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Dissertations / Theses on the topic 'Human colour perception'
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Welbourne, Lauren Elizabeth. "Peripheral factors affecting human colour perception." Thesis, University of York, 2016. http://etheses.whiterose.ac.uk/14319/.
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Human colour perception is mediated by multiple factors. These include: the external environment, physiological structures within the eye, and the neuronal pathways that originate in the eye. The aim of this thesis was to further investigate the impact of three main factors on both the perception and cortical representation of colour. These factors were: the external, changing seasonal environment, genetically determined differences in the number of photoreceptor types, and spatial filters inherent to cortical and pre-cortical luminance and chromatic pathways. Novel findings and methods were demonstrated in this thesis: 1) For the first time, it was found that natural seasonal changes in the chromatic environment (in York, UK) affect the perception of unique yellow; this finding supports the existence of a slow normalisation mechanism, which is governed by changes in the average chromatic environment. 2) Genetically atypical individuals, who have fewer photoreceptor types (dichromats), demonstrated no differences in achromatic contrast discrimination thresholds compared to colour-normal trichromats. Therefore, for this particular measure, dichromats do not appear to benefit from increased neuronal resources from ‘unused’ chromatic pathway populations. A multi-channel LED system was developed to allow the isolation of photoreceptor responses in individuals with an additional photoreceptor type (tetrachromats). Modelling of this system indicated that precision in the cone spectra used to generate the stimulus, relative to the observer’s actual cone sensitivities (i.e. peak wavelength sensitivities), is crucial for successful isolation of the cones. 3) fMRI-based population receptive field (pRF) mapping was used to measure pRF sizes in the pre-cortical channels. Between the pathways, no differences in pRF sizes were found, however, differences in fMRI measures of spatial frequency sensitivity were observed. These data indicate that spatial frequency tuning in early visual cortex may be decoupled from population receptive field sizes.
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Panorgias, Athanasios. "Peripheral human colour vision : from cone contrast to colour perception." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/peripheral-human-colour-vision-from-cone-contrast-to-colour-perception(aa92cad7-477a-40ce-b91e-df87927d0caa).html.
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It is well known that the colour preferences of ganglion and LGN cells do not match the four perceptually simple colours red, green blue and yellow. It is also known that although colour perception is distorted in the peripheral visual field, there are four hues that appear stable with eccentricity. These are defined as peripherally invariant hues. Both of these observations must in some way reflect the physiological substrate of neurons at different stages of the primary visual pathway. The experiments described here are aimed at understanding the link between the physiology and the perception of colour by studying the characteristics of peripheral colour visionThe following questions have been addressed; i) to what extent does colour matching rely on the retinal physiological substrate? ii) what is the reason for the discrepancy between invariant and unique green and how is cone contrast linked to this paradox? iii) how are the `special' hues (invariant and unique) related to human evolution? iv) how does peripheral colour vision vary between males and females?An asymmetric colour matching paradigm and a colour naming task have been employed. In the colour matching task, 24 chromatic axes of variable purity are used. Observers match the chromaticity of a 3 degree peripheral spot with that of a 1 degree parafoveal spot. The results are expressed in terms of hue rotation, saturation match and cone contrast. In the colour naming experiment the observers name 40 chromatic axes as either red, blue, green or yellow and colour naming functions are derived. The central maxima of these functions are defined as the unique hues. The results suggest that colour matching and cone opponency reflect the characteristics of the retinal neural network as they exhibit nasal-temporal asymmetries, similar to known physiological asymmetries. Although three of the peripherally invariant hues match the unique counterparts, invariant and unique green are markedly different for all observers. In an important control experiment unique hues are shown to be stable with eccentricity and purity. This confirms that these attributes are not confounding factors for the observed discrepancy between invariant and unique green. Unlike for the other 'special' hues the RMS cone contrast of invariant green differs markedly between parafoveal and peripheral targets. It is likely that the cone contrast remains unchanged only if the stimuli excite the same number of cones. Two invariant and two unique hues (blue and yellow) fall on the daylight locus suggesting that discrimination in these regions of the colour space is strongly influenced by terrestrial illumination. Moreover, the inter-individual variability is found to be minimised around the daylight locus showing that the blue-yellow system is more stable across colour normal populations than the red-green system. A statistically significant difference is demonstrated between the peripheral colour vision of males and females. This may be attributed to the M-cone polymorphism which in addition to X-chromosome inactivation, results in more than three cone types in the female retina.
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Hedrich, Monika. "Human colour perception : a psychophysical study of human colour perception for real and computer-simulated two-dimensional and three-dimensional objects." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4304.
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Forsmark, Rebecca. "Simulating Perception : Perception based colours in virtual environments." Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-12362.
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This research explores the differences between how game engine cameras and the human visual system (HVS) render colour. The study is motivated by a two part research question: will HVS colours or game camera colours be preferred when experiencing a virtual environment from a 1st-person perspective and how does light intensity relate to preference? While previous research defines perceptual processes which influence the interpretation of colour information this study advances the understanding of how these theories may be applied to 3D colour grading.When evaluating the two colour modes with a combination of quantitative data and qualitative reflections it was possible to establish a correlation between preference and light intensity, in the sense that HVS colours were preferred in high illumination and camera colours in low. The findings implicate that in order to be well received the colours of a virtual environment need to be adjusted according to illumination.
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Lawrance-Owen, Adam John. "Human variation in colour perception and in anthropomorphic characteristics." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648203.
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Stephen, Ian D. "Skin colour, pigmentation and the perceived health of human faces." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/753.
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Bramwell, David. "Colour constancy in simple and complex scenes." Thesis, University of Newcastle Upon Tyne, 1997. http://hdl.handle.net/10443/633.
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Colour constancy is defined as the ability to perceive the surface colours of objects within scenes as approximately constant through changes in scene illumination. Colour constancy in real life functions so seamlessly that most people do not realise that the colour of the light emanating from an object can change markedly throughout the day. Constancy measurements made in simple scenes constructed from flat coloured patches do not produce constancy of this high degree. The question that must be asked is: what are the features of everyday scenes that improve constancy? A novel technique is presented for testing colour constancy. Results are presented showing measurements of constancy in simple and complex scenes. More specifically, matching experiments are performed for patches against uniform and multi-patch backgrounds, the latter of which provide colour contrast. Objects created by the addition of shape and 3-D shading information are also matched against backgrounds consisting of matte reflecting patches. In the final set of experiments observers match detailed depictions of objects - rich in chromatic contrast, shading, mutual illumination and other real life features - within depictions of real life scenes. The results show similar performance across the conditions that contain chromatic contrast, although some uncertainty still remains as to whether the results are indicative of human colour constancy performance or to sensory match capabilities. An interesting division exists between patch matches performed against uniform and multi-patch backgrounds that is manifested as a shift in CIE xy space. A simple model of early chromatic processes is proposed and examined in the context of the results.
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Clery, Stéphane. "Psychophysical studies of interactions between luminance and chromatic information in human vision." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6376.
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In this thesis, I investigated how human vision processes colour and luminance information to enable perception of our environment. I first tested how colour can alter the perception of depth from shading. A luminance variation can be interpreted as either variation of reflectance (patterning) or variation of shape. The process of shape-from-shading interprets luminance variation as changes in the shape of the object (e.g. the shading on an object might elicit the perception of curvature). The addition of colour variation is known to modify this shape-from-shading processing. In the experiments presented here I tested how luminance driven percepts can be modified by colour. My first series of experiments confirmed that depth is modulated by colour. I explored a larger number of participants than previously tested. Contrary to previous studies, a wide repertoire of behaviour was found; participants experienced variously more depth, or less depth, or no difference. I hypothesised that the colour modulation effect might be due to a low-level contrast modulation of luminance by colour, rather than a higher-level depth effect. In a second series of experiments, I therefore tested how the perceived contrast of a luminance target can be affected by the presence of an orthogonal mask. I found that colour had a range of effects on the perception of luminance, again dependant on the participants. Luminance also had a similar wide range of effects on the perceived contrast of luminance targets. This showed that, at supra-threshold levels, a luminance target's contrast can be modulated by a component of another orientation (colour or luminance defined). The effects of luminance and colour were not following a particular rule. In a third series of experiments, I explored this interaction at detection levels of contrast. I showed cross-interaction between luminance target and mask but no effects of a colour mask.
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Durao, M. J. "Colour and space : an analysis of the relationships between colour meaning expression and the perception of space." Thesis, University of Salford, 2000. http://usir.salford.ac.uk/26645/.
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This thesis examines the phenomenon of colour as a means of expression of meaning in spatial contexts. The nature of the underpinning project involved paintings and their integration with an architectural setting. Judgements made-in-situ by users of the building and an expert focus group (architects, designers and fine artists) were comparatively analysed for variance in interpretations of meaning, taking into consideration their experience with colour as a medium of expression. Commonalities and differences in the responses of colour amongst and between the various groups were also analysed. To achieve this a combination of questionnaires, semi-structured interviews, and focus group meetings were used as data sources. The researcher used her experience as a painter to create two large paintings (11.5m x 2m each), which were installed in the public space of the Manchester Bridgewater Concert Hall over a period of four months. One painting was predominantly blue and green, the other was predominantly yellow and red. The installation had two phases, in which the respective paintings were each installed separately and accompanied by a corresponding lighting scheme. Colours were separated into two temperature groups - warm and cold. However, previous research findings had indicated that responses to these two groups of colour differ along other dimensions also. What had not been established by previous research, and was examined in this project, was whether these indicative differences would apply when colour is approached as part of an holistic environmental meaning rather than in isolation. The integration of paintings and colour into the architectural setting made it possible for multiple layers of experience to be examined. Meaning was extracted from the relationship between colour and the perception of two dimensions of space - pictorial space depicted in the paintings and the architectural space. The relationship between both was also explored which allowed the confirmation of previous findings and the analysis of the variables which need to be addressed when dealing with colour for paintings in real architectural environments. The thesis describes the author's conceptual model based on a combination of this empirical evidence and theoretical framework developed from the existing interdisciplinary body of knowledge on colour. The thesis also discusses how relationships between the aesthetic and psychological categories were established. It contributes to the field by demonstrating how the subjectivity of the perceptual experience can be translated into the expression of meaning along cognitive and affective dimensions within the context of a real-life application of colour in space. Additional to the written thesis a short audiovisual provided in both video and CD Rom, was created to show both the making of the paintings and their installation at the Bridgewater Concert Hall.
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Cropper, Simon James. "Human motion detection : different patterns, different detectors?" Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319544.
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Alwawi, Ibrahim. "Cognitive modelling and control of human error processes in human-computer interaction with safety critical IT systems in telehealth." Thesis, Robert Gordon University, 2017. http://hdl.handle.net/10059/2680.
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The field of telehealth has developed rapidly in recent years. It provides medical support particularly to those who are living in remote areas and in emergency cases. Although developments in both technology and practice have been rapid, there are still many gaps in our knowledge with regard to the effective application of telehealth. This study investigated human colour perception in telehealth, specifically the colour red as one of the key symptoms when diagnosing different pathologies. The quality of medical images is safety critical when transmitting the symptoms of pathologies in telehealth, as distorted or degraded colours may result in errors. The study focused on the use of digital images in teleconsultation, particularly on images showing cellulitis (bacterial skin infection) and conjunctivitis (red eye) as case studies, as both of these pathologies involve the colour red in their diagnosis. The study proposed and tested the use of an image quality scale, which represented the level of image resolution; a red colour scale, which represented the intensity of redness in an image; and a confidence scale, which represented the levels of confidence that telehealth users had when judging the colour red. The research involved a series of experiments using hypothetico-deductive and formal hypothesis testing with two groups of participants, medical doctors and non-medical participants. The experiments were conducted in collaboration with the local National Health Service (NHS) Accident and Emergency (A&E) department at Aberdeen Royal Infirmary (ARI). Medical experts in ophthalmology and dermatology were also involved in selecting and verifying the relevant images. The study found that doctors and non-doctors were consistent in the majority of the experiments. The accuracy of the participants was demonstrably higher when using a colour scale with pictures, more so for the non-doctor group than the doctor group. It also found that the level of accuracy for both doctors and nondoctors was higher when using red colour scale of three divisions than when using a scale of five divisions. This result was supported by previous studies, which used telehealth for diagnosing extreme cases. The study also found that when the image quality was poor the participants had higher error rates and less consistency in their answers. The study found poor correlation between accuracy, confidence and time for both participant groups. The study found that most participants in both doctor and non-doctor groups had high confidence most of the time, whether the accuracy was high or low. It was also found that medical background or clinical experience had no effect on the accuracy level across the experiment sets. In some cases, doctors with no or little experience had higher accuracy than those with greater experience. This result may have significant implications for the feasibility of involving non-doctors in the management of telehealth systems, especially in tasks not requiring medical skills, such as colour classification. This has the potential to provide a considerable saving in resources and costs for healthcare providers. An auto-evaluation system was introduced, and proposed for further study, in order to improve the current telehealth diagnostic protocol and to avoid or prevent errors by making red colour classification more objective and accurate.
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Garcia-Suarez, Luis. "Visual perception of gradients : a psychophysical study of the mechanisms of detection and discrimination of achromatic and chromatic gradients." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4329.
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Heckman, Genevieve Marie. "Neural mechanisms of color appearance in the human visual system." Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1432771461&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Christophe, Sidonie. "Aide à la conception de légendes personnalisées et originales : proposition d'une méthode coopérative pour le choix des couleurs." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00515333.
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Aide à la conception de légendes personnalisées et originales : proposition d'une méthode coopérative pour le choix des couleurs Les utilisateurs s'approprient aisément les outils cartographiques numériques pour se construire leur propre carte. Cependant, l'accès aux outils ne suffit pas pour concevoir une légende cartographique de qualité. Il est nécessaire de savoir comment faire de bons choix de représentation graphique, en particulier de bons choix de couleurs. Une expertise cartographique comportant des connaissances en sémiologie graphique et en perception des couleurs (contrastes et harmonies) est nécessaire : soit l'utilisateur possède ces connaissances, soit les outils doivent les lui apporter. Dans ce contexte, nous cherchons à aider les utilisateurs à concevoir des légendes personnalisées et originales, en nous concentrant sur l'aide au choix des couleurs. Nous proposons une méthode de conception coopérative en quatre phases reposant sur des interactions homme-machine : 1- choix d'une source d'inspiration, 2- acquisition des préférences de l'utilisateur sur les sources d'inspiration, 3- interprétation des préférences et construction de légendes adaptées, 4- retouche de légendes. Deux stratégies de conception sont envisagées en utilisant deux types de sources d'inspiration : des échantillons de carte et des toiles de maîtres. En partant du constat que des désaccords entre l'utilisateur et le système peuvent se produire, nous proposons d'utiliser des techniques de dialogue homme-machine pour améliorer l'adaptation du système à l'utilisateur. Le modèle de dialogue ainsi proposé est implémenté dans le prototype COLorLEGend (COLLEG)
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Morita, Tomoyo. "Neural substrates of human color perception revealed by the McCollough effect." Kyoto University, 2003. http://hdl.handle.net/2433/148953.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第10318号
人博第205号
14||169(吉田南総合図書館)
新制||人||50(附属図書館)
UT51-2003-H739
京都大学大学院人間・環境学研究科人間・環境学専攻
(主査)教授 松村 道一, 教授 江島 義道, 教授 前川 覚, 教授 定藤 規弘
学位規則第4条第1項該当
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Wang, Wenyi. "Robust Chroma Keying System Based on Human Visual Perception and Statistical Color Models." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35271.
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In this thesis, we propose a chroma keying system that automatically estimates the
alpha map and the reliable intrinsic color of foreground objects in front of solid background. Our system is designed to be capable of distinguishing the transparent
foreground from the re flective foreground and shaded background, thereby making
the artifacts of the composited image less conspicuous. Speci cally, we assume that
the transparent region tends to be with higher saturation and lightness compared with region re ecting background light. With this assumption, a threshold function (TF) on a saturation-lightness plane is de ned according to human visual experiments. The pixels with color mixed with the background light (conventional unknown pixels) are now further categorized into re ective pixels and transparent pixels according to TF. In this case, the re ective and the transparent regions are separated to improve the alpha matte quality. Furthermore, a new color representation model is proposed to estimate the intrinsic color of each pixel according to the global color distribution of the image. The underlying assumption of our proposed model is that all colors in a natural image can be approximated by a limited number of chrominance values (dominant colors). Speci cally, the color statistics are counted by 2D histogram analysis. Then, we approximate the color distribution by the sum of a set of Gaussian mixture functions (GMF), whose centroids are the dominant colors (Dc) of the image. By choosing colors around each Dc, the possible intrinsic colors for each pixel can be comprehensively and e fficiently selected. Considering the fast development of IP-based video broadcasting, we present a data hiding scheme that can protect the chroma keying results when the image/video data is recorded in the JPEG/H.264 format. According to our simulation, the proposed chroma keying system generates high quality composited images that are little a ected by re ecting, background shading, and intrinsic color missing.
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McLeod, Ryan Nathaniel. "A PROOF OF CONCEPT FOR CROWDSOURCING COLOR PERCEPTION EXPERIMENTS." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1269.
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Accurately quantifying the human perception of color is an unsolved prob- lem. There are dozens of numerical systems for quantifying colors and how we as humans perceive them, but as a whole, they are far from perfect. The ability to accurately measure color for reproduction and verification is critical to indus- tries that work with textiles, paints, food and beverages, displays, and media compression algorithms. Because the science of color deals with the body, mind, and the subjective study of perception, building models of color requires largely empirical data over pure analytical science. Much of this data is extremely dated, from small and/or homogeneous data sets, and is hard to compare. While these studies have somewhat advanced our understanding of color adequately, mak- ing significant, further progress without improved datasets has proven dicult if not impossible. I propose new methods of crowdsourcing color experiments through color-accurate mobile devices to help develop a massive, global set of color perception data to aid in creating a more accurate model of human color perception.
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Chien, Sarina Hui-Lin. "Lightness constancy in 4-month-old human infants : a cue elimination approach /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/9094.
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Berg, Paul D. "Measurement of the spectral and spatial responses of the human eye's blue sensitive system and the effects of lateral inhibition by the red and green sensitive systems /." Online version of thesis, 1986. http://hdl.handle.net/1850/8840.
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Johansson, Björn. "A study of some temporal properties of the human visual evoked potential, and their relation to binocular function /." Linköping : Linköping University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7584.
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Dewing, Wende L. "Perception of Color Quality for Natural Images Viewed, Edited, and Printed Within the Context of a Home Digital Color Imaging System." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/26232.
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Within the home environment there exits a host of digital color imaging (DCI) system configurations. The combination of devices and software at the consumerâ s desktop with devices and services at a remote location (e.g., Print at Kodak), creates a complex interaction of device, contextual, and observer characteristics. In particular, the cathode-ray tube (CRT) display has the potential to influence consumersâ perceptions of image quality and their subsequent image manipulation activities. Depending on the inherent color bias and apparent contrast of the CRT, extensive image manipulation may occur, significantly altering the digital values of the image. Output generated by a remote printer will reflect any image manipulation undertaken by the consumer. If manipulation was extensive, what the consumer receives from a remote printer will appear quite different from the softcopy version and thus, may be deemed unacceptable.
This research was designed to address the softcopy-hardcopy matching issues that arise from the home DCI system configuration just described. The primary study examined how the CRT display influenced perceived color quality of photographs generated at two points in a DCI system; on-screen photographs (softcopy) and photographic quality prints (hardcopy). CRT gamma, color temperature, and excitation purity were manipulated using an orthogonal, blocked, central composite design. Twenty-two Eastman Kodak Company employees viewed 6 photographs under each of the 15 CRT conditions. Participants rated the color quality of each softcopy photograph, then were given an opportunity to edit color balance, brightness, and contrast for each photograph. The edited photos were printed and rated once again for color quality and acceptability.
Results indicated that monitor calibration influenced perceived softcopy color quality, softcopy editing behavior, and subsequent perceived hardcopy color quality. Perception of softcopy color quality ratings was determined predominantly by the CRT gamma level. Participants responded to CRT color balance differences through their editing behavior. In some cases, edits were large enough to significantly and negatively impact perceived hardcopy color quality. Gamma in particular, was the most significant predictor of hardcopy color quality ratings and rejection rates.
Additional differences were observed between first- and third-party photographs.
Results from this research may be applied to the development of monitor calibration tools, scene balancing algorithms, and software, for the purpose of accommodating consumer image manipulation behavior, in the context of the home DCI system presented herein.Ph. D.
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Périssé, Amélie. "Color formulation algorithms improvement through expert knowledge integration for automotive effect paints." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3025.
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Aujourd’hui, le marché de la peinture automobile est gouverné par une demande pour des couleurs profondes et vives avec effets. Dans le domaine de la peinture automobile, l’exigence est très haute car la couleur est associée à un signe de qualité. Dans une collision classique, différentes parties du véhicule peuvent être endommagées avec généralement une partie de la carrosserie qui est touchée. La partie endommagée doit être réparée, poncée et préparée avant d’être repeinte. Pour réduire les coûts, le carrossier doit préparer une peinture avec un bon contretypage de teinte, et ce aussi vite que possible. Il s’agit donc pour la formulation de la peinture de réparation de reproduire les effets, aussi bien colorés que texturés, à partir de pigments absorbants ou à effets (particules d’aluminium, de nacre …). Il est relativement simple de qualifier les effets colorés à partir des courbes de réflectance puis des coordonnées CIELab. Cependant, la définition de la texture engendrée par les particules à effets est assez complexe et n’est encore qu’à ses prémices, avec des paramètres qui souvent ne correspondant pas aux phénomènes réellement perçus par l’œil humain. Dans le cadre de ce travail de thèse, la mobilisation de connaissances expertes à travers différentes sessions de tri libre et de brainstorming a permis la mise en évidence de descripteurs de texture réellement perceptifs. De plus, la mise en place de métriques de texture conçues à partir de préconisations réellement perceptives, a rendu possible l’obtention de valeurs correspondant à un observateur moyen pour chacun de ces paramètres descripteurs. Ces paramètres ayant été élaborés à partir des observations d‘évaluateurs expérimentés. La transposition de ces vérités terrain en descripteurs physiques de texture a permis l’obtention d’une corrélation entre le perceptible et le mesurable. Dans la procédure développée, l’œil humain a été remplacé par un appareil photo numérique agissant en qualité d’intégrateur tristimulaire d’informations radiométriques. En essayant de reproduire les conditions d’observation lors de la phase d’acquisition d’images, il a été ainsi possible de caractériser les phénomènes de texture par analyse d’image et de les corréler aux valeurs de l’observateur moyen préalablement définiNowadays, the automotive coating market is governed by a demand for deep and vibrant colors with effects. In this field, the requirement is very high because the color is associated with a sign of quality. In a typical collision, different parts of the vehicle may be damaged. The damaged part must be repaired, sanded and prepared before being painted. To reduce costs, the body shop must then prepare a paint with a good color matching, and thus as fast as possible. It is therefore necessary for the formulation of the repair coating to reproduce the effects, both colored and textured, from absorbent or effect pigments (aluminum particles, pearlescent materials …) from a characterization of the concerned vehicle coating. It is relatively simple to qualify the colored effects from the reflectance curves and then the CIELab coordinates. However, the description of the texturing effect generated by the distribution of effect particles at the microstructure scale is quite complex. The metrological approach of the perceptive properties is still at its beginnings. The parameters used do not necessarily correspond directly to the phenomena actually perceived by the human eye. As part of this thesis work, the mobilization of expert knowledge through various sessions of free sorting and brainstorming on coated samples made it possible to highlight really perceptive texture descriptors. These descriptors have been the subject of "objective" evaluations by experienced observers. They thus made it possible to associate a quantitative evaluation scale with each descriptor. This stage of the present thesis work allowed the establishment of ground truth data materialized by a set of reference samples representing different ordered levels of a descriptor. These ground truth data were then used to design a set of measurable physical texture descriptors that were directly correlated to perceptual scales constructed in the previous step. In the procedure developed, the human eye has been replaced by a digital camera acting as a tristimulus integrator of radiometric information. The image acquisition phase was a decisive step in the process: it was necessary to reproduce the conditions of evaluation of the properties perceived, recognized and retained during the various stages using expert human observers. It was then possible to characterize the texture phenomena by image analysis and to correlate them with the values of the previously defined mean observer
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Alleysson, David. "Le traitement du signal chromatique dans la rétine : un modèle de base pour la percéption humaine des couleurs." Phd thesis, Université Joseph Fourier (Grenoble ; 1971-2015), 1999. http://www.theses.fr/1999GRE10037.
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La connaissance des principes et des mecanismes de la perception humaine de la couleur permet de mettre en uvre des techniques de reproduction et de traitement industriels de la couleur. Dans le cas de l'equivalence de couleur les etudes de la perception humaine ont joue un role important et ont permis d'etablir des normes par la cie. Mais l'apparence des couleurs dans des conditions quelconques d'observation reste non maitrisee. Dans cette etude, nous proposons des modeles de perception de la couleur bases sur la biologie de la retine. Ces modeles s'appliquent a l'echantillonnage de la couleur par les cones de la retine, aux non-linearites de traitement du signal chromatique et au traitement spatio-temporel du signal chromatique par les couches de neurones de la retine. Ces modeles permettent de comprendre le codage de la couleur en oppositions de couleur, la formation des seuils de discrimination couleur et les caracteristiques de filtrage spatial et temporel du signal de couleur au sein de la retine. Ces elements font de la retine un capteur efficace et robuste pour l'analyse des images naturelles. Les resultats de cette etude permettent d'envisager la realisation de circuits analogiques copiant les caracteristiques de traitement de la retine car nos modeles sont transposables en circuits electriques. Ils permettent egalement la definition d'une colorimetrie adaptative tenant compte des phenomenes d'adaptation dans les conditions de vision photopique. Enfin ils fournissent une methode d'analyse vectoriels des images, pour lesquel on dispose d'un vecteur de caracteristiques en chaque pixel.
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Karlberg, Pontus. "FÄRGERS PÅVERKAN PÅ TIDSUPPLEVELSE : Kopplingen mellan designartefakter och användares upplevelse av tid utifrån ett UXperspektiv." Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17798.
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Enligt tidigare forskning upplever människor att tiden går fortare i lugna trygga miljöer och går långsamt i påfrestande situationer. Något som skapar lugna trygga känslor hos människor är färgen blå medans färgen gul som har ett ständigt tröttande ljus upplevs som påfrestande. Vilket i teorin ska innebära att människor som tittar på något blått upplever att tiden går snabbare än de som betraktar något gult. I föreliggande studie har detta undersökts med två experiment, i första experimentet fick deltagarna slå multiplikationstal på kalkylatorn på en dator medan det var en blå eller gul bakgrund. I det andra experimentet fick deltagarna se en snurra på en gul eller blå bakgrund. I inget av experimenten upptäcktes någon signifikant skillnad. I experimentet var det dessutom fler som svarade att de ville använda den blåa bakgrunden om den fick tiden att upplevas gå fortare än den gula.
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Magaisa, Tatenda. "The colour order: race and colour perception in South Africa." Thesis, 2015. http://hdl.handle.net/10539/21866.
Full textAbstract:
Thesis (M.Fine Arts)--University of the Witwatersrand, Faculty of Humanities, School of Arts, 2016.This paper will be an analysis of the covers and contents of the South African editions of Glamour magazine from September 2014 to August 2015 and True Love magazine from September 2014 to August 2015. The analysis will consider the effects of: globalisation; globalised culture and consumption; and perceptions of race and skin colour, (specifically the notion of colourism) in South Africa. Colourism is a prejudicial system that renders value and perpetuates social hierarchies along perceived tonal difference in skin colour. It has been asserted by writers like Deborah Gabriel and Nicole Fleetwood that this value system exists within communities of people of colour and is perpetuated by mainstream media, but maintains a somewhat obscure presence. I will consider the mechanisms that inform this colour system and will show how globalisation works to facilitate colourism. Finally, I aim to explain how skin colour extends beyond the body and define the effects of global cultural interaction, showing that colourism is not simply about skin colour and tone, but about economic, social, and political realities.
MT2017
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Maguire, John, Neil R. A. Parry, Jan Kremers, I. J. Murray, and Declan J. McKeefry. "Human S-cone electroretinograms obtained by silent substitution stimulation." 2017. http://hdl.handle.net/10454/15502.
Full textAbstract:
YesWe used triple silent substitution stimuli to characterize human S-cone electroretinograms (ERGs) in normal trichromats. Short-wavelength-cone (S-cone) ERGs were found to have different morphological features and temporal frequency response characteristics compared to ERGs derived from L-cones, M-cones, and rod photoreceptors in normal participants. Furthermore, in two cases of retinal pathology, blue cone monochromatism (BCM) and enhanced S-cone syndrome (ESCS), S-cone ERGs elicited by our stimuli were preserved and enhanced, respectively. The results from both normal and pathological retinae demonstrate that triple silent substitution stimuli can be used to generate ERGs that provide an assay of human S-cone function.
Deutsche Forschungsgemeinschaft (DFG) (KR1317/13-1); Bundesministerium für Bildung und Forschung (BMBF) (01DN14009)
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"Chromatic Imaginaries: Color Constructs the Human Experience." Tulane University, 2018.
Find full textAbstract:
Color is powerful. As a physical element in our world that is created in our minds, it is uniquely visceral yet intangible. Color has objective rules, finite categories, subjective interpretations, and embedded meanings. Color can calm, activate, soothe, shock, welcome, stimulate, and rejuvenate. Yet color is often relegated to the realm of ornament, and its powerful performative properties are underutilized in the realm of architecture. If its unique potential was instead realized, color could be used to communicate emotionally and spatially, subjectively and universally. The properties of color have been analyzed through scientific investigation and artistic exploration for their spatial, psychological, and emotional effects. In the realm of painting, color is a fundamental way to imply space on a canvas and stimulate response from viewers. Scientifically, color has been the subject of countless studies for its effects on human behavior as well as its physical properties and universal significance. Theories merging from these fields can be utilized to create a richer, more intentional relationship between color and architecture. Much more than a coat of paint, color can be used to construct the architectural experience. It can be equated with other fundamental elements, such as form, light, and context, as a tool in the creation of space. Through its interaction with these elements, color can amplify spatial intentions, shape perception, and augment the interaction between humans and the built environment. Emphasizing architectureÕs ability to shape the human experience, this thesis constructs a future of architecture where color is fundamental.Yes
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Chen, Sheng-Chang, and 陳勝昌. "Human Visual Perception for Color Breakup Evaluation Index." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/17721126487793437337.
Full textAbstract:
碩士國立交通大學
電機學院光電顯示科技產業專班
96
During the last decade of the 20th century, Liquid Crystal Display (LCD) technologies have been progressing rapidly. With the popularization of multimedia application display devices, internet and wireless, computer and tremendous information interchange have become parts of our lives. The performances of the LCDs were required better and better such as higher color saturation, thinner LCD module, and lower power consumption. However, the Field Sequential Color LCD (FSC-LCD) was one of them which had these features in the LCD products. This method had taken the visual staying phenomenon which three Red, Green, and Blue color fields were integrated in the human visual system. Then, the full color images were perceived by the observers. However, the performances of the FSC-LCDs were better than others. But the Color Breakup (CBU) phenomenon was the most issue of the FSC-LCDs. This issue will degrade the image quality of human visual perception and the observer’s eye will feel uncomfortable under the CBU phenomenon. In order to study or solve the CBU issue, we should need an evaluation index at first. Therefore, we proposed a CBU evaluation index, Color Breakup scores (CBU#), to quantify the CBU phenomenon in this thesis. We based on the smooth pursuit eye movement to establish this evaluation index which can not only consider the human visual perception but also the color information. Then, the more relations between the CBU# and viewing conditions such as brightness, velocity, and viewing distance will be discussed. Finally, this index can be applied successfully on 32”, 15.4”, and 5.6” FSC-LCDs for CBU evaluation.
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Wu, Yi-Chen, and 吳怡真. "Watershed Segmentation of Color Images Based on Human Perception." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/43359279539022523905.
Full textAbstract:
碩士國立中正大學
資訊工程研究所
88
Watershed based on immersion simulations is extensively used in image segmentation, but it is rarely applied in color images because in a color image, it is hard to find a variable to decide the order relation. In this paper, we improve the watershed method based on gradient vectors and propose a new watershed method based on color perceptual vector in order to implement watershed on color images. This method makes use of HVC, the best color space in simulating the human color vision, and National Bureau of Standards (NBS) color distance so that the segmentation result performs satisfactory human visual discrimination. The empirical outcomes show that the HVC color space is better than the LUV color space; moreover, the resulting watershed boundaries identify perceptually different regions.
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Chen, Li-Qi, and 陳立奇. "Image Enhancement Technique for Improving the Abnormal Human Color Perception." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/85497153963335230689.
Full textAbstract:
碩士國立中正大學
電機工程研究所
101
Color deficiencies can only sense part of the visible spectrum. This is usually caused by two major reasons. One is the natural genetic factor, and the other is by the chemicals or the damage of nerve or brain. In the previous research and literature surveys, it shows that there are about 8% of male and 0.5% of female with the red-green color blindness in the world population. Among them, there are 6% the world population with trichromatic vision (weak color vision), 2% the world population with dichromatic vision (partial color blindness), and few world population with monochrome vision (total color blindness). If the color blindness is caused by the environment, it can be cured by medicine. But the natural color blindness cannot be cured by the existing operations. Although there are coated glasses which can be used to “correct”the color vision, no good results are shown presently. There still lack of efficient and suitable pproaches to solve this problem currently. The color blindness cannot choose the job related to art, medicine, chemical, electrical and telecommunications, etc. All these jobs depend on the ability to distinguish different colors. They also cannot take the driving license. To help the color deficiencies, we propose to use the computer algorithms to adjust the color and let the color deficiencies be able to distinguish the difference between the colors. We the algorithms used for digital images, and tested by the color deficiencies. Based on some preliminary research, we would also like to extend and use it for portable devices.
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Li, Hung-Chung, and 李宏中. "A Study of Human Color Perception under Low Illumination Conditions." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/unk66a.
Full textAbstract:
博士國立臺灣科技大學
應用科技研究所
105
How to improve light efficiency and visual comfort are two important aspects of lighting research. To optimize lighting quality, human color perception under various conditions should be studied first. Color perception under photopic vision range have been well studied. However, only few literatures focus on color appearance under low illumination conditions. In dark conditions, white LED spectra can be optimized by taking visual color gamut into account. To optimize lighting of a viewing field, a Light Appearance Model (LAM) is required to predict perceptual colors under high contrast lighting conditions. As strong lighting in the dark conditions would cause annoying afterimages, the visual characteristics of afterimage also should be studied in depth. To optimal white LED spectra for low illumination conditions, a mesopic vision model was applied to maximize mesopic luminance and 3D color gamut volume simultaneously. Simulation results suggest that the peak spectrum response in short wavelength could extend the range of color gamut but produce relatively lower mesopic luminance. Our psychophysical experiments also verified that lower luminance level, higher CCT and higher S/P-ratio white LED spectra obviously improved the speed and accuracy of reflective pattern recognition in low illumination conditions. In terms of light appearance modeling, the color appearance under non-uniform surround conditions with variation of stimulus luminance, surround luminance, background luminance, background orientation, and background size were tested psychophysically. The results show that the background size and surround luminance influence the appearance intensively; whereas the orientation of background pattern has little effect. A method to determine optimal parameters for the CIECAM02 color appearance model in lighting applications is proposed. An UGR-based model also is optimized for brightness estimation. The luminance of adapting field can be estimated by Gaussian-like functions. In terms of visual characteristics of afterimage, psychophysical results show that the intensity of illumination, exposure time and luminance of background are the primary factors influencing characteristic of afterimage. The results not only help lighting researchers to further understand the mechanism of mesopic color vision but also provide useful knowledge and models for future lighting design.
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Hua-ChengKao and 高華成. "A Study for Human Image Perception on Form of Goblets and Color of Inside Liquid." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/60122967479412585679.
Full textAbstract:
碩士國立成功大學
工業設計學系
103
Through the advance with time, the competition in the field of traditional industry and service industry have become furiously. Product that only meets customers’ requirement is not enough anymore nowadays, the mental requirement and inside liquid of customers have become quite critical issue in every field. In the past, the color of inside liquids in goblet is not considered in the previous literatures, instead goblet indeed presents the color of inside liquids in appearance, and also color is the front and most critical element of visual presentation. The image association between the forms of goblet and colors of inside liquid is constructed in this study. In the first experiment, multidimensional scaling was applied to cluster analysis to select several kinds of the most representative samples from the goblet collections from current market. At the meanwhile, the colors mixture of inside liquid and the collection and selection of image word were implemented, the acquired data above was analyzed by multivariate analysis. The image association between the forms of goblet and colors of inside liquid is constructed based on probability neural network. The second verification constructed in this study is to develop a system for mixed drinks with image perceptions, which aims to verify the constructed model and system. The system allows customers to input the required images, which leads the drink venders provide customers the mixed drinks with the image qualified goblets and colors. The mixed drinks that meets customers’ emotions on the instant are provided. The achievement of this study can be applied to develop a drink order system with image perception for the field of service industry such as theme restaurant or PUB, etc. The system provides customer a better visual enjoyment and an innovative interaction way that cultivates new business in the competitive service market.
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Hamburger, Kai [Verfasser]. "Visual illusions : perception of luminance, color, and motion in humans / vorgelegt von Kai Hamburger." 2007. http://d-nb.info/984203826/34.
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McKeefry, Declan J., Mark P. Burton, and A. B. Morland. "The contribution of human cortical area V3A to the perception of chromatic motion: a transcranial magnetic stimulation study." 2010. http://hdl.handle.net/10454/6094.
Full textAbstract:
Area V3A was identified in five human subjects on both a functional and retinotopic basis using functional magnetic resonance imaging techniques. V3A, along with other visual areas responsive to motion, was then targeted for disruption by repetitive transcranial magnetic stimulation (rTMS) whilst the participants performed a delayed speed matching task. The stimuli used for this task included chromatic, isoluminant motion stimuli that activated either the L-M or S-(L+M) cone-opponent mechanisms, in addition to moving stimuli that contained only luminance contrast (L+M). The speed matching task was performed for chromatic and luminance stimuli that moved at slow (2 degrees/s) or faster (8 degrees/s) speeds. The application of rTMS to area V3A produced a perceived slowing of all chromatic and luminance stimuli at both slow and fast speeds. Similar deficits were found when rTMS was applied to V5/MT+. No deficits in performance were found when areas V3B and V3d were targeted by rTMS. These results provide evidence of a causal link between neural activity in human area V3A and the perception of chromatic isoluminant motion. They establish area V3A, alongside V5/MT+, as a key area in a cortical network that underpins the analysis of not only luminance but also chromatically-defined motion.
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Kennedy, Graeme J., and David J. Whitaker. "The chromatic selectivity of visual crowding." 2010. http://hdl.handle.net/10454/6049.
Full textAbstract:
Precortical vision is mediated by three opponent mechanisms that combine receptoral outputs to form a luminance channel (L + M) and two chromatic channels, red-green (L/M) and blue-yellow (S/L + M). Here we ask the extent to which these basic color opponent mechanisms interact in the phenomenon of crowding, where nearby targets interfere with the processing of a central test target. The task was to identify the orientation of a Gabor patch while an annular plaid surrounded the patch. The radius of the annulus was varied in order to produce different separations of the test and flanker. The chromatic content of the Gabor and the annulus could be varied independently along the (L + M), (L/M), and (S/L + M) cardinal axes. For all targets, when the target and flanker shared the same chromaticity, performance decreased with decreasing separation of the target and annulus, i.e., a typical crowding effect was seen. When the test and flanker isolated different chromatic mechanisms, very little crowding was observed, even at the minimum separation of test target and annulus. In addition to this, intermediate chromaticities were found to produce intermediate levels of crowding. Finally, crowding effects using "half-wave rectified" stimuli suggest a locus for crowding effects beyond the level of color opponent mechanisms.
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Harding, Glen, J. M. Harris, and Marina Bloj. "Learning to use illumination gradients as an unambiguous cue to three dimensional shape." 2012. http://hdl.handle.net/10454/6005.
Full textAbstract:
The luminance and colour gradients across an image are the result of complex interactions between object shape, material and illumination. Using such variations to infer object shape or surface colour is therefore a difficult problem for the visual system. We know that changes to the shape of an object can affect its perceived colour, and that shading gradients confer a sense of shape. Here we investigate if the visual system is able to effectively utilise these gradients as a cue to shape perception, even when additional cues are not available. We tested shape perception of a folded card object that contained illumination gradients in the form of shading and more subtle effects such as inter-reflections. Our results suggest that observers are able to use the gradients to make consistent shape judgements. In order to do this, observers must be given the opportunity to learn suitable assumptions about the lighting and scene. Using a variety of different training conditions, we demonstrate that learning can occur quickly and requires only coarse information. We also establish that learning does not deliver a trivial mapping between gradient and shape; rather learning leads to the acquisition of assumptions about lighting and scene parameters that subsequently allow for gradients to be used as a shape cue. The perceived shape is shown to be consistent for convex and concave versions of the object that exhibit very different shading, and also similar to that delivered by outline, a largely unrelated cue to shape. Overall our results indicate that, although gradients are less reliable than some other cues, the relationship between gradients and shape can be quickly assessed and the gradients therefore used effectively as a visual shape cue.
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Chai, Chih-Yao, and 翟志堯. "Discussion for the Stochastic Resonance Effect on Human Visual Perception Created with Strength Variation of R, G, and B Part in Color Images." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/26895239272670865137.
Full textAbstract:
碩士國立清華大學
電機工程學系
99
Noise in nature is often seen to destroy the original signal without any benefits. Because the concept of the Stochastic Resonance has been proposed, the fact that noise can enhance signal recognition is widely concerned and researches in many fields of signal processing are started with this way for the extension of application. Our study is mainly focused on discussion for the Stochastic Resonance effect on human visual perception created with strength variation of R, G, and B part in color images. This thesis is the extension of the previous researches of Stochastic Resonance related to gray-level image and human visual perception. We will begin our research with the explanation of Stochastic Resonance and the quantization for human visual perception then introduce the image quality estimation models used in this thesis. After introducing those models, the experiment procedure will be presented. There are two experiments in this thesis. In the first experiment (experiment A), original natural color images and luminance-shifted are corrupted with various noises and thresholds. The comparison of their results will then be done to verify the fact that weak image is easier to cause the SR effect for human visual perception. For the second experiment (experiment B), we transform the gray-level test image used in previous researches to RGB color space with different color background then make the test images used in this thesis with various noise-threshold. Those test images are used to create the test videos. Ten human subjects are asked to evaluate the test videos and their perception results will be averaged. The image quality results for those test images will be evaluated with image quality estimation models. We present the results with tables and do the analysis and discussion in the text of this thesis. For the results of subjects, we summarize their properties and do the comparison. For the results of image quality estimation models, we perform the inference individually with their properties or mathematical functions. In this experiment, in addition to the image quality estimation models used in previous studies, we will use three other models to make the application wider.
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Hedrich, M., M. Bloj, and A. I. Ruppertsberg. "Color constancy improves for real 3D objects." 2009. http://hdl.handle.net/10454/6011.
Full textAbstract:
In this study human color constancy was tested for two-dimensional (2D) and three-dimensional (3D) setups with real objects and lights. Four different illuminant changes, a natural selection task and a wide choice of target colors were used. We found that color constancy was better when the target color was learned as a 3D object in a cue-rich 3D scene than in a 2D setup. This improvement was independent of the target color and the illuminant change. We were not able to find any evidence that frequently experienced illuminant changes are better compensated for than unusual ones. Normalizing individual color constancy hit rates by the corresponding color memory hit rates yields a color constancy index, which is indicative of observers' true ability to compensate for illuminant changes.
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Merriweather, Tarani Joy. "A [K]ink in the Armor: How the Intersection of Gender and Racial Prototypicality Affect Perceptions of Black Women Aspiring to be Managers." Thesis, 2020. https://doi.org/10.7916/d8-mzep-4z61.
Full textAbstract:
Intersectional analyses have made clear that Black women as a group fare far worse in employment outcomes than their race and gender counterparts. However, there is little research that examines differences among Black women. The purpose of this dissertation is to examine how Black women are perceived intra-intersectionally, or within the intersection of race and gender. Black women are not monolithic and it is important to illuminate how they are perceived differently from one another. This dissertation explores the effects of differences in skin tone and hair texture among Black women seeking a management position. It was hypothesized that Black women with lighter skin and/or straight hair would be characterized more positively than Black women with darker skin and/or kinky hair; this hypothesis was not supported. However, for negative characteristics, the hypothesis that Black women with darker skin would be characterized more negatively than Black women with lighter skin was confirmed. Further, it was found that hair texture significantly interacts with skin tone such that darker-skinned Black women with kinky hair were characterized more negatively than light-skinned women with kinky hair. There were no significant differences found between the skin tone and hair texture of Black women on salary offers, but there was a marginally significant skin tone effect for perceptions of success in that lighter-skinned Black women are perceived to be more successful than darker-skinned Black women. This study sheds light on the need to look at the intersection of both skin tone and hair texture in order to fully understand how negative stereotypes apply to Black women.
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Rosendo, Filipe Alexandre Recto. "Gluten, with or without it: the impact of color of "gluten-free" and "with-gluten" claims in food perception." Master's thesis, 2018. http://hdl.handle.net/10071/18305.
Full textAbstract:
Various trends emerge frequently concerning healthy eating and gluten-free products are one
of the most relevant at the moment. The present research has the goal of understanding how
information regarding this component (claims “with-gluten” and “gluten-free) on the package
of food products impacts the consumer’s evaluations of healthiness, caloric content and taste.
We also seek to understand how the manipulation of the color of this label (green and red) can
lead to a change in said evaluations. In this experimental study conducted online (Qualtrics)
voluntarily participated 370 subjects (77.6% women, Mage = 28.57, SD = 10.61) distributed
randomly between six conditions of the design: 3 (gluten-free, with-gluten and control) x 2 (red
and green). The task consisted on the evaluation of 12 items from two distinct food categories
– biscuits and bakery goods. We verified that subjects tend to consider products with the claim
“gluten-free” as healthier and less caloric than others without claim; the “with gluten” condition
did not differ significantly from the control condition neither from the “gluten-free” one. The
manipulation of color did not impact significantly any of the evaluations. Nor did de evaluations
of taste differ significantly for any of the conditions of the independent variables. It is also
relevant to mention that the self-evaluated knowledge of gluten tends to be underestimated –
when compared to objective knowledge – and that a gluten-free diet is thought of as superior
to a conventional diet. This investigation represents a contribution for the understanding of how
consumers perceive aliments and how this type of informational instruments can bias their food
choices.Várias modas emergem frequentemente no que diz respeito à alimentação saudável e os produtos livres de glúten são uma das mais relevantes atualmente. A presente investigação tem como objetivo entender o impacto da informação relativamente à presença ou ausência deste componente nas embalagens de produtos alimentares (rótulos “com glúten” e “sem glúten”) na perceção dos alimentos. Propomo-nos ainda a entender de que forma a manipulação da cor deste rótulo (verde vs. vermelho) pode influenciar tais avaliações. Neste estudo experimental conduzido online (Qualtrics) colaboraram voluntariamente 370 participantes (77.6% mulheres, MIdade = 28.57 DP = 10.61) distribuídos aleatoriamente pelas seis condições resultantes do delineamento : 3 (livre de glúten; contém glúten; control) x 2 (verde; vermelho). A tarefa consistia em avaliar um conjunto de 12 exemplares de produtos alimentares (e.g., diferentes tipos de pão e bolachas) relativamente à sua salubridade, teor calórico e sabor. Verificou-se que os participantes tendem a considerar mais saudáveis e menos calóricos os alimentos que possuem o rótulo “sem glúten” comparativamente a alimentos sem qualquer rotulagem. Porém, a condição “com glúten” não se diferenciou significativamente diferente da condição “sem glúten” ou da de controlo. Não se verificou um impacto direto da manipulação da cor na perceção dos alimentos, nem uma interação deste fator com o tipo de rótulo. As avaliações de sabor não diferiram significativamente entre as condições de nenhuma das variáveis independentes. É ainda relevante mencionar que os sujeitos tendem a subestimar o seu conhecimento relativamente ao glúten – quando comparado com o seu conhecimento objetivo – e que estes entendem uma dieta livre de glúten como sendo superior a uma dieta convencional. Esta investigação representa uma contribuição para entender como os consumidores percebem os alimentos e de que forma este tipo de instrumentos informativos podem enviesar as suas escolhas alimentares.
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Nevšímalová, Nikola. "Kouzlo a moc červených rtěnek. Jak ovlivňují naše vnímání a komunikaci s okolím?" Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-415477.
Full textAbstract:
This master thesis The magic and power of red lipsticks represents theoretical-empirical analysis that argues how red lipsticks influence our perception and how we communicate through them with our surrounding. The thesis stems from the basic assumption that red lipstick is truly important and bold communication mean that is able to talk to our surrounding in a completely different ways than other colors or color shades. The aim of the thesis was to find out whether the aforementioned assumption matches the reality. Key questions for this master thesis were as follows: How do women communicate with their surrounding through red color (red lipstick)? What do they expect from these communication means? How do they feel when they communicate through these means (when they wear red lipstick)? How to they perceive reactions for this mean of communication? What are these reactions like (men- and women- wise)? The master thesis is based on researches from the field of beauty, human attractiveness or perception of red color that have already been done and it presents several different theories about human beautification as well as cosmetics evolution and evolution of perception of beauty itself. Except these, the thesis focuses on media content and the ways in which media, mainly social media and other...
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Harding, G., and M. Bloj. "Real and predicted influence of image manipulations on eye movements during scene recognition." 2010. http://hdl.handle.net/10454/6004.
Full textAbstract:
In this paper, we investigate how controlled changes to image properties and orientation affect eye movements for repeated viewings of images of natural scenes. We make changes to images by manipulating low-level image content (such as luminance or chromaticity) and/or inverting the image. We measure the effects of these manipulations on human scanpaths (the spatial and chronological path of fixations), additionally comparing these effects to those predicted by a widely used saliency model (L. Itti & C. Koch, 2000). Firstly we find that repeated viewing of a natural image does not significantly modify the previously known repeatability (S. A. Brandt & L. W. Stark, 1997; D. Noton & L. Stark, 1971) of scanpaths. Secondly we find that manipulating image features does not necessarily change the repeatability of scanpaths, but the removal of luminance information has a measurable effect. We also find that image inversion appears to affect scene perception and recognition and may alter fixation selection (although we only find an effect on scanpaths with the additional removal of luminance information). Additionally we confirm that visual saliency as defined by L. Itti and C. Koch's (2000) model is a poor predictor of real observer scanpaths and does not predict the small effects of our image manipulations on scanpaths.
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Μακεδόνας, Ανδρέας. "Οργάνωση και διαχείριση βάσεων εικόνων βασισμένη σε τεχνικές εκμάθησης δεδομένων πολυσχιδούς δομής." Thesis, 2009. http://nemertes.lis.upatras.gr/jspui/handle/10889/2477.
Full textAbstract:
Το ερευνητικό αντικείμενο της συγκεκριμένης διατριβής αναφέρεται στην επεξεργασία έγχρωμης εικόνας με χρήση της θεωρίας γράφων, την ανάκτηση εικόνας καθώς και την οργάνωση / διαχείριση βάσεων δεδομένων με μεθόδους γραφημάτων και αναγνώρισης προτύπων, με εφαρμογή σε πολυμέσα.
Τα συγκεκριμένα προβλήματα προσεγγίστηκαν διατηρώντας τη γενικότητά τους και επιλύθηκαν με βάση τα ακόλουθα σημεία:
1. Ανάπτυξη τεχνικών για την επιλογή χαρακτηριστικών από τις εικόνες βάσει χαρακτηριστικών χαμηλού επιπέδου (χρώματος και υφής), για χρήση τους σε εφαρμογές ομοιότητας και ανάκτησης εικόνας.
2. Υπολογισμός μετρικών και αποστάσεων στο χώρο των χαρακτηριστικών.
3. Μελέτη της πολυσχιδούς δομής των εικόνων μιας βάσης στο χώρο των χαρακτηριστικών.
4. Ελάττωση της διάστασης του χώρου και παραγωγή αναπαραστάσεων δύο διαστάσεων.
5. Εφαρμογή των μεθόδων αυτών σε υποκειμενικές αποστάσεις εικόνων.
Η θεωρία γράφων και οι μέθοδοι αναγνώρισης προτύπων χρησιμοποιήθηκαν προκειμένου να παρουσιαστούν βέλτιστες λύσεις αφενός στο πρόβλημα της ανάκτησης εικόνων από βάσεις δεδομένων και αφετέρου στην οργάνωση και διαχείριση τέτοιων βάσεων εικόνων. Η διατριβή φέρνει πιο κοντά την επεξεργασία εικόνας με μεθόδους προερχόμενες από τη θεωρία γραφημάτων, τη στατιστική και την αναγνώριση προτύπων. Σε όλη τη διάρκεια της διατριβής, ιδιαίτερη έμφαση δόθηκε στο ζήτημα της εύρεσης του κατάλληλου συνδυασμού μεταξύ της αποτελεσματικότητας των συστημάτων και της αποδοτικότητας στα πλαίσια της εφαρμογής των προτεινόμενων αλγοριθμικών διαδικασιών. Τα αναλυτικά πειραματικά αποτελέσματα που πραγματοποιήθηκαν, αποδεικνύουν την βελτιωμένη απόδοση των προτεινόμενων μεθοδολογιών.The subject of this doctoral thesis is related to color image processing using graph theoretic methods, image retrieval and image database management and organization in the reduced feature space, using pattern recognition analysis, with multimedia applications. The author attempted to approach the thesis subject by retaining its genericness and addressing the following points: 1. Development of techniques for extraction of image visual attributes based on low level features (color and texture information), to be used for image similarity and retrieval practices. 2. Calculation of metrics and distances in the feature space. 3. Study of the image manifolds created in the selected feature space. 4. Application of dimensionality reduction techniques and production of biplots. 5. Application of the proposed methodologies using perceptual image distances. Graph theory and pattern recognition methodologies were incorporated in order to provide novel solution to color image retrieval of image databases, as well as to image database management and organization. The current thesis brings closer image processing with graph theoretic methodologies, statistical analysis and pattern recognition. Throughout the thesis, consideration has been taken for finding the best trade off between effectiveness and efficiency when applying the proposed algorithmic procedures. The extended experimental results carried out in all stages of the projected studies reveal the enhanced performance of the proposed methodologies.