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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A color blending model and a color correction algorithm for additive optical see-through displays

Kirshnamachari Sridharan, Srikanth 06 October 2013 (has links)
Optical see-through display (OSTD) is a transparent digital display which simultaneously gives access to the digital contents and the real world objects behind it. Additive optical see-though display is a hardware subtype of OSTD which has its own light source to create the digital contents. In Additive OSTD, light coming from background objects mixes with the light originating from the display causing what is known as the color blending problem. The work in this thesis provides a solution to the color blending problem. In order to understand the problem, this thesis first presents a new color blending model for additive OSTD based on two display induced distortions: the Render distortion and the Material distortion. A new method called Binned Profile (BP) method which accounts for the render distortion is developed to predict the blended color, when applied on the color blending model. BP method is validated with other known methods and is shown to be the most accurate in predicting the color blends with 9 just noticeable differences (JND) in worst case. Based on the BP method, a new color correction algorithm called BP color correction is created to solve the color blending problem. BP-color correction finds the alternative digital color to counter balance the blending. The correction capacity of various digital colors were analysed using the BP color correction approach. BP color correction is also compared and proven to be better than the existing solution. A quicker version of the correction called quick correction is also explored. The thesis concludes with an exploration of the material distortion, explains the limitations of BP-correction, provides design recommendations .
2

A color blending model and a color correction algorithm for additive optical see-through displays

Kirshnamachari Sridharan, Srikanth 06 October 2013 (has links)
Optical see-through display (OSTD) is a transparent digital display which simultaneously gives access to the digital contents and the real world objects behind it. Additive optical see-though display is a hardware subtype of OSTD which has its own light source to create the digital contents. In Additive OSTD, light coming from background objects mixes with the light originating from the display causing what is known as the color blending problem. The work in this thesis provides a solution to the color blending problem. In order to understand the problem, this thesis first presents a new color blending model for additive OSTD based on two display induced distortions: the Render distortion and the Material distortion. A new method called Binned Profile (BP) method which accounts for the render distortion is developed to predict the blended color, when applied on the color blending model. BP method is validated with other known methods and is shown to be the most accurate in predicting the color blends with 9 just noticeable differences (JND) in worst case. Based on the BP method, a new color correction algorithm called BP color correction is created to solve the color blending problem. BP-color correction finds the alternative digital color to counter balance the blending. The correction capacity of various digital colors were analysed using the BP color correction approach. BP color correction is also compared and proven to be better than the existing solution. A quicker version of the correction called quick correction is also explored. The thesis concludes with an exploration of the material distortion, explains the limitations of BP-correction, provides design recommendations .
3

Quality and real-time performance assessment of color-correction methods : A comparison between histogram-based prefiltering and global color transfer

Nilsson, Linus January 2018 (has links)
In the field of computer vision and more specifically multi-camera systems color correction is an important topic of discussion. The need for color-tone similarity among multiple images that are used to construct a single scene is self-evident. The strength and weaknesses of color- correction methods can be assessed by using metrics to measure structural and color-tone similarity and timing the methods. Color transfer has a better structural similarity than histogram-based prefiltering and a worse color-tone similarity. The color transfer method is faster than the histogram-based prefiltering. Color transfer is a better method if the focus is a structural similar image after correction, if better color-tone similarity at the cost of structural similarity is acceptable histogram-based prefiltering is a better choice. Color transfer is a faster method and is easier to run with a parallel computing approach then histogram-based prefiltering. Color transfer might therefore be a better pick for real-time applications. There is however more room to optimize an implementation of histogram-based prefiltering utilizing parallel computing.
4

Investigation on Operating Characteristics of RGB LEDs

Liao, Chi-nan 08 August 2007 (has links)
This thesis seeks to gain a better understanding on operating characteristics of the three primary color light emitting diode (LED). By applying direct, pulse and sinusoidal currents with dimming function on red, green, and blue LEDs, respectively, the operating characteristics are investigated, including electrical characteristics and their effects on the light efficiency, spectral power distribution, chromaticity on each color LED and the resultant color gamut. The analysis reveals that the illumination characteristics intimately relate to the driving current. LEDs that are driven by pulse currents with pulse-width-modulation (PWM) dimming have less color shift than those driven by direct and sinusoidal currents with amplitude modulation dimming. However, the problematic color shifting is not acceptable when LEDs with pulse current are dimmed at a lower level. Based on the investigation results, a dimming scheme with PWM and pulse- amplitude-modulation (PAM) is proposed to correct the chromaticity and hence to improve the color gamut.
5

The study and fabrication of liquid crystal alignment using dimenthylsioxane

Yang, Lu-hsiang 23 July 2007 (has links)
Vertical alignment liquid crystal display has the advantages of wide view angle, high contrast and good response time. Today vertical alignment liquid crystal display get flourishing development, and Multi-Domain Vertical Alignment (MVA) technology is progressive. In this report we would find an alignment materiel which could be fabricated easily, low cost and good E-O characteristic. The use of dimenthysiloxane (PDMS) in fabrication of microfluidic channels technology in biotechnology has the advantages of characteristics foregoing. In this study PDMS was used as LC vertical alignment materiel. We used the MVA structure and ASV structure to align LC direction because PDMS cannot be rubbed. In experiment we found that PDMS exhibited different surface energies when it was baked in different temperature. The results of measuring the pre-tilt angle in the different surface energy conditions are similar. ASV LC samples were fabricated using PDMS alignment layer. MVA LC cells were made using high viscosity PDMS. We found the characteristic of paper white at CIE chromaticity diagram in the ASV LC sample without any color filter and color correction technology.
6

A CAMERA-BASED ENERGY RELAXATION FRAMEWORK TO MINIMIZE COLOR ARTIFACTS IN A PROJECTED DISPLAY

Sanders, Nathaniel 01 January 2007 (has links)
We introduce a technique to automatically correct color inconsistencies in a display composed of one or more digital light projectors (DLP). The method is agnostic to the source of error and can detect and address color problems from a number of sources. Examples include inter- and intra-projector color differences, display surface markings, and environmental lighting differences on the display. In contrast to methods that discover and map all colors into the greatest common color space, we minimize local color discontinuities to create color seamlessness while remaining tolerant to significant color error. The technique makes use of a commodity camera and highdynamic range sensing to measure color gamuts at many different spatial locations. A differentiable energy function is defined that combines both a smoothness and data term. This energy function is globally minimized through the successive application of projective warps defined using gradient descent. After convergence the warps can be applied at runtime to minimize color defects in the display. The framework is demonstrated on displays that suffer from several sources of color error.
7

Color Correction and Contrast Enhancement for Natural Images and Videos / Correction des couleurs et amélioration du contraste pour images et vidéos naturelles

Tian, Qi-Chong 04 October 2018 (has links)
L'amélioration d'image est une sorte de technique pour améliorer la qualité visuelle d'image, qui joue un rôle très important dans les domaines du traitement d'image et de la vision d'ordinateur. En particulier, nous considérons la correction de couleur et l'amélioration de contraste pour améliorer la qualité d'image.Dans la première partie de cette thèse, nous nous concentrons sur la correction des couleurs pour les images naturelles. Tout d'abord, nous donnons un examen simple de la correction des couleurs. Deuxièmement, nous proposons une méthode efficace de correction des couleurs pour la couture d'images via la spécification d'histogramme et la cartographie globale. Troisièmement, nous présentons une approche de cohérence des couleurs pour les collections d'images, basée sur la spécification de la gamme conservation histogramme.Dans la deuxième partie, nous prêtons attention à l'amélioration du contraste pour les images et les vidéos naturelles. Tout d'abord, nous donnons un simple examen de l'amélioration du contraste. Deuxièmement, nous proposons une méthode de préservation du contraste global de naturalité, qui peut éviter une survalorisation. Troisièmement, nous présentons une méthode de fusion à base de variation pour l'amélioration de l'image d'illumination non uniforme, qui peut éviter la sur-amplification ou la sous-amélioration. Enfin, nous étendons le cadre basé sur la fusion pour améliorer les vidéos avec une stratégie temporellement cohérente, qui n'entraîne pas de scintillement des artefacts. / Image enhancement is a kind of technique to improve the image visual quality, which plays a very important role in the domains of image processing and computer vision. Specifically, we consider color correction and contrast enhancement to improve the image quality.In the first part of this thesis, we focus on color correction for natural images. Firstly, we give a simple review of color correction. Secondly, we propose an efficient color correction method for image stitching via histogram specification and global mapping. Thirdly, we present a color consistency approach for image collections, based on range preserving histogram specification.In the second part, we pay attention to contrast enhancement for natural images and videos. Firstly, we give a simple review of contrast enhancement. Secondly, we propose a naturalness preservation global contrast enhancement method, which can avoid over-enhancement. Thirdly, we present a variational-based fusion method for non-uniform illumination image enhancement, which can avoid overenhancement or under-enhancement. Finally, we extend the fusion-based framework to enhance videos with a temporally consistent strategy, which does not result in flickering artifacts.
8

HDR and the Colorist : How new technology affects professionals in the motion picture industry

Westling, Jonas January 2019 (has links)
By utilizing a Research through Design approach this master thesis studies how technological changes might affect professionals working in the motion picture industry, specifically; how the advent of HDR (High Dynamic Range) affects the colorist. The research questions formulated are the following; (1) How can color grading in HDR be approached? (2) What effect can HDR have on visual modality? (3) What specific affordances can HDR offer the colorist? (4) How can HDR affect the creative space of the colorist? Three of the research questions are derived from the theoretical framework applied in this master thesis; starting with the social semiotic implementation of the term modality (models of reality), the Gibsonian term affordance (possibilities for action and meaning making) and its use in communications research, and lastly; the concept of creative space in motion picture production. Analytic autoethnography was used to generate primary data by documenting the process of color grading a 13-minute short film, and also performing semistructured interviews with four colorists. Amongst other findings, this study found that HDR offers a wider range of modality expression than SDR (Standard Dynamic Range); regarding several visual modality markers. Four HDR-specific affordances were formulated; (1) color expandability, (2) highlight differentiability, (3) tonal rangeability, (4) brightness disturbability. Relating to the concept of creative space; the colorists expressed a concern that they will have to create multiple versions when delivering HDR, but not get a bigger budget for it, therefore having less time to spend on other aspects of color grading.
9

Entwurf und Modellierung von Multikanal-CMOS-Farbsensoren

Henker, Stephan 27 September 2006 (has links) (PDF)
Color image acquisition and image processing have become a key in modern data application. In order to provide high quality images, the field of accurate acquisition is most important in respect to all further processing steps. But a whole variety of current image sensors possess incorrect color rendition due to insufficient accuracy of optical sensor parameters. This is detrimental especially for color sensors, because in these cases specific color information will be incorrectly acquired. Further, traditional color correction methods do not use information on the specific sensor spectral sensitivity, thus losing substantial information for color correction. The problem is investigated by introducing an algorithmic correction method which is capable of correcting dysfunctional sensor properties. The correction method is based on an enhancement of the CIE color perception model. According to this, color perception is modelled as a special integral transformation, where the spectral sensitivities of the photo receptors represent the base functions of the transformation. It is shown that different sets of photo receptors show the same perception, when their spectral sensitivities are linear dependent. On the other hand, photo receptors with no linear dependency show different perception and there is no analytical transformation between them. Thus, a perfect color correction is only possible if photo sensor and human perception show a linear dependency. In case of dissentient sensor characteristics, the correction method of spectral reconstruction can determine an optimal solution using a least square error optimization. Applying sensors with more than three color channels, this correction method can show improved results due to a better approximation. For implementation of the color correction scheme, different sensor designs have been developed. Compared with currently dominating CCD (Charge Coupled Device) technology, a realisation of image sensors based on CMOS technology show a high potential. CMOS technology allow the integration of the sensor together with control and image processing on the same chip, thus enabling the design of sensor systems at low cost. But modern sub-100nm technologies show also substantial disadvantages, such as increased leakage currents. Special circuit designs have been developed to especially reduce the influence of leakage currents. For application of the color correction method, new multi-channel photo sensors using vertically stacked photo diodes have been developed. The work further shows different concepts of multi-channel sensors capable of high quality color rendition. This approach is demonstrated on several new CMOS sensor designs with examples, implemented in a 90nm Infineon technology.
10

Editing within The Thriller Genre

Blazevic, Sasha, Kesten, Carl Johan January 2021 (has links)
Thriller är en favoritgenre för många och har funnits längre än de flesta tror. Ursprungligen som en litteraturgenre har den utvecklats till en av de mest eftertraktade genrerna inom film. Tidiga anmärkningsvärda verk som Alfred Hitchcocks filmer i mitten av 1900-talet har banat vägen för genren och utformat dess redigering och cinematografi till vad vi har idag. Trots sin ödmjuka början i mitten av 1900-talet lyckas teknikerna, även om dem är aningen repetitiva, fortfarande vara relevanta idag och har bara utvecklats med åren. I den här artikeln studerar vi grunderna inom thrillergenren, redigerings- och filmtekniker som används; kameraarbete, klippning, PoV och färgsättning. I denna studie är vårt huvudsakliga fokus att förstå varför dessa tekniker används. Utöver kommer vi också gå djupare in i thrillergenren i helhet och trots genrens repetitivitet, försöka förstå oss på varför den lyckas vara relevant idag och hur redigering och cinematografi spelar en stor roll för att förstärka känslorna i thrillers där dessa tendenser härrör från. / Thriller is a favourite genre to many and has been around for longer than most think. Originally starting as a genre of literature, it has evolved into one of the most sought after genres within film. Early notable works such as Alfred Hitchcock's films in the mid 1900s have paved the way for the genre and solidified it’s editing and cinematography into what we have today. Despite its humbling beginnings in the mid 1900s the techniques, although somewhat repetitive, still manage to stay relevant today and have only gotten more advanced with time. In this article, we study the fundamentals within the thriller genre, the editing and cinematography techniques that are utilized; camera framing, cutting, PoV and color. In this study our main focus we intend to work towards is understanding why these techniques are used and the tendencies in which they are facilitated. Although we also intend to go in depth into the thriller genre as a whole and despite the repetitiveness of the genre, why it manages to stay relevant today and how editing and cinematography plays a big part in amplifying the emotions and feelings associated within thrillers in which these tendencies stem from.

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