Dissertations / Theses on the topic 'Color vision'
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Kwok, Pui-yan Veronica, and 郭沛殷. "Learning new color names produces lateralized categorical color perception: a training study." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B49858592.
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Previous behavioral and neuroimaging findings (Drivonikou, et al., 2007; Gilbert, et al., 2006; Tan, et al., 2008; Siok, et al., 2009) indicate that reaction times to targets in visual search are faster in the right than the left visual field when the target and distractor colors straddle a category boundary. This phenomenon is known as the lateralized categorical color perception, which supports the weaker form of Whorf’s hypothesis that linguistic information shapes color perception. Yet, these studies did not demonstrate a definite cause and effect relation between language and perception. The observed lateralized category effect of color perception may either rely on the individual’s innate color categories or his linguistic experience.
In the present study, we used an intensive training method to study categorical perception (CP) of color. We aimed to show a definite causal relation between language and perception. In Experiment 1, 37 native Mandarin speakers were tested with a color discrimination task. We taught 20 participants four new linguistic items for the four stimulus colors which were initially from the same lexical category (two blues and two greens) whilst other participants did not learn any new color names. Performances between the two groups were compared before and after training. Experiment 2 was based on Zhou et al.’s (2010) behavioral study, in which we used the same training procedure and measured and contrasted 19 participants’ brain structure before and after training.
In experiment 1, participants exhibited lateralized Whorf effect when performing the visual search task at the pre-training phase. After training, the experimental group successfully acquired the new color names, reflected by overall shorter reaction time and higher task accuracy, while the control group did not show significant difference in the performance across two phases. The improved performance of experimental group implicated that the newly learned categories altered participants’ color perception pattern. However, we failed to show lateralized Whorf effect at the post-training phase due to several experimental flaws. In Experiment 2, gray matter density is found to increase in color region of the left visual cortex after a short-term training (less than two hours). The data provided strong structural evidence for newly-learned categorical color perception and also suggested structural plasticity of the human brain. The results from this study indicate that language experience shapes perception, both functionally and structurally, after a period of learning that is much shorter than previously established (Draganski, 2004; Carreiras, et al., 2009; Trachtenberg, 2002).published_or_final_version
Linguistics
Master
Master of Philosophy
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Skaff, Sandra. "Spectral models for color vision." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66750.
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This thesis introduces a maximum entropy approach to model surface reflectance spectra. A reflectance spectrum is the amount of light, relative to the incident light, reflected from a surface at each wavelength. While the color of a surface can be in 3D vector form such as RGB, CMY, or YIQ, this thesis takes the surface reflectance spectrum to be the color of a surface. A reflectance spectrum is a physical property of a surface and does not vary with the different interactions a surface may undergo with its environment. Therefore, models of reflectance spectra can be used to fuse camera sensor responses from different images of the same surface or multiple surfaces of the same scene. This fusion improves the spectral estimates that can be obtained, and thus leads to better estimates of surface colors. The motivation for using a maximum entropy approach stems from the fact that surfaces observed in our everyday life surroundings typically have broad and therefore high entropy spectra. The maximum entropy approach, in addition, imposes the fewest constraints as it estimates surface reflectance spectra given only camera sensor responses. This is a major advantage over the widely used linear basis function spectral representations, which require a prespecified set of basis functions. Experimental results show that surface spectra of Munsell and construction paper patches can be successfully estimated using the maximum entropy approach in the case of three different surface interactions with the environment. First, in the case of changes in illumination, the thesis shows that the spectral models estimated are comparable to those obtained from the best approach which computes spectral models in the literature. Second, in the case of changes in the positions of surfaces with respect to each other, interreflections between the surfaces arise. Results show that the fusion of sensor responses from interreflectionCette thèse introduit une approche par entropie maximale pour la modélisation des spectres de réflectance de surface. Un spectre de réflectance est la quantité de lumière, relative à la lumière incidente, réfléchie d'une surface à chaque longueur d'onde. Bien que la couleur d'une surface puisse prendre la forme d'un vecteur 3D tel que RGB, CMY ou YIQ, cette thèse prend le spectre de réflectance de surface comme étant la couleur d'une surface. Un spectre de réflectance est une propriété physique d'une surface et ne varie pas avec les différentes interactions que peut subir une surface avec son environnement. Par conséquent, les modèles de spectres de réflectance peuvent être utilisés pour fusionner les réponses de senseurs de caméra provenant de différentes images d'une même surface ou de multiples surfaces de la même scène. Cette fusion améliore les estimés spectraux qui peuvent être obtenus et mène donc à de meilleurs estimés de couleurs de surfaces.La motivation pour l'utilisation d'une approche par entropie maximale provient du fait que les surfaces observées dans notre environnement habituel ont typiquement un spectre large et donc à haute entropie. De plus, l'approche par entropie maximale impose le moins de contraintes puisqu'elle estime les spectres de réflectance de surface à l'aide seulement des réponses de senseurs de caméra. Ceci est un avantage majeur par rapport aux très répandues représentations spectrales par fonctions de base linéaires qui requièrent une série pré-spécifiée de fonctions de base.Les résultats expérimentaux montrent que les spectres de surface de taches de surface de Munsell et de papier de construction peuvent être estimés avec succès en utilisant l'approche par entropie maximal dans le cas de trois différentes interactions de surfaces avec l'environnement. D'abord, dans le cas de changements dans l'illumination, la t
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Gilbert, B. John. "Color Vision in the Bovine." DigitalCommons@USU, 1985. https://digitalcommons.usu.edu/etd/4117.
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Eight heifers were trained using operant conditioning to press a plate to receive a feed reward. Different wavelengths of light were presented as correct and incorrect stimuli. Positive and negative responses to the stimuli were registered electronically. Daily sessions of 17 minutes were conducted in a chamber with external light being excluded.
The duration of the stimulus was fixed at 17 seconds after which stimuli were randomly presented. Only presses on the plate when the correct stimulus was presented were reinforced with feed. A 75% correct choice was the criterion used as acceptable discrimination.
Ratios of correct to incorrect responses were computed. A stability of response was judged to occur when the median of these ratios over 5 days did not differ by more than .05 from the median of the ratios from the previous 5 sessions. Three colors i.e. green {535nm), red {610nm), and blue {450nm) were compared pairwise during 8 trials. Trial 7 was a repeat trial of green vs red and trial 8 was a comparison of green vs green.
Heifers gave random response to green vs green. Red was distinguished from blue by five of the heifers: 1, 2, 3, 4, and 5 at 76%, 91%, 78%, 88%, and 81% correct choice respectively. Blue was distinguished from green by three of the heifers: 1, 2, and 5 at 89%, 88%, and 85% correct choice respectively. Green was distinguished from red by three of the heifers: 1, 5, and 7 at 90%, 84%, and 85% correct choice respectively. These last discriminations we r e made in the repeat trial of green vs red after heifers failed to do so in the first trial of green vs red. Color discrimination and discrimination learning have been demonstrated by these results.
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Voraphani, Natthapongs. "Color vision screening using eye movements." [Ames, Iowa : Iowa State University], 2007.
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Shayeghpour, Omid. "Improving information perception from digital images for users with dichromatic color vision." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-101984.
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Color vision deficiency (CVD) is the inability or limited ability to recognize colors and discriminate between them. A person with this condition perceives a narrower range of colors compared to a person with a normal color vision. A growing number of researchers are striving to improve the quality of life for CVD patients. Finding cure, making rectification equipment, providing simulation tools and applying color transformation methods are among the efforts being made by researchers in this field. In this study we concentrate on recoloring digital images in such a way that users with CVD, especially dichromats, perceive more details from the recolored images compared to the original image. The main focus is to give the CVD user a chance to find information within the picture which they could not perceive before. However, this transformed image might look strange or unnatural to users with normal color vision. During this color transformation process, the goal is to keep the overall contrast of the image constant while adjusting the colors that might cause confusion for the CVD user. First, each pixel in the RGB-image is converted to HSV color space in order to be able to control hue, saturation and intensity for each pixel and then safe and problematic hue ranges need to be found. The method for recognizing these ranges was inspired by a condition called “unilateral dichromacy” in which the patient has normal color vision in one eye and dichromacy in another. A special grid-like color card is designed, having constant saturation and intensity over the entire image, while the hue smoothly changes from one block to another to cover the entire hue range. The next step is to simulate the way this color card is perceived by a dichromatic user and finally to find the colors that are perceived identically from two images and the ones that differ too much. This part makes our method highly customizable and we can apply it to other types of CVD, even personalize it for the color vision of a specific observer. The resulting problematic colors need to be dealt with by shifting the hue or saturation based on some pre-defined rules. The results for the method have been evaluated both objectively and subjectively. First, we simulated a set of images as they would be perceived by a dichromat and compared them with simulated view of our transformed images. The results clearly show that our recolored images can eliminate a lot of confusion from user and convey more details. Moreover, an online questionnaire was created and 39 users with CVD confirmed that the transformed images allow them to perceive more information compared to the original images.
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Stokman, Harro. "Robust photometric invariance in machine color vision." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/56969.
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Wright, Anne R. (Anne Renée). "A low-cost color vision tracking system." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10896.
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Neuschwanger, Christina Mary. "The development of color and motion processing /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3096419.
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Martinez, Elizabeth. "Bisection of cognitive color space : do individual "midpoint" judgements reveal the dimensional structure of suprathreshold color differences /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3112197.
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Szmajda, Brett A. "Subcortical pathways for colour vision /." Connect to thesis, 2006. http://eprints.unimelb.edu.au/archive/00003165.
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Thesis (Ph.D.)--University of Melbourne, The National Vision Research Institute of Australia and Dept. of Optometry & Vision Sciences, 2007.Typescript. Includes bibliographical references (leaves 95-111).
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Redfield, Signe Anne. "Efficient object recognition using color quantization." [Gainesville, Fla.] : University of Florida, 2001. http://purl.fcla.edu/fcla/etd/UFE0000347.
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Thesis (Ph. D.)--University of Florida, 2001.Title from title page of source document. Document formatted into pages; contains xiv, 150 p.; also contains graphics. Includes vita. Includes bibliographical references.
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Reniff, Lisa. "Visual determination of color differences using Probit analysis : phase II /." Online version of thesis, 1989. http://hdl.handle.net/1850/11544.
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Cerda-Company, Xim. "Understanding color vision: from psychophysics to computational modeling." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667177.
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En aquest doctorat, hem estudiat la visió del color dels humans des de dos punts de vista diferents: la psicofísica i la modelització computacional. Primer, hem avaluat 15 "tone-mapping operators" (TMOs) diferents en dos experiments que consideren criteris diferents: el primer té en compte les relacions locals entre nivells d'intensitat i el segon avalua l'aparença global de la imatge resultant respecte l'escena física (presentades una al costat de l'altra). La conclusió és que els rankings depenen del criteri utilitzat i que no estan correlacionats. Considerant els dos criteris, els millors TMOs són el KimKautz (Kim and Kautz, 2008) i el Krawczyk (Krawczyk et al., 2005). Tot i això, s'han de definir criteris estàndards per a poder fer una comparació justa entre els diferents TMOs.
Després, hem realitzat diferents experiments psicofísics per estudiar la inducció del color. Bàsicament, hem estudiat dues propietats diferents dels estímuls: la freqüència temporal i la distribució espaial de la lluminància. Per a estudiar la freqüència temporal, vam definir uns estímuls equiluminants compostos per voltants uniformes i ratllats, els quals els vam mostrar durant un flash. En els voltants uniformes, els resultats mostren que la inducció del color depèn de la duració del flash i de la cromaticitat del inductor. Tal com esperàvem, en totes les diferents condicions cromàtiques, es va induir contrast cromàtic. Per contra, en els voltants ratllats, esperàvem induir assimilació cromàtica, però vam observar contrast o no inducció. Com que estímuls ratllats similars, que no són equiluminants, indueixen assimilació del color, vam concloure que les diferències llumíniques podien ser un factor clau per a la inducció. Per tant, hem analitzat l'efecte de les diferències llumíniques en l'assimilació. Vam variar les diferències de lluminància entre la regió d'interès i els seus inductors i vam veure que l'assimilació cromàtica depèn d'aquestes diferències i de la cromaticitat del inductor. En la condició vermell-verd (quan el primer inductor és vermell i el segon és verd), l'assimilació de color es produeix en gairebé totes les condicions llumíniques. En canvi, en el cas del verd-vermell, mai s'observa assimilació del color. Les condicions lila-llima i llima-lila mostren clarament que la diferència llumínica és un factor clau per induir assimilació del color. Quan la regió d'interès és més fosca que el seu voltant, l'efecte és més fort en la condició lila-llima, mentre que quan la regió d'interès és més brillant, l'efecte és més fort en la condició llima-lila (efecte mirall). A més a més, vam avaluar si l'assimilació del color ve donada per diferències llumíniques o de brillantor. De manera similar a la condició equiluminant, no s'observa assimilació del color quan l'estímul és equibrillant. Els nostres resultats donen suport a la hipòtesis que la inhibició mútua juga un rol important en la percepció del color, o com a mínim en la inducció del color.
Finalment, hem definit un nou model del processament del color (del "parvocellular pathway") a V1. Hem modelitzat dues capes diferents: les capes 4Cβ i 2/3. El nostre model és una xarxa dinàmica recurrent que considera neurones excitadores i inhibidores i les seves connexions laterals. A més, també considera les diferències laminars existents i les diferents cèl·lules que les componen. Per tant, hem modelitzat les neurones simples "single-" i "double-opponent" i les neurones complexes, les quals es consideren un conjunt de neurones simples "double-opponent". Per testejar l'arquitectura, hem utilitzat un conjunt the "drifting gratings" sinusoïdals i hem variat algunes de les seves propietats com la freqüència temporal i espaial, la seva àrea i la seva orientació. Per repoduir les observacions electrofisiològiques, vam haver de suposar l'existència d'unes neurones "double-opponent" sense selectivitat a orientació i la falta de connexions laterals entre neurones "single-opponent". A més a més, hem testejat les connexions laterals modelitzades simulant la modulació del centre i voltant. Hem observat que quan l'estímul té un alt contrast, el resultat d'aquestes connexions és inhibitori, però és facilitatori quan el contrast és baix.In this PhD we have approached the human color vision from two different points of view: psychophysics and computational modeling. First, we have evaluated 15 different tone-mapping operators (TMOs). We have conducted two experiments that consider two different criteria: the first one evaluates the local relationships among intensity levels and the second one evaluates the global appearance of the tone-mapped images w.r.t. the physical one (presented side by side). We conclude that the rankings depend on the criterion and they are not correlated. Considering both criteria, the best TMOs are KimKautz (Kim and Kautz, 2008) and Krawczyk (Krawczyk et al., 2005). Another conclusion is that a more standardized evaluation criteria is needed to do a fair comparison among TMOs. Secondly, we have conducted several psychophysical experiments to study the color induction. We have studied two different properties of the visual stimuli: temporal frequency and luminance spatial distribution. To study the temporal frequency we defined equiluminant stimuli composed by both uniform and striped surrounds and we flashed them varying the flash duration. For uniform surrounds, the results show that color induction depends on both the flash duration and inducer's chromaticity. As expected, in all chromatic conditions color contrast was induced. In contrast, for striped surrounds, we expected to induce color assimilation, but we observed color contrast or no induction. Since similar but not equiluminant striped stimuli induce color assimilation, we concluded that luminance differences could be a key factor to induce color assimilation. Thus, in a subsequent study, we have studied the luminance differences' effect on color assimilation. We varied the luminance difference between the target region and its inducers and we observed that color assimilation depends on both this difference and the inducer's chromaticity. For red-green condition (where the first inducer is red and the second one is green), color assimilation occurs in almost all luminance conditions. Instead, for green-red condition, color assimilation never occurs. Purple-lime and lime-purple chromatic conditions show that luminance difference is a key factor to induce color assimilation. When the target is darker than its surround, color assimilation is stronger in purple-lime, while when the target is brighter, color assimilation is stronger in lime-purple ('mirroring' effect). Moreover, we evaluated whether color assimilation is due to luminance or brightness differences. Similarly to equiluminance condition, when the stimuli are equibrightness no color assimilation is induced. Our results support the hypothesis that mutual-inhibition plays a major role in color perception, or at least in color induction. Finally, we have defined a new firing rate model of color processing in the V1 parvocellular pathway. We have modeled two different layers of this cortical area: layers 4Cβ and 2/3. Our model is a recurrent dynamic computational model that considers both excitatory and inhibitory cells and their lateral connections. Moreover, it considers the existent laminar differences and the cells' variety. Thus, we have modeled both single- and double-opponent simple cells and complex cells, which are a pool of double-opponent simple cells. A set of sinusoidal drifting gratings have been used to test the architecture. In these gratings we have varied several spatial properties such as temporal and spatial frequencies, grating's area and orientation. To reproduce the electrophysiological observations, the architecture has to consider the existence of non-oriented double-opponent cells in layer 4Cβ and the lack of lateral connections between single-opponent cells. Moreover, we have tested our lateral connections simulating the center-surround modulation and we have reproduced physiological measurements where for high contrast stimulus, the result of the lateral connections is inhibitory, while it is facilitatory for low contrast stimulus.
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Azeff, Liza. "The role of color vision in shape discrimination /." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97897.
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The purpose of this project is to study the role of human color vision in shape processing. We examine the extent to which color vision can contribute to complex shape processing tasks or whether they are accomplished mainly by the achromatic pathways of the brain. We tested normal human visual performance using psychophysical experiments. The stimuli were presented on a monitor and the task of the subject is to indicate whether shape differences in the stimuli have been seen. Each psychophysical trial was run four-to-five times using a two-interval forced choice paradigm. Stimuli were calibrated so that they selectively activate either the achromatic pathways (black & white) pathways or the color (red-green and blue-yellow) pathways of the human brain. The results of the study show that color vision can perform many of the various types of shape discrimination tasks at similar levels to achromatic vision.
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Seemiller, Eric S. "Selective pressures influencing color-vision in Neotropical primates." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1309883439.
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Liu, Yan. "Negative feedback control of the visual system and systematic colors vision model /." Online version of thesis, 1991. http://hdl.handle.net/1850/11211.
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Eisen, Paul S. "An evaluation of the manipulation of color in alternative color spaces." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43852.
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The amenability of various color-controlling algorithms to the real-time operator control of color stimuli was investigated. Mathematical models based on eight color spaces were employed: three uniform color spaces (L*u*v*, L*h*C*, and Y 2.2u' VI), a graphics algorithm (HLS), an opponent color model, the NTSC broadcast signals (YIQ), and two sets of color primaries. Eighty subjects, divided equally among the color spaces, were required to match colors under time-limited conditions.
The apparatus employed was a color-manipulation device using LEDs, custom-built in the Displays and Controls Laboratory at Virginia Tech. The device allows for 12-bit resolution on each color channel and higher stability of luminance and chrominance over the short and long term than can be achieved with experimental quality CRTs.Master of Science
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Gunther, Karen La Vaughn. "The neural mechanisms underlying color perception /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3044771.
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Heckaman, Rodney L. "Brilliance, contrast, colorfulness, and the perceived volume of device color gamut /." Online version of thesis, 2008. http://hdl.handle.net/1850/8433.
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Balonon-Rosen, Mitchell. "An uncertainty analysis of a color tolerance database /." Online version of thesis, 1993. http://hdl.handle.net/1850/11066.
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Forsyth, D. A. "Colour constancy and its applications in machine vision." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670357.
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Kurdziel, Michael Scott. "A monocular color vision system for road intersection detection /." Online version of thesis, 2008. http://hdl.handle.net/1850/6208.
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Rodriguez, Joaquin. "Calibration and 3D vision with a color-polarimetric camera." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2023. http://www.theses.fr/2023UBFCK062.
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Parmi les différentes modalités employées en détection, les capteurs de vision sont ceux qui fournissent le plus d'informations sur l'environnement. L'utilisation d'objectifs à courte focale permet en outre d'augmenter facilement la zone observée. L'apparition sur le marché d'imageurs couleurs et polarimétriques permet d'étendre encore davantage les applications en estimation de profondeur. En effet, les paramètres de polarisation de la lumière réfléchies ont liés à la nature des objets ainsi qu'à leur géométrie et peuvent être utilisés avantageusement. Dans cette thèse, notre objectif principal est d'étudier l'utilisation des données de polarisation pour améliorer les capacités de perception appliquées aux tâches robotiques, notamment dans la reconstruction de la profondeur de scène. De plus, nous visons à enrichir les connaissances dans le domaine de l'imagerie de polarisation en fournissant à d'autres chercheurs un ensemble d'outils qui leur permettront d'accéder rapidement à la modalité de polarisation. Après avoir effectué une introduction complète à la théorie et à la modélisation de la polarisation, nous décrivons comment calibrer un capteur de polarisation de division de plan focale. Ce dispositif de détection permet de capturer deux modalités (couleur et polarisation) avec une seule prise de vue. La nouvelle technique de calibration que nous proposons permet à ce dispositif de fournir des mesures plus précises en ajustant un modèle mathématique selon chaque pixel. La méthode que nous présentons ici vise à réduire la quantité d'équipement, donc le temps expérimental nécessaire pour obtenir des mesures calibrées. Nous détaillons également toute la physique sous-jacente à la technique de Shape-from-polarization (SfP) qui permet d'estimer le champ des normales d'un objet en utilisant l'information de la polarisation. Les équations nécessaires et les modèles inverses pour dériver les paramètres des vecteurs depuis l'état de polarisation sont détaillées tout en tenant compte du type de réflexion et du matériau. Nous mettons ici en avant l'intérêt de notre algorithme de calibrage sur l'estimation du champ de normales par polarisation L'estimation d'informations de profondeur grâce à l'intelligence artificielle a connu un essort très important ces dernières années. Dans ce contexte, nous proposons également un réseau d'apprentissage profond pour estimer la profondeur basé sur une architecture de fusion intermédiaire et une fonction de perte polarimétrique. L'objectif de ce développement est de montrer comment intégrer efficacement les contraintes de la théorie de la polarisation dans un algorithme basé sur les données. Une évaluation qualitative et quantitative des résultats démontrent l'intérêt de l'utilisation d'un imageur RGB-polarimétrique grâce à l'apport des informations de polarisation. Lors de ces travaux de recherche, une boîte à outils logiciel scomplète a également été développée proposant ainsi à la communauté scientifique un logiciel d'accès simplifié à l'imagerie polarimétriqueAmong the different sensing modalities, vision sensors are the ones thatprovide the most abundant environmental information. Additionally, the usage ofa short focal length lens allows to easily increase the observed area. The releaseof color and polarimetric imagers makes it possible to extend even more thepolarimetric application related to depth estimation. Indeed, the polarizationparameters of the reflected light are related to the nature and to the geometryof the objects, which can be used advantageously. In this thesis, our mainobjective is to study the usage of polarization data to enhance theperception capabilities applied to robotics tasks, particularly in the task ofscene depth reconstruction. Furthermore, we aim to push the knowledge in thefield of polarization imaging by providing other researchers with a set of toolsthat will allow them to quickly access the polarization modality. After doing acomplete introduction to the polarization theory and modeling, we describe howto calibrate a DoFP sensor. This sensing device allows to capture twomodalities (color and polarization) with a single snapshot. The new calibrationtechnique that we propose enables this device to provide more accuratemeasurements by fitting a mathematical model to each individual pixel. Themethod we present here aims to reduce the amount of equipment and, thus theexperimental time required to obtain calibrated measurements. We make a detailedexplanation of the physics underlying the Shape-from-Polarization technique, which enablesthe normal field estimation of an object by using polarization cues. All therequired equations as well as their inverted versions for deriving the vectorparameters from the polarization state are detailed while taking intoconsideration the type of reflection and material. We also put in evidence theeffects of our calibration algorithm over the estimation of the normal vectorfield by using polarization. The estimation of depth information usingartificial intelligence has seen significant growth in recent years. In thiscontext, we also propose a deep-learning network to estimate depth based on amiddle-fusion architecture, and a polarimetric loss function. The objective ofthis development is to show how to effectively integrate the polarization theoryconstraints into a data-driven algorithm. A qualitative and quantitativeevaluation of the results shows the interest of using an RGB-polarimetric imagerthanks to the contribution of the polarization information. During this researchwork, a complete software toolbox was also developed, providing the scientificcommunity with simplified access to polarimetric imaging
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Kim, Taek Gyu. "Comparing color appearance models using pictorial images /." Online version of thesis, 1994. http://hdl.handle.net/1850/11756.
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Aljarrah, Inad A. "Color face recognition by auto-regressive moving averaging." Ohio : Ohio University, 2002. http://www.ohiolink.edu/etd/view.cgi?ohiou1174410880.
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North, Amy D. "Investigation of observer variability using a new method for determining color matching functions /." Online version of thesis, 1991. http://hdl.handle.net/1850/11099.
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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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Dominy, Nathaniel J. "Trichromacy and the ecology of food selection in four African primates." Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B42576167.
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Peterson, Jason W. "Visual assessment of object color chroma and colorfulness /." Online version of thesis, 1994. http://hdl.handle.net/1850/11868.
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Machado, Gustavo Mello. "A model for simulation of color vision deficiency and a color contrast enhancement technique for dichromats." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/26950.
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As Deficiências na Percepção de Cores (DPC) afetam aproximadamente 200 milhões de pessoas em todo o mundo, comprometendo suas habilidades para efetivamente realizar tarefas relacionadas com cores e com visualização. Isto impacta significantemente os âmbitos pessoais e profissionais de suas vidas. Este trabalho apresenta um modelo baseado na fisiologia para simulação da percepção de cores. Além de modelar visão de cores normal, ele também compreende os tipos mais predominantes de deficiências na visão de cores (i.e., protanopia, deuteranopia, protanomalia e deuteranomalia), cujas causas são hereditárias. Juntos estes representam aproximadamente 99.96% de todos os casos de DPC. Para modelar a percepção de cores da visão humana, este modelo é baseado na teoria dos estágios e é derivado de dados reportados em estudos eletrofisiológicos. Ele é o primeiro modelo a consistentemente tratar visão de cores normal, tricromacia anômala e dicromacia de modo unificados. Seus resultados foram validados por avaliações experimentais envolvendo grupos de indivíduos com deficiência na percepção de cores e outros com visão de cores normal. Além disso, ele pode proporcionar a melhor compreensão e um feedback sobre como aperfeiçoar as experiências de visualização por indivíduos com DPC. Ele também proporciona um framework para se testar hipóteses sobre alguns aspectos acerca das células fotoreceptoras na retina de indivíduos com deficiência na percepção de cores. Este trabalho também apresenta uma técnica automática de recoloração de imagens que visa realçar o contraste de cores para indivíduos dicromatas com custo computacional variando linearmente com o número de pixels. O algoritmo proposto pode ser eficientemente implementado em GPUs, e para imagens com tamanhos tipicos ele apresenta performance de até duas ordens de magnitude mais rápida do que as técnicas estado da arte atuais. Ao contrário das abordagens anteriores, a técnica proposta preserva coerência temporal e, portanto, é adequado para recoloração de vídeos. Este trabalho demonstra a efetividade da técnica proposta ao integrá-la a um sistema de visualização e apresentando, pela primeira vez, cenas de visualização recoloridas para dicromatas em tempo-real e com alta qualidade.Color vision deficiency (CVD) affects approximately 200 million people worldwide, compromising the ability of these individuals to effectively perform color and visualizationrelated tasks. This has a significant impact on their private and professional lives. This thesis presents a physiologically-based model for simulating color perception. Besides modeling normal color vision, it also accounts for the hereditary and most prevalent cases of color vision deficiency (i.e., protanopia, deuteranopia, protanomaly, and deuteranomaly), which together account for approximately 99.96% of all CVD cases. This model is based on the stage theory of human color vision and is derived from data reported in electrophysiological studies. It is the first model to consistently handle normal color vision, anomalous trichromacy, and dichromacy in a unified way. The proposed model was validated through an experimental evaluation involving groups of color vision deficient individuals and normal color vision ones. This model can provide insights and feedback on how to improve visualization experiences for individuals with CVD. It also provides a framework for testing hypotheses about some aspects of the retinal photoreceptors in color vision deficient individuals. This thesis also presents an automatic image-recoloring technique for enhancing color contrast for dichromats whose computational cost varies linearly with the number of input pixels. This approach can be efficiently implemented on GPUs, and for typical image sizes it is up to two orders of magnitude faster than the current state-of-the-art technique. Unlike previous approaches, the proposed technique preserves temporal coherence and, therefore, is suitable for video recoloring. This thesis demonstrates the effectiveness of the proposed technique by integrating it into a visualization system and showing, for the first time, real-time high-quality recolored visualizations for dichromats.
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Yamagishi, Naomi Rochelle. "A woman of color in education, a postmodern vision quest." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21656.pdf.
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Garbers, Christian [Verfasser], and Thomas [Akademischer Betreuer] Wachtler. "Color vision in polychromatic animals / Christian Garbers ; Betreuer: Thomas Wachtler." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1129598322/34.
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Chakraborty, Manali. "Real-time image-based motion detection using color and structure." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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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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Hendrikse, Egbert Johannes. "Influence of blue/green versus red and white light sources on human dark adaptation and other selected visual functions." Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1009497.
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Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range.
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Svoke, Joseph T. "Perception of Color Vision In the Asian Small-Clawed Otter (Aonyx cinerea)." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/biology_theses/31.
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Color vision can affect our assumptions of an animals’ natural history. It can be determined by testing sensory or perception ability, which was employed here. Two Asian small-clawed otters (Aonyx cinerea), of opposite sexes, housed at ZooAtlanta, were trained via operant conditioning to discriminate stimuli within 7 tasks, primarily in a two-choice fashion. Varying shades of the colors blue, green and red were tested against varying greys, all which differed in intensity, served as the stimuli for the first 4 tasks. The remaining 3 tasks, the colors were tested against each other. The male reached criterion for the first 6 tasks, indicating an ability to discriminate the stimuli based on color. The female however participated only in 2, and could not achieve criterion as set, though there were indications of discrimination ability. Taken together with sensory work on two related otter species, Asian small-clawed otters possess color vision.
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Rezec, Amira A. "Effects of attention on visual motion processing /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3119178.
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Gorzynski, Mark E. "Achromatic perception in color image displays /." Online version of thesis, 1992. http://hdl.handle.net/1850/11243.
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Smith, Nicolette. "Colour perception: A phenomenological study into people's spontaneous physical, psychological, emotional and spiritual reactions, through experiential use, to colour." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 1999. https://ro.ecu.edu.au/theses/1238.
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The predominance of colour as a therapy is becoming more apparent in our culture at present. It is a well-known fact, which has been thoroughly documented, that colour affects our senses in many ways and on many levels. Colour is considered to possess a healing element. A phenomenological study will be conducted to investigate people's spontaneous physical, psychological, emotional, and spiritual reactions to colour. This will be explored through the experiential use of colour by the participants. The use of a pre-test questionnaire, post-test questionnaires, observation and de-briefing will be the main research instruments. A pilot study will be used to fine tune the methodology. Its application to Art Therapy will also be explored.
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King, William E. "Using an FPGA-Based Processing Platform in an Industrial Machine Vision System." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/31799.
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This thesis describes the development of a commercial machine vision system as a case study for utilizing the Modular Reprogrammable Real-time Processing Hardware (MORRPH) board. The commercial system described in this thesis is based on a prototype system that was developed as a test-bed for developing the necessary concepts and algorithms. The prototype system utilized color linescan cameras, custom framegrabbers, and standard PCs to color-sort red oak parts (staves). When a furniture manufacturer is building a panel, very often they come from edge-glued paneled parts. These are panels formed by gluing several smaller staves together along their edges to form a larger panel. The value of the panel is very much dependent upon the â matchâ of the individual stavesâ i.e. how well they create the illusion that the panel came from a single board as opposed to several staves.
The prototype system was able to accurately classify staves based on color into classes defined through a training process. Based on Trichromatic Color Theory, the system developed a probability density function in 3-D color space for each class based on the parts assigned to that class during training. While sorting, the probability density function was generated for each scanned piece, and compared with each of the class probability density functions. The piece was labeled the name of the class whose probability density function it most closely matched. A â best-faceâ algorithm was also developed to arbitrate between pieces whose top and bottom faces did not fall into the same classes. [1] describes the prototype system in much greater detail.
In developing a commercial-quality machine vision system based on the prototype, the primary goal was to improve throughput. A Field Programmable Gate Array (FPGA)-based Custom Computing Machine (FCCM) called the MORRPH was selected to assume most of the computational burden, and increase throughput in the commercial system. The MORRPH was implemented as an ISA-bus interface card, with a 3 x 2 array of Processing Elements (PE). Each PE consists of an open socket which can be populated with a Xilinx 4000 series FPGA, and an open support socket which can be populated with support chips such as external RAM, math processors, etc.
In implementing the prototype algorithms for the commercial system, a partition was created between those algorithms that would be implemented on the MORRPH board, and those that would be left as implemented on the host PC. It was decided to implement such algorithms as Field-Of-View operators, Shade Correction, Background Extraction, Gray-Scale Channel Generation, and Histogram Generation on the MORRPH board, and to leave the remainder of the classification algorithms on the host.
By utilizing the MORRPH board, an industrial machine vision system was developed that has exceeded customer expectations for both accuracy and throughput. Additionally, the color-sorter received the International Woodworking Fairâ s Challengers Award for outstanding innovation.Master of Science
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Kauppinen, H. (Hannu). "Development of a color machine vision method for wood surface inspection." Doctoral thesis, University of Oulu, 1999. http://urn.fi/urn:isbn:9514254244.
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Abstract
The purpose of this thesis is to present a case study of the development, implementation and performance analysis of a color-based visual surface inspection method for wood properties. The main contribution of the study is to answer the need of design strategies, performance characterization methods and case studies in the field of automated visual inspection, and especially wood surface inspection.
In real time color-based inspection, the complexity of the methods is important. In this study, defect detection and recognition methods based on color histogram percentile features are proposed. The color histogram percentile features were noticed to be able to recognize well wood surface defects with relatively low complexity.
A common problem in visual inspection applications is the collection and labelling of training material since human made labellings can be errorneous. Further, the classifiers are relatively static when once trained, thus offering only little possibilities for adjusting classification. In the study, a self-organizing map (SOM) -based approach for classifier user interface in visual surface inspection problems is introduced. The approach relieves the labelling of training material, simplifies retraining, provides an illustrative an intuitive user interface and offers a convenient way of controlling classification.
The study is illustrated with four experiments related to the method development and analysis. In the first experiment, a simulator environment is used for determining the relationship of the defect detection and recognition and grading accuracy. The second experiment considers the suitability of different color spaces for wood defect recognition under changing illumination. RGB color space gives the best results compared to grey-level and other color spaces. The third experiment presents the experimental wood surface inspection setup implementing the method developed in this study. Comparative performance analysis results are presented and the difficulties, mainly caused by segmentation of the defects, are discussed. The fourth experiment demonstrates the suitability of the method for parquet sorting and shows the potential of the non-segmenting approach.
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Lau, Hoi Ying. "Neural inspired color constancy model based on double opponent neurons /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?ECED%202008%20LAU.
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Cady, Paul Stevens. "THE EFFECTS OF AGING ON COLOR DISCRIMINATION OF CAPSULES (DIABETES, MEDICATION, VISION)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/291334.
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Tan, Zhigang. "A region merging methodology for color and texture image segmentation." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43224143.
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Highnote, Susan M. "Color discrimination of small targets /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3089477.
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Carney, Ovidia Cornelia Blough. "Effects of age and ethnicity on color preference and on association of color with symbol and with emotion." CSUSB ScholarWorks, 2001. https://scholarworks.lib.csusb.edu/etd-project/1882.
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Wernet, Mathias F. "Patterning the retina of Drosophila melanogaster for color and polarized light vision." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974431206.
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Gheiratmand, Mina. "Orientation tuning in human color vision at detection threshold: a psychophysical approach." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123169.
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Object processing is an essential task of the human visual system that is thought to beaccomplished through hierarchical processing of objects attributes in the ventral occipitotemporal cortex. An object can primarily be delineated by its shape and surface information,including its color and texture. A shape can initially be defined as a set of oriented elementsdefined in luminance or color contrast. It is now thought that red-green color vision can detectcolor-defined edges almost as well as luminance vision can detect luminance-defined edges. Thisis supported by evidence from both psychophysical experiments and single cell recordings.However, it is not yet well understood how color contrast is used by the visual system in formprocessing. Color vision can have an important additional role to luminance vision in objectperception, by processing the surface color of an object. Evidence from single cell recordings inprimates have shown the presence of a neurons population of about 10% in V1 that respondexclusively to full field color stimuli and are not tuned to spatial frequency or orientation,making them candidates for surface color processing. Psychophysical experiments, however,have not revealed any direct evidence for non-oriented color mechanisms.In this thesis I use the psychophysical method of subthreshold summation to determine theorientation tuning of the red-green color mechanisms in human vision, and for luminancecontrast under equivalent conditions. Psychophysical models, based on the presence of multipletuned detectors or a single, non-oriented mechanism, are used to determine tuning properties ofthe neural detectors underlying the psychophysical responses.The first set of experiments revealed evidence for two types of red-green color mechanism: 1)non-oriented revealed monocularly at low spatial frequencies (0.25-0.375 cycles/degree), and 2)oriented that appeared binocularly or at higher spatial frequencies (1.5 cycles/degree). Inluminance vision, evidence supported the presence of orientation tuning at all spatial scales andviewing conditions. Based on these findings, further experiments were done to measure the fullmonocular orientation tuning responses of color vision, in comparison to luminance vision, atdifferent spatial scales. At mid spatial frequencies, similar orientation tuning responses andneural detector bandwidth estimates were found for color and luminance vision (16 and 13 degsrespectively). At low spatial frequencies, tuning curves for color contrast were extremely broadand fitted reasonably by a model involving isotropic detectors. For luminance vision, orientationtuning is preserved with no change in detector bandwidth. Finally, binocular responses weremeasured using dichoptic chromatic stimuli that revealed orientation tuning at both low and midspatial frequencies. In summary, the results of this thesis have revealed the presence of twodistinct pathways in color vision at the behavioral level that are best equipped, respectively forthe representation of an object's surface-color and form, and have provided estimates of theorientation bandwidth of their underlying neural detectors.Le traitement des objets est une tache essentielle pour le système visuel humain que l'on penseêtre accomplie à travers un traitement hiérarchique des attributs de l'objet dans la régionoccipito-temporale ventrale du cerveau. Premièrement un objet peut être délimité par sesinformations de forme et de surface, ce qui inclut sa couleur et sa texture. La forme peut êtreinitialement définie comme un groupe d'éléments orientés définis par leur contraste enluminance ou couleur. On pense maintenant que la vision de la couleur rouge-verte est capablede détecter des arêtes définies par leur couleur presque aussi bien que la vision de la luminancepeut détecter des arêtes définies par leur luminances. Les preuves a l'appui proviennent à la foisd'expériences en psychophysique et d'enregistrements électrophysiologiques cellule simple.Cependant on ne comprend pas encore très bien comment le contraste en couleur est utilise par lesystème visuel pour le traitement de la forme. La vision de la couleur peut avoir un rôleadditionnel important pour la vision de la luminance dans la perception des objets, en traitant lacouleur de la surface de l'objet. Des preuves provenant d'enregistrements cellule simple ontmontré l'existence d'une population de neurones - représentant environ 10% des neurones de V1- qui répond exclusivement aux stimuli couleur plein champ et qui n'est sensible ni à lafréquence spatiale ni à l'orientation, ce qui rend ces neurones de bon candidats pour le traitementdes surfaces colorées. En revanche, aucune expérience en psychophysique n'a mise en évidenceun mécanisme couleur non-orienté.Dans cette thèse j'utilise la méthode psychophysique de sommation subliminaire pour déterminerla sélectivité aux orientations et la sensibilité au contraste de luminance des mécanismes de lacouleur rouge-verte dans la vision humaine avec des conditions comparables. Des modèlespsychophysiques basés sur l'existence, soit de multiples détecteurs sensibles à l'orientation, soitd'un unique mécanisme non-orienté, ont été utilisés pour déterminer les propriétés de sensibilitédes détecteurs neuraux qui sous-tendent les réponses psychophysiques.Un premier groupe d'expériences a révélé l'existence de deux types de mécanisme de la couleurrouge-verte: 1) un mécanisme non-orienté qui a été mis en évidence en vision monoculaire et ce,à basses fréquences spatiales (0.25-0.375 cycles/degré) et 2) un mécanisme sensible àl'orientation qui est apparue en vision binoculaire mais également à haute fréquence spatiale (1.5cycles/degré). Dans la vision de la luminance les preuves supportent l'existence de mécanismessensibles à l'orientation pour toutes les fréquences spatiales et pour toutes les conditions de vue.Au regard de ces résultats, les expériences suivantes ont été menées afin de mesurer le spectreentier de la sensibilité aux orientations de la vision de la couleur sous condition monoculaire, dele comparer à celui de la vision de la luminance et ce, à différentes échelles spatiales. Pour lesfréquences spatiales intermédiaires, la vision de la couleur et la vision de la luminanceprésentaient des réponses de sensibilité aux orientations semblables et des estimations de bandespassantessimilaires pour les détecteurs neuraux. Pour les basses fréquences spatiales, les courbesde sensibilité au contraste de couleur étaient très larges et s'expliquaient raisonnablement bien àl'aide d'un modèle impliquant des détecteurs isotropiques. Dans le cas de la vision de laluminance, la sensibilité aux orientations est préservée sans changement de bandes-passantes dudétecteur. Enfin les réponses binoculaires ont été mesurées à l'aide de stimuli chromatiquesprésentés de façon dichoptique pour révéler en même temps la sensibilité aux orientations dansles basses fréquences spatiales et dans les fréquences spatiales intermédiaires.
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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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Mangine, Heather Noelle. "Variability in experimental color matching conditions effects of observers, daylight simulators, and color inconstancy /." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117549884.
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