water, lipid, and protein. We designed phantoms with tissue-like properties as our reference standards for calibration purposes. The calibration was created by fitting phantom values using non-linear regression of quadratic and truncated polynomials. Dual-energy measurements were performed on tissue-mimicking phantoms using a bone densitometer unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the biological compositional compartments. The components for the solid phantom were tested and their high energy/low energy attenuation ratios are in good correspondent to water, lipid, and protein for the densitometer x-ray region. The three-dimensional body shape was reconstructed from the depth maps generated by Microsoft Kinect for Windows. We used open-source Point Cloud Library and freeware software to produce dense point clouds. Accuracy and precision of compositional and thickness measures were calculated. The error contributions due to two modalities were estimated. The preliminary phantom composition and shape measurements are found to demonstrate the feasibility of the method proposed. PMID:25083118

Malkov, Serghei; Shepherd, John

2014-01-01

241

Novel Recognition Method of Blast Furnace Dust Composition by Multifeature Analysis Based on Comprehensive Image-Processing Techniques  

NASA Astrophysics Data System (ADS)

The traditional artificial recognition methods for the blast furnace dust composition have several disadvantages, including a great deal of information to dispose, complex operation, and low working efficiency. In this article, a multifeature analysis method based on comprehensive image-processing techniques was proposed to automatically recognize the blast furnace dust composition. First, the artificial recognition and feature analysis, which included image preprocessing, Harris corner feature, Canny edge feature, and Ruffle feature analysis, was designed to build the template image, so that any unknown dust digital image could be tested. Second, the composition of coke, microvariation pulverized coal, vitric, ash, and iron from dust would be distinguished according to their different range of values based on the multifeature analysis. The method is valid for recognizing the blast furnace dust composition automatically, and it is fast and has a high recognition accuracy.

Guo, Hongwei; Su, Buxin; Bai, Zhenlong; Zhang, Jianliang; Li, Xinyu

2014-09-01

242

Novel Recognition Method of Blast Furnace Dust Composition by Multifeature Analysis Based on Comprehensive Image-Processing Techniques  

NASA Astrophysics Data System (ADS)

The traditional artificial recognition methods for the blast furnace dust composition have several disadvantages, including a great deal of information to dispose, complex operation, and low working efficiency. In this article, a multifeature analysis method based on comprehensive image-processing techniques was proposed to automatically recognize the blast furnace dust composition. First, the artificial recognition and feature analysis, which included image preprocessing, Harris corner feature, Canny edge feature, and Ruffle feature analysis, was designed to build the template image, so that any unknown dust digital image could be tested. Second, the composition of coke, microvariation pulverized coal, vitric, ash, and iron from dust would be distinguished according to their different range of values based on the multifeature analysis. The method is valid for recognizing the blast furnace dust composition automatically, and it is fast and has a high recognition accuracy.

Guo, Hongwei; Su, Buxin; Bai, Zhenlong; Zhang, Jianliang; Li, Xinyu

2014-11-01

243

The Impact of Biochemistry vs. Population Membership on Floral Scent Profiles in Colour Polymorphic Hesperis matronalis  

PubMed Central

Background and Aims Studies of floral scent evolution often attribute variation in floral scent to differences in pollinator behaviour, ignoring the potential for shared biochemistry between floral scent and floral colour to dictate patterns of phenotypic variation in scent production. To determine the relative effects of shared biochemistry and/or localized population-level phenomena on floral scent phenotype, floral scent composition and emission rate were examined in five wild populations of colour polymorphic Hesperis matronalis (Brassicaceae). Methods Floral scent was collected by in situ dynamic headspace extraction on purple and white colour morphs in each of five wild populations. Gas chromatography–mass spectroscopy of extracts allowed determination of floral scent composition and emission rate for all individuals, which were examined by non-metric multidimensional scaling and analysis of variance (ANOVA), respectively, to determine the contributions of floral colour and population membership to scent profile variation. Key Results Despite the fact that colour morph means were very similar in some populations and quite different in other populations, colour morphs within populations did not differ from each other in terms of scent composition or emission rate. Populations differed significantly from one another in terms of both floral scent composition and emission rate. Conclusions Shared biochemistry alone cannot explain the variation in floral scent phenotype found for H. matronalis. Such a result may suggest that the biochemical association between floral scent and floral colour is complex or dependent on genetic background. Floral scent does vary significantly with population membership; several factors, including environmental conditions, founder effects and genetics, may account for this differentiation and should be considered in future studies. PMID:18819948

Majetic, Cassie J.; Raguso, Robert A.; Ashman, Tia-Lynn

2008-01-01

244

Colour Mathematics: With Graphs and Numbers  

ERIC Educational Resources Information Center

The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just…

LoPresto, Michael C.

2009-01-01

245

Pigment chemistry and colour of Pelargonium flowers  

Microsoft Academic Search

The major factors responsible for colour variation in a range of Pelargonium species and cultivars were shown to be the types and relative levels of pigments present. Variations in pH and copigment levels were not found to contribute significantly. Flowers with colours ranging from cream and pink through to deep purple, including salmon, orange and red, were studied. While either

Kevin A. Mitchell; Kenneth R. Markham; Murray R. Boase

1998-01-01

246

Mineralization in Rust-coloured Acarospora  

Microsoft Academic Search

The upper cortex and extracellular hyphal wall matrix are mineralized in both rust-coloured Acarospora sinopica and the paler A. smaragdula ‘f. subochracea’ in the form of microgranular or microbotryoidal phases. Analysis confirmed the distinctive colours are not simply due to hydrated iron oxides, as previously believed, and suggests mixed sulphide and oxide phases with little crystallinity, as well as other

O. William Purvis; Anton Kearsley; Gordon Cressey; Anna T. Crewe; Mats Wedin

2008-01-01

247

Visual Star Colours from Instrumental Photometry  

NASA Astrophysics Data System (ADS)

In order to display graphically the visual colours of stars and other astronomical objects, photometric broadband R, V, B colours are used to proxy for the r, g, b colours of the three visual sensors of the eye. From photometric Johnson B-V and V-R colour indices, R, V, and B magnitudes (V = 0) are calculated, and from these the respective brightnesses (r, v = 1 = g, and b) are calculated. After suitable normalization these are then placed in a ternary diagram having r, g, and b as the vertices. All B-V and V-R are adjusted so that the Sun falls in the same place as a blackbody at 5800 K. The resulting ternary plot shows all of its objects (stars, planets) in their visual colours at their relative positions in the ternary diagram. The star colours displayed on a computer monitor screen or as a print with a colour printer are more vivid than the usual visual impressions of isolated stars, undoubtedly because of properties of the dark-adapted eye, but double-star pairs with contrasting colours correspond nicely to telescopic visual impressions.

Kohman, Truman P.

2005-06-01

248

An incomplete Kochen-Specker colouring  

Microsoft Academic Search

A particular incomplete Kochen-Specker colouring, suggested by Appleby in dimension three, is generalized to arbitrary dimension. We investigate its effectivity as a function of dimension, using two different measures. A limit is derived for the fraction of the sphere that can be coloured using the generalized Appleby construction as the number of dimensions approaches infinity. The second, and physically more

Helena Granstrom

249

Vertex Colouring and Forbidden Subgraphs - A Survey  

Microsoft Academic Search

There is a great variety of colouring concepts and results in the literature. Here our focus is to survey results on vertex colourings of graphs defined in terms of forbidden induced subgraph conditions. Thus, one who wishes to obtain useful results from a graph coloring formulation of his problem must do more than just show that the problem is equivalent

Bert Randerath; Ingo Schiermeyer

2004-01-01

250

Generalized Colourings (Matrix Partitions) of Cographs  

Microsoft Academic Search

Ordinary colourings of cographs are well understood; we focus on more general colourings, known as matrix partitions. We show that all matrix partition problems for cographs admit polynomial time algorithms and forbidden induced subgraph characterizations, even for the list version of the problems. Cographs are the largest natural class of graphs that have been shown to have this property. We

Tomás Feder; Pavol Hell; Winfried Hochstättler

251

DIFFRACTION: QCD EFFECTS IN COLOUR SINGLET EXCHANGE  

E-print Network

DIFFRACTION: QCD EFFECTS IN COLOUR SINGLET EXCHANGE Anthony T. Doyle \\Lambda Department of Physics and the Tevatron are reviewed. A short introduction to the theoretical background is presented where colour singlet and the four­momentum transfer at the proton vertex, given by t = (P \\Gamma P 0 ) 2 . Fig. 1. Kinematic

Glasgow, University of

252

Skin colour and bilirubin in neonates  

Microsoft Academic Search

The correlation between the yellow colour of the skin and serum bilirubin concentration, reserve albumin concentration, and pH was investigated in 76 icteric neonates. Significant linear correlation existed between yellow colour of the skin and serum bilirubin concentration, reciprocal of the reserve albumin concentration, and the squared hydrogen ion concentration. Furthermore, the basic yellowness of the skin at birth correlated

A Knudsen; R Brodersen

1989-01-01

253

Colour polymorphism in birds: causes and functions  

Microsoft Academic Search

We studied polymorphism in all species of birds that are presently known to show intraspecific variation in plumage colour. At least three main mecha- nisms have been put forward to explain the maintenance of polymorphism: apostatic, disruptive and sexual selection. All of them make partly different predictions. Our aims were to investigate evolutionary causes and adaptive functions of colour polymorphism

P. Galeotti; D. Rubolini; P. O. Dunn; M. Fasola

2003-01-01

254

Brilliant Colours from a White Snow Cover  

ERIC Educational Resources Information Center

Surprisingly colourful views are possible from sparkling white snow. It is well known that similarly colourful features can exist in the sky whenever appropriate ice crystals are around. However, the transition of light reflection and refraction from ice crystals in the air to reflection and refraction from those in snow on the ground is not…

Vollmer, Michael; Shaw, Joseph A

2013-01-01

255

PROGRESS ON DEVELOPING SONIC INFRARED IMAGING FOR DEFECT DETECTION IN COMPOSITE STRUCTURES  

SciTech Connect

At last year's QNDE conference, we presented our development of Sonic IR imaging technology in metal structures, with results from both experimental studies and theoretical computing. In the latest aircraft designs, such as the B787 from Boeing, composites have become the major materials in structures such as the fuselage and wings. This is in contrast to composites' use only in auxiliary components such as flaps and spoilers in the past. With today's advanced technology of fabrication, it is expected the new materials can be put in use in even more aircraft structures due to its light weight and high strength (high strength-to-weight ratio), high specific stiffness, tailorability of properties, design flexibility etc. Especially, with increases in fuel cost, reducing the aircraft's body weight becomes more and more appealing. In this presentation, we describe the progress on our development of Sonic IR imaging for aircraft composite structures. In particular, we describe the some unexpected results discovered while modeling delaminations. These results were later experimentally verified with an engineered delamination.

Han Xiaoyan; He Qi; Li Wei [Department of Electrical and Computer Engineering, Institute for Manufacturing Research Wayne State University, Detroit, MI 48202 (United States); Newaz, Golam; Favro, Lawrence D. [Institute for Manufacturing Research Wayne State University, Detroit, MI 48202 (United States); Thomas, Robert L. [Department of Physics and Astronomy, Institute for Manufacturing Research Wayne State University, Detroit, MI 48202 (United States)

2010-02-22

256

Limits of colour vision in dim light.  

PubMed

Humans and most vertebrates have duplex retinae with multiple cone types for colour vision in bright light, and one single rod type for achromatic vision in dim light. Instead of comparing signals from multiple spectral types of photoreceptors, such species use one highly sensitive receptor type thus improving the signal-to-noise ratio at night. However, the nocturnal hawkmoth Deilephila elpenor, the nocturnal bee Xylocopa tranquebarica and the nocturnal gecko Tarentola chazaliae can discriminate colours at extremely dim light intensities. To be able to do so, they sacrifice spatial and temporal resolution in favour of colour vision. We review what is known about colour vision in dim light, and compare colour vision thresholds with the optical sensitivity of the photoreceptors in selected animal species with lens and compound eyes. PMID:20883328

Kelber, Almut; Lind, Olle

2010-09-01

257

Digital colour tone for fluorescence sensing: a direct comparison of intensity, ratiometric and hue based quantification.  

PubMed

The hue parameter of HSV colour-space for digital imaging is shown to be accessible for convenient quantitative fluorescence imaging. A commercially available pH probe was utilized in solution and incorporated into optical ?-sensors for microscopy applications. PMID:24603672

Hakonen, Aron; Beves, Jonathon E; Strömberg, Niklas

2014-07-21

258

Colour in insect thermoregulation: empirical and theoretical tests in the colour-changing grasshopper, Kosciuscola tristis.  

PubMed

Body colours can result in different internal body temperatures, but evidence for the biological significance of colour-induced temperature differences is inconsistent. We investigated the relationship between body colour and temperature in a model insect species that rapidly changes colour. We used an empirical approach and constructed a heat budget model to quantify whether a colour change from black to turquoise has a role in thermoregulation for the chameleon grasshopper (Kosciuscola tristis). Our study shows that colour change in K. tristis provides relatively small temperature differences that vary greatly with wind speed (0.55 °C at ms(-1) to 0.05 °C at 10 ms(-1)). The biological significance of this difference is unclear and we discuss the requirement for more studies that directly test hypotheses regarding the fitness effects of colour in manipulating body temperature. PMID:23108152

Umbers, K D L; Herberstein, M E; Madin, J S

2013-01-01

259

Arnheim's Gestalt theory of visual balance: Examining the compositional structure of art photographs and abstract images  

PubMed Central

In Art and Visual Perception, Rudolf Arnheim, following on from Denman Ross's A Theory of Pure Design, proposed a Gestalt theory of visual composition. The current paper assesses a physicalist interpretation of Arnheim's theory, calculating an image's centre of mass (CoM). Three types of data are used: a large, representative collection of art photographs of recognised quality; croppings by experts and non-experts of photographs; and Ross and Arnheim's procedure of placing a frame around objects such as Arnheim's two black disks. Compared with control images, the CoM of art photographs was closer to an axis (horizontal, vertical, or diagonal), as was the case for photographic croppings. However, stronger, within-image, paired comparison studies, comparing art photographs with the CoM moved on or off an axis (the ‘gamma-ramp study’), or comparing adjacent croppings on or off an axis (the ‘spider-web study’), showed no support for the Arnheim–Ross theory. Finally, studies moving a frame around two disks, of different size, greyness, or background, did not support Arnheim's Gestalt theory. Although the detailed results did not support the Arnheim–Ross theory, several significant results were found which clearly require explanation by any adequate theory of the aesthetics of visual composition. PMID:23145250

McManus, I C; Stover, Katharina; Kim, Do

2011-01-01

260

Genetics of colour traits in common vetch ( Vicia sativa L.)  

Microsoft Academic Search

Five parents of common vetch (Vicia sativa L.) having orange\\/beige cotyledon colour, brown\\/white testa colour, purple\\/green seedling colour and purple\\/white flower colour were crossed as a full diallele set. The inheritance patterns of cotyledon, testa or seed coat colour, flower and seedling colour, were studied by analyzing their F1, F2, BC1 and BC2 generations. The segregation pattern in F2, BC1

Doza M. S. Chowdhury; Jane M. Rathjen; Max E. Tate; Glenn McDonald

2004-01-01

261

Colour-magnitude diagrams of transiting Exoplanets - II. A larger sample from photometric distances  

E-print Network

Colour-magnitude diagrams form a traditional way of presenting luminous objects in the Universe and compare them to each others. Here, we estimate the photometric distance of 44 transiting exoplanetary systems. Parallaxes for seven systems confirm our methodology. Combining those measurements with fluxes obtained while planets were occulted by their host stars, we compose colour-magnitude diagrams in the near and mid-infrared. When possible, planets are plotted alongside very low-mass stars and field brown dwarfs, who often share similar sizes and equilibrium temperatures. They offer a natural, empirical, comparison sample. We also include directly imaged exoplanets and the expected loci of pure blackbodies. Irradiated planets do not match blackbodies; their emission spectra are not featureless. For a given luminosity, hot Jupiters' daysides show a larger variety in colour than brown dwarfs do and display an increasing diversity in colour with decreasing intrinsic luminosity. The presence of an extra absorben...

Triaud, Amaury H M J; Smalley, Barry; Gillon, Michael

2014-01-01

262

Modeling dental composite shrinkage by digital image correlation and finite element methods  

NASA Astrophysics Data System (ADS)

Dental composites are light-curable resin-based materials with an inherent defect of polymerization shrinkage which may cause tooth deflection and debonding of restorations. This study aimed to combine digital image correlation (DIC) and finite element analysis (FEA) to model the shrinkage behaviors under different light curing regimens. Extracted human molars were prepared with proximal cavities for composite restorations, and then divided into three groups to receive different light curing protocols: regular intensity, low intensity, and step-curing consisting of low and high intensities. For each tooth, the composite fillings were consecutively placed under both unbonded and bonded conditions. At first, the shrinkage of the unbonded restorations was analyzed by DIC and adopted as the setting of FEA. The simulated shrinkage behaviors obtained from FEA were further validated by the measurements in the bonded cases. The results showed that different light curing regimens affected the shrinkage in unbonded restorations, with regular intensity showing the greatest shrinkage strain on the top surface. The shrinkage centers in the bonded cases were located closer to the cavity floor than those in the unbonded cases, and were less affected by curing regimens. The FEA results showed that the stress was modulated by the accumulated light energy density, while step-curing may alleviate the tensile stress along the cavity walls. In this study, DIC provides a complete description of the polymerization shrinkage behaviors of dental composites, which may facilitate the stress analysis in the numerical investigation.

Chen, Terry Yuan-Fang; Huang, Pin-Sheng; Chuang, Shu-Fen

2014-10-01

263

Nanoscale Imaging of Mineral Crystals inside Biological Composite Materials Using X-Ray Diffraction Microscopy  

NASA Astrophysics Data System (ADS)

We for the first time applied x-ray diffraction microscopy to the imaging of mineral crystals inside biological composite materials—intramuscular fish bone—at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization. Based on the experimental results and biomineralization analyses, we suggested a dynamic model to account for the nucleation and growth of mineral crystals in the collagen matrix. The results obtained from this study not only further our understanding of the complex structure of bone, but also demonstrate that x-ray diffraction microscopy will become an important tool to study biological materials.

Jiang, Huaidong; Ramunno-Johnson, Damien; Song, Changyong; Amirbekian, Bagrat; Kohmura, Yoshiki; Nishino, Yoshinori; Takahashi, Yukio; Ishikawa, Tetsuya; Miao, Jianwei

2008-01-01

264

Using composite images to assess accuracy in personality attribution to faces.  

PubMed

Several studies have demonstrated some accuracy in personality attribution using only visual appearance. Using composite images of those scoring high and low on a particular trait, the current study shows that judges perform better than chance in guessing others' personality, particularly for the traits conscientiousness and extraversion. This study also shows that attractiveness, masculinity and age may all provide cues to assess personality accurately and that accuracy is affected by the sex of both of those judging and being judged. Individuals do perform better than chance at guessing another's personality from only facial information, providing some support for the popular belief that it is possible to assess accurately personality from faces. PMID:17319053

Little, Anthony C; Perrett, David I

2007-02-01

265

Physicochemical and physiological basis of dichromatic colour  

NASA Astrophysics Data System (ADS)

Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here, we report that evident change of the hue of the colour (i.e., from green to red) is due to a change in concentration or the thickness of a layer in some exceptional substances such as pumpkin seed oil or an aqueous solution of bromophenol blue. In some regions of Central Europe, salad dressing is made preferably with the pumpkin seed oil, which has a strong characteristic nut-like taste and remarkable properties of the colour: it appears red in a bottle, but green when served as a salad dressing. The colour of the pumpkin seed oil was previously described as brownish yellow, dark green, dark green to red ochre or dark reddish brown to light yellow green. We elucidated the physicochemical and physiological basis of such dichromatism by Beer-Lambert law and by the characteristics of human colour perception. Our concept was corroborated by the outcome of calculations of colour from spectral properties using colour matching functions. We found that dichromatism is observed if the absorption spectrum of any substance has at least two local minima: one wide but shallow and one narrow but deep local minimum.

Kreft, Samo; Kreft, Marko

2007-11-01

266

Biological components of colour preference in infancy.  

PubMed

Adult colour preference has been summarized quantitatively in terms of weights on the two fundamental neural processes that underlie early colour encoding: the S-(L+M) ('blue-yellow') and L-M ('red-green') cone-opponent contrast channels (Ling, Hurlbert & Robinson, 2006; Hurlbert & Ling, 2007). Here, we investigate whether colour preference in 4-5-month-olds may be analysed in the same way. We recorded infants' eye-movements in response to pairwise presentations of eight colour stimuli varying only in hue. Infants looked longest at reddish and shortest at greenish hues. Analyses revealed that the L-M and S-(L+M) contrast between stimulus colour and background explained around half of the variation in infant preference across the hue spectrum. Unlike adult colour preference patterns, there was no evidence for sex differences in the weights on either of the cone-opponent contrast components. The findings provide a quantitative model of infant colour preference that summarizes variation in infant preference across hues. PMID:20136931

Franklin, Anna; Bevis, Laura; Ling, Yazhu; Hurlbert, Anya

2010-03-01

267

Colour and lighting in hospital design  

NASA Astrophysics Data System (ADS)

Little information or guidance has been available to assist the development of a hospital's visual environment. A report on lighting and colour design schemes, accessible to non professionals with responsibility for refurbishment strategies, was required by NHS Estates. Firstly, 20 hospitals were audited to establish a picture of current practice and to identify key issues where colour design could broadly enhance the environment for patients, staff and visitors. Critical areas were outlined in this report, where colour design can be utilised and applied, for the benefit of all users, from ambience to essential legal requirements such as colour contrast for the visually impaired. Provision of staff relaxation rooms that are different in terms of colour and lux levels from immediate work spaces, or thoughtfully designed areas for patients awaiting intensive treatment, have been shown to have some beneficial effects on a sense of well being. Colour and design have not been established as a definite cure for sickness and ill health, but certainly monotony and poor conditions in premises that have not been refurbished with any care, have had a detrimental affect on recovery rates and staff morale. The realisation that a well balanced and attractive environment is of major importance to patients' health is, in no way new; Florence Nightingale observed that 'a variety of form and brilliance of colour in the objects presented to patients are an actual means of recovery'.

Dalke, Hilary; Little, Jenny; Niemann, Elga; Camgoz, Nilgun; Steadman, Guillaume; Hill, Sarah; Stott, Laura

2006-06-01

268

Evaluation of the quality of image for various breast composition and exposure conditions in digital mammography  

NASA Astrophysics Data System (ADS)

Breast density has a close relationship with breast cancer risk. The exposure parameters must be appropriately chosen for each breast. However, the optimal exposure conditions for digital mammography are uncertain in clinical. The exposure parameters in digital mammography must be optimized with maximization of image quality and minimization of radiation dose. We evaluated image quality under different exposure conditions to investigate the most advantageous tube voltage. For different compressed breast phantom thicknesses and compositions, we measured the Wiener spectrum (WS), noise-equivalent number of quanta (NEQ), and detective quantum efficiency (DQE). In this study, the signal-to-noise ratios were derived from a perceived statistical decision theory model with the internal noise of eye-brain system (SNRi), contrived and studied by Loo et al.1 and Ishida et al.2 These were calculated under a fixed average glandular dose. The WS values were obtained with a fixed image contrast. For 4-cm-thick and 50% glandular breast phantoms, the NEQ showed that high voltages gave a superior noise property of images, especially for thick breasts, but the improvement in the NEQ by tube voltage was not so remarkable. On the other hand, the SNRi value with a Mo filter was larger than that with a Rh filter. The SNRi increased when the tube voltage decreased. The result differed from those of WS and NEQ. In this study, the SNRi depended on the contrast of signal. Accuracy should be high with an intense, low-contrast object.

Yamada, Maki; Kato, Yuri; Fujita, Naotoshi; Kodera, Yoshie

2011-03-01

269

Colouration and Colour Changes of the Fiddler Crab, Uca capricornis: A Descriptive Study  

PubMed Central

Colour changes in animals may be triggered by a variety of social and environmental factors and may occur over a matter of seconds or months. Crustaceans, like fiddler crabs (genus Uca), are particularly adept at changing their colour and have been the focus of numerous studies. However, few of these studies have attempted to quantitatively describe the individual variation in colour and pattern or their adaptive significance. This paper quantitatively describes the colour patterns of the fiddler crab Uca capricornis and their ability to change on a socially significant timescale. The most dramatic changes in colour pattern are associated with moulting. These ontogenetic changes result in a general reduction of the colour pattern with increasing size, although females are more colourful and variable than similarly-sized males. Uca capricornis are also capable of rapid colour changes in response to stress, but show no endogenous rhythms associated with the semilunar and tidal cycles commonly reported in other fiddler crabs. The extreme colour polymorphism and the relative stability of the colour patterns in Uca capricornis are consistent with their use in visually mediated mate recognition. PMID:18286186

Detto, Tanya; Hemmi, Jan M.; Backwell, Patricia R. Y.

2008-01-01

270

Bleeding detection in wireless capsule endoscopy using adaptive colour histogram model and support vector classification  

NASA Astrophysics Data System (ADS)

Wireless Capsule Endoscopy (WCE) is a colour imaging technology that enables detailed examination of the interior of the gastrointestinal tract. A typical WCE examination takes ~ 8 hours and captures ~ 40,000 useful images. After the examination, the images are viewed as a video sequence, which generally takes a clinician over an hour to analyse. The manufacturers of the WCE provide certain automatic image analysis functions e.g. Given Imaging offers in their Rapid Reader software: The Suspected Blood Indicator (SBI), which is designed to report the location in the video of areas of active bleeding. However, this tool has been reported to have insufficient specificity and sensitivity. Therefore it does not free the specialist from reviewing the entire footage and was suggested only to be used as a fast screening tool. In this paper we propose a method of bleeding detection that uses in its first stage Hue-Saturation-Intensity colour histograms to track a moving background and bleeding colour distributions over time. Such an approach addresses the problem caused by drastic changes in blood colour distribution that occur when it is altered by gastrointestinal fluids and allow detection of other red lesions, which although are usually "less red" than fresh bleeding, they can still be detected when the difference between their colour distributions and the background is large enough. In the second stage of our method, we analyse all candidate blood frames, by extracting colour (HSI) and texture (LBP) features from the suspicious image regions (obtained in the first stage) and their neighbourhoods and classifying them using Support Vector Classifier into Bleeding, Lesion and Normal classes. We show that our algorithm compares favourably with the SBI on the test set of 84 full length videos.

Mackiewicz, Michal W.; Fisher, Mark; Jamieson, Crawford

2008-03-01

271

Segregated Optical-NIR colour distributions of MDS galaxies  

E-print Network

We present a K survey of 29 fields covering approximately 90 arcmin^2 from the Medium Deep Survey (MDS) catalogue down to a completeness magnitude of K=18.0 (limiting magnitude K=19.0). The morphology obtained by the MDS team using high resolution images from HST/WFPC2 along with our NIR observations allow a Colour-Magnitude and Colour-Colour analysis that agrees in general with spectral evolution models (Bruzual & Charlot 1998) especially if a reasonable range of metallicities for the Simple Stellar Populations used (0.2 signal the existence of non-negligible star formation in ellipticals and bulges at medium redshift. A number counts calculation for different morphological types show disks become the dominant population at faint magnitudes. The median redshift of the sample is z~0.2, from a photometric redshift estimation using V-K and I-K. A search for EROs in the survey field was also performed, with no detection of objects having I-K > 4.5, setting an upper limit to the number density of EROs at dn_{EROs}/d\\Omega < 0.011 arcmin^{-2} (K < 18.0).

I. Ferreras; L. Cayon; E. Martinez-Gonzalez; N. Benitez; .

1998-10-14

272

Microscopic image analysis for quantitative characterization of muscle fiber type composition.  

PubMed

Skeletal muscles consist of muscle fibers that are responsible for contracting and generating force. Skeletal muscle fibers are categorized into distinct subtypes based on several characteristics such as contraction time, force production and resistance to fatigue. The composition of distinct muscle fibers in terms of their number and cross-sectional areas is characterized by a histological examination. However, manual delineation of individual muscle fibers from digitized muscle histology tissue sections is extremely time-consuming. In this study, we propose an automated image analysis system for quantitative characterization of muscle fiber type composition. The proposed system operates on digitized histological muscle tissue slides and consists of the following steps: segmentation of muscle fibers, registration of successive slides with distinct stains, and classification of muscle fibers into distinct subtypes. The performance of the proposed approach was tested on a dataset consisting of 25 image pairs of successive muscle histological cross-sections with different ATPase stain. Experimental results demonstrate a promising overall segmentation and classification accuracy of 89.1% in identifying muscle fibers of distinct subtypes. PMID:21342753

Sertel, Olcay; Dogdas, Belma; Chiu, Chi Sung; Gurcan, Metin N

2011-01-01

273

High-speed hyperspectral Raman imaging for label-free compositional microanalysis  

PubMed Central

We present high-speed hyperspectral Raman imaging with integrated active-illumination for label-free compositional microanalysis. We show that high-quality Raman spectra can be acquired from as many as ~1,000 spots/sec semi-randomly distributed among a ~100x100 ?m2 area without mechanical scanning. We demonstrate rapid data acquisition from three types of samples: 1) uniform, strong Raman scatterers, e.g., silicon substrates; 2) non-uniform, medium-strength Raman scatterers, e.g., polymer microparticles; and, 3) non-uniform, relatively weak Raman scatterers, e.g., bacterial spores. We compare the system performance to that of point-scan with an electron-multiplied CCD camera, as implemented in some commercial systems. The results suggest that our system not only provides significant imaging speed advantage for various types of samples, but also permits substantially longer integration time per spot, leading to superior signal-to-noise ratio data. Our system enables the rapid collection of high quality Raman spectra for reliable and robust compositional microanalysis that are potentially transformative in applications such as semiconductor material and device, polymer blend and biomedicine. PMID:24298401

Qi, Ji; Li, Jingting; Shih, Wei-Chuan

2013-01-01

274

Micro-measurements of mechanical properties for adhesives and composites using digital imaging technology  

NASA Technical Reports Server (NTRS)

The need for a constituent based durability or accelerated life prediction procedure to be used for the engineering design of polymer matrix composites is discussed in the light of current plans for the High Speed Civil Transport (HSCT) concerns about the U.S. infrastructure (bridges, pipelines, etc.) and other technological considerations of national concern. It is pointed out that good measurement procedures for insitu resin properties are needed for both adhesives and composites. A double cantilever beam (DCB) specimen which shows promise for the easy determination of adhesive shear properties is presented and compared with measurements of strains within the bondline using a new optical digital imaging micro-measurement system (DIMMS). The DCB specimen is also used to assess damage in a bonded joint using a dynamic mechanical thermal analysis system (DMTA). The possible utilization of the same DIMMS and DMTA procedures to determine the insitu properties of the resin in a composite specimen are discussed as well as the use of the procedures to evaluate long term mechanical and physical aging. Finally, a discussion on the state-of-the art of the measurement of strains in micron and sub-micron domains is given.

Brinson, Hal F.

1994-01-01

275

Blending of animal colour patterns by hybridization  

PubMed Central

Biologists have long been fascinated by the amazing diversity of animal colour patterns. Despite much interest, the underlying evolutionary and developmental mechanisms contributing to their rich variety remain largely unknown, especially the vivid and complex colour patterns seen in vertebrates. Here, we show that complex and camouflaged animal markings can be formed by the 'blending' of simple colour patterns. A mathematical model predicts that crossing between animals having inverted spot patterns (for example, 'light spots on a dark background' and 'dark spots on a light background') will necessarily result in hybrid offspring that have camouflaged labyrinthine patterns as 'blended' intermediate phenotypes. We confirmed the broad applicability of the model prediction by empirical examination of natural and artificial hybrids of salmonid fish. Our results suggest an unexplored evolutionary process by means of 'pattern blending', as one of the possible mechanisms underlying colour pattern diversity and hybrid speciation. PMID:20842190

Miyazawa, Seita; Okamoto, Michitoshi; Kondo, Shigeru

2010-01-01

276

Determining thermal diffusivity and defect attributes in ceramic matrix composites by infrared imaging.  

SciTech Connect

Ceramic matrix composites are being developed for numerous high temperature applications, including rotors and combustors for advanced turbine engines, heat exchanger and hot-gas filters for coal gasification plants. Among the materials of interest are silicon-carbide-fiber-reinforced-silicon-carbide (SiC{sub (f)}/SiC), silicon-carbide-fiber-reinforced-silicon-nitride (SiC{sub (f)}/Si{sub 3}N{sub 4}), aluminum-oxide-reinforced-alumina (Al{sub 2}O{sub 3(f)}/Al{sub 2}O{sub 3}), etc. In the manufacturing of these ceramic composites, the conditions of the fiber/matrix interface are critical to the mechanical and thermal behavior of the component. Defects such as delaminations and non-uniform porosity can directly effect the performance. A nondestructive evaluation (NDE) method, developed at Argonne National Laboratory has proved beneficial in analyzing as-processed conditions and defect detection created during manufacturing. This NDE method uses infrared thermal imaging for fill-field quantitative measurement of the distribution of thermal diffusivity in large components. Intensity transform algorithms have been used for contrast enhancement of the output image. Nonuniformity correction and automatic gain control are used to dynamically optimize video contrast and brightness, providing additional resolution in the acquired images. Digital filtering, interpolation, and least-squares-estimation techniques have been incorporated for noise reduction and data acquisition. The Argonne NDE system has been utilized to determine thermal shock damage, density variations, and variations in fiber coating in a full array of test specimens.

Ahuja, S.; Ellingson, W. A.; Koehl, E. R.; Stuckey, J.

1997-12-05

277

Tracking colour objects using adaptive mixture models  

Microsoft Academic Search

Abstract The use of adaptive Gaussian mixtures to model the colour distributions of objects is described. These models are used to perform robust, real-time tracking under varying illumination, viewing geometry and camera parameters. Observed log-likelihood measurements were used to perform selective adaptation. q,1999 Elsevier Science B.V. All rights reserved. Keywords: Real-time tracking; Colour model; Gaussian mixture model; Adaptive learning

Stephen J. Mckenna; Yogesh Raja; Shaogang Gong

1999-01-01

278

Plants and colour: Flowers and pollination  

NASA Astrophysics Data System (ADS)

While there is a range of colours found in plants the predominant colour is green. Pigments in plants have several roles e.g. photosynthesis and signalling. If colour is to be used as a signal then it must stand out from green. However, one should be aware that there are also coloured compounds where we have not yet fully investigated the role of colour in their functions—they may have roles in, for example, defence or heat exchange. In this paper, we will describe the basic chemistry of the major pigments found in plants and especially floral pigments. We will then discuss their locations in parts of the flower (such as sepals, petals, pollen and nectar), the cells in which they are found and their sub-cellular locations. Floral pigments have a large role to play in pollination of flowers by animals. They can and are modified in many ways during the development of flowers in nature, for example, at emergence and post-pollination. There are a range of biochemical mechanisms of colour change both within flowers and in isolated pigments. Some of the factors influencing colour are temperature, co-pigments, pH, metals, sugars, anthocyanin stacking and cell shape. There is a renewed interest in analysing floral pigments and how they are modified partly because of advances in recombinant DNA technologies, but also because of pollinators and their significance to biodiversity and for evolutionary studies. There is continued strong interest from the horticultural industry for the introduction of new colours e.g. the blue rose and for the exploitation of natural dyes. Funding in this area may impact future research in a potentially beneficial way but it must not deflect us from science-based conservation.

Miller, Renee; Owens, Simon J.; Rørslett, Bjørn

2011-03-01

279

Contextual service loading by dependency graph colouring  

Microsoft Academic Search

While installing applications on mobiles devices, we may face issues due to the limit of the device resources. In this paper, we propose AxSeL: A conteXtual Service Loader that considers services-oriented applications and loads them from a distant repository. Services dependencies are represented in a graph that is coloured considering the devices and services constraints. The graph colouring aims to

Amira Ben Hamida; Frédéric Le Mouël; Stéphane Frénot; Mohamed Ben Ahmed

2008-01-01

280

Colour Reagent for Paper Chromatography of Steroids  

Microsoft Academic Search

FOR the paper chromatography of steroids several colour reagents are used, such as 2,4-dinitrophenyl-hydrazine, Zimmermann's reagent, phosphomolybdic acid, antimony trichloride, etc. Their common defect is that the reagent gives some colour with the paper itself, and so the contrast between spot and paper is too small. We have found that acid aniline phthalate in alcoholic solution-the reagent Partridge used for

A. Bodánszky; J. Kollonitsch

1955-01-01

281

THE COLOUR GLASS CONDENSATE: AN INTRODUCTION  

SciTech Connect

In these lectures, the authors develop the theory of the Colour Glass Condensate. This is the matter made of gluons in the high density environment characteristic of deep inelastic scattering or hadron-hadron collisions at very high energy. The lectures are self contained and comprehensive. They start with a phenomenological introduction, develop the theory of classical gluon fields appropriate for the Colour Glass, and end with a derivation and discussion of the renormalization group equations which determine this effective theory.

IANCU,E.; LEONIDOV,A.; MCLERRAN,L.

2001-08-06

282

Partitioning Based Algorithms for Some Colouring Problems  

Microsoft Academic Search

We discuss four variants of the graph colouring problem, and present algorithms for solving them. The problems are k-Colourability, Max Ind k-COL, Max Val k-COL, and, finally, Max k-COL, which is the unweighted case of the Max k-Cut problem. The algorithms are based on the idea of partitioning the domain of the problems into disjoint subsets, and then considering all

Ola Angelsmark; Johan Thapper

2005-01-01

283

Physicochemical and physiological basis of dichromatic colour  

Microsoft Academic Search

Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties\\u000a of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here,\\u000a we report that evident change of the hue of the colour (i.e., from green to red) is due to a change

Samo Kreft; Marko Kreft

2007-01-01

284

Diagnosis of ventricular septal rupture after myocardial infarction: value of colour flow mapping.  

PubMed Central

Twenty patients with ventricular septal rupture after myocardial infarction were investigated by cross sectional echocardiography with integrated pulsed and continuous wave Doppler and colour flow mapping. Confirmatory cardiac catheterisation was performed in 12 patients. Eighteen patients had surgical repair with inspection of the defect. Six patients in whom recurrent ventricular septal rupture developed were also investigated by Doppler echocardiography and colour flow mapping. Cross sectional echocardiography correctly predicted the infarct territory in all cases but visualised the septal rupture in only seven (35%). Pulsed and continuous wave Doppler detected a disturbance of right ventricular systolic flow that was diagnostic of a ventricular septal rupture in 19 (95%), but this only accurately predicted the site in 14 (70%). Colour flow mapping studies showed a mosaic jet traversing the interventricular septum in all 20 cases, and this accurately predicted the site of rupture. In addition colour flow mapping defined three sites of ventricular septal rupture: apical, posterior, and anterior trabecular. Five of the six patients with recurrent rupture were correctly diagnosed by pulsed and continuous wave Doppler and all six were diagnosed by colour flow mapping. Cross sectional echocardiography with colour flow mapping is a highly sensitive and rapid technique for the assessment of postinfarction ventricular septal rupture before and after operation. It was more informative about the site of the rupture than pulsed and continuous wave Doppler echocardiography. Images Fig 3 Fig 4 Fig 1 Fig 2 Fig 5 PMID:2803871

Smyllie, J; Dawkins, K; Conway, N; Sutherland, G R

1989-01-01

285

Angle-Insensitive Structural Colours based on Metallic Nanocavities and Coloured Pixels beyond the Diffraction Limit  

PubMed Central

To move beyond colorant-based pigmentation display technologies, a variety of photonic and plasmonic crystal based structures have been designed and applied as colour filters. Nanostructure based colour filtering offers increased efficiencies, low power consumption, slim dimensions, and enhanced resolution. However, incident angle tolerance still needs to be improved. In this work, we propose a new scheme through localized resonance in metallic nanoslits by light funneling. Angle insensitive colour filters up to ±80 degrees have been achieved, capable of wide colour tunability across the entire visible band with pixel size beyond the diffraction limit (~?/2). This work opens the door to angle insensitive manipulation of light with structural filtering. PMID:23378925

Wu, Yi-Kuei Ryan; Hollowell, Andrew E.; Zhang, Cheng; Guo, L. Jay

2013-01-01

286

Salience of Primary and Secondary Colours in Infancy  

ERIC Educational Resources Information Center

Primary colour terms ("black", "white", "red", "green", "yellow", and "blue") are more fundamental in colour language than secondary colour terms ("pink", "purple", "orange", "brown", and "grey"). Here, we assess whether this distinction exists in the absence of language, by investigating whether primary colours attract and sustain preverbal…

Franklin, Anna; Pitchford, Nicola; Hart, Lynsey; Davies, Ian R. L.; Clausse, Samantha; Jennings, Siobhan

2008-01-01

287

Facial parity edge colouring of plane pseudographs Jlius Czapa  

E-print Network

is presently known as the Four Colour Theorem (4CT). From the 4CT the following result follows, see [1510, 05C15 1. Introduction The famous Four Colour Problem has served as a motivation for many equivalent colour- ing problems, see e.g. the book of Saaty and Kainen [15]. The Four Colour Problem

Paris-Sud XI, Université de

288

Fano colourings of cubic graphs and the Fulkerson Conjecture  

Microsoft Academic Search

A Fano colouring is a colouring of the edges of a cubic graph by points of the Fano plane such that the colours of any three mutually adjacent edges form a line of the Fano plane. It has recently been shown by Holroyd and Skoviera (J. Combin. Theory Ser. B, to appear) that a cubic graph has a Fano colouring

Edita Mácajová; Martin Skoviera

2005-01-01

289

Flower colour adaptation in a mimetic orchid  

PubMed Central

Although the tremendous variability in floral colour among angiosperms is often attributed to divergent selection by pollinators, it is usually difficult to preclude the possibility that floral colour shifts were driven by non-pollinator processes. Here, we examine the adaptive significance of flower colour in Disa ferruginea, a non-rewarding orchid that is thought to attract its butterfly pollinator by mimicking the flowers of sympatric nectar-producing species. Disa ferruginea has red flowers in the western part of its range and orange flowers in the eastern part—a colour shift that we hypothesized to be the outcome of selection for resemblance to different local nectar-producing plants. Using reciprocal translocations of red and orange phenotypes as well as arrays of artificial flowers, we found that the butterfly Aeropetes tulbaghia, the only pollinator of the orchid, preferred both the red phenotype and red artificial flowers in the west where its main nectar plant also has red flowers, and both the orange phenotype and orange artificial flowers in the east, where its main nectar plant has orange flowers. This phenotype by environment interaction demonstrates that the flower colour shift in D. ferruginea is adaptive and driven by local colour preference in its pollinator. PMID:22298842

Newman, Ethan; Anderson, Bruce; Johnson, Steven D.

2012-01-01

290

Flesh colour dominates consumer preference for chicken.  

PubMed

Existing research investigating interactions between visual and oral sensory cues has tended to use model food systems. In contrast, this study compared product quality assessments of corn-fed and wheat-fed chicken products among persons recruited in Northern Ireland. Three approaches have been adopted to investigate the effect of colour upon consumer choice of chicken: sensory assessment under normal lighting; focus group discussion; and sensory assessment under controlled lighting conditions. Initial consumer sensory assessment indicated that wheat-fed chicken was perceived to be tenderer and to have a more intense flavour than that which was corn-fed. Qualitative enquiry discerned that this was because consumers perceived the yellow colour of corn-fed chicken negatively. Yellow-coloured corn-fed chicken was therefore again compared with wheat-fed chicken in terms of flavour, texture and overall liking with the flesh colour disguised by means of controlled lighting. Quality ratings for corn-fed chicken were more positive when the yellow flesh colour was disguised, with corn-fed chicken judged to be tenderer than wheat-fed chicken and more flavoursome. This study illustrates the importance of using a combination of methods to gain insight into interactions between different sensory modalities in consumer quality judgements and adds to previous research on the importance of colour upon consumer choice of real foods. PMID:15808892

Kennedy, Orla B; Stewart-Knox, Barbara J; Mitchell, Peter C; Thurnham, David I

2005-04-01

291

Colourful parrot feathers resist bacterial degradation  

PubMed Central

The brilliant red, orange and yellow colours of parrot feathers are the product of psittacofulvins, which are synthetic pigments known only from parrots. Recent evidence suggests that some pigments in bird feathers function not just as colour generators, but also preserve plumage integrity by increasing the resistance of feather keratin to bacterial degradation. We exposed a variety of colourful parrot feathers to feather-degrading Bacillus licheniformis and found that feathers with red psittacofulvins degraded at about the same rate as those with melanin and more slowly than white feathers, which lack pigments. Blue feathers, in which colour is based on the microstructural arrangement of keratin, air and melanin granules, and green feathers, which combine structural blue with yellow psittacofulvins, degraded at a rate similar to that of red and black feathers. These differences in resistance to bacterial degradation of differently coloured feathers suggest that colour patterns within the Psittaciformes may have evolved to resist bacterial degradation, in addition to their role in communication and camouflage. PMID:20926430

Burtt, Edward H.; Schroeder, Max R.; Smith, Lauren A.; Sroka, Jenna E.; McGraw, Kevin J.

2011-01-01

292

Mode of action of creatinine on colour of cuprous oxide precipitate in Benedict's qualitative sugar test  

PubMed Central

Creatinine appears to alter the colour and bulky nature of the cuprous oxide precipitate not by altering the chemical composition of the precipitate but by the physical process of retardation of the growth of newly formed yellow cuprous oxide crystals to large red crystals by adhering to their surface and blocking some sites for further crystal growth. PMID:4646302

Sur, B. K.; Shukla, R. K.; Agashe, V. S.

1972-01-01

293

Responses to coloured patterns in the macaque lateral geniculate nucleus: Pattern processing in single neurones  

Microsoft Academic Search

Cell responses to complex visual patterns such as compositions of broad-band (non-monochromatic) colour areas are presented. Patterns were scanned over the receptive field, and cell response at each point was recorded. “Response patterns” were constructed which display the cell transform of the stimulus pattern. Parvocellular layer (PCL) cells in the lateral geniculate nucleus, in a very sustained fashion, signal the

H. C. Nothdurft; B. B. Lee

1982-01-01

294

“We Are Multiculturalism”: A Self-study of Faculty of Colour With Pre-service Teachers of Colour  

Microsoft Academic Search

This paper reports a self-study of three faculty of colour engaged in teaching a special summer session geared to recruiting people of colour to teaching. Given our past experiences in institutions of higher education, we recognised the unique situation and potential of faculty of colour teaching a class made up almost exclusively of students of colour. We analysed our own

Patricia Prado-Olmos; Francisco Ríos; Lillian Vega Castañeda

2007-01-01

295

A Handheld LED Coloured-Light Mixer for Students to Learn Collaboratively the Primary Colours of Light  

ERIC Educational Resources Information Center

To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny…

Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

2009-01-01

296

Seasonal Changes in Colour: A Comparison of Structural, Melanin- and Carotenoid-Based Plumage Colours  

PubMed Central

Background Plumage coloration is important for bird communication, most notably in sexual signalling. Colour is often considered a good quality indicator, and the expression of exaggerated colours may depend on individual condition during moult. After moult, plumage coloration has been deemed fixed due to the fact that feathers are dead structures. Still, many plumage colours change after moult, although whether this affects signalling has not been sufficiently assessed. Methodology/Principal Findings We studied changes in coloration after moult in four passerine birds (robin, Erithacus rubecula; blackbird, Turdus merula; blue tit, Cyanistes caeruleus; and great tit, Parus major) displaying various coloration types (melanin-, carotenoid-based and structural). Birds were caught regularly during three years to measure plumage reflectance. We used models of avian colour vision to derive two variables, one describing chromatic and the other achromatic variation over the year that can be compared in magnitude among different colour types. All studied plumage patches but one (yellow breast of the blue tit) showed significant chromatic changes over the year, although these were smaller than for a typical dynamic trait (bill colour). Overall, structural colours showed a reduction in relative reflectance at shorter wavelengths, carotenoid-based colours the opposite pattern, while no general pattern was found for melanin-based colours. Achromatic changes were also common, but there were no consistent patterns of change for the different types of colours. Conclusions/Significance Changes of plumage coloration independent of moult are probably widespread; they should be perceivable by birds and have the potential to affect colour signalling. PMID:20644723

Delhey, Kaspar; Burger, Claudia; Fiedler, Wolfgang; Peters, Anne

2010-01-01

297

Total-colouring of plane graphs with maximum degree nine  

Microsoft Academic Search

The central problem of the total-colourings is the Total-Colouring Conjecture, which asserts that every graph of maximum degree admits a ( + 2)-total-colouring. Similarly to edge-colourings—with Vizing's edge-colouring conjecture—this bound can be decreased by one for plane graphs of higher maximum degree. More precisely, it is known that if 10 then every plane graph of maximum degree is (

Lukasz Kowalik; Jean-Sebastien Sereni

298

All-Angle Negative Refraction and Imaging Effects for Both Polarizations in Pure Dielectric Composite Two-Dimensional Photonic Crystals  

NASA Astrophysics Data System (ADS)

Due to the band separation between two polarization modes, it is usually difficult to realize all-angle negative refraction (AANR) for both polarizations from normal dielectric-rod or air-hole photonic crystals (PCs). In this letter, we propose a pure dielectric composite PC that shows much suppressed band structures that are quite useful for the formation of a common frequency area of AANR for both polarizations. Further simulations have first demonstrated the common AANR and imaging effects in such composite PC and we can control the property of the image by changing the cutoff at surface termination and the PC thickness.

Jiang, Liyong; Wu, Hong; Zheng, Gaige; Li, Xiangyin

2012-01-01

299

Flower colour and cytochromes P450†  

PubMed Central

Cytochromes P450 play important roles in biosynthesis of flavonoids and their coloured class of compounds, anthocyanins, both of which are major floral pigments. The number of hydroxyl groups on the B-ring of anthocyanidins (the chromophores and precursors of anthocyanins) impact the anthocyanin colour, the more the bluer. The hydroxylation pattern is determined by two cytochromes P450, flavonoid 3?-hydroxylase (F3?H) and flavonoid 3?,5?-hydroxylase (F3?5?H) and thus they play a crucial role in the determination of flower colour. F3?H and F3?5?H mostly belong to CYP75B and CYP75A, respectively, except for the F3?5?Hs in Compositae that were derived from gene duplication of CYP75B and neofunctionalization. Roses and carnations lack blue/violet flower colours owing to the deficiency of F3?5?H and therefore lack the B-ring-trihydroxylated anthocyanins based upon delphinidin. Successful redirection of the anthocyanin biosynthesis pathway to delphinidin was achieved by expressing F3?5?H coding regions resulting in carnations and roses with novel blue hues that have been commercialized. Suppression of F3?5?H and F3?H in delphinidin-producing plants reduced the number of hydroxyl groups on the anthocyanidin B-ring resulting in the production of monohydroxylated anthocyanins based on pelargonidin with a shift in flower colour to orange/red. Pelargonidin biosynthesis is enhanced by additional expression of a dihydroflavonol 4-reductase that can use the monohydroxylated dihydrokaempferol (the pelargonidin precursor). Flavone synthase II (FNSII)-catalysing flavone biosynthesis from flavanones is also a P450 (CYP93B) and contributes to flower colour, because flavones act as co-pigments to anthocyanins and can cause blueing and darkening of colour. However, transgenic plants expression of a FNSII gene yielded paler flowers owing to a reduction of anthocyanins because flavanones are precursors of anthocyanins and flavones. PMID:23297355

Tanaka, Yoshikazu; Brugliera, Filippa

2013-01-01

300

Insights into the chemical composition of Equisetum hyemale by high resolution Raman imaging.  

PubMed

Equisetaceae has been of research interest for decades, as it is one of the oldest living plant families, and also due to its high accumulation of silica up to 25% dry wt. Aspects of silica deposition, its association with other biomolecules, as well as the chemical composition of the outer strengthening tissue still remain unclear. These questions were addressed by using high resolution (<1 microm) Confocal Raman microscopy. Two-dimensional spectral maps were acquired on cross sections of Equisetum hyemale and Raman images calculated by integrating over the intensity of characteristic spectral regions. This enabled direct visualization of differences in chemical composition and extraction of average spectra from defined regions for detailed analyses, including principal component analysis (PCA) and basis analysis (partial least square fit based on model spectra). Accumulation of silica was imaged in the knobs and in a thin layer below the cuticula. In the spectrum extracted from the knob region as main contributions, a broad band below 500 cm(-1) attributed to amorphous silica, and a band at 976 cm(-1) assigned to silanol groups, were found. From this, we concluded that these protrusions were almost pure amorphous, hydrated silica. No silanol group vibration was detected in the silicified epidermal layer below and association with pectin and hemicelluloses indicated. Pectin and hemicelluloses (glucomannan) were found in high levels in the epidermal layer and in a clearly distinguished outer part of the hypodermal sterome fibers. The inner part of the two-layered cells revealed as almost pure cellulose, oriented parallel along the fiber. PMID:18057960

Gierlinger, Notburga; Sapei, Lanny; Paris, Oskar

2008-04-01

301

Structural colour and iridescence in plants: the poorly studied relations of pigment colour  

PubMed Central

Background Colour is a consequence of the optical properties of an object and the visual system of the animal perceiving it. Colour is produced through chemical and structural means, but structural colour has been relatively poorly studied in plants. Scope This Botanical Briefing describes the mechanisms by which structures can produce colour. In plants, as in animals, the most common mechanisms are multilayers and diffraction gratings. The functions of structural colour are then discussed. In animals, these colours act primarily as signals between members of the same species, although they can also play roles in camouflaging animals from their predators. In plants, multilayers are found predominantly in shade-plant leaves, suggesting a role either in photoprotection or in optimizing capture of photosynthetically active light. Diffraction gratings may be a surprisingly common feature of petals, and recent work has shown that they can be used by bees as cues to identify rewarding flowers. Conclusions Structural colour may be surprisingly frequent in the plant kingdom, playing important roles alongside pigment colour. Much remains to be discovered about its distribution, development and function. PMID:20142263

Glover, Beverley J.; Whitney, Heather M.

2010-01-01

302

Anim. Behav., 1997, 53, 10431052 Innate colour preferences and flexible colour learning in the  

E-print Network

interactions between flowering plants and their pollinators are the result of a long coevolutionary history, and the evolutionary history of their relationships, it is necessary to understand the sensory and behavioural colours with sugar rewards. Colour vision is an important component of intra- and inter

Weiss, Martha R.

303

Formation of multifunctional Fe3O4/Au composite nanoparticles for dual-mode MR/CT imaging applications  

NASA Astrophysics Data System (ADS)

Recent advances with iron oxide/gold (Fe3O4/Au) composite nanoparticles (CNPs) in dual-modality magnetic resonance (MR) and computed tomography (CT) imaging applications are reviewed. The synthesis and assembly of “dumbbelllike” and “core/shell” Fe3O4/Au CNPs is introduced. Potential applications of some developed Fe3O4/Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail.

Hu, Yong; Li, Jing-Chao; Shen, Ming-Wu; Shi, Xiang-Yang

2014-07-01

304

Thermal diffusivity imaging of continuous fiber ceramic composite materials and components  

SciTech Connect

Continuous-fiber ceramic matrix composites (CFCCs) are currently being developed for various high-temperature applications, including use in advanced turbine engines. In such composites, the condition of the interfaces between the fibers and matrix or between laminae in a two-dimensional weave lay-up are critical to the mechanical and thermal behavior of the component. A nondestructive evaluation method that could be used to assess the interface condition and/or detect other `defects` has been developed at Argonne National Laboratory (ANL) and uses infrared thermal imaging to provide `single-shot` full- field quantitative measurement of the distribution of thermal diffusivity in large components. By applying digital filtering, interpolation, and least-squares-estimation techniques for noise reduction, shorter acquisition and analysis times have been achieved with submillimeter spatial resolution for materials with a wide range of `thermal thicknesses`. The system at ANL has been used to examine the effects of thermal shock, oxidation treatment, density variations, and variations in fiber coating in a full array of test specimens. In addition, actual subscale CFCC components of nonplanar geometries have been inspected for manufacturing-induced variations in thermal properties.

Ahuja, S.; Ellingson, W.A. [Argonne National Lab., IL (United States); Steckenrider, J.S. [Northwestern Univ., Evanston, IL (United States); King, S. [Argonne National Lab., IL (United States)

1995-12-31

305

Automated segmentation of muscle and adipose tissue on CT images for human body composition analysis  

NASA Astrophysics Data System (ADS)

The ability to compute body composition in cancer patients lends itself to determining the specific clinical outcomes associated with fat and lean tissue stores. For example, a wasting syndrome of advanced disease associates with shortened survival. Moreover, certain tissue compartments represent sites for drug distribution and are likely determinants of chemotherapy efficacy and toxicity. CT images are abundant, but these cannot be fully exploited unless there exist practical and fast approaches for tissue quantification. Here we propose a fully automated method for segmenting muscle, visceral and subcutaneous adipose tissues, taking the approach of shape modeling for the analysis of skeletal muscle. Muscle shape is represented using PCA encoded Free Form Deformations with respect to a mean shape. The shape model is learned from manually segmented images and used in conjunction with a tissue appearance prior. VAT and SAT are segmented based on the final deformed muscle shape. In comparing the automatic and manual methods, coefficients of variation (COV) (1 - 2%), were similar to or smaller than inter- and intra-observer COVs reported for manual segmentation.

Chung, Howard; Cobzas, Dana; Birdsell, Laura; Lieffers, Jessica; Baracos, Vickie

2009-02-01

306

Monitoring of wildfires in boreal forests using large area AVHRR NDVI composite image data  

SciTech Connect

Normalized difference vegetation index (NDVI) composite image data, produced from AVHRR data collected in 1990, were evaluated for locating and mapping the areal extent of wildfires in the boreal forests of Alaska during that year. A technique was developed to map forest fire boundaries by subtracting a late-summer AVHRR NDVI image from an early summer scene. The locations and boundaries of wildfires within the interior region of Alaska were obtained from the Alaska Fire Service, and compared to the AVHRR-derived fire-boundary map. It was found that AVHRR detected 89.5% of all fires with sizes greater than 2,000ha with no false alarms and that, for most cases, the general shape of the fire boundary detected by AVHRR matched those mapped by field observers. However, the total area contained within the fire boundaries mapped by AVHRR were only 61% of those mapped by the field observers. However, the AVHRR data used in this study did not span the entire time period during which fires occurred, and it is believed the areal estimates could be improved significantly if an expanded AVHRR data set were used.

Kasischke, E.S.; French, N.H.F. (Environmental Research Inst. of Michigan, Ann Arbor (United States)); Harrell, P.; Christensen, N.L. Jr. (Duke Univ., Durham, NC (United States)); Ustin, S.L. (Univ. of California, Davis (United States)); Barry, D. (U.S. Bureau of Land Management, Fairbanks, AK (United States))

1993-06-01

307

Ocean colour analysis by hyperspectral MIVIS radiometer: model-derived algorithms  

Microsoft Academic Search

Presents the results of a theoretical work aiming to evaluate the potential of MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) visible channels for marine parameter estimate, and to propose the relevant algorithms. The methodology used for algorithm retrieval is based on a model of ocean colour, briefly recalled, which was used to generate a large number of reflectance curves for

P. Cipollini; G. Corsini

1995-01-01

308

Colour preferences in nest-building zebra finches.  

PubMed

Some bird species are selective in the materials they choose for nest building, preferring, for example, materials of one colour to others. However, in many cases the cause of these preferences is not clear. One of those species is the zebra finch, which exhibits strong preferences for particular colours of nest material. In an attempt to determine why these birds strongly prefer one colour of material over another, we compared the preferences of paired male zebra finches for nest material colour with their preferences for food of the same colours. We found that birds did indeed prefer particular colours of nest material (in most cases blue) but that they did not generally prefer food of one colour over the other colours. It appears, then, that a preference for one colour or another of nest material is specific to the nest-building context. This article is part of a Special Issue entitled: insert SI title. PMID:23860278

Muth, Felicity; Steele, Matthew; Healy, Susan D

2013-10-01

309

Multi-colour detection of gravitational arcs  

NASA Astrophysics Data System (ADS)

Strong gravitational lensing provides fundamental insights into the understanding of the dark matter distribution in massive galaxies, galaxy clusters, and the background cosmology. Despite their importance, few gravitational arcs have been discovered so far. The urge for more complete, large samples and unbiased methods of selecting candidates increases. Several methods for the automatic detection of arcs have been proposed in the literature, but large amounts of spurious detections retrieved by these methods force observers to visually inspect thousands of candidates per square degree to clean the samples. This approach is largely subjective and requires a huge amount of checking by eye, especially considering the actual and upcoming wide-field surveys, which will cover thousands of square degrees. In this paper we study the statistical properties of the colours of gravitational arcs detected in the 37 deg2 of the CFHTLS-Archive-Research Survey (CARS). Most of them lie in a relatively small region of the (g' - r', r' - i') colour-colour diagram. To explain this property, we provide a model that includes the lensing optical depth expected in a ?CDM cosmology that, in combination with the sources' redshift distribution of a given survey, in our case CARS, peaks for sources at redshift z ~ 1. By furthermore modelling the colours derived from the spectral energy distribution of the galaxies that dominate the population at that redshift, the model reproduces the observed colours well. By taking advantage of the colour selection suggested by both data and model, we automatically detected 24 objects out of 90 detected by eye checking. Compared with the single-band arcfinder, this multi-band filtering returns a sample complete to 83% and a contamination reduced by a factor of ~6.5. New gravitational arc candidates are also proposed.

Maturi, Matteo; Mizera, Sebastian; Seidel, Gregor

2014-07-01

310

MUNSELL COLOR ANALYSIS OF LANDSAT COLOR-RATIO-COMPOSITE IMAGES OF LIMONITIC AREAS IN SOUTHWEST NEW MEXICO.  

USGS Publications Warehouse

Green areas on Landsat 4/5 - 4/6 - 6/7 (red - blue - green) color-ratio-composite (CRC) images represent limonite on the ground. Color variation on such images was analyzed to determine the causes of the color differences within and between the green areas. Digital transformation of the CRC data into the modified cylindrical Munsell color coordinates - hue, value, and saturation - was used to correlate image color characteristics with properties of surficial materials. The amount of limonite visible to the sensor is the primary cause of color differences in green areas on the CRCs. Vegetation density is a secondary cause of color variation of green areas on Landsat CRC images. Digital color analysis of Landsat CRC images can be used to map unknown areas. Color variations of green pixels allows discrimination among limonitic bedrock, nonlimonitic bedrock, nonlimonitic alluvium, and limonitic alluvium.

Kruse, Fred A.

1984-01-01

311

Imagery, colour and illness: a review.  

PubMed

This paper reviews research on the role of colour and imagery in relation to illness and examines how this might improve communication between the sufferer and those treating or caring for them. It describes a method by which colour can be related to situations such as an individual's mood and how this might be used to predict response to treatment. Furthermore, it provides evidence that documenting the imagery of an illness might give insight into the patients' fears and concerns about their condition as well as helping non-sufferers to understand what they are going through. PMID:22023001

Carruthers, Helen R

2011-09-01

312

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns  

NASA Technical Reports Server (NTRS)

A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)

2010-01-01

313

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns  

NASA Technical Reports Server (NTRS)

A technique, associated system and program code, for retrieving depth information about at least one surface of an object. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the object; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)

2008-01-01

314

Symphony of colours in the Tarantula  

NASA Astrophysics Data System (ADS)

hi-res Size hi-res: 1058 Kb Credits: ESA/NASA, ESO and Danny LaCrue Symphony of colours in the Tarantula The Tarantula is situated 170 000 light-years away in the Large Magellanic Cloud (LMC) in the southern sky and is clearly visible to the naked eye as a large milky patch. Astronomers believe that this smallish irregular galaxy is currently going through a violent period in its life. It is orbiting around the Milky Way and has had several close encounters with it. It is believed that the interaction with the Milky Way has caused an episode of energetic star formation - part of which is visible as the Tarantula Nebula. Just above the centre of the image there is a huge cluster of very hot stars called R136. The stars in R136 are also among the most massive stars we know. R136 is also a very young cluster, its oldest stars being 'just' 5 million years old or so. Its smallest stars, however, are still forming, so astronomers observe R136 to try to understand the early stages of stellar evolution. Near the lower edge of the image we find the star cluster Hodge 301. Hodge 301 is almost 10 times older than R136. Some of the stars in Hodge 301 are so old that they have already exploded as supernovae. The shockwave from this explosion has compressed the gas in the Tarantula into the filaments and sheets that are seen around the cluster. This mosaic of the Tarantula Nebula consists of images from the NASA/ESA Hubble Space Telescope’s Wide Field and Planetary Camera 2 (WFPC2) and was created by 23 year old amateur astronomer Danny LaCrue. The image was constructed by 15 individual exposures taken through three narrow-band filters allowing light from ionised oxygen (501 nm, shown as blue), hydrogen-alpha (656 nm, shown as green) and ionised sulphur (672 nm, shown as red). The exposure time for the individual WFPC2 images vary between 800 and 2800 seconds in each filter. The Hubble data have been superimposed onto images taken through matching narrow-band filters with the European Southern Observatory’s New Technology Telescope at the La Silla Observatory, Chile. The Tarantula Nebula, also known as 30 Doradus, is situated 170 000 light-years away in the Large Magellanic Cloud (LMC) in the southern sky and is clearly visible to the naked eye as a large milky patch. Astronomers believe that this smallish, irregular galaxy is currently going through a violent period in its life cycle. It is orbiting the Milky Way and has had several close encounters with it. It is believed that the interaction with the Milky Way has caused an episode of energetic star formation - part of which is visible as the Tarantula Nebula. The Tarantula is the largest stellar nursery we know in the local universe. In fact if this enormous complex of stars, gas and dust were at the distance of the Orion Nebula it would be visible during the day and cover a quarter of the sky. Over the years the NASA/ESA Hubble Space Telescope has returned again and again to observe this interesting region of the sky and in this way Hubble has built up an archival treasure of more than a thousand images and spectra of the Tarantula. A few weeks ago, 23 year old amateur astronomer Danny LaCrue sifted through the data and found that 15 of the exposures made with Hubble’s Wide Field and Planetary Camera 2 could be combined to create a beautiful mosaic of the central parts of the unique Tarantula. Danny submitted his image to the Hubble European Space Agency Information Centre in the hope that the image could be shared with a wider audience. “I always wondered what it would be like to create the pictures from Hubble, but I never imagined that I would one day actually get to make one myself”. Driven by his interest in astronomy and graphical design and excited at the prospect of processing real images taken by Hubble, Danny recently downloaded the ESA/ESO/NASA Photoshop FITS Liberator from the Spacetelescope.org website. The FITS Liberator is a software tool released six months ago that enables laypeople to work with the somewhat special format of astronomical images (called

2004-12-01

315

Digital-image-correlation-based experimental stress analysis of reinforced concrete beams, strengthened using carbon composites  

NASA Astrophysics Data System (ADS)

The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.

Helm, Jeffrey; Kurtz, Stephen

2004-12-01

316

Digital-image-correlation-based experimental stress analysis of reinforced concrete beams strengthened using carbon composites  

NASA Astrophysics Data System (ADS)

The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.

Helm, Jeffrey; Kurtz, Stephen

2005-01-01

317

How feather colour reflects its carotenoid content  

Microsoft Academic Search

Summary 1. Many birds sequester carotenoid pigments in colourful patches of feathers to advertise or compete for mates. Because carotenoids can be scarce in nature and serve valuable physiological functions, only the highest-quality individuals are thought to acquire or allocate more pigments for use in sexual displays. 2. A critical but rarely tested assumption of carotenoid-based signals is that the

Lauri Saks; Kevin McGraw; Peeter Horak

2003-01-01

318

Odonata colour: more than meets the eye?  

Microsoft Academic Search

Interpretations of behavioural visual cues, based on human perception of colour, may mislead because of the difference in our visual range compared to other animals. Investigations into ultraviolet (UV) reflectance have shown that this can be an important mode of communication in many animals. The present study focused on 10 species of British Odonata. Digital photography was used to capture

Wendy E. Harris; Dan W. Forman; Roy D. Battell; Marie T. R. Battell; Alan K. Nelson; Paul F. Brain

2011-01-01

319

Dietary tannins improve lamb meat colour stability  

Microsoft Academic Search

Fourteen male Comisana lambs were divided into two groups at 45days of age: lambs fed a concentrate diet (C), or lambs fed the same concentrate with the addition of quebracho (Schinopsis lorentzii) tannins (T). Sheep were slaughtered at 105days of age. Lipid oxidation, colour coordinates, haem pigment concentration, and metmyoglobin percentages were measured on minced semimembranosus muscle (SM) over 14days

G. Luciano; F. J. Monahan; V. Vasta; L. Biondi; M. Lanza; A. Priolo

2009-01-01

320

Genetics of human iris colour and patterns.  

PubMed

The presence of melanin pigment within the iris is responsible for the visual impression of human eye colouration with complex patterns also evident in this tissue, including Fuchs' crypts, nevi, Wolfflin nodules and contraction furrows. The genetic basis underlying the determination and inheritance of these traits has been the subject of debate and research from the very beginning of quantitative trait studies in humans. Although segregation of blue-brown eye colour has been described using a simple Mendelian dominant-recessive gene model this is too simplistic, and a new molecular genetic perspective is needed to fully understand the biological complexities of this process as a polygenic trait. Nevertheless, it has been estimated that 74% of the variance in human eye colour can be explained by one interval on chromosome 15 that contains the OCA2 gene. Fine mapping of this region has identified a single base change rs12913832 T/C within intron 86 of the upstream HERC2 locus that explains almost all of this association with blue-brown eye colour. A model is presented whereby this SNP, serving as a target site for the SWI/SNF family member HLTF, acts as part of a highly evolutionary conserved regulatory element required for OCA2 gene activation through chromatin remodelling. Major candidate genes possibly effecting iris patterns are also discussed, including MITF and PAX6. PMID:19619260

Sturm, Richard A; Larsson, Mats

2009-10-01

321

The cultural origins of colour categories  

E-print Network

? ­ Nativism: genetic makeup. ­ Empiricism: interaction with the environment. ­ Culturalism: culturalThe cultural origins of colour categories Tony Belpaeme Artificial Intelligence Lab Vrije.g. Elman et al., 1996; Yendrikhovskij, 2001) ­ This all happens without the influence of culture

Belpaeme, Tony

322

Testing the AUDI2000 colour-difference formula for solid colours using some visual datasets with usefulness to automotive industry  

NASA Astrophysics Data System (ADS)

Colour-difference formulas are tools employed in colour industries for objective pass/fail decisions of manufactured products. These objective decisions are based on instrumental colour measurements which must reliably predict the subjective colour-difference evaluations performed by observers' panels. In a previous paper we have tested the performance of different colour-difference formulas using the datasets employed at the development of the last CIErecommended colour-difference formula CIEDE2000, and we found that the AUDI2000 colour-difference formula for solid (homogeneous) colours performed reasonably well, despite the colour pairs in these datasets were not similar to those typically employed in the automotive industry (CIE Publication x038:2013, 465-469). Here we have tested again AUDI2000 together with 11 advanced colour-difference formulas (CIELUV, CIELAB, CMC, BFD, CIE94, CIEDE2000, CAM02-UCS, CAM02-SCD, DIN99d, DIN99b, OSA-GP-Euclidean) for three visual datasets we may consider particularly useful to the automotive industry because of different reasons: 1) 828 metallic colour pairs used to develop the highly reliable RIT-DuPont dataset (Color Res. Appl. 35, 274-283, 2010); 2) printed samples conforming 893 colour pairs with threshold colour differences (J. Opt. Soc. Am. A 29, 883-891, 2012); 3) 150 colour pairs in a tolerance dataset proposed by AUDI. To measure the relative merits of the different tested colour-difference formulas, we employed the STRESS index (J. Opt. Soc. Am. A 24, 1823-1829, 2007), assuming a 95% confidence level. For datasets 1) and 2), AUDI2000 was in the group of the best colour-difference formulas with no significant differences with respect to CIE94, CIEDE2000, CAM02-UCS, DIN99b and DIN99d formulas. For dataset 3) AUDI2000 provided the best results, being statistically significantly better than all other tested colour-difference formulas.

Martínez-García, Juan; Melgosa, Manuel; Gómez-Robledo, Luis; Li, Changjun; Huang, Min; Liu, Haoxue; Cui, Guihua; Luo, M. Ronnier; Dauser, Thomas

2013-11-01

323

A novel segmentation method to identify left ventricular infarction in short-axis composite strain-encoded magnetic resonance images  

NASA Astrophysics Data System (ADS)

Composite Strain Encoding (CSENC) is a new Magnetic Resonance Imaging (MRI) technique for simultaneously acquiring cardiac functional and viability images. It combines the use of Delayed Enhancement (DE) and the Strain Encoding (SENC) imaging techniques to identify the infracted (dead) tissue and to image the myocardial deformation inside the heart muscle. In this work, a new unsupervised segmentation method is proposed to identify infarcted left ventricular tissue in the images provided by CSENC MRI. The proposed method is based on the sequential application of Bayesian classifier, Otsu's thresholding, morphological opening, radial sweep boundary tracing and the fuzzy C-means (FCM) clustering algorithm. This method is tested on images of twelve patients with and without myocardial infarction (MI) and on simulated heart images with various levels of superimposed noise. The resulting clustered images are compared with those marked up by an expert cardiologist who assisted in validating results coming from the proposed method. Infarcted myocardium is correctly identified using the proposed method with high levels of accuracy and precision.

Algohary, Ahmad O.; Metwally, Muhammad K.; El-Bialy, Ahmed M.; Kandil, Ahmed H.; Osman, Nael F.

2011-03-01

324

Perception of colour in unilateral tritanopia.  

PubMed Central

The unilateral tritanope described in the previous paper (Alpern, Kitahara & Krantz, 1983) was able to match every narrow-band light presented to his tritanopic eye with lights from a tristimulus colorimeter viewed in the adjacent field by the normal eye. In two regions of the spectrum (called isochromes) physically identical lights appeared identical to the observer's two eyes. One isochrome was close to 'blue' for the normal eye, the other was in the long-wave spectral region seen by the normal eye predominantly as 'red'. Between these isochromes the normal eye required less than spectral purity to match, dropping to near zero purity at 560-570 nm. A mixture of the two isochromes that appeared purple to the normal eye appeared neutral to the tritanopic eye. Hence dichoptic matches grossly violate Grassmann's additivity law. For the normal eye colour naming conformed to typical normal results. For the tritanopic eye the results were coherent with those found by dichoptic matching: the spectrum was divided into two regions by the achromatic neutral band. To the short-wave side, only the colour names 'blue' and 'white' were ever used. To the long-wave side the predominant colour names were 'red' and 'white' with some 'yellow'. Spectral lights appeared neither 'red-blue' nor greenish. Surrounding the test with an annulus either 430 nm, 650 nm, or a mixture of these, fails to induce any greenish appearance, although the achromatic band shifted in the expected directions. It is concluded that there must be exactly three functionally independent, essentially non-linear central codes for colour perception, and that these codes are different from those suggested in existing theories of colour perception. PMID:6603509

Alpern, M; Kitahara, K; Krantz, D H

1983-01-01

325

Period-colour and amplitude-colour relations in classical Cepheid variables - V. The Small Magellanic Cloud Cepheid models  

NASA Astrophysics Data System (ADS)

Period-colour (PC) and amplitude-colour (AC) relations at maximum, mean and minimum light are constructed from a large grid of full amplitude hydrodynamic models of Cepheids with a composition appropriate for the Small Magellanic Cloud (SMC). We compare these theoretical relations with those from observations. The theoretical relations are, in general, in good agreement with their observational counterparts, though there exist some discrepancy for short period (log[P] < 1) Cepheids. We outline a physical mechanism which can, in principle, be one factor to explain the observed PC/AC relations for the long and short period Cepheids in the Galaxy, Large Magellanic Cloud (LMC) and SMC. Our explanation relies on the hydrogen ionization front (HIF)-photosphere interaction and the way this interaction changes with pulsation period, pulsation phase and metallicity. Since the PC relation is connected with the period-luminosity (PL) relation, it is postulated that such a mechanism can also explain the observed properties of the PL relation in these three galaxies.

Kanbur, Shashi M.; Ngeow, Chow-Choong; Feiden, Greg

2007-09-01

326

A rapid colour stabilization technique for radiochromic film dosimetry  

NASA Astrophysics Data System (ADS)

Various forms of GAFChromic film have been used for several years as radiographic media for measuring dose distributions of brachytherapy sources and small radiation fields. Upon irradiation the film changes colour and darkens with time post-irradiation. The darkening is most rapid in the first 24 h, and it has been suggested that for accurate dosimetry a waiting period of 24 h should occur before any optical density (OD) measurements are taken. A more rapid colour stabilization (RCS) procedure has been developed and is evaluated. The procedure consists of heating the film post-irradiation for a period of 2 h at images/0031-9155/43/10/001/img1.gif" ALIGN="MIDDLE"/>C. The RCS procedure is compared with a control group and the dose response is tested for linearity, stability and reproducibility using two densitometers with light sources at different wavelengths (632.8 nm and 671 nm). The rise in net optical density (NOD) for the period 3-168 h is less than 3% for the RCS group as compared with 12% for the controls. In the first 24 h, the increase in NOD for the RCS samples is less than 0.5%, as opposed to 6% for the control group.

Reinstein, L. E.; Gluckman, G. R.; Meek, A. G.

1998-10-01

327

Composite  

NASA Astrophysics Data System (ADS)

Particle distribution and hot workability of an in situ Al-TiCp composite were investigated. The composite was fabricated by an in situ casting method using the self-propagating high-temperature synthesis of an Al-Ti-C system. Hot-compression tests were carried out, and power dissipation maps were constructed using a dynamic material model. Small globular TiC particles were not themselves fractured, but the clustering and grain boundary segregation of the particles contributed to the cracking of the matrix by causing the debonding of matrix/particle interfaces and providing a crack propagation path. The efficiency of power dissipation increased with increasing temperature and strain rate, and the maximum efficiency was obtained at a temperature of 723 K (450 °C) and a strain rate of 1/s. The microstructural mechanism occurring in the maximum efficiency domain was dynamic recrystallization. The role of particles in the plastic flow and the microstructure evolution were discussed.

Kim, Su-Hyeon; Cho, Young-Hee; Lee, Jung-Moo

2014-06-01

328

Composite Amplitude Modulated Phase Only Filter Based Detection and Tracking of the Back-Reflection of KDP Images  

SciTech Connect

An algorithm for determining the position of the KDP back-reflection image was developed. It was compared to a centroid-based algorithm. While the algorithm based on centroiding exhibited a radial standard deviation of 9 pixels, the newly proposed algorithm based on classical matched filtering (CMF) and a Gaussian fit to correlation peak provided a radial standard deviation of less than 1 pixel. The speed of the peak detection was improved from an average of 5.5 seconds for Gaussian fit to 0.022 seconds by using a polynomial fit. The performance was enhanced even further by utilizing a composite amplitude modulated phase only filter; producing a radial standard deviation of 0.27 pixels. The proposed technique was evaluated on 900+ images with varying degrees of noise and image amplitude as well as real National Ignition Facility (NIF) images.

Awwal, A S; McClay, W A; Ferguson, S W; Candy, J V; Salmon, J T; Wegner, P J

2004-08-26

329

Composites  

NASA Astrophysics Data System (ADS)

The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

Taylor, John G.

330

Colour management is a socio-technical problem  

Microsoft Academic Search

This paper describes how achieving consistent colour reproduction across different devices is a complicated matter. Although there is a technological infrastructure for managing colour across devices this is very rarely used as intended. This infrastructure has been created by modelling the problem of colour management as a wholly technical one. In this paper we illustrate the importance of understanding the

Jacki O'neill; David Martin; Tommaso Colombino; Frédéric Roulland; Jutta Willamowski

2008-01-01

331

EXERCISES IN CARTOGRAPHY AND GEOINFORMATICS: TEACHING THE COLOURS Arzu LTEKN  

E-print Network

employ colour as information. In a Remote-Sensing data based forest classification map, the classes production. #12;2. What is Colour 2.1. Definition Colour is light. In other words, it is a side product of the light-spectrum. The light is reflected or absorbed by the objects, and we "see" the reflected ones

�öltekin, Arzu

332

The representation of colours in the cerebral cortex  

Microsoft Academic Search

New insights into how colour is represented in the cerebral cortex and what variables govern the responses of single cortical colour-coded cells have been gained by the discovery of specific visual cortical areas rich in colour-coded cells.

S. Zeki

1980-01-01

333

Skin Blood Perfusion and Oxygenation Colour Affect Perceived Human Health  

Microsoft Academic Search

Skin blood perfusion and oxygenation depends upon cardiovascular, hormonal and circulatory health in humans and provides socio-sexual signals of underlying physiology, dominance and reproductive status in some primates. We allowed participants to manipulate colour calibrated facial photographs along empirically-measured oxygenated and deoxygenated blood colour axes both separately and simultaneously, to optimise healthy appearance. Participants increased skin blood colour, particularly oxygenated,

Ian D. Stephen; Vinet Coetzee; Miriam Law Smith; David I. Perrett; Rebecca Sear

2009-01-01

334

Summing Large-N Towers in Colour Flow Evolution  

E-print Network

We consider soft gluon evolution in the colour flow basis. We give explicit expressions for the colour structure of the (one-loop) soft anomalous dimension matrix for an arbitrary number of partons, and show how the successive exponentiation of classes of large-N contributions can be achieved to provide a systematic expansion of the evolution in terms of colour supressed contributions.

Simon Plätzer

2013-12-09

335

Inheritance of coat colour in the field spaniel dog  

E-print Network

Note Inheritance of coat colour in the field spaniel dog R Robinson St Stephens Nursery, Stephens known as roan. dog genetics / coat colour / field spaniel / breed R�sum� - H�r�dit� de la couleur du for the heredity of coat colour in the dog (Little, 1957; Robinson, 1990), it has become apparent as work

Paris-Sud XI, Université de

336

Colour contribution to children's wayfinding in school environments  

Microsoft Academic Search

The purpose of this study was to explore the contribution of colour to children's wayfinding ability in school environments and to examine the differences between colours in terms of their remembrance and usability in route learning process. The experiment was conducted with three different sample groups for each of three experiment sets differentiated by their colour arrangement. The participants totalled

Nilgün Olguntürk

2011-01-01

337

A NEW PROOF OF THE FOUR-COLOUR THEOREM  

Microsoft Academic Search

The four-colour theorem, that every loopless planar graph admits a vertex-colouring with at most four dierent colours, was proved in 1976 by Appel and Haken, using a computer. Here we announce another proof, still using a computer, but simpler than Appel and Haken's in several respects. For our purposes a graph G consists of a nite set V (G) of

NEIL ROBERTSON; DANIEL P. SANDERS; PAUL SEYMOUR; ROBIN THOMAS

1996-01-01

338

Extending partial 3-colourings in a planar graph  

Microsoft Academic Search

Let D be a disc, and let X be a finite subset of points on the boundary of D. An essential part of the proof of the four colour theorem is the fact that many sets of 4-colourings of X do not arise from the proper 4-colourings of any graph drawn in D. In contrast to this, we show that

Matt Devos; Paul D. Seymour

2003-01-01

339

Four colours suffice: how the map problem was solved  

Microsoft Academic Search

This book contains an account of the history of the Four Colour Problem and its solution. Suppose one wants to assign colours to the countries on a map in such a way that no two neighbouring countries — with a common boundary consisting of more than just isolated points — receive the same colour. (We assume the map is drawn

Robin Wilson; Charles Nash

2003-01-01

340

Rotation sequences and edge-colouring of binary tree pairs  

Microsoft Academic Search

The famous four-colour problem of planar maps is equivalent, by an optimally fast reduction, to the problem of colouring pairs of binary trees (CPBT). Extant proofs of the four colour theorem lack conciseness, are not lucid in their detail and require hours of electronic computation. The search for a more satisfactory proof continues and, in this spirit, we explore one

Alan Gibbons; Paul Sant

2004-01-01

341

The Sylvester-Gallai theorem, colourings and algebra  

Microsoft Academic Search

Our point of departure is the following simple common gen- eralisation of the Sylvester-Gallai theorem and the Motzkin-Rabin the- orem: Let S be a finite set of points in the plane, with each point coloured red or blue or with both colours. Suppose that for any two distinct points A, B 2 S sharing a colour there is a third

Lourens M. Pretorius; Konrad J. Swanepoel

2009-01-01

342

Dependence between colour and individual anthocyanin content in ripening grapes  

Microsoft Academic Search

Three red grape cultivars of different coloration (Flame seedless, Exotic and Monastrell), grown in Murcia (southeast Spain) were analysed during ripening for external colour and individual pigment content. The application of the CIRG colour index, calculated from the coordinates hue angle (h), lightness (L*) and chroma (C*) of the CIELAB colour space, and defined as [(180-h)\\/(L*+C*)], permitted an objective evaluation

José A Fernández-López; Luis Almela; José A Muñoz; Venancio Hidalgo; Juan Carreño

1998-01-01

343

THE EFFECTIVENESS OF COLOUR IN LEARNING FROM EDUCATIONAL TELEVISION  

Microsoft Academic Search

The author reviews recent research comparing both the relative learning gains and relative attitudes of students using colour or monochrome television material. It is concluded that all users of educational television should resist the temptation to spend large sums on colour television equipment merely because colour is now widely preferred by society at large.

Geoffrey Roberts

1978-01-01

344

Identification of "ever-cropped" land (1984-2010) using Landsat annual maximum NDVI image composites: Southwestern Kansas case study.  

PubMed

A time series of 230 intra- and inter-annual Landsat Thematic Mapper images was used to identify land that was ever cropped during the years 1984 through 2010 for a five county region in southwestern Kansas. Annual maximum Normalized Difference Vegetation Index (NDVI) image composites (NDVI(ann-max)) were used to evaluate the inter-annual dynamics of cropped and non-cropped land. Three feature images were derived from the 27-year NDVI(ann-max) image time series and used in the classification: 1) maximum NDVI value that occurred over the entire 27 year time span (NDVI(max)), 2) standard deviation of the annual maximum NDVI values for all years (NDVI(sd)), and 3) standard deviation of the annual maximum NDVI values for years 1984-1986 (NDVI(sd84-86)) to improve Conservation Reserve Program land discrimination.Results of the classification were compared to three reference data sets: County-level USDA Census records (1982-2007) and two digital land cover maps (Kansas 2005 and USGS Trends Program maps (1986-2000)). Area of ever-cropped land for the five counties was on average 11.8 % higher than the area estimated from Census records. Overall agreement between the ever-cropped land map and the 2005 Kansas map was 91.9% and 97.2% for the Trends maps. Converting the intra-annual Landsat data set to a single annual maximum NDVI image composite considerably reduced the data set size, eliminated clouds and cloud-shadow affects, yet maintained information important for discriminating cropped land. Our results suggest that Landsat annual maximum NDVI image composites will be useful for characterizing land use and land cover change for many applications. PMID:22423150

Maxwell, Susan K; Sylvester, Kenneth M

2012-06-01

345

Colour-magnitude diagrams of transiting Exoplanets - II. A larger sample from photometric distances  

NASA Astrophysics Data System (ADS)

Colour-magnitude diagrams form a traditional way of presenting luminous objects in the Universe and compare them to each other. Here, we estimate the photometric distance of 44 transiting exoplanetary systems. Parallaxes for seven systems confirm our methodology. Combining those measurements with fluxes obtained while planets were occulted by their host stars, we compose colour-magnitude diagrams in the near and mid-infrared. When possible, planets are plotted alongside very low mass stars and field brown dwarfs, who often share similar sizes and equilibrium temperatures. They offer a natural, empirical, comparison sample. We also include directly imaged exoplanets and the expected loci of pure blackbodies. Irradiated planets do not match blackbodies; their emission spectra are not featureless. For a given luminosity, hot Jupiters' daysides show a larger variety in colour than brown dwarfs do and display an increasing diversity in colour with decreasing intrinsic luminosity. The presence of an extra absorbent within the 4.5 ?m band would reconcile outlying hot Jupiters with ultra-cool dwarfs' atmospheres. Measuring the emission of gas giants cooler than 1000 K would disentangle whether planets' atmospheres behave more similarly to brown dwarfs' atmospheres than to blackbodies, whether they are akin to the young directly imaged planets, or if irradiated gas giants form their own sequence.

Triaud, Amaury H. M. J.; Lanotte, Audrey A.; Smalley, Barry; Gillon, Michaël

2014-10-01

346

Capturing Natural-Colour 3D Models of Insects for Species Discovery and Diagnostics  

PubMed Central

Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity—past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens “from all angles” and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. (“Natural-colour” is used to contrast with “false-colour”, i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research, education, art, entertainment, biodiversity assessment and biosecurity control. PMID:24759838

Nguyen, Chuong V.; Lovell, David R.; Adcock, Matt; La Salle, John

2014-01-01

347

Composites  

NASA Astrophysics Data System (ADS)

It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-N?dza, A.; Mackiewicz, S.; Dutkiewicz, J.

2014-11-01

348

A new sample substrate for imaging and correlating organic and trace metal composition in biological cells and tissues  

Microsoft Academic Search

Many disease processes involve alterations in the chemical makeup of tissue. Synchrotron-based infrared (IR) and X-ray fluorescence\\u000a (XRF) microscopes are becoming increasingly popular tools for imaging the organic and trace metal compositions of biological\\u000a materials, respectively, without the need for extrinsic labels or stains. Fourier transform infrared microspectroscopy (FTIRM)\\u000a provides chemical information on the organic components of a material at

Lisa M. Miller; Qi Wang; Randy J. Smith; Hui Zhong; Donald Elliott; John Warren

2007-01-01

349

Direct observation and measurement of fiber architecture in short fiber-polymer composite foam through micro-CT imaging  

Microsoft Academic Search

A non-destructive X-ray imaging technique was used to determine internal structure in a polymer foam reinforced with short fibers. The technique, known as micro-CT (for computerized tomography), was used to measure the fiber length distribution (FLD) and fiber orientation distribution (FOD), two parameters that are critical to the behavior of short-fiber-reinforced composites. Phenolic foam reinforced with short glass fibers was

Hongbin Shen; Steven Nutt; David Hull

2004-01-01

350

White-light digital image cross-correlation (DICC) analysis of the deformation of composite materials with random microstructure  

Microsoft Academic Search

A sophisticated image cross-correlation algorithm (J. Appl. Opt. 33 (1994) 6667) has been used to measure both components of in-plane displacement at the surface of a deforming composite material. The natural random pattern present on the surface of a polished polymer bonded explosive (PBX) sample is photographed using a high-resolution digital camera mounted on an optical microscope. Frames are taken

P. J Rae; S. J. P Palmer; H. T Goldrein; A. L Lewis; J. E Field

2004-01-01

351

Determination of pigments in colour layers on walls of some selected historical buildings using optical and scanning electron microscopy  

SciTech Connect

For successful restoration of painted walls and painted coloured finishing coats it is necessary to determine the composition of the original colour layers. Identification of the pigments used in The Cistercian Abbey of Sticna and The Manor of Novo Celje was carried out using optical and scanning electron microscopy. Selected samples of wall paintings were inspected by the combined application of an optical microscope and a low-vacuum Scanning Electron Microscope to determine their colour and structural features and to identify the position of individual pigment grains. Energy dispersive spectroscopy was used to determine the elemental distribution on selected surfaces and elemental composition of individual pigments. It was found that the most abundantly used pigments were iron oxide red, cinnabar, green earth, umber, calcium carbonate white, ultramarine, yellow ochre and carbon black. These identifications have allowed us to compare the use of various pigments in buildings from different historical periods.

Skapin, A. Sever [Slovenian National Building and Civil Engineering Institute, Dimiceva 12, 1000 Ljubljana (Slovenia)], E-mail: andrijana.skapin@zag.si; Ropret, P. [Institute for the Protection of Cultural Heritage of Slovenia, Restoration Center, Poljanska 40, 1000 Ljubljana (Slovenia)], E-mail: polona.ropret@rescen.si; Bukovec, P. [University of Ljubljana, Faculty of Chemistry and Chemical Technology, Askerceva 5, 1000 Ljubljana (Slovenia)], E-mail: peter.bukovec@uni-lj.si

2007-11-15

352

Design guidelines of 1-3 piezoelectric composites dedicated to ultrasound imaging transducers, based on frequency band-gap considerations.  

PubMed

Periodic piezoelectric composites are widely used for imaging applications such as biomedical imaging or nondestructive evaluation. In this paper such structures are considered as phononic crystals, and their properties are investigated with respect to periodicity. This approach is based on the investigation of band gaps, that strongly depend on the properties of the considered composites (geometry, size, nature of materials). It is motivated by the fact that band gaps in principle allow one to excite the thickness mode without exciting other parasitic propagating waves. The used plane-wave-expansion method has already been applied to periodic piezoelectric composites, but, in contrast to previous approaches, not only waves propagating in the symmetry plane of the composite are considered, but also waves propagating with a nonzero angle of incidence with this plane. The method is applied to a representative 1-3 connectivity piezocomposite in order to demonstrate its potentialities for design purposes. The evolution of band gaps is explored with respect to the wave vector component parallel to piezoelectric transducer-rod axis. All bulk waves that contribute to the setting up of plate modes in the vicinity of the thickness mode are found and identified. PMID:17672629

Wilm, M; Khelif, A; Laude, V; Ballandras, S

2007-08-01

353

Diagnosing synaesthesia with online colour pickers: maximising sensitivity and specificity.  

PubMed

The most commonly used method for formally assessing grapheme-colour synaesthesia (i.e., experiencing colours in response to letter and/or number stimuli) involves selecting colours from a large colour palette on several occasions and measuring consistency of the colours selected. However, the ability to diagnose synaesthesia using this method depends on several factors that have not been directly contrasted. These include the type of colour space used (e.g., RGB, HSV, CIELUV, CIELAB) and different measures of consistency (e.g., city block and Euclidean distance in colour space). This study aims to find the most reliable way of diagnosing grapheme-colour synaesthesia based on maximising sensitivity (i.e., ability of a test to identify true synaesthetes) and specificity (i.e., ability of a test to identify true non-synaesthetes). We show, applying ROC (receiver operating characteristics) to binary classification of a large sample of self-declared synaesthetes and non-synaesthetes, that the consistency criterion (i.e., cut-off value) for diagnosing synaesthesia is considerably higher than the current standard in the field. We also show that methods based on perceptual CIELUV and CIELAB colour models (rather than RGB and HSV colour representations) and Euclidean distances offer an even greater sensitivity and specificity than most currently used measures. Together, these findings offer improved heuristics for the behavioural assessment of grapheme-colour synaesthesia. PMID:23458658

Rothen, Nicolas; Seth, Anil K; Witzel, Christoph; Ward, Jamie

2013-04-30

354

Colour-tunable fluorescent multiblock micelles.  

PubMed

Emerging strategies based on the self-assembly of block copolymers have recently enabled the bottom-up fabrication of nanostructured materials with spatially distinct functional regions. Concurrently, a drive for further miniaturization in applications such as optics, electronics and diagnostic technology has led to intense interest in nanomaterials with well-defined patterns of emission colour. Using a series of fluorescent block copolymers and the crystallization-driven living self-assembly approach, we herein describe the synthesis of multicompartment micelles in which the emission of each segment can be controlled to produce colours throughout the visible spectrum. This represents a bottom-up synthetic route to objects analogous to nanoscale pixels, into which complex patterns may be written. Because of their small size and high density of encoded information, these findings could lead to the development of new materials for applications in, for example, biological diagnostics, miniaturized display technology and the preparation of encoded nanomaterials with high data density. PMID:24594554

Hudson, Zachary M; Lunn, David J; Winnik, Mitchell A; Manners, Ian

2014-01-01

355

Colour-tunable fluorescent multiblock micelles  

NASA Astrophysics Data System (ADS)

Emerging strategies based on the self-assembly of block copolymers have recently enabled the bottom-up fabrication of nanostructured materials with spatially distinct functional regions. Concurrently, a drive for further miniaturization in applications such as optics, electronics and diagnostic technology has led to intense interest in nanomaterials with well-defined patterns of emission colour. Using a series of fluorescent block copolymers and the crystallization-driven living self-assembly approach, we herein describe the synthesis of multicompartment micelles in which the emission of each segment can be controlled to produce colours throughout the visible spectrum. This represents a bottom-up synthetic route to objects analogous to nanoscale pixels, into which complex patterns may be written. Because of their small size and high density of encoded information, these findings could lead to the development of new materials for applications in, for example, biological diagnostics, miniaturized display technology and the preparation of encoded nanomaterials with high data density.

Hudson, Zachary M.; Lunn, David J.; Winnik, Mitchell A.; Manners, Ian

2014-03-01

356

Thermodynamics of two-colour QCD  

NASA Astrophysics Data System (ADS)

We discuss the thermodynamics of two-colour QCD with four flavours of staggered quarks on 8 3 × 4 and 16 3 × 4 lattices. In our simulations we use the Naik action for the fermions and a (1,2) tree-level improved gauge action. We analyze the deconfinement and chiral phase transitions for four different quark masses (m=0.1,0.05,0.025,0.015). Contrary to three-colour QCD the peak in the Polyakov loop susceptibility decreases with decreasing quark mass. This reflects an early breaking of the string in the heavy quark potential, which we verify explicitly by calculating the heavy quark potential at finite temperature using Polyakov loop correlations.

Kaczmarek, O.; Karsch, F.; Laermann, E.

1999-03-01

357

The HS chromaticity diagram and the Lmn colour space  

NASA Astrophysics Data System (ADS)

In this paper a new HS chromaticity diagram for 10-degree observer with more linear colour distribution is presented. Both, the spectral locus and curve of purple colours generate unity circle -the HS diagram. By using the CIE lightness L as the third dimension, the Lrnn colour space is generated. This new colour space is embedded into cylinder radius of 100 (it stands for chroma) and height of 100 (it stands for lightness). If n is plotted against m the points in resulting Lmn-space are not uniquely related to chromaticity because their position depends on the value of L. The colours of all object-colour stimuli fall within this cylinder boundary. The spectrum locus of the monochromatic stimuli is generally well outside the boundary of object-colour stimuli.

Dohnal, Miroslav

2006-03-01

358

How to Calculate Colourful Cross Sections Efficiently  

SciTech Connect

Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities, where the CSW technique has efficiencies comparable or better than both of the other two methods.

Gleisberg, Tanju; Hoeche, Stefan; Krauss, Frank

2008-09-03

359

Colour Magnitude Diagrams of Transiting Exoplanets  

NASA Astrophysics Data System (ADS)

Colour-Magnitude diagrams form a traditional way of representing luminous objects in the Universe and compare them to each others. Here, the photometric distances of 44 transiting exoplanetary systems were estimated. For seven of those, parallaxes confirm the methodology. From the combination of those measurements with fluxes obtained while planets were occulted by their host stars, colour-magnitude diagrams are composed in the near and mid IR. When possible, planets are plotted with field brown dwarfs who often have similar sizes and equilibrium temperatures, thus offering a natural empirical comparison sample. Exoplanets are also compared to the expected loci of pure blackbodies. In general planets do not agree with the brown dwarfs sequences, and neither do they match blackbodies. It is however possible to affirm that they are not featureless and that they display an increasing diversity in colour with decreasing intrinsic luminosity. A missing source of absorption within the [4.5 ?m] band, for some planets, would generally reconcile hot Jupiters with brown dwarfs’ cool atmospheres. Alternatively, measuring the emission of gas giants cooler than 1 000 K would disentangle whether planets’ atmospheres behave like brown dwarfs’ atmospheres, like blackbodies, or whether they form their own sequence.

Triaud, Amaury H. M. J.

2014-06-01

360

Background complexity affects colour preference in bumblebees  

NASA Astrophysics Data System (ADS)

Flowers adapted for hummingbird pollination are typically red. This correlation is usually explained by the assertion that nectar- or pollen-stealing bees are “blind” to red flowers. However, laboratory studies have shown that bees are capable of locating artificial red flowers and often show no innate preference for blue over red. We hypothesised that these findings might be artefacts of the simplified laboratory environment. Using bumblebees ( Bombus impatiens) that had been trained to visit red and blue artificial flowers, we tested whether colour preference was influenced by complexity of the background on which they were foraging. Many bees were indifferent to flower colour when tested using a uniform green background like those commonly used in laboratory studies, but all bees showed strong colour preferences (usually for blue) when flowers were presented against a photograph of real foliage. Overall, preference for blue flowers was significantly greater on the more realistic, complex background. These results support the notion that the red of “hummingbird syndrome” flowers can function to reduce bee visits despite the ability of bees to detect red and highlight the need to consider context when drawing inferences about pollinator preferences from laboratory data.

Forrest, Jessica; Thomson, James D.

2009-08-01

361

Colourful antenna subtraction for gluon scattering  

E-print Network

In this talk I discuss the application and generalization of the antenna subtraction method to processes involving incoherent interferences of partial amplitudes, which are generically present for the sub-leading colour contributions to processes involving more than five partons. The approach makes use of the known infrared (IR) singularity structure of one- and two-loop matrix elements to guide the construction of the subtraction terms. A set of integrated dipoles are defined which can be used to express the poles of one- and two-loop matrix elements in terms of integrated antennae. The unintegrated counterparts of these subtraction terms are then inferred to construct the double real and real-virtual subtraction terms. The method has been tested by computing the NNLO sub-leading colour contribution dijet production via gluon scattering. The double real and real virtual matrix elements for this process can be written purely in terms of incoherent interferences and so the successful removal of all singularities and divergences demonstrates the ability of the antenna subtraction method to handle general sub-leading colour contributions

James Currie

2013-11-24

362

Radiometric normalization, compositing, and quality control for satellite high resolution image mosaics over large areas  

Microsoft Academic Search

An objective normalization procedure has been developed to create image mosaics of radiometric equalization radiometric normalization for image mosaics (RNIM). The procedure employs a band-specific principal component analysis for overlap areas to achieve accurate and consistent radiometric transforms in each spectral band. It is demonstrated that the result of radiometric equalization is independent of the order of images to be

Yong Du; Josef Cihlar; Jean Beaubien; Rasim Latifovic

2001-01-01

363

Nondestructive Superresolution Imaging of Defects and Nonuniformities in Metals, Semiconductors, Dielectrics, Composites, and Plants Using Evanescent Microwaves  

NASA Technical Reports Server (NTRS)

We have imaged and mapped material nonuniformities and defects using microwaves generated at the end of a microstripline resonator with 0.4 micrometer lateral spatial resolution at 1 GHz. Here we experimentally examine the effect of microstripline substrate permittivity, the feedline-to-resonator coupling strength, and probe tip geometry on the spatial resolution of the probe. Carbon composites, dielectrics, semiconductors, metals, and botanical samples were scanned for defects, residual stresses, subsurface features, areas of different film thickness, and moisture content. The resulting evanescent microwave probe (EMP) images are discussed. The main objective of this work is to demonstrate the overall capabilities of the EMP imaging technique as well as to discuss various probe parameters that can be used to design EMPs for different applications.

Tabib-Azar, M.; Pathak, P. S.; Ponchak, G.; LeClair, S.

1999-01-01

364

Spatial Frequency Domain Imaging of Port Wine Stain Biochemical Composition in Response to Laser Therapy: A Pilot Study  

PubMed Central

Background and Objective Objective methods to assess port wine stain (PWS) response to laser treatment have been the subject of various research efforts for several years. Herein, we present a pilot study using a newly developed, light emitting diode (LED) based spatial frequency domain imaging (SFDI) device to record quantitatively biochemical compositional changes in PWS after laser therapy. Study Design/Patients and Methods A SFDI system was used to image before, and after, five PWS treatment sessions [n = 4 subjects (one subject was imaged before and after two consecutive laser treatments)]. SFDI derived wide-field optical properties (absorption and scattering) and tissue chromophore concentrations including oxy-hemoglobin (ctO2Hb), deoxy-hemoglobin (ctHHb), total hemoglobin (ctTHb), and tissue oxygen saturation (stO2) are presented for skin imaged prior to and immediately after laser treatment. The SFDI derived images were analyzed by comparing the above measurements in PWS to those of normal skin and tracking changes immediately after laser exposure. Results Elevated oxy-hemoglobin (>20%) and tissue oxygen saturation (>5%) were measured in all PWS lesions and compared to values for normal skin prior to treatment. Laser treatment resulted in an increase in deoxy-hemoglobin (>100%), decrease in tissue oxygen saturation (>10%), and reduced scattering (>15%) in all PWS lesions. One subject was followed before and after two consecutive laser treatments and the overall improvement in PWS lesion blanching was quantitatively assessed by measuring a 45% decrease in dermal blood volume. Conclusion SFDI is a rapid non-contact wide-field optical technique that shows potential as an imaging device that can be used to quantify biochemical compositional changes in PWS after laser therapy. Future work will investigate the potential of SFDI to provide intra-operative guidance for laser therapy of PWS lesions on an individual patient basis. PMID:22911574

Mazhar, Amaan; Sharif, Seyed A.; Cuccia, J. David; Nelson, J. Stuart; Kelly, Kristen M.; Durkin, Anthony J.

2012-01-01

365

Direct Numerical Simulation of Fracture Behaviour for Random Short Wood Fibres Reinforced Composites, Comparison with Digital Image Correlation Experiments  

NASA Astrophysics Data System (ADS)

The work is to predict fracture behaviour of bio-composites from the tensile properties of its components. In this work, we have realized a direct numerical simulation of fracture behaviour for random short spruce fibers reinforced composites. For calculations, wood fibers have been considered as linear elastic bodies, polypropylene matrix as an elastic-plastic material. Then, numerical results have been compared with experimental results that have been obtained by digital image correlation. This comparison indicates that random fiber FE model of random short spruce fibers reinforced composites can be able to fairly reflect the influence of random fibers microstructure in the composite on its fracture behavior. The calculation of both random fiber and homogeneous FE model and their comparison with experiments show that the average values of J-integral in a region in the front of the crack tip from both numerical FE models are in good agreement with the average J value of DIC experiment in the same region when the numerical and experimental CT specimens of the short spruce fiber reinforced composite are subjected to the same extension at their loading point.

Shen, M.; Touchard, F.; Bezine, G.; Brillaud, J.

2010-06-01

366

A shared chemical basis of avian host-parasite egg colour mimicry  

PubMed Central

Avian brood parasites lay their eggs in other birds' nests and impose considerable fitness costs on their hosts. Historically and scientifically, the best studied example of circumventing host defences is the mimicry of host eggshell colour by the common cuckoo (Cuculus canorus). Yet the chemical basis of eggshell colour similarity, which impacts hosts' tolerance towards parasitic eggs, remains unknown. We tested the alternative scenarios that (i) cuckoos replicate host egg pigment chemistry, or (ii) cuckoos use alternative mechanisms to produce a similar perceptual effect to mimic host egg appearance. In parallel with patterns of similarity in avian-perceived colour mimicry, the concentrations of the two key eggshell pigments, biliverdin and protoporphyrin, were most similar between the cuckoo host-races and their respective hosts. Thus, the chemical basis of avian host–parasite egg colour mimicry is evolutionarily conserved, but also intraspecifically flexible. These analyses of pigment composition reveal a novel proximate dimension of coevolutionary interactions between avian brood parasites and hosts, and imply that alternative phenotypes may arise by the modifications of already existing biochemical and physiological mechanisms and pathways. PMID:21920975

Igic, Branislav; Cassey, Phillip; Grim, Tomas; Greenwood, David R.; Moskat, Csaba; Rutila, Jarkko; Hauber, Mark E.

2012-01-01

367

A shared chemical basis of avian host-parasite egg colour mimicry.  

PubMed

Avian brood parasites lay their eggs in other birds' nests and impose considerable fitness costs on their hosts. Historically and scientifically, the best studied example of circumventing host defences is the mimicry of host eggshell colour by the common cuckoo (Cuculus canorus). Yet the chemical basis of eggshell colour similarity, which impacts hosts' tolerance towards parasitic eggs, remains unknown. We tested the alternative scenarios that (i) cuckoos replicate host egg pigment chemistry, or (ii) cuckoos use alternative mechanisms to produce a similar perceptual effect to mimic host egg appearance. In parallel with patterns of similarity in avian-perceived colour mimicry, the concentrations of the two key eggshell pigments, biliverdin and protoporphyrin, were most similar between the cuckoo host-races and their respective hosts. Thus, the chemical basis of avian host-parasite egg colour mimicry is evolutionarily conserved, but also intraspecifically flexible. These analyses of pigment composition reveal a novel proximate dimension of coevolutionary interactions between avian brood parasites and hosts, and imply that alternative phenotypes may arise by the modifications of already existing biochemical and physiological mechanisms and pathways. PMID:21920975

Igic, Branislav; Cassey, Phillip; Grim, Tomás; Greenwood, David R; Moskát, Csaba; Rutila, Jarkko; Hauber, Mark E

2012-03-22

368

The contrast sensitivity of the colour mechanisms of the human eye  

PubMed Central

1. To isolate the colour receptive systems of the eye, a sinusoidal grating of one colour was superimposed on a bright background of another colour and the threshold contrast for resolving the grating was determined. 2. A procedure is described which allows one to estimate the extent by which the bright background reduces the contrast of the test grating of another colour. Using this procedure, the measured threshold contrasts of the test grating were replotted in terms of the effective contrast sensitivity for the composite target. 3. The effectivity of a red background in reducing the contrast of a green grating was found to be determined not by its apparent brightness but rather by the extent to which it excited the green mechanism. 4. The effective contrast sensitivities for a green grating on a green background, for a green grating on a red background, and for a red grating on a green background were found to be not significantly different. 5. Visual acuity for a blue grating on a yellow background was reduced from normal by about a factor of six. This loss in visual acuity was due to both a reduction in contrast sensitivity and a reduction in resolution. PMID:5652884

Green, Daniel G.

1968-01-01

369

Writing with Visual Images: Examining the Video Composition Processes of High School Students  

ERIC Educational Resources Information Center

This teacher-researcher study explored the manner in which students created video compositions in a secondary English language arts media studies program. A review of research literature indicates fundamental differences between print and video compositions, which include modality of representation, task setting, and curricular role. Another…

Bruce, David L.

2009-01-01

370

Plexus structure imaging with thin slab MR neurography: rotating frames, fly-throughs, and composite projections  

Microsoft Academic Search

We explored multiple image processing approaches by which to display the segmented adult brachial plexus in a three-dimensional manner. Magnetic resonance neurography (MRN) 1.5-Tesla scans with STIR sequences, which preferentially highlight nerves, were performed in adult volunteers to generate high-resolution raw images. Using multiple software programs, the raw MRN images were then manipulated so as to achieve segmentation of plexus

David T. Raphael; Diane McIntee; Jay S. Tsuruda; Patrick Colletti; Raymond Tatevossian; James Frazier

2006-01-01

371

Familiarity effects in the construction of facial-composite images using modern software systems.  

PubMed

We investigate the effect of target familiarity on the construction of facial composites, as used by law enforcement to locate criminal suspects. Two popular software construction methods were investigated. Participants were shown a target face that was either familiar or unfamiliar to them and constructed a composite of it from memory using a typical 'feature' system, involving selection of individual facial features, or one of the newer 'holistic' types, involving repeated selection and breeding from arrays of whole faces. This study found that composites constructed of a familiar face were named more successfully than composites of an unfamiliar face; also, naming of composites of internal and external features was equivalent for construction of unfamiliar targets, but internal features were better named than the external features for familiar targets. These findings applied to both systems, although benefit emerged for the holistic type due to more accurate construction of internal features and evidence for a whole-face advantage. STATEMENT OF RELEVANCE: This work is of relevance to practitioners who construct facial composites with witnesses to and victims of crime, as well as for software designers to help them improve the effectiveness of their composite systems. PMID:22103723

Frowd, Charlie D; Skelton, Faye C; Butt, Neelam; Hassan, Amal; Fields, Stephen; Hancock, Peter J B

2011-12-01

372

An Evanescent Microwave Probe for Super-Resolution Nondestructive Imaging of Metals, Semiconductors, Dielectrics, Composites and Biological Specimens  

NASA Technical Reports Server (NTRS)

Using evanescent microwaves with decay lengths determined by a combination of microwave wavelength (lambda) and waveguide termination geometry, we have imaged and mapped material non-uniformities and defects with a resolving capability of lambda/3800=79 microns at 1 GHz. In our method a microstrip quarter wavelength resonator was used to generate evanescent microwaves. We imaged materials with a wide range of conductivities. Carbon composites, dielectrics (Duroid, polymers), semiconductors (3C-SiC, polysilicon, natural diamond), metals (tungsten alloys, copper, zinc, steel), high-temperature superconductors, and botanical samples were scanned for defects, residual stresses, integrity of brazed junctions, subsurface features, areas of different film thickness and moisture content. The evanescent microwave probe is a versatile tool and it can be used to perform very fast, large scale mapping of a wide range of materials. This method of characterization compares favorably with ultrasound testing, which has a resolution of about 0.1 mm and suffers from high absorption in composite materials and poor transmission across boundaries. Eddy current methods which can have a resolution on the order of 50 microns are restricted to evaluating conducting materials. Evanescent microwave imaging, with careful choice of operating frequency and probe geometry, can have a resolution of up to 1 micron. In this method we can scan hot and moving objects, sample preparation is not required, testing is non-destructive, non-invasive and non-contact, and can be done in air, in liquid or in vacuum.

Pathak, P. S.; Tabib-Azar, M.; Ponchak, G.

1998-01-01

373

Upconversion nanoparticles and their composite nanostructures for biomedical imaging and cancer therapy  

NASA Astrophysics Data System (ADS)

Upconversion nanoparticles (UCNPs), particularly lanthanide-doped nanocrystals, which emit high energy photons under excitation by the near-infrared (NIR) light, have found potential applications in many different fields, including biomedicine. Compared with traditional down-conversion fluorescence imaging, the NIR light excited upconversion luminescence (UCL) imaging relying on UCNPs exhibits improved tissue penetration depth, higher photochemical stability, and is free of auto-fluorescence background, which promises biomedical imaging with high sensitivity. On the other hand, the unique upconversion process of UCNPs may be utilized to activate photosensitive therapeutic agents for applications in cancer treatment. Moreover, the integration of UCNPs with other functional nanostructures could result in the obtained nanocomposites having highly enriched functionalities, useful in imaging-guided cancer therapies. This review article will focus on the biomedical imaging and cancer therapy applications of UCNPs and their nanocomposites, and discuss recent advances and future prospects in this emerging field.

Cheng, Liang; Wang, Chao; Liu, Zhuang

2012-12-01

374

The colour centre in the cerebral cortex of man  

Microsoft Academic Search

ANATOMICAL and physiological studies have shown that there is an area specialized for the processing of colour (area V4) in the prestriate cortex of macaque monkey brain1. Earlier this century, suggestive clinical evidence for a colour centre in the brain of man2,3 was dismissed4-8 because of the association of other visual defects with the defects in colour vision4,5,7. However, since

C. J. Lueck; S. Zeki; K. J. Friston; M.-P. Deiber; P. Cope; V. J. Cunningham; A. A. Lammertsma; C. Kennard; R. S. J. Frackowiak

1989-01-01

375

How big does a coloured overlay have to be?  

PubMed

Coloured overlays and coloured lenses can both increase reading speed, but when they do their colour is not necessarily the same, suggesting that the beneficial effects of a coloured filter might depend upon the area of the visual field that it colours. We investigated the effects of overlays on reading speed and varied the size of the overlay and the colour of the surround. Children who had been assessed with coloured overlays were required to read a passage of randomly ordered common words. The words were printed in black ink as a block of text positioned centrally on an A4 page of white paper in landscape orientation. The speed of reading was compared under four conditions: (1) without an overlay; (2) with an overlay of the chosen colour covering the entire page; (3) with the overlay cut so that it just covered the text but left the margin white; (4) with the overlay of the chosen colour covering the text but with the margin coloured a complementary colour, using a second overlay. The children who were using an overlay read more quickly with the overlay; those who were no longer using the overlay did not. Although the block of text covered less than half the page, the colour and nature of the margin did not affect reading speed significantly. These findings suggest that in order to be effective at improving reading speed an overlay needs to cover the text, but not necessarily the remainder of the page, which means that smaller overlays may sometimes be sufficient. PMID:14687202

Waldie, Michelle; Wilkins, Arnold

2004-01-01

376

On the red colour of raspberry ( Rubus idaeus)  

Microsoft Academic Search

Anthocyanins are the ubiquitous water-soluble pigments that are found in flowers and fruits, and are responsible for their impressive red and blue colours. Many examples of the strategies used by nature to obtain colour in plants are based on co-pigmentation, a phenomenon that stabilises and intensifies colours at pH values where the anthocyanin pigment alone is colourless. Several examples of

Maria João Melo; Margarida C Moncada; Fernando Pina

2000-01-01

377

Strong edge-colouring of sparse planar graphs Julien Bensmaila  

E-print Network

is a planar graph then s(G) 4 + 4, for 3. The proof of Theorem 1 uses the Four Colour Theorem. The authorsStrong edge-colouring of sparse planar graphs Julien Bensmaila , Ararat Harutyunyanb , Hervé, LIP, �quipe MC2, 46, allée d'Italie, 69342 Lyon Cedex 07, France Abstract A strong edge-colouring

Paris-Sud XI, Université de

378

Control of shell colour changes in the lobster, Panulirus cygnus.  

PubMed

The transition from juvenile to adult in the Australian western rock lobster, Panulirus cygnus (George), is preceded by a mass migration from inshore nursery reefs to offshore breeding grounds. Associated with this migration is a moult which results in the animals that are due to migrate undergoing characteristic colour change from deep red to pale pink, known as the ;white' phase, which is believed to be triggered by environmental factors. To investigate this phenomenon, the colour change of wild-caught animals was measured over two separate years in response to two important modifiers of crustacean shell colour, dietary carotenoid and background substrate colour. Changes in shell colour during this colour transition period were influenced more greatly by other factors independent of diet or background substrate and no mass colour change was induced during this time. Shell colour measurement and carotenoid quantification confirmed the presence of animals similar to wild-caught ;whites', regardless of the treatment. From these experimental observations we infer that the ;white' phase of the western rock lobster is not triggered by dietary modification or in response to background substrate. We propose that this transition is under the regulation of an ontogenetic program activated at a specific moult, which induces presently unidentified molecular changes linked to shell colour production. This unique colour transition may have evolved to provide protective camouflage during migration, and serves as an excellent model to study the genetic mechanisms underlying crustacean shell colouration. These data also provide insight into the changes in carotenoid levels induced by environmental factors, and the ability to modify crustacean shell colour in aquaculture. PMID:18424686

Wade, Nicholas M; Melville-Smith, Roy; Degnan, Bernard M; Hall, Michael R

2008-05-01

379

The Categorisation of Non-Categorical Colours: A Novel Paradigm in Colour Perception  

PubMed Central

In this paper, we investigate a new paradigm for studying the development of the colour ‘signal’ by having observers discriminate and categorize the same set of controlled and calibrated cardinal coloured stimuli. Notably, in both tasks, each observer was free to decide whether two pairs of colors were the same or belonged to the same category. The use of the same stimulus set for both tasks provides, we argue, an incremental behavioural measure of colour processing from detection through discrimination to categorisation. The measured data spaces are different for the two tasks, and furthermore the categorisation data is unique to each observer. In addition, we develop a model which assumes that the principal difference between the tasks is the degree of similarity between the stimuli which has different constraints for the categorisation task compared to the discrimination task. This approach not only makes sense of the current (and associated) data but links the processes of discrimination and categorisation in a novel way and, by implication, expands upon the previous research linking categorisation to other tasks not limited to colour perception. PMID:23536899

Cropper, Simon J.; Kvansakul, Jessica G. S.; Little, Daniel R.

2013-01-01

380

Difficulties in examination of the origin of the vertebral artery by duplex and colour-coded Doppler sonography: anatomical considerations  

Microsoft Academic Search

Despite progress in ultrasonographic techniques visualisation of the origin of the vertebral arteries, particularly the left, by duplex and colour Doppler imaging, still poses a problem in a significant number of patients. In anatomical and radiological studies we demonstrated an anomalous origin in 6%, the left vertebral artery originating directly from the aorta in most cases. The origin from the

S. Trattnig; C. Matula; F. Karnel; K. Daha; M. Tschabitscher; B. Schwaighofer

1993-01-01

381

Development of a forensic skin colour predictive test.  

PubMed

There is growing interest in skin colour prediction in the forensic field. However, a lack of consensus approaches for recording skin colour phenotype plus the complicating factors of epistatic effects, environmental influences such as exposure to the sun and unidentified genetic variants, present difficulties for the development of a forensic skin colour predictive test centred on the most strongly associated SNPs. Previous studies have analysed skin colour variation in single unadmixed population groups, including South Asians (Stokowski et al., 2007, Am. J. Hum. Genet, 81: 1119-32) and Europeans (Jacobs et al., 2013, Hum Genet. 132: 147-58). Nevertheless, a major challenge lies in the analysis of skin colour in admixed individuals, where co-ancestry proportions do not necessarily dictate any one person's skin colour. Our study sought to analyse genetic differences between African, European and admixed African-European subjects where direct spectrometric measurements and photographs of skin colour were made in parallel. We identified strong associations to skin colour variation in the subjects studied from a pigmentation SNP discovery panel of 59 markers and developed a forensic online classifier based on naïve Bayes analysis of the SNP profiles made. A skin colour predictive test is described using the ten most strongly associated SNPs in 8 genes linked to skin pigmentation variation. PMID:25082135

Maroñas, Olalla; Phillips, Chris; Söchtig, Jens; Gomez-Tato, Antonio; Cruz, Raquel; Alvarez-Dios, José; de Cal, María Casares; Ruiz, Yarimar; Fondevila, Manuel; Carracedo, Angel; Lareu, María V

2014-11-01

382

Colour contribution to children's wayfinding in school environments  

NASA Astrophysics Data System (ADS)

The purpose of this study was to explore the contribution of colour to children's wayfinding ability in school environments and to examine the differences between colours in terms of their remembrance and usability in route learning process. The experiment was conducted with three different sample groups for each of three experiment sets differentiated by their colour arrangement. The participants totalled 100 primary school children aged seven and eight years old. The study was conducted in four phases. In the first phase, the participants were tested for familiarity with the experiment site and also for colour vision deficiencies by using Ishihara's tests for colour-blindness. In the second phase, they were escorted on the experiment route by the tester one by one, from one starting point to one end point and were asked to lead the tester to the end point by the same route. In the third phase, they were asked to describe verbally the route. In the final phase, they were asked to remember the specific colours at their correct locations. It was found that colour has a significant effect on children's wayfinding performances in school environments. However, there were no differences between different colours in terms of their remembrances in route finding tasks. In addition, the correct identifications of specific colours and landmarks were dependent on their specific locations. Contrary to the literature, gender differences were not found to be significant in the accuracy of route learning performances.

Helvac?o?lu, Elif; Olguntürk, Nilgün

2011-03-01

383

Metal-polymer nano-composite films with ordered vertically aligned metal cylinders for sub-wavelength imaging  

NASA Astrophysics Data System (ADS)

We propose a self-assembled and anisotropically metal loaded large area PS-b-P4VP diblock copolymer film as a medium with hyperbolic dispersion for application in superlensing and nanolithography. We obtained domain sizes from 30 to 100 nm with successful demonstration of metal loading inside the nano-templates. The separation between the individual nanorods and their radius was effectively controlled by varying the molecular weights and compositions of the polymers. We apply Maxwell-Garnett homogenization and FDTD simulations to show the sub-wavelength imaging and lithography potential of these hyperbolic metamaterials (HMMs). A proof of principle nanolithography result demonstrates sub-wavelength imaging and lithography using the proposed HMMs.

Wu, Linda Y. L.; Leng, B.; Bisht, A.

2014-09-01

384

Principles and appraisal of combined images in NMR.  

PubMed

The interpretation of NMR images at Aberdeen is most often performed by the individual study of the proton density, difference, inversion recovery and T1 image. This report investigates the usefulness of presenting the information from a pair of images, in this instance the T1 and proton density images, in a single composite image. Information from the two images is combined such that the values from one image are represented by a change in hue (colour), and the values from the other by a change in luminance (intensity). To test the advantages of such combined images, a trial was run using a selection of prediagnosed abnormal brain scans. The information perceived as hue and luminance in the combined images was compared with that from separate conventional monochrome proton density and T1 images. Medical and nonmedical users were told the final diagnosis and were asked whether it was possible to see more, less, or the same information with regard to clinically relevant details in the structure of the abnormality and the image as whole. The results have revealed that for the majority of cases the combined image format can effectively represent the information normally contained in both the monochrome proton density and T1 images--thus speeding up the image viewing process. PMID:2601449

Wells, M G; Sharp, P F; Law, A N

1989-05-01

385

Colour vision deficiency in the medical profession.  

PubMed Central

Colour is often used as a sign in medicine, yet there have been few studies into the effects of a colour vision deficiency (CVD) on doctors' medical skills. Using a literature search, the results indicate the prevalence of CVD in the medical profession and its effects on medical skills. For the congenital form among male doctors in the United Kingdom, the prevalence is shown to be probably about the same as for the population at large; i.e. 8%. However, the data is insufficient for any estimate to be made of the small number of female doctors and for the acquired forms of CVD. The effect on skills is also shown. Because of certain features of their work, general practitioners may have special problems. Thus, it is concluded that medical students and doctors should be screened for the deficiency and advised about it, and that there should be more study of the effects of CVD on decision-making in general practice and some specialties. PMID:10562750

Spalding, J A

1999-01-01

386

Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array  

NASA Technical Reports Server (NTRS)

To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

Halama, G.; McAdoo, J.; Liu, H.

1998-01-01

387

Recent advances in photorefractivity of poly(4-diphenylaminostyrene) composites: Wavelength dependence and dynamic holographic images  

NASA Astrophysics Data System (ADS)

To expand upon our previous report [Appl. Phys. Express 5, 064101 (2012) 064101], we provide here the modified poly(4-diphenylaminostyrene) (PDAS)-based photorefractive (PR) device on the basis of wavelength dependency, and demonstrate dynamic holographic images by using the PDAS-based PR device under the obtained appropriate conditions. The PR devices containing the triphenylamine unit have potential application to dynamic holographic images, which will be useful for real-time holographic displays.

Tsujimura, Sho; Kinashi, Kenji; Sakai, Wataru; Tsutsumi, Naoto

2014-08-01

388

[Colouring balms in a system of testing of their potential mutagenic action in genetically modified microorganisms].  

PubMed

Using the Ames semiquantitative technique with metabolic activation by the postmitochondrial fraction of rat liver homogenate preprocessed by phenobarbital sodium salt (for induction of monooxygenases of mixed function) potential mutagenic activity of 17 colouring balms which are used as cosmetic products for hair dyeing has been studied. The balms include water soluble dyes and pigments depositing on the surface of the hair. Potential mutagenic activity of almost all investigated colouring products has been shown. Three compositions (red tree, chestnut and black) have appeared to be the most active inductors of gene mutations showing the effect of "mean force" according to our classification. One of balms (burgund) has appeared as genetically inert. The rest balms have shown mutagen effect of "gentle force" with the ratio of control value excess from 2 up to 5-fold. PMID:16396322

Ialovenko, O I; Ostanina, N V; Duhan, O M

2005-01-01

389

The development of conceptual colour categories in pre-school children: Influence of perceptual  

E-print Network

structure of developing conceptual colour space during the period in which children acquire basic colourThe development of conceptual colour categories in pre-school children: Influence of perceptual investigates the influence of perceptual colour categorization on the development of conceptual colour space

Mullen, Kathy T.

390

Colour polymorphic prey ( Littorina saxatilis Olivi) and predatory effects of a crab population ( Carcinus maenas L.)  

Microsoft Academic Search

Many marine animal species are genetically polymorphic in colour. Visual selective predation is commonly suggested as a mechanism maintaining colour polymorphism in prey species and may, for example, result in correlations between colour frequencies and the background colour. Such correlations are commonly observed as, for example, in the polymorphic gastropod Littorina saxatilis. On Swedish shores the colour polymorphism of this

Anette Ekendahl

1998-01-01

391

Three-dimensional reconstruction of flame temperature and emissivity distribution using optical tomographic and two-colour pyrometric techniques  

NASA Astrophysics Data System (ADS)

This paper presents an experimental investigation, visualization and validation in the three-dimensional (3D) reconstruction of flame temperature and emissivity distributions by using optical tomographic and two-colour pyrometric techniques. A multi-camera digital imaging system comprising eight optical imaging fibres and two RGB charged-couple device (CCD) cameras are used to acquire two-dimensional (2D) images of the flame simultaneously from eight equiangular directions. A combined logical filtered back-projection (LFBP) and simultaneous iterative reconstruction and algebraic reconstruction technique (SART) algorithm is utilized to reconstruct the grey-level intensity of the flame for the two primary colour (red and green) images. The temperature distribution of the flame is then determined from the ratio of the reconstructed grey-level intensities and the emissivity is estimated from the ratio of the grey level of a primary colour image to that of a blackbody source at the same temperature. The temperature measurement of the system was calibrated using a blackbody furnace as a standard temperature source. Experimental work was undertaken to validate the flame temperature obtained by the imaging system against that obtained using high-precision thermocouples. The difference between the two measurements is found no greater than ±9%. Experimental results obtained on a laboratory-scale propane fired combustion test rig demonstrate that the imaging system and applied technical approach perform well in the reconstruction of the 3D temperature and emissivity distributions of the sooty flame.

Moinul Hossain, Md; Lu, Gang; Sun, Duo; Yan, Yong

2013-07-01

392

Estimates of the Lunar Surface Composition with Clementine Images and LSCC Data  

NASA Technical Reports Server (NTRS)

There have been several approaches to develop remote sensing technique to estimate composition of the lunar surface using multispectral observations. We present a new approach based on statistical analysis of spectral and compositional data for lunar samples by the Lunar Soil Characterization Consortium (LSCC) and using the UVVIS Clementine data with 1 km resolution. This technique allows us to estimate and map the abundance of TiO2, SiO2, and FeO, pyroxene and plagioclase content, and maturity degree (Is/FeO).

Shkuratov, Yu.; Pieters, C.; Omelchenko, V.; Stankevich, D.; Kaydash, V.; Taylor, L.

2003-01-01

393

Correlating multispectral imaging and compositional data from the Mars Exploration Rovers and implications for Mars Science Laboratory  

NASA Astrophysics Data System (ADS)

In an effort to infer compositional information about distant targets based on multispectral imaging data, we investigated methods of relating Mars Exploration Rover (MER) Pancam multispectral remote sensing observations to in situ alpha particle X-ray spectrometer (APXS)-derived elemental abundances and Mössbauer (MB)-derived abundances of Fe-bearing phases at the MER field sites in Gusev crater and Meridiani Planum. The majority of the partial correlation coefficients between these data sets were not statistically significant. Restricting the targets to those that were abraded by the rock abrasion tool (RAT) led to improved Pearson’s correlations, most notably between the red-blue ratio (673 nm/434 nm) and Fe3+-bearing phases, but partial correlations were not statistically significant. Partial Least Squares (PLS) calculations relating Pancam 11-color visible to near-IR (VNIR; ?400-1000 nm) “spectra” to APXS and Mössbauer element or mineral abundances showed generally poor performance, although the presence of compositional outliers led to improved PLS results for data from Meridiani. When the Meridiani PLS model for pyroxene was tested by predicting the pyroxene content of Gusev targets, the results were poor, indicating that the PLS models for Meridiani are not applicable to data from other sites. Soft Independent Modeling of Class Analogy (SIMCA) classification of Gusev crater data showed mixed results. Of the 24 Gusev test regions of interest (ROIs) with known classes, 11 had >30% of the pixels in the ROI classified correctly, while others were mis-classified or unclassified. k-Means clustering of APXS and Mössbauer data was used to assign Meridiani targets to compositional classes. The clustering-derived classes corresponded to meaningful geologic and/or color unit differences, and SIMCA classification using these classes was somewhat successful, with >30% of pixels correctly classified in 9 of the 11 ROIs with known classes. This work shows that the relationship between SWIR multispectral imaging data and APXS- and Mössbauer-derived composition/mineralogy is often weak, a perhaps not entirely unexpected result given the different surface sampling depths of SWIR imaging (uppermost few microns) vs. APXS (tens of ?m) and MB measurements (hundreds of ?m). Results from the upcoming Mars Science Laboratory (MSL) rover’s ChemCam Laser Induced Breakdown Spectroscopy (LIBS) instrument may show a closer relationship to Mastcam SWIR multispectral observations, however, because the initial laser shots onto a target will analyze only the upper few micrometers of the surface. The clustering and classification methods used in this study can be applied to any data set to formalize the definition of classes and identify targets that do not fit in previously defined classes.

Anderson, Ryan B.; Bell, James F.

2013-03-01

394

Correlating multispectral imaging and compositional data from the Mars Exploration Rovers and implications for Mars Science Laboratory  

USGS Publications Warehouse

In an effort to infer compositional information about distant targets based on multispectral imaging data, we investigated methods of relating Mars Exploration Rover (MER) Pancam multispectral remote sensing observations to in situ alpha particle X-ray spectrometer (APXS)-derived elemental abundances and Mössbauer (MB)-derived abundances of Fe-bearing phases at the MER field sites in Gusev crater and Meridiani Planum. The majority of the partial correlation coefficients between these data sets were not statistically significant. Restricting the targets to those that were abraded by the rock abrasion tool (RAT) led to improved Pearson’s correlations, most notably between the red–blue ratio (673 nm/434 nm) and Fe3+-bearing phases, but partial correlations were not statistically significant. Partial Least Squares (PLS) calculations relating Pancam 11-color visible to near-IR (VNIR; ?400–1000 nm) “spectra” to APXS and Mössbauer element or mineral abundances showed generally poor performance, although the presence of compositional outliers led to improved PLS results for data from Meridiani. When the Meridiani PLS model for pyroxene was tested by predicting the pyroxene content of Gusev targets, the results were poor, indicating that the PLS models for Meridiani are not applicable to data from other sites. Soft Independent Modeling of Class Analogy (SIMCA) classification of Gusev crater data showed mixed results. Of the 24 Gusev test regions of interest (ROIs) with known classes, 11 had >30% of the pixels in the ROI classified correctly, while others were mis-classified or unclassified. k-Means clustering of APXS and Mössbauer data was used to assign Meridiani targets to compositional classes. The clustering-derived classes corresponded to meaningful geologic and/or color unit differences, and SIMCA classification using these classes was somewhat successful, with >30% of pixels correctly classified in 9 of the 11 ROIs with known classes. This work shows that the relationship between SWIR multispectral imaging data and APXS- and Mössbauer-derived composition/mineralogy is often weak, a perhaps not entirely unexpected result given the different surface sampling depths of SWIR imaging (uppermost few microns) vs. APXS (tens of ?m) and MB measurements (hundreds of ?m). Results from the upcoming Mars Science Laboratory (MSL) rover’s ChemCam Laser Induced Breakdown Spectroscopy (LIBS) instrument may show a closer relationship to Mastcam SWIR multispectral observations, however, because the initial laser shots onto a target will analyze only the upper few micrometers of the surface. The clustering and classification methods used in this study can be applied to any data set to formalize the definition of classes and identify targets that do not fit in previously defined classes.

Anderson, Ryan B.; Bell, James F., III

2013-01-01

395

Bone-composition imaging using coherent-scatter computed tomography: Assessing bone health beyond bone mineral density  

SciTech Connect

Quantitative analysis of bone composition is necessary for the accurate diagnosis and monitoring of metabolic bone diseases. Accurate assessment of the bone mineralization state is the first requirement for a comprehensive analysis. In diagnostic imaging, x-ray coherent scatter depends upon the molecular structure of tissues. Coherent-scatter computed tomography (CSCT) exploits this feature to identify tissue types in composite biological specimens. We have used CSCT to map the distributions of tissues relevant to bone disease (fat, soft tissue, collagen, and mineral) within bone-tissue phantoms and an excised cadaveric bone sample. Using a purpose-built scanner, we have measured hydroxyapatite (bone mineral) concentrations based on coherent-scatter patterns from a series of samples with varying hydroxyapatite content. The measured scatter intensity is proportional to mineral density in true g/cm{sup 3}. Repeated measurements of the hydroxyapatite concentration in each sample were within, at most, 2% of each other, revealing an excellent precision in determining hydroxyapatite concentration. All measurements were also found to be accurate to within 3% of the known values. Phantoms simulating normal, over-, and under-mineralized bone were created by mixing known masses of pure collagen and hydroxyapatite. An analysis of the composite scatter patterns gave the density of each material. For each composite, the densities were within 2% of the known values. Collagen and hydroxyapatite concentrations were also examined in a bone-mimicking phantom, incorporating other bone constituents (fat, soft tissue). Tomographic maps of the coherent-scatter properties of each specimen were reconstructed, from which material-specific images were generated. Each tissue was clearly distinguished and the collagen-mineral ratio determined from this phantom was also within 2% of the known value. Existing bone analysis techniques cannot determine the collagen-mineral ratio in intact specimens. Finally, to demonstrate the in situ potential of this technique, the mineralization state of an excised normal cadaveric radius was examined. The average collagen-mineral ratio of the cortical bone derived from material-specific images of the radius was 0.53{+-}0.04, which is in agreement with the expected value of 0.55 for healthy bones.

Batchelar, Deidre L.; Davidson, Melanie T.M.; Dabrowski, Waldemar; Cunningham, Ian A. [Imaging Research Laboratories, Roberts Research Institute, London, Ontario, N6A 5K8 (Canada) and Department of Medical Biophysics, University of Western Ontario, London, Ontario, N6A 5C1 (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario, N6A 5K8 (Canada); Imaging Research Laboratories, Robarts Research Institute, London, Ontario, N6A 5K8 (Canada) and Department of Medical Biophysics, The University of Western Ontario, London, Ontario, N6A 5C1 (Canada)

2006-04-15

396

Micro-Measurements of Mechanical Properties for Adhesives and Composites Using Digital Imaging Technology.  

National Technical Information Service (NTIS)

The need for a constituent based durability or accelerated life prediction procedure to be used for the engineering design of polymer matrix composites is discussed in the light of current plans for the High Speed Civil Transport (HSCT) concerns about the...

H. F. Brinson

1994-01-01

397

Strain measurements and imaging of metal matrix composites using high-energy X-rays  

Microsoft Academic Search

Metal matrix composites (MMCs) are of technological importance for a variety of applications [1, 2]. One important aspect of MMCs is their unique mechanical behavior, which is controlled by the load transfer occurring between matrix and reinforcement. Load transfer is affected by the mismatch in stiffness between matrix and reinforcement, by plastic deformation of the metallic matrix and by damage

Marcus L. Young

2006-01-01

398

Digital Image Correlation and biaxial test on composite material for anisotropic damage law identification  

E-print Network

materials usually exhibit complex, namely, anisotropic and non linear behaviors. Ceramic Matrix Composites (CMCs) in particular be- have in very distinct ways depending on the loading direction wrt. the fiber prin- cipal strain. Conversely, fiber breakage and interface debonding are related to the fiber

Paris-Sud XI, Université de

399

Analyzing objects in images for estimating the delamination influence on load carrying capacity of composite laminates  

Microsoft Academic Search

The use of fiber reinforced plastics has increased in the last decades due to their unique properties. Advantages of their use are related with low weight, high strength and stiffness. Drilling of composite plates can be carried out in conventional machinery with some adaptations. However, the presence of typical defects like delamination can affect mechanical properties of produced parts. In

Luis Miguel Durao; Antonio G. Magalhaes; Joao Manuel R. S. Tavares; A. Torres Marques

2008-01-01

400

Analyzing objects in images for estimating the delamination influence on load carrying capacity of composite laminates  

Microsoft Academic Search

The use of fiber reinforced plastics has increased in the last decades due to their unique properties. Advantages of their use are related with low weight, high strength and stiffness. Drilling of composite plates can be carried out in conventional machinery with some adaptations. However, the presence of typical defects like delamination can affect mechanical properties of produced parts. In

Luís Miguel Durão; António G. Magalhães; João Manuel; R. S. Tavares; A. Torres Marques

401

Methods for greyscale representation of HEp2 colour images  

Microsoft Academic Search

Detection of antibodies via indirect immunofluorescence (IIF) is a common marker in patients with suspected connective tissue diseases. IIF readings are affected by several issues limiting their reproducibility and reliability: hence, the development of a computer-aided diagnosis (CAD) tool supporting IIF diagnostic procedure would be beneficial in many respects. Although some works in the literature use greyscale cooled cameras for

Ermanno Cordelli; Paolo Soda

2010-01-01

402

Chapter 116 Signal Functions of Carotenoid Colouration8  

E-print Network

, in relation to other classes of pigments15 and structural colours, has been outlined in Chapter 10. But colour that signals are honest because they are costly to produce [2]. For32 example, the tail of a peacock (Pavo with longer tails should be higher quality35 individuals, because relatively poor quality individuals should

McGraw, Kevin J.

403

Correlation between dichromatic colour vision and jumping performance in horses.  

PubMed

There is general agreement that horses have dichromatic colour vision with similar capabilities to human beings with red-green colour deficiencies. However, whether colour perception has an impact on equine jumping performance and how pronounced the colour stimulus might be for a horse is unknown. The present study investigated the relationship between the colour of the fences (blue or green) and the show jumping performance of 20 horses ridden by two riders using an indoor and outdoor set of green and blue fences. In the indoor arena, significantly more touches and faults were made on blue fences in comparison to green fences (median difference of 2.5 bars). When only touched bars were included, a significant median difference of one bar was found. Mares (n?=?4) demonstrated more faults and had a significantly greater difference in touches and faults between the two colours than male horses (n?=?16). Repeating the same experiment with eight horses in an outdoor grass arena revealed no significant differences between the two colours. In order to draw any definite conclusions, more research concerning the colour perception, influence of contrast with the arena surface and sex of horse is required. PMID:25193409

Spaas, Julie; Helsen, Werner F; Adriaenssens, Maurits; Broeckx, Sarah; Duchateau, Luc; Spaas, Jan H

2014-10-01

404

they form juxtaposed pointillistic colour centres which, to our  

E-print Network

, the Nireus group that is indigenous to the Afrotropics, concurrently employs a fluorescent pigment fluorescent pigment and colour- producing or colour-controlling nanostructures are so closely tied together and pattern; how larval food plant quality affects male sexual quality indicators; how the forms and relative

Sokolowski, Marla

405

Utilization of new attributes for evaluating a flower colour spectrum  

Microsoft Academic Search

Flower colour spectra were initially used in India to characterize the flora of urban localities (Nagrathna, 1968; Oommachan, 1973), but only on a presence-absence basis. In order to have a quantitative appraisal of the flower colour spectrum of the vegetation at a particular locality, the density of the species and the number of flowers on each plant should be taken

Rajani Varma; R. R. Das

1983-01-01

406

Children's Models about Colours in Nahuatl-Speaking Communities  

NASA Astrophysics Data System (ADS)

This paper presents the development and structure of indigenous children's ideas about mixing colours as well as their ideas about each colour, derived from their traditions. The children were interviewed both at school and outside it, and an educational proposal was implemented. Ideas expressed in the school context were analysed using the partial possible model, which states that the inferences and explanations used to describe a subject consist of constricting ideas, rules of correspondence, and a set of phenomenological inferences about processes. After identifying these components in the children's ideas, we developed models to describe their conceptions about mixing colours. We employed a different approach to analyse children's ideas related to their cultural context. The results showed that children change from a conception that focuses on colours as entities that do not change and as properties of objects (model 1) to the idea that colour represents a quality of substances or objects that can be modified by mixing colours (model 2). Cultural context analysis showed that stories are independent from one another and that they are not connected to colour mixing processes, only to the actions of colour on people. We concluded that students generate independent constructions between school and cultural knowledge.

Gallegos-Cázares, Leticia; Flores-Camacho, Fernando; Calderón-Canales, Elena; Perrusquía-Máximo, Elvia; García-Rivera, Beatriz

2014-10-01

407

The absolute threshold of colour vision in the horse.  

PubMed

Arrhythmic mammals are active both during day and night if they are allowed. The arrhythmic horses are in possession of one of the largest terrestrial animal eyes and the purpose of this study is to reveal whether their eye is sensitive enough to see colours at night. During the day horses are known to have dichromatic colour vision. To disclose whether they can discriminate colours in dim light a behavioural dual choice experiment was performed. We started the training and testing at daylight intensities and the horses continued to choose correctly at a high frequency down to light intensities corresponding to moonlight. One Shetland pony mare, was able to discriminate colours at 0.08 cd/m(2), while a half blood gelding, still discriminated colours at 0.02 cd/m(2). For comparison, the colour vision limit for several human subjects tested in the very same experiment was also 0.02 cd/m(2). Hence, the threshold of colour vision for the horse that performed best was similar to that of the humans. The behavioural results are in line with calculations of the sensitivity of cone vision where the horse eye and human eye again are similar. The advantage of the large eye of the horse lies not in colour vision at night, but probably instead in achromatic tasks where presumably signal summation enhances sensitivity. PMID:19002261

Roth, Lina S V; Balkenius, Anna; Kelber, Almut

2008-01-01

408

Floral colour versus phylogeny in structuring subalpine flowering communities  

PubMed Central

The relative number of seeds produced by competing species can influence the community structure; yet, traits that influence seed production, such as pollinator attraction and floral colour, have received little attention in community ecology. Here, we analyse floral colour using reflectance spectra that include near-UV and examined the phylogenetic signal of floral colour. We found that coflowering species within communities tended to be more divergent in floral colour than expected by chance. However, coflowering species were not phylogenetically dispersed, in part due to our finding that floral colour is a labile trait with a weak phylogenetic signal. Furthermore, while we found that locally rare and common species exhibited equivalent floral colour distances from their coflowering neighbours, frequent species (those found in more communities) exhibited higher colour distances from their coflowering neighbours. Our findings support recent studies, which have found that (i) plant lineages exhibit frequent floral colour transitions; and (ii) traits that influence local population dynamics contribute to community structure. PMID:20484236

McEwen, Jamie R.; Vamosi, Jana C.

2010-01-01

409

Iris colour and relationship of tyrosinase activity to adrenergic innervation  

Microsoft Academic Search

IRIS colour to some degree depends on the sympathetic innervation of the eye. Chance clinical observations of humans and experimental studies in animals have demonstrated consistently a gradual lessening of colour intensity in the iris after interruption of the sympathetic pathways to the eye1,2. Similarly, full iris pigmentation fails to develop when the sympathetic innervation to the eye is absent

Alan M. Laties

1975-01-01

410

Fine colour discrimination requires differential conditioning in bumblebees  

Microsoft Academic Search

Accurate recognition requires that visual systems must be able to discriminate between target and distractor stimuli. Flowers are learned and recognised by bees using visual cues including colour and shape. We investigated whether bees were able to learn to discriminate between colours differently depending upon absolute or differential conditioning. For absolute conditioning bees were rewarded with sucrose solution for visits

Adrian G. Dyer; Lars Chittka

2004-01-01

411

Behavioural evidence of colour vision in free flying stingless bees.  

PubMed

Colour vision was first demonstrated with behavioural experiments in honeybees 100 years ago. Since that time a wealth of quality physiological data has shown a highly conserved set of trichromatic colour receptors in most bee species. Despite the subsequent wealth of behavioural research on honeybees and bumblebees, there currently is a relative dearth of data on stingless bees, which are the largest tribe of the eusocial bees comprising of more than 600 species. In our first experiment we tested Trigona cf. fuscipennis, a stingless bee species from Costa Rica in a field setting using the von Frisch method and show functional colour vision. In a second experiment with these bees, we use a simultaneous colour discrimination test designed for honeybees to enable a comparative analysis of relative colour discrimination. In a third experiment, we test in laboratory conditions Tetragonula carbonaria, an Australian stingless bee species using a similar simultaneous colour discrimination test. Both stingless bee species show relatively poorer colour discrimination compared to honeybees and bumblebees; and we discuss the value of being able to use these behavioural methods to efficiently extend our current knowledge of colour vision and discrimination in different bee species. PMID:24519371

Spaethe, J; Streinzer, M; Eckert, J; May, S; Dyer, A G

2014-06-01

412

Colour gamuts in polychromatic dielectric elastomer artificial chromatophores  

NASA Astrophysics Data System (ADS)

Chromatophores are the colour changing organelles in the skins of animals including fish and cephalopods. The ability of cephalopods in particular to rapidly change their colouration in response to environmental changes, for example to camouflage against a new background, and in social situations, for example to attract a mate or repel a rival, is extremely attractive for engineering, medical, active clothing and biomimetic robotic applications. The rapid response of these chromatophores is possible by the direct coupling of fast acting muscle and pigmented saccules. In artificial chromatophores we are able to mimic this structure using electroactive polymer artificial muscles. In contrast to prior research which has demonstrated monochromatic artificial chromatophores, here we consider a novel multi-colour, multi-layer, artificial chromatophore structure inspired by the complex dermal chromatophore unit in nature and which exploits dielectric elastomer artificial muscles as the electroactive actuation mechanism. We investigate the optical properties of this chromatophore unit and explore the range of colours and effects that a single unit and a matrix of chromatophores can produce. The colour gamut of the multi-colour chromatophore is analysed and shows its suitability for practical display and camouflage applications. It is demonstrated how, by varying actuator strain and chromatophore base colour, the gamut can be shifted through colour space, thereby tuning the artificial chromatophore to a specific environment or application.

Rossiter, Jonathan; Conn, Andrew; Cerruto, Antonio; Winters, Amy; Roke, Calum

2014-03-01

413

Spectral mouth colour of nestlings changes with carotenoid availability  

Microsoft Academic Search

Summary 1. Despite the proliferation of studies on the role of nestling mouth colour in parent-offspring communication, there has been very little work regarding the proximate mechanism for mouth pigmentation. 2. Carotenoids, a class of phytochemicals important for immune function and gained by birds only through their diet, also serve as pigments for yellow-orange colours. Carotenoids have been shown to

R. Thorogood; R. M. Kilner; F. Karada?; J. G. Ewen

2008-01-01

414

On four-colourings of the rational four-space  

Microsoft Academic Search

Summary LetQ4 denote the graph, obtained from the rational points of the 4-space, by connecting two points iff their Euclidean distance is one. It has been known that its chromatic number is 4. We settle a problem of P. Johnson, showing that in every four-colouring of this graph, every colour class is every-where dense.

Joseph Zaks

1989-01-01

415

Estimating limits on colour vision performance in natural scenes  

E-print Network

633 Estimating limits on colour vision performance in natural scenes David H. FOSTER School scenes under different daylights. Three limits were estimated for each scene: the number of discriminable coloured surfaces under a single daylight, the relative frequency of metamerism across two daylights, and

Foster, David H.

416

Colour mimicry and sexual deception by Tongue orchids ( Cryptostylis)  

NASA Astrophysics Data System (ADS)

Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic ( Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids’ single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids’ bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects’ innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

Gaskett, A. C.; Herberstein, M. E.

2010-01-01

417

Colour measurements of surfaces to evaluate the restoration materials  

NASA Astrophysics Data System (ADS)

In this paper two case studies on the application of colour measurements for the evaluation of some restoration materials are discussed. The materials related to the research are: watercolours employed in restoration of wall paintings and preservative/consolidants for wood artifacts. Commercial watercolours, supplied by Maimeri, Windsor&Newton and Talens factories have been tested. Colour measurements have been performed by means of a reflectance spectrophotometer (RS) before and after accelerated ageing of watercolours at 92% relative humidity (RH) and in a Solar Box chamber. The experimental results show that watercolours based on natural earths and artificial ultramarine undergo the main colour changes, expressed as L*, a* and b* variations and total colour difference (?E*). In the other cases colour differences depend on both watercolour typology and suppliers. The other example concerns the evaluation of colour change due to surface treatment of Poplar (Populus sp.) and chestnut (Castanea sativa L.) wood samples. The wooden samples have been treated with a novel organic preservative/consolidant product that has been tested also in a real case as comparison. The treated samples have been artificially aged in Solar Box chamber equipped with a 280 nm UV filter. Colour has been measured before and after the artificial ageing by means of a RS. Colour changes have been determined also for the main door of an historical mansion in Viterbo, made of chestnut wood, and exposed outdoors.

Lo Monaco, Angela; Marabelli, Maurizio; Pelosi, Claudia; Picchio, Rodolfo

2011-06-01

418

Structural colour of porous dielectrics processed by direct laser write technique  

NASA Astrophysics Data System (ADS)

We report realisation of structural colour in dielectrics using direct laser write technique. 3D porous dielectric structures with woodpile photonic crystal architecture were fabricated by femtosecond direct laser write lithography in photoresist and characterised structurally and optically. The fabricated samples were found to exhibit resonant high-reflectance bands at visible wavelengths depending on the lattice parameters, and correspondingly, led to coloration of the structure without light absorption or emission. Structural colour was found to originate from slow-light spectral regions occurring in some higher photonic bands at visible wavelengths. Visible coloration in samples with relatively large lattice period, a > 1?m can be achieved due to this peculiarity, which helps alleviate the requirement for high resolution of the fabrication, shortened the fabrication time. In the future, similar structures may be useful for preparation of photonic crystal-based environmental and imaging sensors.

Mizeikis, Vygantas; Purlys, Vytautas; Buividas, Ri?ardas; Juodkazis, Saulius

2014-03-01

419

Colour and carotenoid changes of pasteurised orange juice during storage.  

PubMed

The correlation of carotenoid changes with colour degradation of pasteurised single strength orange juice was investigated at 20, 28, 35 and 42°C for a total of 32weeks of storage. Changes in colour were assessed using the CIELAB system and were kinetically described by a zero-order model. L(?), a(?), b(?), ?E(?), Cab(?) and hab were significantly changed during storage (p<0.05). Activation energies for all colour parameters were 64-73kJmol(-1). Several carotenoids showed important changes and appeared to have different susceptibilities to storage. A decrease of ?-cryptoxanthin was observed at higher temperatures, whereas antheraxanthin started to decrease at lower temperatures. Depending on the time and temperature, changes in carotenoids could be due to isomerisation reactions, which may lead to a perceptible colour change. Although the contribution of carotenoids was recognised to some extent, other reactions seem of major importance for colour degradation of orange juice during storage. PMID:25308677

Wibowo, Scheling; Vervoort, Liesbeth; Tomic, Jovana; Santiago, Jihan Santanina; Lemmens, Lien; Panozzo, Agnese; Grauwet, Tara; Hendrickx, Marc; Van Loey, Ann

2015-03-15

420

Implementation and characterization of a fibre-optic colour sensor  

NASA Astrophysics Data System (ADS)

In this paper the implementation of a fibre-optic sensor for colour detection based on reflective colour sensing is proposed. The sensor consists of three plastic optical fibres emitting red, green and blue components and one optical fibre collecting light reflected from the object. Red, green and blue LEDs are excited at different frequencies. In this way detection of the reflected signal is achieved with only one photodetector and three bandpass filters. Bandpass filters are implemented as digital IIR (infinite impulse response) filters on the microcontroller. Results obtained from the proposed sensor are compared with commercial available colour sensors and the results are satisfactory. Analyses of the sensor performance both in RGB and HSV colour space are done. The proposed solution shows that in specific applications by using the HSV model the sensor can be used both as a colour and distance sensor.

Baji?, Jovan S.; Stupar, Dragan Z.; Daki?, Bojan M.; Manojlovi?, Lazo M.; Slankamenac, Miloš P.; Živanov, Miloš B.

2014-09-01

421

Colour-octet bound states, induced by Higgs mechanism  

E-print Network

The current limits for fourth generation quarks allows to expect their mass of the order of 500 GeV. In this mass region for quark-anti-quark pair the additional Yukawa-type attraction due to Higgs mechanism is expected to emerge. This Higgs induced attraction greatly exceeds strong interaction between quarks and leads to the formation of bound states in both colour octet $S^{(8)}$ and singlet $S^{(1)}$ states. In the key of recent works on significance of colour octet channel for production of colour singlet state of fourth generation $Q\\bar{Q}$ we calculated the binding energies for both octet and singlet states. Such attraction localizes quarks in extremely small area. Hence colour octet pair of fourth generation quarks can form the "nucleus" and together with colour neutralizing light particle that is captured by strong interaction in orbit around the nucleus, create particle, similar by its structure to Deuterium.

Bladwell, S; Flambaum, V V; Kozlov, A

2012-01-01

422

Changes in colour contrast sensitivity associated with operating argon lasers.  

PubMed Central

A new test of colour vision using computer graphics has been used to obtain quantitative estimates of colour contrast sensitivity in ophthalmologists before and after they have treated patients by argon laser retinal photocoagulation. The colour vision of all subjects is normal when tested with the 100-hue test and HRR (Hardy, Rittler, Rand) plates, but colour contrast sensitivity measured along a tritan colour confusion line is selectively impaired after a treatment session. No such change occurs after a medical session spent examining patients with a fundus camera. In younger ophthalmologists the sensitivity recovers several hours after the treatment session ends, but in some persons there is a prolonged and possibly permanent elevation of threshold. PMID:2713300

Gunduz, K; Arden, G B

1989-01-01

423

Camouflage, communication and thermoregulation: lessons from colour changing organisms  

PubMed Central

Organisms capable of rapid physiological colour change have become model taxa in the study of camouflage because they are able to respond dynamically to the changes in their visual environment. Here, we briefly review the ways in which studies of colour changing organisms have contributed to our understanding of camouflage and highlight some unique opportunities they present. First, from a proximate perspective, comparison of visual cues triggering camouflage responses and the visual perception mechanisms involved can provide insight into general visual processing rules. Second, colour changing animals can potentially tailor their camouflage response not only to different backgrounds but also to multiple predators with different visual capabilities. We present new data showing that such facultative crypsis may be widespread in at least one group, the dwarf chameleons. From an ultimate perspective, we argue that colour changing organisms are ideally suited to experimental and comparative studies of evolutionary interactions between the three primary functions of animal colour patterns: camouflage; communication; and thermoregulation. PMID:19000973

Stuart-Fox, Devi; Moussalli, Adnan

2008-01-01

424

New results with colour-sextet quarks  

E-print Network

We study QCD with 2 and 3 flavours of colour-sextet quarks. The 2-flavour theory is a candidate Walking Technicolor theory. Since we are attempting to distinguish whether this theory is walking or conformal, we also study the 3-flavour theory, which is believed to be conformal, for comparison. We simulate lattice QCD with 2 and 3 flavours of colour-sextet staggered quarks at finite temperatures to determine the scales of confinement and chiral-symmetry breaking from the positions of the deconfinement and chiral-symmetry restoration transitions. Unlike the case with fundamental quarks, these transitions are far apart. For 2 flavours the values of beta=6/g^2 for both transitions increase as Ta is decreased from 1/4 to 1/6 to 1/8, as expected for a theory whose coupling runs to smaller values as the lattice spacing is decreased. However, for the chiral transition, the increase in beta between Ta=1/4 and Ta=1/6 is much larger than the increase between Ta=1/6 and Ta=1/8. This suggests that between Ta=1/4 and Ta=1/6 we are at strong coupling where the theory is effectively quenched, while between Ta=1/6 and Ta=1/8 we are emerging into the weak coupling regime. It will require even smaller Ta values to determine whether the running of the chiral-transition coupling is controlled by asymptotic freedom and the theory walks, or if it reaches a non-zero limit when the transition becomes a bulk transition and the theory is conformal. The 3 flavour case at Ta=1/4 and Ta=1/6 behaves similarly to the 2 flavour case. Since this theory is expected to be conformal, the interpretation that we are seeing strong-coupling behaviour, inaccessible from the weak-coupling limit (continuum) is the most likely interpretation.

D. K. Sinclair; J. B. Kogut

2010-08-14

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Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components  

NASA Technical Reports Server (NTRS)

Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed