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Dissertations / Theses on the topic 'Color computer graphics'
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Rose, Brian J. "Color logic : interactively defining color in the context of computer graphics /." Online version of thesis, 1992. http://hdl.handle.net/1850/11614.
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Fang, Chong he. "A high performance colour graphics display system." Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09SM/09smf2115.pdf.
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Collery, Michael T. "Color in three-dimensional shaded computer graphics and animation." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1102107854.
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Leahy, Thomas G. "Color in computing /." Online version of thesis, 1994. http://hdl.handle.net/1850/11726.
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Hodgkinson, Derek Anthony Martin. "Computer graphics applications in offshore hydrodynamics." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26705.
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The results of hydrodynamic analyses of two problems involving offshore structures are displayed graphically. This form of presentation of the results and the liberal use of colour have been found to significantly help the ease in which the results are interpreted.
For the transformation of waves around an artificial island, a time history of the evolution of the regular, unidirectional wave field around an artificial island is obtained. Through the use of colour, regions in which wave breaking occurs have been clearly defined. The numerical technique used is based on the finite element method using eight noded isoparametric elements. The determination of the transformed wave field takes wave breaking, wave refraction, diffraction, reflection and shoaling into account. The graphical display is achieved by using a plotting program developed for the output of finite element analyses.
The motions of a semi-submersible rig are computed from the RAO curves of the rig, used to obtain its' small response in a random sea. The numerical technique used in the analysis assumes that the vertical members are slender and may be analysed using the Morison equation whereas the hulls are treated as large members which are discretised and analysed using diffraction theory. The discretisation of the cylinders and hulls together with the time history of the rig's motions are displayed graphically. Once again, the graphical display is plotted using a program developed for the output of finite element analyses for four noded elements. In this case, a finite element technique has not been employed but the results were ordered to act as though this is the case. The slender members (cylinders) and large members (hulls) are clearly distinguishable by using different colours. The elements used in the analysis are also clearly shown.
The VAX 11/730 system was used to obtain the results shown. A video tape, using the results of a time stepping procedure, was made by successively recording the hardcopies produced by the VAX printer. The time stepping could also be seen, in real time, on the IRIS.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Poe, Daryl Thomas. "One- and two-pass color quantization methods in computer graphics." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1335454027.
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Yang, Steve Wuter. "Display of molecular models with interactive computer graphics /." Online version of thesis, 1987. http://hdl.handle.net/1850/10347.
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Schmitt, Ryan Daniel. "GPU-Accelerated Point-Based Color Bleeding." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/810.
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Traditional global illumination lighting techniques like Radiosity and Monte Carlo sampling are computationally expensive. This has prompted the development of the Point-Based Color Bleeding (PBCB) algorithm by Pixar in order to approximate complex indirect illumination while meeting the demands of movie production; namely, reduced memory usage, surface shading independent run time, and faster renders than the aforementioned lighting techniques.
The PBCB algorithm works by discretizing a scene’s directly illuminated geometry into a point cloud (surfel) representation. When computing the indirect illumination at a point, the surfels are rasterized onto cube faces surrounding that point, and the constituent pixels are combined into the final, approximate, indirect lighting value.
In this thesis we present a performance enhancement to the Point-Based Color Bleeding algorithm through hardware acceleration; our contribution incorporates GPU-accelerated rasterization into the cube-face raster phase. The goal is to leverage the powerful rasterization capabilities of modern graphics processors in order to speed up the PBCB algorithm over standard software rasterization. Additionally, we contribute a preprocess that generates triangular surfels that are suited for fast rasterization by the GPU, and show that new heterogeneous architecture chips (e.g. Sandy Bridge from Intel) simplify the code required to leverage the power of the GPU. Our algorithm reproduces the output of the traditional Monte Carlo technique with a speedup of 41.65x, and additionally achieves a 3.12x speedup over software-rasterized PBCB.
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Koutsogiannis, Vassilis. "A study of color image data compression /." Online version of thesis, 1992. http://hdl.handle.net/1850/11060.
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Gibson, Christopher J. "Point-Based Color Bleeding With Volumes." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/533.
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The interaction of light in our world is immensely complex, but with mod-
ern computers and advanced rendering algorithms, we are beginning to reach
the point where photo-realistic renders are truly difficult to separate from real
photographs. Achieving realistic or believable global illumination in scenes with
participating media is exponentially more expensive compared to our traditional
polygonal methods. Light interacts with the particles of a volume, creating com-
plex radiance patterns.
In this thesis, we introduce an extension to the commonly used point-based
color bleeding (PCB) technique, implementing volume scatter contributions. With
the addition of this PCB algorithm extension, we are able to render fast, be-
lievable in- and out-scattering while building on existing data structures and
paradigms.
The proposed method achieves results comparable to that of existing Monte
Carlo integration methods, obtaining render speeds between 10 and 36 times
faster while keeping memory overhead under 5%.
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Cheng, Cheuk Hong. "Color bit-depth expansion for contour removal and demosaicking of spatial varying exposure array for high dynamic range image capturing /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20CHENG.
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Fang, Meng-Tieh Saint-Saëns Camille Saint-Saëns Camille Saint-Saëns Camille. "Colors of the music /." Online version of thesis, 2009. http://hdl.handle.net/1850/10840.
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Chhabra, Vikram. "Reconstructing specular objects with image based rendering using color caching." Link to electronic thesis, 2001. http://www.wpi.edu/Pubs/ETD/Available/etd-0427101-111305.
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Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: scene reconstruction vision, image based rendering, graphics, color consistency, specular objects. Includes bibliographical references (p. 56-57).
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Damera-Venkata, Niranjan. "Analysis and design of vector error diffusion systems for image halftoning /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004247.
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Leung, Wing Pan. "Visual cryptography for color images : formal security analysis and new construction /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?mphil-cs-b23759100f.pdf.
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Thesis (M.Phil.)--City University of Hong Kong, 2009."Submitted to Department of Computer Science in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references (leaves 103-108)
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Morovič, Ján. "To develop a universal gamut mapping algorithm." Thesis, University of Derby, 1998. http://hdl.handle.net/10545/200029.
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Pulli, Kari. "Surface reconstruction and display from range and color data /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6952.
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Onyejekwe, Egondu Rosemary Ezirim. "Using neural networks and abductive modeling for color error reduction in multimedia applications." Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179949708.
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Yang, Hsien-Min 1957. "IC defect detection using color information and image processing." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276831.
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Most current commercial automated IC inspection systems use gray-level or binary images for IC defect detection in spite of the fact that color permits defect detection where gray-level information is insufficient. Three color image processing techniques including the spectral-spatial clustering, principal components, and hue-saturation-value (HSV) color features have been investigated to evaluate the usefulness of color for IC defect detection. The AMOEBA spectral-spatial clustering algorithm, an un-supervised color segmentation approach, with a sequence of image processing procedures resulted in segmentation results with high accuracy and discriminated successfully an isolated and homogeneous defect with an unique color signature. The principal components transformation and the HSV color features, two color enhancement/separation algorithms, have proven useful for enhancing and isolating weak spectral signatures in the defect regions. The results of this investigation into the use of color are promising.
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Parker, Brendan D. "Assessing interpretability of visual symbols of varied colors across demographic profiles /." Online version of thesis, 2010. http://hdl.handle.net/1850/12245.
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Rael, Joshua. "Colormoo: An Algorithmic Approach to Generating Color Palettes." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/cmc_theses/975.
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Selecting one color can be done with relative ease, but this task becomes more difficult with each subsequent color. Colormoo is an online tool aimed at solving this problem. We implement three algorithms for generating color palettes based off of a starting color. Data is collected for each palette that is generated. Our analysis reveals two of the algorithms are preferred, but under different circumstances. Furthermore, we find that users prefer palettes containing colors that are compatible, but not too similar. With refined heuristics, we believe these techniques can be extended and applied beyond the field of graphic design alone.
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Feeney, Nicholas D. "Point Based Approximate Color Bleeding With Cuda." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/970.
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Simulating light is a very computationally expensive proposition. There are a wide variety of global illumination algorithms that are implemented and used by major motion picture companies to render interesting and believable scenes. Every algorithm strives to find a balance between speed and accuracy. The Point Based Approximate Color Bleeding algorithm is one of the most widely used algorithms in the field today. The Point Based Approximate Color Bleeding(PBACB) global illumination algorithm is based on the central idea that the geometry and direct illumination of the scene can be approximated by using a point cloud representation. This point cloud representation can then be used to generate the indirect illumination. The most basic unit of the point cloud is a surfel. A surfel is a two dimensional circle in space that contains the direct illumination for that section of space. The surfels are gathered in a tree structure and approximations are generated for the different levels of the tree. This tree is then used to calculate the appropriate color bleeding effect to apply to the surfaces in a rendered image. The main goal of this project was to explore the possibility of applying CUDA to the PBACB global illumination algorithm. CUDA is an extension of the C/C++ programing languages which allows for GPU parallel programming. In this paper, we present our GPU based implementation of the PBACB algorithm. The PBACB algorithm involves three central steps, creation of a surfel point cloud, generation of the spherical harmonics approximations for the point cloud, and using the surfel point cloud to generate an approximation for global illumi- nation. For this project, CUDA was applied to two of the steps of the PBACB algorithm, the generation of the spherical harmonic representations and the ap- plication of the surfel point cloud to generate indirect illumination. Our final GPU algorithm was able to obtain a 4.0 times speedup over our CPU version. We also discuss future work which could include the use of CUDA’s Dynamic Parallelism and a stack free implementation which could increase the speedups seen by our algorithm.
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Ryan, David B. "Improving Brain-Computer Interface Performance: Giving the P300 Speller Some Color." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etd/1328.
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Individuals who suffer from severe motor disabilities face the possibility of the loss of speech. A Brain-Computer Interface (BCI) can provide a means for communication through non-muscular control. Current BCI systems use characters that flash from gray to white (GW), making adjacent character difficult to distinguish from the target. The current study implements two types of color stimulus (grey to color [GC] and color intensification [CI]) and I hypotheses that color stimuli will; (1) reduce distraction of nontargets (2) enhance target response (3) reduce eye strain. Online results (n=21) show that GC has increased information transfer rate over CI. Mean amplitude revealed that GC had earlier positive latency than GW and greater negative amplitude than CI, suggesting a faster perceptual process for GC. Offline performance of individual optimal channels revealed significant improvement over online standardized channels. Results suggest the importance of a color stimulus for enhanced response and ease of use.
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Philbrick, Gregory Eric. "Color Relationship Transfer for Digital Painting." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5552.
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A digital painter uses reference photography to add realism to a scene. This involves making n colors in a painting relate to each other more like n corresponding colors in a photograph, in terms of value and temperature. Doing this manually requires either experience or tedious experimentation. Color relationship transfer performs the task automatically, recoloring n regions of a painting so they relate in value and temperature more like n corresponding regions of a photograph. Relationship transfer also has applications in computational photography. In fact, it introduces a new paradigm for image editing in general, based on treating an image's fundamental relationships.
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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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Lahlou, Mouncef. "Color-Based Surface Reflectance Separation for Scene Illumination Estimation and Rendering." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/381.
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Given the importance of color processing in computer vision and computer graphics, estimating and rendering illumination spectral reflectance of image scenes is important to advance the capability of a large class of applications such as scene reconstruction, rendering, surface segmentation, object recognition, and reflectance estimation. Consequently, this dissertation proposes effective methods for reflection components separation and rendering in single scene images. Based on the dichromatic reflectance model, a novel decomposition technique, named the Mean-Shift Decomposition (MSD) method, is introduced to separate the specular from diffuse reflectance components. This technique provides a direct access to surface shape information through diffuse shading pixel isolation. More importantly, this process does not require any local color segmentation process, which differs from the traditional methods that operate by aggregating color information along each image plane.
Exploiting the merits of the MSD method, a scene illumination rendering technique is designed to estimate the relative contributing specular reflectance attributes of a scene image. The image feature subset targeted provides a direct access to the surface illumination information, while a newly introduced efficient rendering method reshapes the dynamic range distribution of the specular reflectance components over each image color channel. This image enhancement technique renders the scene illumination reflection effectively without altering the scene’s surface diffuse attributes contributing to realistic rendering effects.
As an ancillary contribution, an effective color constancy algorithm based on the dichromatic reflectance model was also developed. This algorithm selects image highlights in order to extract the prominent surface reflectance that reproduces the exact illumination chromaticity. This evaluation is presented using a novel voting scheme technique based on histogram analysis.
In each of the three main contributions, empirical evaluations were performed on synthetic and real-world image scenes taken from three different color image datasets. The experimental results show over 90% accuracy in illumination estimation contributing to near real world illumination rendering effects.
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Clemens, Alexander. "Investigating the Inclusivity of Face Detection." Scholarship @ Claremont, 2018. http://scholarship.claremont.edu/cmc_theses/1836.
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Face detection refers to a number of techniques that identify faces in images and videos. As part of the senior project exercise at Pomona College, I explore the process of face detection using a JavaScript library called CLMtrackr. CLMtrackr works in any browser and detects faces within the video stream captured by a webcam. The focus of this paper is to explore the shortcomings in the inclusivity of the CLMtrackr library and consequently that of face detection. In my research, I have used two datasets that contain human faces with diverse backgrounds, in order to assess the accuracy of CLMtrackr. The two datasets are the MUCT and PPB. In addition, I investigate whether skin color is a key factor in determining face detection's success, to ascertain where and why a face might not be recognized within an image. While my research and work produced some inconclusive results due to a small sample size and a couple outliers in my outputs, it is clear that there is a trends toward the CLMtrackr algorithm recognizing faces with lighter skin tones more often than darker ones.
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Chien, Chi-Hao. "A comparison study of the implementation of digital camera's RAW and JPEG and scanner's TIFF file formats, and color management procedures for inkjet textile printing applications /." Online version of thesis, 2009. http://hdl.handle.net/1850/10886.
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Heath, Andrew Michael. "Colour coding scales and computer graphics." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38031.
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Karlsson, Fredrik. "Matting of Natural Image Sequences using Bayesian Statistics." Thesis, Linköping University, Department of Science and Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2355.
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The problem of separating a non-rectangular foreground image from a background image is a classical problem in image processing and analysis, known as matting or keying. A common example is a film frame where an actor is extracted from the background to later be placed on a different background. Compositing of these objects against a new background is one of the most common operations in the creation of visual effects. When the original background is of non-constant color the matting becomes an under determined problem, for which a unique solution cannot be found.
This thesis describes a framework for computing mattes from images with backgrounds of non-constant color, using Bayesian statistics. Foreground and background color distributions are modeled as oriented Gaussians and optimal color and opacity values are determined using a maximum a posteriori approach. Together with information from optical flow algorithms, the framework produces mattes for image sequences without needing user input for each frame.
The approach used in this thesis differs from previous research in a few areas. The optimal order of processing is determined in a different way and sampling of color values is changed to work more efficiently on high-resolution images. Finally a gradient-guided local smoothness constraint can optionally be used to improve results for cases where the normal technique produces poor results.
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Barros, Renan Sales. "Simulation of human skin pigmentation disorders." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/78876.
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Nosso trabalho apresenta um modelo de simulação de transtornos de pigmentação humana. Nosso modelo é formado por um conjunto de equações diferenciais que definem um sistema reação-difusão. Nosso sistema simula algumas características do sistema pigmentar humano. Alterações nesse sistema podem levar a desequilíbrios na distribuição de melanina na pele resultando em artefatos conhecidos como lesões de pigmentação. Nosso modelo tem como objetivo reproduzir essas alterações e assim sintetizar lesões de pigmentação humanas. Nosso sistema reação-difusão foi elaborado tomando como base dados biológicos a respeito da pele humana, do sistema pigmentar e do ciclo de vida dos melanócitos, que são as principais células envolvidas nesse tipo de transtorno. A simulação desse tipo de transtorno apresenta diversas aplicações em dermatologia como, por exemplo, suporte para o treinamento de dermatologistas e auxílio no diagnóstico de transtornos de pigmentação. No entanto, nosso trabalho se concentra em aplicações relacionadas com computação gráfica. Assim, nós também apresentamos um método para transferir os resultados do nosso modelo de simulação para texturas e imagens de pele humana. Nesse contexto, o nosso modelo contribui para a geração de texturas de pele mais realistas e consequentemente para a geração de modelos de serem humanos mais realistas. Além disso, nós também comparamos os resultados da nossa simulação com lesões de pigmentações reais objetivando avaliar a qualidade das lesões geradas pelo nosso modelo. Para realizar essa comparação nós extraímos métricas das lesões sintetizadas e das lesões reais e comparamos os valores dessas métricas. Com base nessa comparação, nós observamos que as lesões sintetizadas apresentam as mesmas características das lesões reais. Ainda, para efeito de comparações visuais, nós também apresentamos imagens de lesões reais lado a lado com imagens sintetizadas e podemos observar que o método utilizado para produzir imagens de lesões a partir do resultado do nosso modelo de simulação produz resultados que são indistinguíveis das imagens reais.Our work presents a simulation model of human pigmentation disorders. Our model is formed by a set of differential equations that defines a reaction-diffusion system. Our system simulates some features of the human pigmentary system. Changes in this system can lead to imbalances in the distribution of melanin in the skin resulting in artifacts known as pigmented lesions. Our model aims to reproduce these changes and consequently synthesize human pigmented lesions. Our reaction-diffusion system was developed based on biological data regarding human skin, pigmentary system and melanocytes life cycle. The melanocytes are the main cells involved in this type of human skin disorders. The simulation of such disorders has many applications in dermatology, for example, to assist dermatologists in diagnosis and training related to pigmentation disorders. However, our study focuses on applications related to computer graphics. Thus, we also present a method to transfer the results of our simulation model for textures and images of human skin. In this context, our model contributes to the generation of more realistic skin textures and consequently for the generation of more realistic human models. Moreover, we also compared the results of our simulation with real pigmented lesions to evaluate the quality of the lesions generated by our model. To perform this comparison we measured some features of real and synthesized pigmented lesions and we compared the results of these measurements. Based on this comparison, we observed that synthesized lesions exhibit the same characteristics of real lesions. Still, for the purpose of visual comparisons, we also present images of real lesions along with images of synthesized lesions. In this visual comparison, we can note that the method used to produce lesions images from the results of our simulation generates images that are indistinguishable from real images.
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Chandler, Simon Robert. "The development of a colour graphics workstation." Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376291.
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Chen, Chih-Ming. "The economic feasibility of Computer-to-Plate technology for use in magazine production /." Online version of thesis, 1995. http://hdl.handle.net/1850/12176.
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Pancholy, Rajiv. "A multiprocessor interface for a colour graphics animation system /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60110.
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This thesis describes the design and hardware implementation of a high speed multi-processor interface used in a colour graphics animation system. The design involves the use of Direct Memory Access to move data between the memories of the various CPUs constituting the Grads system. The system accommodates the various bus protocols, word sizes, and interrupt schemes of the different processors. An evaluation of the completed system is presented.
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He, Yiyang. "A Physically Based Pipeline for Real-Time Simulation and Rendering of Realistic Fire and Smoke." Thesis, Stockholms universitet, Numerisk analys och datalogi (NADA), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-160401.
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With the rapidly growing computational power of modern computers, physically based rendering has found its way into real world applications. Real-time simulations and renderings of fire and smoke had become one major research interest in modern video game industry, and will continue being one important research direction in computer graphics. To visually recreate realistic dynamic fire and smoke is a complicated problem. Furthermore, to solve the problem requires knowledge from various areas, ranged from computer graphics and image processing to computational physics and chemistry. Even though most of the areas are well-studied separately, when combined, new challenges will emerge. This thesis focuses on three aspects of the problem, dynamic, real-time and realism, to propose a solution in form of a GPGPU pipeline, along with its implementation. Three main areas with application in the problem are discussed in detail: fluid simulation, volumetric radiance estimation and volumetric rendering. The weights are laid upon the first two areas. The results are evaluated around the three aspects, with graphical demonstrations and performance measurements. Uniform grids are used with Finite Difference (FD) discretization scheme to simplify the computation. FD schemes are easy to implement in parallel, especially with ComputeShader, which is well supported in Unity engine. The whole implementation can easily be integrated into any real-world applications in Unity or other game engines that support DirectX 11 or higher.
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Veeramoni, Mythili Sankaranarayanan. "How To Color A Map." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/338714.
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We study the maximum differential coloring problem, where an n-vertex graph must be colored with colors numbered 1, 2...n such that the minimal difference between the two colors of any edge is maximized. This problem is motivated by coloring maps in which not all countries are contiguous. Since it is known that this problem is NP-hard for general graphs; we consider planar graphs and subclasses thereof. In Chapter 1 we introduce the topic of this thesis and in Chapter 2 we review relevant definitions and basic results. In Chapter 3 we prove that the maximum differential coloring problem remains NP-hard even for planar graphs. Then, we present tight bounds for regular caterpillars and spider graphs and close-to-optimal differential coloring algorithms for general caterpillars and biconnected triangle-free outer-planar graphs. In Chapter 4 we introduce the (d, kn)-differential coloring problem. While it was known that the problem of determining whether a general graph is (2, n)-differential colorable is NP-complete, in this chapter we provide a complete characterization of bipartite, planar and outerplanar graphs that admit (2, n)-differential colorings. We show that it is NP-complete to determine whether a graph admits a (3, 2n)-differential coloring. The same negative result holds for the ([2n/3], 2n)-differential coloring problem, even when input graph is planar. In Chapter 5 we experimentally evaluate and compare several algorithms for coloring a map. Motivated by different application scenarios, we classify our approaches into two categories, depending on the dimensionality of the underlying color space. To cope with the one dimensional color space (e.g., gray-scale colors), we employ the (d, kn)-differential coloring. In Chapter 6 we describe a practical approach for visualizing multiple relationships defined on the same dataset using a geographic map metaphor, where clusters of nodes form countries and neighboring countries correspond to nearby clusters. The aim is to provide a visualization that allows us to compare two or more such maps. In the case where we are considering multiple relationships we also provide an interactive tool to visually explore the effect of combining two or more such relationships. Our method ensures good readability and mental map preservation, based on dynamic node placement with node stability, dynamic clustering with cluster stability, and dynamic coloring with color stability. Finally in Chapter 7 we discuss future work and open problems.
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Willey, Stephen. "Improving the pipeline for stereo post-production." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760908.
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We investigate some problems commonly found when dealing with stereo images. Working within the context of visual effects for films, we explore software solutions to issues arising with stereo images captured on-set. These images originate from a wide variety of hardware which may or may not provide additional data support for post-production needs. Generic software solutions are thus greatly to be preferred. This dissertation documents contributions in the following three areas. Each project was undertaken at Double Negative and investigated with the aim of improving the post-production pipeline for 3D films. Colour matching is the process whereby the colours of one view from a stereo pair are matched with those of the other view. This process is necessary due to the fact that slight differences in hardware and viewing angle can result in some surprisingly large colour discrepancies. Chapter 3 presents a novel approach to colour matching between stereo pairs of images, with a new tool for visual effects artists given in section 6.2.Vertical alignment of stereo images is key to providing a comfortable experience for the viewer, yet we are rarely presented with perfectly aligned footage from the outset. In chapter 4 we discuss the importance of correcting misalignments for both the final audience and the artists working on these images. We provide a tool for correcting misalignments in section 6.3.Disparity maps are used in many areas of post-production, and so in chapter 5 we investigate ways in which disparity map generation can be improved for the benefit of many existing tools at Double Negative. In addition, we povide an extensive exploration of the requirements of 3D films in order to make them presentable in the cinema. Through these projects, we have provided improvements to the stereo workflow and shown that academic research is a necessary component of developing tools for the visual effects pipeline. We have provided new algorithms to improve the 3D experience for moviegoers, as well as artists, and conclude by discussing the future work that will provide further gains in the field.
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Zhuang, Yuwen. "Metric Based Automatic Event Segmentation and Network Properties Of Experience Graphs." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337372416.
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Miranda, Gisele Helena Barboni. "Método para processamento e análise computacinal de imagens histopatológicas visando apoiar o diagnóstico de câncer de colo de útero." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/95/95131/tde-24012012-154506/.
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A histopatologia é considerada um dos recursos diagnósticos mais importantes na prática médica e caracteriza-se pelo estudo das alterações estruturais e morfológicas das células e dos tecidos causadas por doenças. Atualmente, o principal método utilizado no diagnóstico histopatológico de imagens microscópicas, obtidas por meio de amostras em exames convencionais, é a avaliação visual do patologista, a qual se baseia na experiência do mesmo. O uso de técnicas de processamento computacional de imagens possibilita a identificação de elementos estruturais e a determinação de características inerentes, subsidiando o estudo da organização estrutural das células e de suas variações patológicas. A utilização de métodos computacionais no auxílio ao diagnóstico visa diminuir a subjetividade do processo de avaliação e classificação realizado pelo médico. Diferentes características dos tecidos podem ser mapeadas por meio de métricas específicas que poderão ser utilizadas em sistemas de reconhecimento de padrões. Dentro desta perspectiva, o objetivo geral deste trabalho inclui a proposta, a implementação e a avaliação de um método para a identificação e a análise de estruturas histológicas, a ser utilizado para a análise de lesões neoplásicas do colo do útero (NICs) a partir de amostras histopatológicas. Este trabalho foi desenvolvido em colaboração com uma equipe de patologistas, especialistas do domínio. As imagens microscópicas digitalizadas foram adquiridas a partir de lâminas previamente fixadas, contendo amostras de biópsias. Para segmentação dos núcleos celulares, foi implementado um pipeline de operadores morfológicos. Métodos de segmentação baseados em cor também foram testados e comparados à abordagem morfológica. Foi proposta e implementada uma abordagem baseada em camadas para representação do tecido, adotando-se a Triangulação de Delaunay (TD) como modelo de grafo de vizinhança. A TD apresenta algumas propriedades particulares que permitem a extração de métricas específicas. Foram utilizados algoritmos de agrupamento e morfologia de grafos, adotando-se critérios de semelhança e relações de adjacência entre os triângulos da rede, a fim de se obter a fronteira entre as camadas histológicas do tecido epitelial de forma automática. As seguintes métricas foram extraídas dos agrupamentos resultantes: grau médio, entropia e taxa de ocupação dos triângulos da rede. Finalmente, foi projetado um classificador estatístico levando-se em consideração os diferentes agrupamentos que poderiam ser obtidos a partir das imagens de treinamento. Valores de acurácia, sensitividade e especificidade foram utilizadas para avaliação dos resultados obtidos. Foi implementada validação cruzada em todos os experimentos realizados e foi utilizado um total de 116 imagens. Primeiro, foi avaliado a acurácia da metodologia proposta na determinação correta da presença de anomalia no tecido, para isto, todas as imagens que apresentavam NICs foram agrupadas em uma mesma classe. A maior taxa de acurácia obtida neste experimento foi de 88%. Em uma segunda etapa, foram realizadas avaliações entre as seguintes classes: Normal e NIC-I; NIC-I e NIC-II, e, NIC-II e NIC-III, obtendo-se taxas de acurácia máximas de 73%, 77% e 86%, respectivamente. Além disso, foi verificada também, a acurácia na discriminação entre os três tipos de NICs e regiões normais, obtendo-se acurácia de 64%. As taxas de ocupação relativas aos agrupamentos representativos das camadas basais e superficiais, foram os atributos que levaram às maiores taxas de acurácia. Os resultados obtidos permitem verificar a adequação do método proposto na representação e análise do processo de evolução das NICs no tecido epitelial do colo uterino.Histopathology is considered one of the most important diagnostic tools in medical routine and is characterized by the study of structural and morphological changes of the cells in biological tissues caused by diseases. Currently, the visual assessment of the pathologist is the main method used in the histopathological diagnosis of microscopic images obtained from biopsy samples. This diagnosis is usually based on the experience of the pathologist. The use of computational techniques in the processing of these images allows the identification of structural elements and the determination of inherent characteristics, supporting the study of the structural organization of tissues and their pathological changes. Also, the use of computational methods to improve diagnosis aims to reduce the subjectivity of the evaluation made by the physician. Besides, different tissue characteristics can be mapped through specific metrics that can be used in pattern recognition systems. Within this perspective, the overall objective of this work includes the proposal, the implementation and the evaluation of a methodology for the identification and analysis of histological structures. This methodology includes the specification of a method for the analysis of cervical intraepithelial neoplasias (CINs) from histopathological samples. This work was developed in collaboration with a team of pathologists. Microscopic images were acquired from blades previously stained, containing samples of biopsy examinations. For the segmentation of cell nuclei, a pipeline of morphological operators were implemented. Segmentation techniques based on color were also tested and compared to the morphological approach. For the representation of the tissue architecture an approach based on the tissue layers was proposed and implemented adopting the Delaunay Triangulation (DT) as neighborhood graph. The DT has some special properties that allow the extraction of specific metrics. Clustering algorithms and graph morphology were used in order to automatically obtain the boundary between the histological layers of the epithelial tissue. For this purpose, similarity criteria and adjacency relations between the triangles of the network were explored. The following metrics were extracted from the resulting clusters: mean degree, entropy and the occupation rate of the clusters. Finally, a statistical classifier was designed taking into account the different combinations of clusters that could be obtained from the training process. Values of accuracy, sensitivity and specificity were used to evaluate the results. All the experiments were taken in a cross-validation process (5-fold) and a total of 116 images were used. First, it was evaluated the accuracy in determining the correct presence of abnormalities in the tissue. For this, all images presenting CINs were grouped in the same class. The highest accuracy rate obtained for this evaluation was 88%. In a second step, the discrimination between the following classes were analyzed: Normal/CIN 1; CIN 1/CIN 2, and, CIN 2/CIN 3, which represents the histological grading of the CINs. In a similar way, the highest accuracy rates obtained were 73%, 77% and 86%, respectively. In addition, it was also calculated the accuracy rate in discriminating between the four classes analyzed in this work: the three types of CINs and the normal region. In this last case, it was obtained a rate of 64%.The occupation rate for the basal and superficial layers were the attributes that led to the highest accuracy rates. The results obtained shows the adequacy of the proposed method in the representation and classification of the CINs evolution in the cervical epithelial tissue.
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Lefrère, Laurent. "Contribution au développement d'outils pour l'analyse automatique de documents cartographiques." Rouen, 1993. http://www.theses.fr/1993ROUES045.
Full textAbstract:
Les travaux présentés dans ce mémoire abordent différents aspects de l'analyse de documents cartographiques, du prétraitement couleur à la reconnaissance de toponymes en passant par l'extraction d'objets géographiques. Le premier chapitre est consacré à la classification couleur. Ce prétraitement permet d'obtenir, à partir d'images de cartes numérisées en cyan, magenta, yellow, les plans couleurs rouge, vert, bleu et noir proches des planches-mères ayant permis l'impression des cartes. L'originalité de la segmentation CMY/TS est sa capacité à reconstruire les objets masqués par les superpositions. Cette classification permet d'apporter une information plus compacte et plus complète aux modules d'extraction subséquents. Le second chapitre présente d'une part, une méthode de caractérisation et d'extraction de zones texturées basée sur une modélisation structurelle et statistique des textures. Cette méthode permet de modéliser conjointement l'aspect macroscopique régulier et structuré des textures ainsi que leur aspect microscopique plus aléatoire. D'autre part, est présenté un module d'extraction des réseaux linéaires et plus particulièrement des réseaux routiers basé sur un suivi de trait particulier contrôlé par un ensemble de mesures statistiques regroupées en un critère dit de Gibbs. Le dernier chapitre présente une stratégie particulière de reconstruction de toponymes à partir d'une méthode originale de reconnaissance de caractères invariante à la translation, à l'homothétie et à la rotation. Ce module permet de plus de reconstituer les limites de parcelles formées de pointillés. Ces différents modules fournissent, à partir des cartes papier existantes, des données structurées et organisées, prêtes à être intégrées dans des systèmes d'information géographique
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Chen, Chien-Hsiung. "Color in human-computer interaction." 1998. http://books.google.com/books?id=MMTaAAAAMAAJ.
Full textAbstract:
Thesis (Ph. D.)--University of Kansas, Special Studies, 1998.eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 183-197).
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Fang, Chong he. "A high performance colour graphics display system." Thesis, 1987. http://hdl.handle.net/2440/110095.
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Lee, Juhyun. "Robust color-based vision for mobile robots." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4770.
Full textAbstract:
An intelligent agent operating in the real world needs to be
fully aware of the surrounding environment to make the best decision
possible at any given point of time. There are many forms of input
devices for a robot that gather real-time information of the
surroundings, such as video cameras, laser/sonar range finders, and GPS
to name a few. In this thesis, a vision system for a mobile robot
navigating through different illumination conditions is investigated.
Many state-of-the-art object recognition algorithms employ methods
running on grayscale images, because using color is difficult for
several reasons: (a) The object-of-interest's true colors may not be
recorded by the camera hardware due to illumination artifacts, and (b)
colors are often too ambiguous to be a robust visual descriptor of an
object. In this dissertation, we address these two challenges and
present new color-based vision algorithms for mobile robots that are
robust and efficient.
The first part of this dissertation focuses on the problem of color
constancy for mobile robots under different lighting conditions.
Specifically, We use a generate-and-test methodology to evaluate which
simulated global illumination condition leads to the generated view that
most closely matches what the robot actually sees. We assume the
diagonal color model when generating views of the object of interest
under previously unseen conditions.
In the second part of the dissertation, we present a vision framework
for mobile robots that enables observation of illumination artifacts in
a scene and reasoning about the lighting conditions to achieve robust
color-based object tracking. Before implementing this framework, we
first devise a novel vision-based localization correction algorithm with
graphics hardware support, and present how to find possibly shaded
regions in the recorded scene by using techniques from 3D computer
graphics. We then demonstrate how to integrate a color-based object
tracker from the first part of this dissertation with our vision
framework.
Even with the contributions from the first two parts of the
dissertation, there remains some degree of uncertainty in robot's
assessment of an object's true color. The final part of this
dissertation introduces a novel algorithm to overcome this uncertainty
in color-based object tracking. We show how an agent can achieve robust
color-based object tracking by combining multiple different visual
characteristics of an object for more accurate robot vision in the real
world.text
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(6623771), In Kwon Choi. "Geo-temporal visualization for tourism data using color curves." Thesis, 2019.
Find full textAbstract:
A study on using colors to represent the floating population of tourists
and local residents on the map by each hour in each month. The
resulting visualization can assist the decision-making in various areas
by providing a vivid description of the movement of people in a day.
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Hayes, Thomas Patrick. "Rapidly mixing Markov chains for graph colorings /." 2003. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3097114.
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Wen-TiHuang and 黃文帝. "A Photorealistic Computer Graphics Detection Algorithm by Using the Characteristics of Color Filter Array." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/93271205005151438853.
Full textAbstract:
碩士國立成功大學
電腦與通信工程研究所
100
In recent years, computer graphics technology is constantly in progress, if some people employ the technology in crime, such as falsi cation of identity, or forgeries of scandal photos, the consequences would be disastrous. Thus it makes Photorealistic computer graphics (PRCG) detection to become a major issue of modern technology. In this thesis, a scheme to distinguish photographic images (PIM) from PRCG images by using a periodic phenomenon of variance of pixel values resulting from demosaicing process is proposed. The periodic phenomenon is measured as a feature in Fourier domain feature and combined with a simple classi er to distinguish PIM images from PRCG images. Based on the phenomenon, the proposed scheme is composed of color space transformation, high-pass ltering feature extraction, and classi cation. Experimental results show that proposed scheme can not only detect PIM images but also determine what brand of a camera is used. Compared with existing methods, the precision and recall rates of proposed scheme are higher. The result shows that the performance of the proposed scheme is better than existing methods.
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"Colorization in Gabor space and realistic surface rendering on GPUs." Thesis, 2011. http://library.cuhk.edu.hk/record=b6075109.
Full textAbstract:
Based on the construction of Gabor feature space, which is important in applying pixel similarity computations, we formalize the space using rotation-invariant Gabor filter banks and apply optimizations in texture feature space. In image colorizations, the pixels that have similar Gabor features appear similar colors, our approach can colorize natural images globally, without the restriction of the disjoint regions with similar texture-like appearances. Our approach supports the two-pass colorization processes: coloring optimization in Gabor space and color detailing for progressive effects. We further work on the video colorization using the optimized Gabor flow computing, including coloring keyframes, color propagation by Gabor filtering, and optimized parallel computing over the video. Our video colorization is designed in a spatiotemporal manner to keep temporal coherence, and provides simple closed-form solutions in energy optimization that yield fast colonizations. Moreover, we develop parallel surface texturing of geometric models on GPU, generating spatially-varying visual appearances. We incorporate the Gabor feature space for the searching of 2D exemplars, to determine the k-coherence candidate pixels. The multi-pass correction in synthesis is applied to the local neighborhood for parallel processes. The iso/aniso-scale texture synthesis leverages the strengths of GPU computing, so to synthesize the iso/aniso-scale texturing appearance in parallel over arbitrary surfaces. Our experimental results showed that our approach produces simply controllable texturing effects of surface synthesis, generating texture-similar and spatially-varying visual appearances with GPU accelerated performance.Texture feature similarity has long been crucial and important topic in VR/graphics applications, such as image and video colorizations, surface texture synthesis and geometry image applications. Generally, the image feature is highly subjective, depending on not only the image pixels but also interactive users. Existing colorization and surface texture synthesis pay little attention to the generation of conforming color/textures that accurately reflect exemplar structures or user's intension. Realistic surface synthesis remains a challenging task in VR/graphics researches. In this dissertation, we focus on the encoding of the Gabor filter banks into texture feature similarity computations and GPU-parallel surface rendering faithfully, including image/vodeo colorizations, parallel texturing of geometric surfaces, and multiresolution rendering on sole-cube maps (SCMs).
We further explore the GPU-based multiresolution rendering on solecube maps (SCMs). Our SCMs on GPU generate adaptive mesh surfaces dynamically, and are fully developed in parallelization for large-scale and complex VR environments. We also encapsulate the differential coordinates in SCMs, reflecting the local geometric characteristics for geometric modeling and interactive animation applications. For the future work, we will work on improving the image/ video feature analysis framework in VR/graphics applications. The further work lying in the surface texture synthesis includes the interactive control of texture orientations by surface vector fields using sketch editing, so to widen the gamut of interactive tools available for texturing artists and end users.
Sheng, Bin.
Adviser: Hanqin Sun.
Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (leaves 128-142).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
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Eichelbaum, Sebastian, Mario Hlawitschka, Bernd Hamann, and Gerik Scheuermann. "Image-space Tensor Field Visualization Using a LIC-like Method." 2012. https://ul.qucosa.de/id/qucosa%3A32504.
Full textAbstract:
Tensors are of great interest to many applications in engineering and in medical imaging, but a proper analysis and visualization remains challenging. Physics-based visualization of tensor fields has proven to show the main features of symmetric second-order tensor fields, while still displaying the most important information of the data, namely the main directions in medical diffusion tensor data using texture and additional attributes using color-coding, in a continuous representation. Nevertheless, its application and usability remains limited due to its computational expensive and sensitive nature.
We introduce a novel approach to compute a fabric-like texture pattern from tensor fields motivated by image-space line integral convolution (LIC). Although, our approach can be applied to arbitrary, non-selfintersecting surfaces, we are focusing on special surfaces following neural fibers in the brain.We employ a multipass rendering approach whose main focus lies on regaining three-dimensionality of the data under user interaction as well as being able to have a seamless transition between local and global structures including a proper visualization of degenerated points.
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"The First-Fit Algorithm Uses Many Colors on Some Interval Graphs." Doctoral diss., 2010. http://hdl.handle.net/2286/R.I.8626.
Full textAbstract:
abstract: Graph coloring is about allocating resources that can be shared except where there are certain pairwise conflicts between recipients. The simplest coloring algorithm that attempts to conserve resources is called first fit. Interval graphs are used in models for scheduling (in computer science and operations research) and in biochemistry for one-dimensional molecules such as genetic material. It is not known precisely how much waste in the worst case is due to the first-fit algorithm for coloring interval graphs. However, after decades of research the range is narrow. Kierstead proved that the performance ratio R is at most 40. Pemmaraju, Raman, and Varadarajan proved that R is at most 10. This can be improved to 8. Witsenhausen, and independently Chrobak and Slusarek, proved that R is at least 4. Slusarek improved this to 4.45. Kierstead and Trotter extended the method of Chrobak and Slusarek to one good for a lower bound of 4.99999 or so. The method relies on number sequences with a certain property of order. It is shown here that each sequence considered in the construction satisfies a linear recurrence; that R is at least 5; that the Fibonacci sequence is in some sense minimally useless for the construction; and that the Fibonacci sequence is a point of accumulation in some space for the useful sequences of the construction. Limitations of all earlier constructions are revealed.Dissertation/Thesis
Ph.D. Mathematics 2010
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Moretti, Giovanni S. "A calculation of colours: towards the automatic creation of graphical user interface colour schemes : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Computer Science at Massey University, Palmerston North, New Zealand." 2010. http://hdl.handle.net/10179/1492.
Full textAbstract:
Interface colour scheme design is complex, but important. Most software allows users to choose the colours of single items individually and out of context, but does not acknowledge colour schemes or aid in their design. Creating colour schemes by picking individual colours can be time-consuming, error-prone, and frustrating, and the results are often mediocre, especially for those without colour design skills. Further, as colour harmony arises from the interactions between all of the coloured elements, anticipating the overall eff ect of changing the colour of any single element can be difficult. This research explores the feasibility of extending artistic colour harmony models to include factors pertinent to user interface design. An extended colour harmony model is proposed and used as the basis for an objective function that can algorithmically assess the colour relationships in an interface colour scheme. Its assessments have been found to agree well with human evaluations and have been used as part of a process to automatically create harmonious and usable interface colour schemes. A three stage process for the design of interface colour schemes is described. In the fi rst stage, the designer speci es, in broad terms and without requiring colour design expertise, colouring constraints such as grouping and distinguishability that are needed to ensure that the colouring of interface elements reflects their semantics. The second stage is an optimisation process that chooses colour relationships to satisfy the competing requirements of harmonious colour usage, any designer-specified constraints, and readability. It produces sets of coordinates that constitute abstract colour schemes: they de fine only relationships between coloured items, not real colours. In the third and fi nal stage, a user interactively maps an abstract scheme to one or more real colour schemes. The colours can be fi ne-tuned as a set (but not altered individually), to allow for such "soft" factors as personal, contextual and cultural considerations, while preserving the integrity of the design embodied in the abstract scheme. The colours in the displayed interface are updated continuously, so users can interactively explore a large number of colour schemes, all of which have readable text, distinguishable controls, and conform to the principles of colour harmony. Experimental trials using a proof-of-concept implementation called the Colour Harmoniser have been used to evaluate a method of holistic colour adjustment and the resulting colour schemes. The results indicate that the holistic controls are easy to understand and eff ective, and that the automatically produced colour schemes, prior to fi ne-tuning, are comparable in quality to many manually created schemes, and after fi ne-tuning, are generally better. By designing schemes that incorporate colouring constraints specifi ed by the user prior to scheme creation, and enabling the user to interactively fi ne-tune the schemes after creation, there is no need to specify or incorporate the subtle and not well understood factors that determine whether any particular set of colours is "suitable". Instead, the approach used produces broadly harmonious schemes, and defers to the developer in the choice of the fi nal colours.