Chromatic Characteristics Research Articles

Robust Image Hashing Based on Selective Quaternion Invariance

Robust image hashing, which maps the perceptual contents of image to a short digest, is a key technique for tackling the challenges of content-based indexing, searching and copyright protection. In this letter, we propose a quaternion invariance based hashing algorithm that can fuse complementary visual features to compact hash. The proposed algorithm leverages quaternion polar cosine transform to holistically capture the spatial and chromatic characteristics of digital image, and rotation-invariant features are derived from the phase information in the quaternion frequency domain. In addition, we also propose an information theoretic based metric for feature quality assessment and a greedy strategy to select the optimal subset of features for hash computation. Extensive experiments over a large database demonstrate that the proposed work shows higher content identification accuracy than most competing algorithms, and the resulting hash is compact and easy to compute.

Effects of Phosphor Concentration and Leadframe Reflectivity for Phosphor-Converted LEDs

We propose the effects of phosphor concentration and leadframe reflectivity on phosphor-converted LEDs (pc-LEDs) manufactured using the dispensing method in this study. Simulation results showed that the luminous flux increased with the phosphor concentration and reflectivity of the reflective cup, even as the total output power decreased as the phosphor concentration increasing. It was also found that the leadframe reflectivity would dominate the optical and chromatic characteristics of pc-LEDs as well as the phosphor concentration. Specifically, for the pc-LEDs with a low phosphor concentration, the leadframe reflectivity and phosphor concentration were crucial factors determining the total output power and chromaticity deviation. However, for the pc-LEDs with a high phosphor concentration, only the phosphor concentration determined the chromaticity deviation.

Polyphenolic Compositions and Chromatic Characteristics of Bog Bilberry Syrup Wines

Phenolic compounds determine the color quality of fruit wines. In this study, the phenolic compound content and composition, color characteristics and changes during 6 months of bottle aging were studied in wines fermented with bog bilberry syrup under three different pHs. The total anthocyanins and total phenols were around 15.12–16.23 mg/L and 475.82 to 486.50 mg GAE/L in fresh wines and declined 22%–31% and about 11% in bottle aged wines, respectively. In fresh wines, eight anthocyanins, six phenolic aids and 14 flavonols, but no flavon-3-ols were identified; Malvidin-3-O-glucoside, petunidin-3-O-glucoside and delphinium-3-O-glucoside were the predominant pigments; Chlorogentic acid was the most abundant phenolic acid, and quercetin-3-O-galactoside and myricetin-3-O-galactoside accounted for nearly 90% of the total flavonols. During 6 months of bottle storage, the amounts of all the monomeric anthocyanins and phenolic acids were reduced dramatically, while the glycosidyl flavonols remained constant or were less reduced and their corresponding aglycones increased a lot. The effects of aging on blueberry wine color were described as the loss of color intensity with a dramatic change in color hue, from initial red-purple up to final red-brick nuances, while the pH of the fermentation matrix was negatively related to the color stability of aged wine.

Differential Adsorption of Ochratoxin A and Anthocyanins by Inactivated Yeasts and Yeast Cell Walls during Simulation of Wine Aging.

The adsorption of ochratoxin A (OTA) by yeasts is a promising approach for the decontamination of musts and wines, but some potential competitive or interactive phenomena between mycotoxin, yeast cells, and anthocyanins might modify the intensity of the phenomenon. The aim of this study was to examine OTA adsorption by two strains of Saccharomyces cerevisiae (the wild strain W13, and the commercial isolate BM45), previously inactivated by heat, and a yeast cell wall preparation. Experiments were conducted using Nero di Troia red wine contaminated with 2 μg/L OTA and supplemented with yeast biomass (20 g/L). The samples were analyzed periodically to assess mycotoxin concentration, chromatic characteristics, and total anthocyanins over 84 days of aging. Yeast cell walls revealed the highest OTA-adsorption in comparison to thermally-inactivated cells (50% vs. 43% toxin reduction), whilst no significant differences were found for the amount of adsorbed anthocyanins in OTA-contaminated and control wines. OTA and anthocyanins adsorption were not competitive phenomena. Unfortunately, the addition of yeast cells to wine could cause color loss; therefore, yeast selection should also focus on this trait to select the best strain.

Effect of Oak Chip Addition at Different Winemaking Stages on Phenolic Composition of Moravia Agria Red Wines

This study compared changes in the phenolic composition of Moravia Agria wine and its effect on colour, co-pigmentation as well as on physicochemical properties, such as antioxidant capacity, caused by adding oak chips at different stages of the winemaking process. Moravia Agria control wine was made following traditional winemaking processes, without oak chips. Oak chips were added to the rest of the wines at two dose rates (3 and 6 g/L) at different stages of the winemaking process: for one week during alcoholic fermentation, during malolactic fermentation and in young red Moravia Agria wine. Only slight significant differences were found in phenolic composition, antioxidant activity and chromatic characteristics between the Moravia Agria wines treated with oak chips and the control wine. However, oak chip addition slightly decreased the content of non-polymeric red pigments (monomeric anthocyanins and pyranoanthocyanins) and also of resveratrol-monomer stilbenes. It is suggested that oak chip addition to Moravia Agria wines can be selected as part of the targeted sensory profile (relative intensity of sensory descriptors provided by grape and oak wood), since only a few changes have been observed in the phenolic profiles, antioxidant capacity value and colour characteristics.

Influence of different withering conditions on phenolic composition of Avanà, Chatus and Nebbiolo grapes for the production of ‘Reinforced’ wines

The impact of postharvest withering rates on the phenolic composition of ‘reinforced’ wines produced with partially dehydrated grapes was evaluated. The study was performed on winegrape varieties with anthocyanin profiles differently constituted of di- and tri-substituted forms. Dehydration induced limited changes in the anthocyanin profile of berry skins. Nevertheless, the greatest abundance of total anthocyanins and their more stable forms (malvidin-3-glucoside and acylated glucosides) corresponded to the wines made from slow withered Chatus grapes, which were in turn the darkest. In contrast, the wines made from withered Avanà grapes did not meet good chromatic characteristics due to low contents of total anthocyanins and high ratios between di- and tri-substituted forms. Nebbiolo wines showed intermediate values of this ratio, and therefore of clarity and color intensity. The fast process is recommended because higher percentages of galloylated flavanols in the seeds of slow withered Nebbiolo grapes may have a negative influence on wine astringency.

Preliminary study of the effect of ultrasound on physicochemical properties of red wine

Ultrasound is regarded as a potential alternative method for improving the quality of some wines. This study was initiated with the objective of evaluating the effects of ultrasound on some important physicochemical properties of red wine such as chromatic characteristics (CC), electrical conductivity (EC), pH, titratable acidity (TA), total phenolic compounds (TPCs) and DPPH (1,1-diphenyl-2-picryl-hydrazyl) free radical scavenging activity (DFRSA). The operational parameters assessed were ultrasound power, ultrasound frequency, exposure time and bath temperature. Results illustrated that there were significant changes in CC, EC and TPC while pH and TA hardly changed except for samples treated at high temperatures. DFRSA was correlated to TPC during ultrasonic treatment. Application of principal component analysis to the experimental data suggested that exposure time was the factor with the greatest ability to induce changes on wine. Results suggested that ultrasound may be applied to improve some physicochemical properties of red wine.

Influence of strawberry jam color and phenolic compounds on acceptance during storage

The objective of this study was to evaluate the influence of the color and phenolic compounds of strawberry jam on acceptance during storage. Jams were processed, stored for 120 days and evaluated monthly for chromatic characteristics, total phenolic compounds, total anthocyanins (ANT), total ellagic acid (TEA), flavonoids and free ellagic acid (FEA), and sensory acceptance as well. Data were submitted to analysis of variance (ANOVA) and the means were compared by the Least Significant Difference (LSD). Cluster Analysis and Partial Least Square Regression (PLS) were performed to investigate the relationships between instrumental data and acceptance. Contents of ANT, TEA and redness decreased during storage. Other chemical characteristics and sensory acceptance showed a nonlinear behavior. Higher acceptance was observed after 60 days, suggesting a trend of quality improvement followed by decline to the initial levels. The same trend was observed for lightness, non-pigment flavonoids and FEA. According to PLS map, for consumers in cluster 2, acceptance was associated to jams at 60 days and to luminosity, FEA, and non-pigment flavonoids. For cluster 1, a positive association between flavor liking, jam at initial storage, and the contents of TEA and ANT was indicated. Jams at 120 days were positively associated to hue and negatively associated to color liking, for cluster 1. Color and texture were positively correlated to overall liking for cluster 2, whereas for cluster 1, overall acceptance seemed to be more associated to flavor liking. Changes in color and phenolic compounds slightly influenced the acceptance of strawberry jams, but in different ways for consumers clusters.

Thermal and optical investigations of high power LEDs with metal embedded printed circuit boards

To improve the thermal and optical performances for high power LEDs, a metal embedded printed circuit board (MEPCB), with a columnar copper slug inside the low cost FR4 material, was introduced in this paper. This novel structure makes it possible to connect the LED component directly to the outside environment. The thermal performances, including thermal resistances and temperature distributions of the MEPCB were evaluated by employing the finite element analysis method (FEA) and transient thermal measurement. The luminous and chromatic characteristics were also measured and analyzed at transient state and steady state. Results showed that the maximum reductions in the total thermal resistance and junction temperature were 65.60% and 56.25% by using the MEPCB compared with the conventional metal core printed circuit board (MCPCB). Benefiting from the excellent thermal performance of the MEPCB, up to 24.14% increase in steady state luminous flux was obtained compared with the MCPCB. Moreover, the correlated color temperature (CCT) shift value between 150mA and 900mA could be controlled within 93K. This work demonstrates that the MEPCB is more suitable for LEDs working at wide current ranges.

Chromatic characterization of ion-exchanged glass binary phase plates for mode-division multiplexing.

Mode-division multiplexing (MDM) in few-mode fibers is regarded as a promising candidate to increase optical network capacity. A fundamental element for MDM is a modal transformer to LP modes which can be implemented in a free-space basis by using multiregion phase plates, that is, LP plates. Likewise, several wavelengths have to be used due to wavelength multiplexing purposes, optical amplification tasks, and so on. In this work we show that efficient monolithic binary phase plates for different wavelengths can be fabricated by ion-exchange in glass and used for MDM tasks. We introduce an optical characterization method of the chromatic properties of such phase plates which combines the inverse Wentzel-Kramers-Brillouin (IWKB) together with Mach-Zehnder and Michelson-based interferometric techniques. The interferometric method provides a measurement of the phase step for several wavelengths, which characterizes the chromatic properties of the phase plate. Consequently, it is shown that the IWKB method allows us to design and characterize the phase plates in an easy and fast way.

The influence of surface finishes on the energy demand of HVAC systems for existing buildings

In historical centres, the buildings are characterized by pitched roofs, sometimes not insulated, with low thermal inertia and coated in brick tiles with low solar reflection factor. So, the attics show high energy costs for heating and cooling.This paper analyses the energy saving obtainable by applying innovative surface finishes on interior and exterior surfaces of opaque envelope components of existing buildings. This simple and inexpensive retrofit action determines energy cost reductions for heating and cooling, but also benefits regarding indoor thermal comfort and useful life of buildings, because condensation problems and thermal shock are reduced; moreover, it preserves the architectural and chromatic characteristics of the building envelope.The analysis is performed by means of a building energy simulation code, considering typical HVAC systems for various Italian and European cities. A technical-economic and environmental investigation is also performed.Thermal energy needs of buildings for summer cooling can be reduced up to 60% by applying “cool paints” on the external surface of walls and roof, while internal low infrared emissivity coatings can reduce winter thermal requirements up to 12.5%.Significant primary energy savings for heating and cooling and reductions of greenhouse gas emissions (up to 60%) can be obtained, as well as a payback value of few years in most cases.

Influence of radiation processing of grapes on wine quality

Abstract Grapes (Var. Shiraz and Cabernet) were subjected to radiation processing (up to 2 kGy) and wines were prepared and matured (4 months, 15 °C). The wines were analyzed for chromatic characteristics, total anthocyanin (TA), phenolic (TP) and total antioxidant (TAC) content. Aroma of wines was analyzed by GC/MS and sensory analysis was carried out using descriptive analysis. TA, TP and TAC were 77, 31 and 37 percent higher for irradiated (1500 Gy) Cabernet wines, while irradiated Shiraz wines demonstrated 47, 18 and 19 percent higher TA, TP and TAC, respectively. HPLC-DAD analysis revealed that radiation processing of grapes resulted in increased extraction of phenolic constituents in wine with no qualitative changes. No major radiation induced changes were observed in aroma constituents of wine. Sensory analysis revealed that 1500 Gy irradiated samples had higher fruity and berry notes. Thus, radiation processing of grapes resulted in wines with improved organoleptic and antioxidant properties.

RANGE AND IMAGE BASED MODELLING: A WAY FOR FRESCOED VAULT TEXTURING OPTIMIZATION

Abstract. In the restoration of the frescoed vaults it is not only important to know the geometric shape of the painted surface, but it is essential to document its chromatic characterization and conservation status. The new techniques of range-based and image-based modelling, each with its limitations and advantages, offer a wide range of methods to obtain the geometric shape. In fact, several studies widely document that laser scanning enable obtaining three-dimensional models with high morphological precision. However, the quality level of the colour obtained with built-in laser scanner cameras is not comparable to that obtained for the shape. It is possible to improve the texture quality by means of a dedicated photographic campaign. This procedure, however, requires to calculate the external orientation of each image identifying the control points on it and on the model through a costly step of post processing. With image-based modelling techniques it is possible to obtain models that maintain the colour quality of the original images, but with variable geometric precision, locally lower than the laser scanning model. This paper presents a methodology that uses the camera external orientation parameters calculated by image based modelling techniques to project the same image on the model obtained from the laser scan. This methodology is tested on an Italian mirror (a schifo) frescoed vault. In the paper the different models, the analysis of precision and the efficiency evaluation of proposed methodology are presented.

Mechanical and barrier properties of guar gum based nano-composite films

Guar gum based nano-composite films were prepared using organically modified (cloisite 20A) and unmodified (nanofil 116) nanoclays. Effect of nanoclay incorporation on mechanical strength, water vapor barrier property, chromatic characteristics and opacity of films was evaluated. Nano-composites were characterized using X-ray scattering, FTIR and scanning electron microscopy. A nanoclay concentration dependent increase in mechanical strength and reduction in water vapor transmission rate was observed. Films containing nanofil 116 (2.5% w/w guar gum) and closite 20A (10% w/w guar gum) demonstrated a 102% and 41% higher tensile strength, respectively, as compared to the control. Lower tensile strength of cloisite 20A films as compared to nanofil 116 films was due to its incompatibility with guar gum. X-ray scattering analysis revealed that interstitial spacing between nanofil 116 and cloisite 20A sheets increased due to intercalation by guar gum polymer. This resulted in improved mechanical and barrier properties of nano-composites compared to control.

The preservation of the chromatic image of historical cities as a cultural value. The old city of Valencia (Spain)

Abstract Understanding the physical and material characteristics of our historical cities is essential for the preservation of their hereditary and cultural values. Beyond the historical logic of the urban scene and its functional nature, the city is sensed through the spaces, which it creates and configures. The spaces of the historical city represent the soul of its history and the final result of its development. Through the architectural configuration of these spaces, we can visualize the historical and vital logic that underlies the city, the heritage of the people and cultures that make it up. The Study for the Recovery of Urban Spaces in Valencia Historical Center is an interdisciplinary project of intervention in patrimonial architecture, aiming to recover the original image of spaces in the historical city center. This is a project started in 1995 and ended in 2013, which is formed by a series of activities in which both, the Polytechnic University of Valencia as a research institution and the public administrations involved in the processes of regeneration and restoration of the historic center, take part. The aim of the project has been the start-up of a dynamic restoration process of the city's historic urban centre and its landscape value. By combining scientific studies, tasks of awareness and sensitization of population, it aims to determine the formal and chromatic characteristics of original spaces that create the architecture of the city.

강진과 부안 청자 도편의 비교연구

Celadon shards from Gangjin and Buan were analyzed for their color, chemistry and microstructures. They exhibited similar chromatic characteristics in a CIEL * a * b * analysis. All of the glazes assessed showed comparable compositional areas, while the bodies from Gangjin shards had higher RO2 concentrations. A high degree of similarity was also noted in the microstructures of the glaze and bodies from both regions. Anorthite crystals appeared in the glaze layer, and phase separation behavior developed around these crystals. This may have been caused by the glaze chemistry and the sintering process given the lengthy heating and cooling time. A Raman analysis indicated higher isolated SiO₄ unit (Q?) values for the Buan samples. This can stem from the higher firing temperature or the longer sintering process.

The role of egg-nest contrast in the rejection of brood parasitic eggs

Hosts of avian brood parasites can avoid the reproductive costs of raising genetically unrelated offspring by rejecting parasitic eggs. The perceptual cues and controls mediating parasitic egg discrimination and ejection are well studied: hosts are thought to use differences in egg color, brightness, maculation, size and shape to discriminate between their own and foreign eggs. Most theories of brood parasitism implicitly assume that the primary criteria to which hosts attend when discriminating eggs are differences between the eggs themselves. However, this assumption is confounded by the degree to which chromatic and achromatic characteristics of the nest lining co-vary with egg coloration, so that egg-nest contrast per se might be the recognition cue driving parasitic egg detection. Here, we systematically tested whether and how egg-nest contrast itself contributes to foreign egg discrimination. In an artificial parasitism experiment, we independently manipulated egg color and nest lining color of the egg-ejector American robin (Turdus migratorius), a host of the obligate brood parasitic brown-headed cowbird (Molothrus ater). We hypothesized that the degree of contrast between foreign eggs and the nest background would affect host egg rejection behavior. We predicted that experimentally decreasing egg-nest chromatic and achromatic contrast (i.e. rendering parasitic eggs more cryptic against the nest lining) would decrease rejection rates, while increasing egg-nest contrast would increase rejection rates. In contrast to our predictions, egg-nest contrast was not a significant predictor of egg ejection patterns. Instead, egg color significantly predicted responses to parasitism. We conclude that egg-egg differences are the primary drivers of egg rejection in this system. Future studies should test for the effects of egg-nest contrast per se in predicting parasitic egg recognition in other host-parasite systems, including those hosts building enclosed nests and those parasites laying cryptic eggs, as an alternative to hypothesized effects of egg-egg contrast.

Study of the Bloodstains in the Shroud of Turin: Chromatic Analysis and Possible Interpretation

This work presents a chromatic characterization of the bloodstains of the Shroud of Turin. The analysis is carried out by considering the chromatic values of the bloodstains and by calculating the chromatic ratios to be adopted in a comparative analysis. Six categories were obtained and characterized. By considering the geometry of the body and the position of the sheet, the analysis allowed the formulation of hypotheses on the dynamics of blood formation and flowing.

Optoelectronic sensor device for monitoring the maceration of red wine: Design issues and validation

Enologists usually rely on spectrophotometers to perform the chromatic characterization of red wines. This work reports an optoelectronic instrument based on absorbance measurements aiming not only at the assessment of the chromatic characteristics of finished red wines, but at the supervision of the gradual maceration of fermenting grape musts as well. Maceration is a chemical process that takes place during the early stages of the fermentation that finally results in red wine. It is through maceration that wine acquires its distinctive chromatic features. Key issues related to the selection of optoelectronic components, the system design and its final validation using diluted wine samples are thoroughly discussed. Resolution figures lie in the range of one thousandth of an absorbance unit. Maceration has been successfully monitored with the proposed instrument using grape must samples extracted during the first three days from two different fermentations.

Improvement of yield and grape and wine composition in field-grown Monastrell grapevines by partial root zone irrigation, in comparison with regulated deficit irrigation

Regulated deficit irrigation (RDI) and partial root zone irrigation (PRI) were compared for four years (2009–2012), each at two different irrigation volumes (110mmyear−1 (1) and 78mmyear−1 (2)), in field-grown Monastrell grapevines grafted onto 1103P, in South Eastern Spain. The aim was to distinguish the effects of deficit irrigation per se from specific PRI effects (placement of water) on yield response and berry and wine quality. Vines grown with PRI-1 or RDI-1 received around 30% of the ETc from budburst to fruit set, 13–15% ETc from fruit set to véraison and 20% ETc from véraison to harvest. The RDI-2 and PRI-2 vines received around 20% ETc from budburst to fruit set, no irrigation from fruit set to véraison and a recovery (21-24% ETc) thereafter. In general, the PRI-2 and RDI-2 vines (the most-severely water-stressed) showed greater yield reduction and lower overall berry and wine quality (including technological and phenolic composition) than the moderately-water-stressed vines (RDI-1 and PRI-1). Compared to RDI-1, PRI-1 improved the yield response—increasing mean yield, cluster number per vine and berry weight and maintaining better bunch health at late ripening and a greater proportion of bigger bunches. In addition, PRI-1 increased the anthocyanin and amino acid concentrations of the berries and altered their composition, improving the phenolic and chromatic characteristics of the wine and enhancing the health-promoting value of the fruit. It was also the option most economically viable under the present conditions of the wine grape market, compared to RDI-1 and the rest of the treatments. In contrast, PRI-2, although it improved some technological quality attributes and phenolic and chromatic characteristics of Monastrell berries and wines compared to RDI-2, did not have a positive effect on yield (yield and cluster and berry weight decreased in some years) and its implementation was economically unviable under these soil and climatic conditions. The significant interaction between irrigation volume (high vs. low) and irrigation placement (PRI vs. RDI) indicate that the response to PRI also depended on the volume of water applied in the wet root zone and the soil total water availability.