Digital Color Imaging

This paper surveys current technology and research in the area of digital color imaging. In order to establish the background and lay down terminology, fundamental concepts of color perception and measurement are first presented us-ing vector-space notation and terminology. Present-day color recording and reproduction systems are reviewed along with the common mathematical models used for representing these devices. Algorithms for processing color images for display and communication are surveyed, and a forecast of research trends is attempted. An extensive bibliography is provided

Multispectral photography for earth resources

A guide for producing accurate multispectral results for earth resource applications is presented along with theoretical and analytical concepts of color and multispectral photography. Topics discussed include: capabilities and limitations of color and color infrared films; image color measurements; methods of relating ground phenomena to film density and color measurement; sensitometry; considerations in the selection of multispectral cameras and components; and mission planning

Teaching and learning color. An insight into STEM/STEAM approach

The paper aims to help define the STEM/STEAM approach to Color Education. Nowadays more and more schools embrace this approach as it seems to respond to a need for renewal of teaching while adapting it to the present time. However, this approach is not univocally defined, so that under this label fall experiences of color education of various kinds and different educational effectiveness. Therefore, this work intends to clarify the meaning of this approach. The article is divided into three parts that show the methodological path undertaken. In the first part, some invariant properties of situations classified as STEM/STEAM were identified; in the second part, the invariants were described in terms of didactic variables inferred from the literature and some STEM/STEAM teaching activities; in the third part, some procedural principles to guide teachers' work were formulated and discussed in the context of teaching and learning about color

Analysis of Umberger\u27s theory for subtractive color reproduction

A method, proposed by Umberger, for the identification of additive stimuli representative of the red, green, and blue primaries controlled by dyes obeying Beer\u27s law was examined. The primary stability study suggests that for a set of colors created of various dye concentrations, the pattern of Umberger\u27s primary distribution is a translation of the original colors on a chromaticity diagram. Results of a theoretical color reproduction study where the colormatching functions of Umberger\u27s primaries were assumed as the color reproduction system\u27s spectral sensitivities indicate an increase in metric chroma of reproduced colors. Color reproduction errors for a large number of colors were minimized for spectral sensitivities corresponding to Umberger\u27s primaries controlled by dye concentrations resulting in an 18% transmittance gray color. A technique was proposed for optimizing the system\u27s spectral sensitivities to colors constituting the reproduced scene

Molecular And Biochemical Analysis Of Water Stress Induced Responses In Grape

Water stress affects vine productivity, disease tolerance, and enological characteristics of grape. Florida Hybrid Bunch grape are developed through hybridization of local grape spp with Vitis vinifera. These cultivars are mostly grown in southeast region of United States. Water deficit conditions resulted due to failure of rains in the region has developed concern among Florida grape growers to increase water use efficiency of grape. The goal of this research is to identify genes and proteins differentially expressed in response to water stress and to correlate these changes with enological characteristics. Investigating transcripts and proteins will allow us to correlate them and confirm the involvement of specific genes responding to stress. Florida hybrid bunch ‘Suwannee’ grape plants were maintained under green house conditions. Water stress was induced by withholding irrigation. The leaf samples were collected from both irrigated and stressed plants at 5, 10, 15 and 20 day interval. We generated over 200 Subtractive Hybridization PCR products from control and water stressed leaf tissues. Cloning, sequencing and transcript analysis revealed that, 54 genes related to drought and defense regulated pathways out of 125 characterized transcripts. Proteins were extracted from leaf tissue with trichloroacetic acid /acetone and separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The proteins were sequenced in LC/Mass Spectrophotometer. The most important differentially expressed genes include sucrose synthase, actin, isoprene synthase, ABF3, SNF1 related protein kinase, WRKY type transcription factors, AP2, ASR2, glyoxalase I and, cytochrome b which play significant role in cell permeability, transportation, photosynthesis and, maintenance in osmotic stress. We have found that ribulose bisphosphate carboxylase and phosphoribulokinase, which play major role in photosynthesis, were suppressed in response to water stress in Florida hybrid bunch. The results suggested that water stress affects expression of cDNAs associated with defense and drought regulated functions. Such profiling studies will be used to explicate specific pathways disconcerted by water deficit treatments, and in the identification of varietal differences

Optimising Light Source Spectrum to Reduce the Energy Absorbed by Objects

Light is used to illuminate objects in the built environment. Humans can only observe light reflected from an object. Light absorbed by an object turns into heat and does not contribute to visibility. Since the spectral output of the new lighting technologies can be tuned, it is possible to imagine a lighting system that detects the colours of objects and emits customised light to minimise the absorbed energy. Previous optimisation studies investigated the use of narrowband LEDs to maximise the efficiency and colour quality of a light source. While these studies aimed to tune a white light source for general use, the lighting system proposed here minimises the energy consumed by lighting by detecting colours of objects and emitting customised light onto each coloured part of the object. This thesis investigates the feasibility of absorption-minimising light source spectra and their impact on the colour appearance of objects and energy consumption. Two computational studies were undertaken to form the theoretical basis of the absorption-minimising light source spectra. Computational simulations show that the theoretical single-peak spectra can lower the energy consumption up to around 38 % to 62 %, and double-peak test spectra can result in energy savings up to 71 %, without causing colour shifts. In these studies, standard reference illuminants, theoretical test spectra and coloured test samples were used. These studies are followed by the empirical evidence collected from two psychophysical experiments. Data from the experiments show that observers find the colour appearance of objects equally natural and attractive under spectrally optimised spectra and reference white light sources. An increased colour difference, to a certain extent, is found acceptable, which allows even higher energy savings. However, the translucent nature of some objects may negatively affect the results

Optical Printing of Multiscale Hydrogel Structures

Hydrogel has been a promising candidate to recapitulate the chemical, physical and mechanical properties of natural extracellular matrix (ECM), and they have been widely used for tissue engineering, lab on a chip and biophotonics applications. A range of optical fabrication technologies such as photolithography, digital projection stereolithography and laser direct writing have been used to shape hydrogels into structurally complex functional devices and constructs. However, it is still greatly challenging for researchers to design and fabricate multiscale hydrogel structures using a single fabrication technology. To address this challenge, the goal of this work is the design and develop novel multimode optical 3D printing technology capable of printing hydrogels with multiscale features ranging from centimeter to micrometer sizes and in the process transforming simple hydrogels into functional devices for many biomedical applications. Chapter 2 presents a new multimode optical printing technology that synergistically combined large-scale additive manufacturing with small-scale additive/subtractive manufacturing. This multiscale fabrication capability was used to (i) align cells using laser induced densification in Chapter 3, (ii) develop diffractive optics based on changes in refractive indices in Chapter 4, (iii) print diffractive optical elements in Chapter 5, and (iv) digitally print complex microfluidic devices and other 3D constructs in Chapter 6. Overall, this work open doors to a new world of fabrication where multiscale functional hydrogel structures are possible for a range biomedical application

Master of Science

thesisIn this thesis the origin of angle-independent yellowish-green coloration of the exoskeleton of a beetle was studied. The beetle chosen was a weevil with the Latin name Eupholus chevrolati. The origin of this weevil's coloration was investigated by optical and structural characterization techniques, including optical microscopy, scanning electron microscopy imaging and focused ion beam milling, combined with three-dimensional modeling and photonic band structure calculations. Furthermore, using color theory the pixel-like coloring of the weevil's exoskeleton was investigated and an interesting additive color mixing scheme was discovered. For optical studies, a microreflectance microscopy/spectroscopy set-up was optimized. This set-up allowed not only for imaging of individual colored exoskeleton domains with sizes ~2-10 μm, but also for obtaining reflection spectra of these micrometer-sized domains. Spectra were analyzed in terms of reflection intensity and wavelength position and shape of the reflection features. To find the origin of these colored exoskeleton spots, a combination of focused ion beam milling and scanning electron microscopy imaging was employed. A three-dimensional photonic crystal in the form of a face-centered cubic lattice of ABC-stacked air cylinders in a biopolymeric cuticle matrix was discovered. Our photonic band structure calculations revealed the existence of different sets of stop-gaps for the lattice constant of 360, 380 and 400 nm in the main lattice directions, Γ-L, Γ-X, Γ-U, Γ-W and Γ-K

Caracterização física de preparações líquidas não estéreis: aparência

The present dissertation consists in the development of a visual and instrumental method for the evaluation of the color of a non-sterile liquid formulation. The color of the formulation was analyzed at different time intervals, after being subjected to different conditions of temperature and relative humidity in its pre-stability period. The evaluation occurred by comparing the formulation with different color scales reproduced based on the European Pharmacopoeia 9.7. Due to the fact that the visual assessment could be subjective, an instrumental color evaluation was performed from three- and two-dimensional color spaces, namely the CIELAB color space. Since the two-dimensional representation used to the instrumental specification of color does not consider all the attributes associated with color (does not include brightness), the CIELAB Difference (ΔE∗) between the color of the standard solutions of the scales and the formulation analyzed under different conditions was determined. The CIELAB Difference between two colors considers all the parameters that influence the color sensation and allows determining which of the standard solution has the most similar color to the formulation under analysis. Finally, using the standard solution with the most intense color of one of the scales reproduced, a rectangular color tolerance box was established to limit the acceptable tolerance for the coordinates of the formulation under analysis: all the formulations with the color coordinates outside the tolerance limits should be potentially rejected and investigated. However, the tolerance defined with the most intense color of one of the scales is merely representative: the main objective is, over time, to obtain a history of the coordinates of the color of the formulation and establish as tolerance limit the coordinates of the color associated with a formulation that is at the limit of the specifications associated with itA presente dissertação tem como objetivo o desenvolvimento e implementação de um método de avaliação da cor de uma preparação líquida não estéril analisada em diferentes intervalos de tempo, após estar sujeita a diferentes condições de temperatura e humidade relativa no seu período de pré-estabilidade. A avaliação ocorreu através da comparação entre a formulação e diferentes escalas da cor reproduzidas com base na Farmacopeia Europeia 9.7. Devido ao facto de a avaliação visual poder ser subjetiva, procedeu-se a uma avaliação instrumental da cor a partir de espaços de cor tridimensionais e bidimensionais, nomeadamente o espaço de cor CIELAB. Dado que a representação bidimensional utilizada para a especificação instrumental da cor não considera todos os atributos associados à mesma (não inclui a luminosidade), determinou-se a Diferença CIELAB (Δ"∗) entre a cor das amostras de referência das escalas e a cor da formulação em análise. A Diferença CIELAB considera todos os parâmetros que influenciam a sensação da cor e permite determinar qual das amostras de referência tem a cor mais semelhante à formulação em análise. Por fim, recorrendo à amostra de referência com a cor mais intensa de uma das escalas, estabeleceu-se uma caixa retangular de tolerância para a cor da formulação em avaliação: todas as formulações com coordenadas fora do limite da caixa devem ser rejeitadas e investigadas. No entanto, a tolerância definida com as coordenadas da cor mais intensa de uma das escalas é meramente representativa: o objetivo é, através de histórico de coordenadas da cor da formulação ao longo do tempo, estabelecer o limite de tolerância com as coordenadas associadas a uma formulação que se encontre no limite das especificações associadas à mesmaMestrado em Engenharia Químic

The Hybrid Color Film: Multiplicity of Space, Time, and Matter

Hybrid color films of the 1920s such as The King of Kings (Cecil B. DeMille, 1927)—that is, films comprising a mix of different historical color processes—are a particularly fruitful resource for the comparison of the silent era’s various color technologies. This article analyzes these cinematic hybridizations and argues that this type of film is much more than the sum of its parts. In embodying a multiplicity of layers of space, time, and color on a literal and metaphorical level, hybrid color films are not only symptomatic of the transformation of the medium in the 1920s but also symbolic of current approaches to film historiography based on media archaeology