Hue Variation Research Articles

AuAg alloy film-based colorful SPR imaging sensor for highly sensitive immunodetection of benzo[a]pyrene in water.

A colorful surface plasmon resonance imaging (SPRi) sensor with the hue-based enhanced sensitivity has been developed by using sputtered AuAg alloy thin film as the sensing layer. The condition for optimizing the hue-based sensitivity of the SPRi sensor was achieved, that is, the initial resonance wavelength is in the range from 595 to 610nm. Under this condition, the hue-based refractive index sensitivity of the SPRi sensor was measured as high as Δhue/Δnc=29879/RIU. This sensitivity is 8 times higher than that obtained with a gold-layer SPRi sensor (Δhue/Δnc=3658/RIU) and 7.7 times as high in magnitude as the spectral sensitivity of the same sensor (ΔλR/Δnc=3897.6 nm/RIU). After functionalization of the AuAg alloy film with the monoclonal antibody, the sensor was used for quantitative immunodetection of highly carcinogenic benzo[a]pyrene (BaP) in water. According to the experimental results, the average hue of the SPR color image (300 pixels×300 pixels) experiences an initial rapid increase and then stabilizes 15min after exposure of the functionalized AuAg alloy film to an aqueous BaP solution sample. The variation of average hue obtained at the equilibrium of surface immunoreaction is a linear function of BaP concentration with the slope being Δhue/Δc=132.2/(μg·L-1). A cooled CCD camera is able to distinguish a change of Δhue=1, offering the colorful SPRi sensor the BaP detection limit of 0.01 μg·L-1. The comparative measurements of the sensor's responses indicate that the hue variation obtained with 0.1 μg·L-1 of BaP is equal to that obtained either with 5 μg·L-1 of benzanthracene or with 5 μg·L-1 of benzofluoranthene, revealing the sensor's excellent specificity to BaP. The work demonstrated that the AuAg alloy film-based colorful SPRi sensor can be used not only for visualized analysis of molecular interaction at the surface but also for quantitative trace detection of small-molecule analytes.

Examining Implicit Discretization in Spectral Schemes

AbstractTwo of the primary reasons rainbow color maps are considered ineffective trace back to the idea that they implicitly discretize encoded data into hue‐based bands, yet no research addresses what this discretization looks like or how consistent it is across individuals. This paper presents an exploratory study designed to empirically investigate the implicit discretization of common spectral schemes and explore whether the phenomenon can be modeled by variations in lightness, chroma, and hue. Our results suggest that three commonly used rainbow color maps are implicitly discretized with consistency across individuals. The results also indicate, however, that this implicit discretization varies across different datasets, in a way that suggests the visualization community's understanding of both rainbow color maps, and more generally effective color usage, remains incomplete.

Decoration Cylinder Pressure and it’s Influence on the Hue Variation of Ceramic Tiles Decorated by the Laser Engraving Silicone Cylinder Method

Several factors can influence the hue variation of tiles through contact elements; the pressure on the surface to be decorated is an important feature. This paper studied this variable applied to decoration by silicone cylinders. A variation of height was made between the cylinder and the tile. The influence of the feature is linked to cylinder wear and distance decrease. The reflectance, as well as the shape and filling of the decorated dots of gray scale values (5, 25 and 85%) were analyzed; the heights studied were 0.8; 1.0; 1.3 and 1.5mm. A similar behavior was observed in the engraving studied; in low shades of gray the reflectance decreases with increasing pressure and then becomes directly proportional; in the middle and high tones range the general trend was an increase in reflectance with increasing pressure on the ceramic tile.

The effect of landscape colour, complexity and preference on viewing behaviour

ABSTRACTWhat we comprehend and recollect in a landscape is closely related to how we look; therefore, attention to and understanding of human viewing behaviour is required. In our study, we employed eye-tracking technology as a means to understand visual perception. The objective of this study is to examine the relationships among landscape characteristics, landscape preference and viewing behaviour. A total of 45 subjects were asked to view 20 sets of photographs freely in a two-by-two display. Same landscape types were grouped together. The results indicated that higher hue variation and chroma encourages visual fixation. A strong relationship was identified between landscape preference and fixation count in mountain, aquatic and forest landscapes. People tend to have different preferences and different viewing behaviour while viewing different landscape types. It is concluded that magenta-green variation, yellow-blue colour field, and hue variation is an important factor in mountain, aquatic, and open landscapes, respectively.

The processing of color preference in the brain

Decades of research has established that humans have preferences for some colors (e.g., blue) and a dislike of others (e.g., dark chartreuse), with preference varying systematically with variation in hue (e.g., Hurlbert and Owen, 2015). Here, we used functional MRI to investigate why humans have likes and dislikes for simple patches of color, and to understand the neural basis of preference, aesthetics and value judgements more generally. We looked for correlations of a behavioural measure of color preference with the blood oxygen level-dependent (BOLD) response when participants performed an irrelevant orientation judgement task on colored squares. A whole brain analysis found a significant correlation between BOLD activity and color preference in the posterior midline cortex (PMC), centred on the precuneus but extending into the adjacent posterior cingulate and cuneus. These results demonstrate that brain activity is modulated by color preference, even when such preferences are irrelevant to the ongoing task the participants are engaged. They also suggest that color preferences automatically influence our processing of the visual world. Interestingly, the effect in the PMC overlaps with regions identified in neuroimaging studies of preference and value judgements of other types of stimuli. Therefore, our findings extends this literature to show that the PMC is related to automatic encoding of subjective value even for basic visual features such as color.

PixelBNN: Augmenting the PixelCNN with Batch Normalization and the Presentation of a Fast Architecture for Retinal Vessel Segmentation.

Analysis of retinal fundus images is essential for eye-care physicians in the diagnosis, care and treatment of patients. Accurate fundus and/or retinal vessel maps give rise to longitudinal studies able to utilize multimedia image registration and disease/condition status measurements, as well as applications in surgery preparation and biometrics. The segmentation of retinal morphology has numerous applications in assessing ophthalmologic and cardiovascular disease pathologies. Computer-aided segmentation of the vasculature has proven to be a challenge, mainly due to inconsistencies such as noise and variations in hue and brightness that can greatly reduce the quality of fundus images. The goal of this work is to collate different key performance indicators (KPIs) and state-of-the-art methods applied to this task, frame computational efficiency–performance trade-offs under varying degrees of information loss using common datasets, and introduce PixelBNN, a highly efficient deep method for automating the segmentation of fundus morphologies. The model was trained, tested and cross tested on the DRIVE, STARE and CHASE_DB1 retinal vessel segmentation datasets. Performance was evaluated using G-mean, Mathews Correlation Coefficient and F1-score, with the main success measure being computation speed. The network was 8.5× faster than the current state-of-the-art at test time and performed comparatively well, considering a 5× to 19× reduction in information from resizing images during preprocessing.

How the observed color of the Swallow Tanager (Tersina viridis) changes with viewing geometry

Non-iridescent coloration in birds’ plumage is associated with the quasi-ordered nanostructures of short-range order present within the feather barbs. Even though this type of color does not change with the observation direction, a few bird species which exhibit the so called non-iridescent structurally colored feathers, present significant hue variations as the relative angle between incidence and detection directions is varied. Among these, the Swallow Tanager constitutes an excellent system to investigate this phenomenon as its hue changes remarkably from greens to blues as the angle between the illumination and observation directions increases, and independently of feather orientation. In this paper we elucidate the origin of the striking color change of the Swallow Tanager plumage by computing the reflectance spectra of the feathers’ microstructure. We show that the color observed under different illumination-detection conditions can be predicted quite accurately by applying averaging techniques and by considering the air-spheres microstructure of their feathers’ barbs as the main responsible for the observed color change. This work opens up new possibilities for the design of devices with special color characteristics.

Experiments on the effects of varying subcooled conditions on the dynamics of single vapor bubble and heat transfer rates in nucleate pool boiling regime

Dependence of bubble dynamic parameters and the associated heat transfer mechanisms on varying levels of sub-cooled conditions has been experimentally studied. Isolated nucleate pool boiling experiments have been performed to generate a single vapor bubble on an ITO (Indium Tin Oxide) glass substrate for three degrees of sub-cooling (ΔTsub-cooled = 2 °C, 5 °C and 0 °C). Field measurements have been made using gradient-based rainbow schlieren deflectometry. Various sub-phenomena associated with a bubble cycle, for instance, bubble inception and its growth, bubble oscillation and its departure from the heated substrate, have been visualized in real time for the range of bulk conditions employed. The recorded rainbow schlieren images have been analyzed to determine the transient variations of bubble dynamic parameters such as equivalent bubble diameter, bubble base diameter and aspect ratio. Effects of sub-cooled level on bubble oscillations have been estimated based on the dynamic variations in the hue values in the vicinity of the oscillating bubble. Spectral analysis of the hue variations showed an increasing trend in the oscillation frequency with sub-cooling conditions (foscillation = 52.8 Hz and 47.2 Hz for ΔTsubcool = 5 °C and 2 °C respectively). Based on the whole-field temperature distribution retrieved through the quantitative analysis of the schlieren images, individual contributions of the various heat transfer mechanisms (natural convection, bubble growth and superheat layer) towards the overall heat transfer rates have been determined. Results revealed that the contribution of natural convection heat transfer increases from 54% under saturation conditions to up to 99% for ΔTsub-cooling = 5 °C.

Objective criterion for evaluation of the quality decoration in ceramic floor tile production prior to the sintering process

Abstract In the ceramic tile decoration process, the set of variables that can cause hue variation is quite wide and independent of the methodology used in the production. The understanding of the effects of these variables over the final expected result is of great importance to the producers, especially if it could be done before the ceramic tile’s sintering stage. The quality of the decoration is linked to the deposited dot shape and its filling with ink. It is proposed in this paper the determination of a ‘quality index’, comparing the theoretical deposition pattern and a real deposition obtained with samples. Measuring the values of the areas with and without ink, using the statistical tool of the ROC curve, it was obtained the values for sensibility=0.791, specificity=0.830, precision=0.802 and quality index=0.768. The method is intended to be used prior to the sintering step for hue variation control.

Red clypeal membrane color predicts immune function in a burying beetle (Coleoptera: Silphidae)

AbstractRed and orange coloration commonly signals individual quality, especially in non‐mammalian vertebrates. Because the molecules that create red pigments are involved in immune function, acting as antioxidants among other functions, red and orange body coloration can indicate parasite load and the host's ability to mount a strong immune response. Although body color and immunity are associated in fishes, birds and lizards, to our knowledge no studies have examined the role of red or orange color patches as an indicator of immune function in invertebrates. Burying beetles in the genus Nicrophorus often have clypeal membranes directly above their mandibles which scale hyperallometrically with body size and appear red or orange to the human eye. We investigate whether the hue (a chromatic measure) or brightness (an achromatic measure) of this membrane is associated with melanistic encapsulation response to a foreign body inserted into the abdomen. We find that clypeal membrane hue in the red–orange range and brightness are associated with immune response in Nicrophorus pustulatus beetles. Male clypeal membranes show greater hue variation between individuals; however, for both sexes, redder and darker membranes indicate a stronger encapsulation response. Body size was also correlated with the observed variation in immune response, with smaller individuals tending to encapsulate more strongly. Hue and brightness were also associated with body size, with larger individuals having clypeal membranes that were more orange and brighter, especially for males. This represents the first report of an association between hue and brightness of red integumentary color and induced immunity in an invertebrate animal. Investigation into relationships between color and immunity in a broader range of taxa will augment our understanding of relevant ecological factors leading to the evolution of color signals of immune function.

Estimating the age of Heliconius butterflies from calibrated photographs.

Mating behaviour and predation avoidance in Heliconius involve visual colour signals; however, there is considerable inter-individual phenotypic variation in the appearance of colours. In particular, the red pigment varies from bright crimson to faded red. It has been thought that this variation is primarily due to pigment fading with age, although this has not been explicitly tested. Previous studies have shown the importance of red patterns in mate choice and that birds and butterflies might perceive these small colour differences. Using digital photography and calibrated colour images, we investigated whether the hue variation in the forewing dorsal red band of Heliconius melpomene rosina corresponds with age. We found that the red hue and age were highly associated, suggesting that red colour can indeed be used as a proxy for age in the study of wild-caught butterflies.

First Application of Mix Metallic Salt Mordant Combinations to Develop Newer Shades on Wool with Bixa orellana Natural Dye Using Reflectance Spectroscopy

ABSTRACTAnnatto colorants derived from Bixa orellana L. seeds have been extensively used in a wide range of food commodities such as dairy products, flour confectionery, fish, soft drinks, meat products, snack foods, and dry mixes. To exploit its use as a colorant for textiles, this research study investigates for the first time pre-mordanting of wool with bi and tri metal salt combinations using aluminum potassium sulfate, ferrous sulfate, and stannous chloride mordants in order to develop natural and beautiful shades on wool with variation in hue and tone. The dyeing was carried by exhaustion method and dyed samples were analyzed using a Reflective Spectrophotometer in terms of CIELAB (L*, a*and b*) and K/S values and washing and light fastnesses were investigated according to I.S.O. standard recommendations. In the dyeing experiments, wool samples pre-mordanted with Fe + Sn displayed highest color strength followed by Fe + Al and Al + Sn combinations. The results showed that overall 36 different shades having good to very good fastness properties were produced by the use of different metallic salt combinations in the natural dyeing of wool using annatto dye.

Fly-ash contribution to Nd:YAG laser yellowing and its mitigation using UV-B light

Abstract Nd:YAG Q-Switched laser cleaning of soiled stone at 1064 nm can sometimes result in yellower appearances than other conventional cleaning techniques. The yellowing effect is known to be at least partially due to the laser beam interaction with soiling matter, especially with infra-red absorbing components such as iron oxides, carbonaceous particles or fly-ash. In this study, pure plaster plates were artificially soiled with natural black crust and fly-ash powders. The morphology and crystalline structure of the soiling materials was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Soiled plaster plates were then treated by Nd:YAG QS laser light at 1064 nm. The laser irradiation led to the appearance of a yellow tone in all cases, highlighting the fly-ash contribution to the yellowing effect. Afterwards, the irradiated plaster plates were exposed to UV-B light (313 nm) for a few dozen hours using an accelerated UV ageing chamber. This treatment resulted in a significant attenuation of the yellow colour for all the samples. Colour measurements revealed that this photo-bleaching effect was essentially due to brightness L* and saturation C* variations and not to hue h* variation towards less yellow shades. As hue variation is often related to chemical transformations of chromophores, this result tends to indicate that the yellowing reduction was mainly due to scattering effects.

Hue shifts produced by temporal asymmetries in chromatic signals depend on the alignment of the first and second harmonics.

When M- or L-cone-isolating sawtooth waveforms flicker at frequencies between 4 and 13.3 Hz, there is a mean hue shift in the direction of the shallower sawtooth slope. Here, we investigate how this shift depends on the alignment of the first and second harmonics of sawtooth-like waveforms. Below 4 Hz, observers can follow hue variations caused by both harmonics, and reliably match reddish and greenish excursions. At higher frequencies, however, the hue variations appear as chromatic flicker superimposed on a steady light, the mean hue of which varies with second-harmonic alignment. Observers can match this mean hue against a variable-duty-cycle rectangular waveform and, separately, set the alignment at which the mean hue flips between reddish and greenish. The maximum hue shifts were approximately frequency independent and occurred when the peaks or troughs of the first and second harmonics roughly aligned at the visual input-consistent with the hue shift's being caused by an early instantaneous nonlinearity that saturates larger hue excursions. These predictions, however, ignore phase delays introduced within the chromatic pathway between its input and the nonlinearity that produces the hue shifts. If the nonlinearity follows the substantial filtering implied by the chromatic temporal contrast-sensitivity function, phase delays will alter the alignment of the first and second harmonics such that at the nonlinearity, the waveforms that produce the maximum hue shifts might well be those with the largest differences in rising and falling slopes-consistent with the hue shift's being caused by a central nonlinearity that limits the rate of hue change.

Color generalization across hue and saturation in chicks described by a simple (Bayesian) model.

Color conveys important information for birds in tasks such as foraging and mate choice, but in the natural world color signals can vary substantially, so birds may benefit from generalizing responses to perceptually discriminable colors. Studying color generalization is therefore a way to understand how birds take account of suprathreshold stimulus variations in decision making. Former studies on color generalization have focused on hue variation, but natural colors often vary in saturation, which could be an additional, independent source of information. We combine behavioral experiments and statistical modeling to investigate whether color generalization by poultry chicks depends on the chromatic dimension in which colors vary. Chicks were trained to discriminate colors separated by equal distances on a hue or a saturation dimension, in a receptor-based color space. Generalization tests then compared the birds' responses to familiar and novel colors lying on the same chromatic dimension. To characterize generalization we introduce a Bayesian model that extracts a threshold color distance beyond which chicks treat novel colors as significantly different from the rewarded training color. These thresholds were the same for generalization along the hue and saturation dimensions, demonstrating that responses to novel colors depend on similarity and expected variation of color signals but are independent of the chromatic dimension.

Indoor lighting quality: Effects of different wall colours

This paper reports the results of measurements performed in a test room to investigate the impact of using different wall colours and light scenes on indoor lighting quality. Eye level spectral irradiances were measured for a user located inside the room and seated at a desk. These measurements allow the use of the Irradiance Toolbox, which makes it possible to calculate equivalent illuminances for the photopigments in the human eye. Moreover, the CIECAM02 colour appearance model was used to investigate the variations in hue and chroma values of the different wall colours when changing the light scene. The results demonstrate that there are significant variations in eye level spectral irradiance distributions, photoreceptor stimulation and hue and chroma values with different combinations of wall colours and light scenes.

Production Speed and its Influence on Hue Variation on Tiles Decoration Based on Silicon Cylinder Technique Laser Engraving Method

On the ceramic tile production there are plenty of different possible origins inside the process that can lead to hue variation. Many tile producers use to increase the speed of production and the machinery industry follow this tendency to please their costumers; and so this scenario creates a need of a study on the influence of the speed production on hue variation. In this work this influence was verified using the silicon laser engraving method, one of the most methods worldwide used.

Clinical and Spectrophotometric Evaluation of LED and Laser Activated Teeth Bleaching.

Background:Auxiliary power sources (LED and laser) are used in in-office teeth bleaching techniques to accelerate the redox reaction of the whitening gel to increase ease of use, to improve comfort and safety, and to decrease the procedure time.Objective:The aim this study is to evaluate the efficiency of the teeth whitening procedures performed with hydrogen peroxide and carbamide peroxide, LED or Laser activated.Method:18 patients, affected by exogenous dyschromia, were treated with a bleaching agent composed by 35% hydrogen peroxide and 10% carbamide peroxide. They were divided into two groups: in the first group the bleaching agent was activated by a LED lamp; in the second group it was activated by a Laser diode lamp. Both groups were subjected to 3 bleaching cycle of 15’ each. The chromatic evaluations were performed before and after one week from the treatment, using a chromatic scale and a spectrophotometer. The mean value of pre, post bleaching and follow-up were analyzed using a T-test, with results statistically significant for P<0,05.Results:Results showed that the variations in brightness, chroma and hue are significantly influenced by the interaction between the whitening agent and the original colour of the teeth. Laser-activation has marginally improved the bleaching effectiveness. All patients treated with laser activation complained an increase in dental sensitivity.Conclusion:The use of laser-activating systems did not improve the efficacy of bleaching.

Synchrotron radiation-based multi-analytical approach for studying underglaze color: The microstructure of Chinese Qinghua blue decors (Ming dynasty)

In this paper, we develop a methodological approach combining macro-X-ray fluorescence and synchrotron radiation-based techniques (μXRF, full-field XANES and μXRD) to determine the composition and microstructure of underglaze decors of Qinghua porcelains (Ming dynasty). Various transition metal elements (Fe, Mn, Co) are present in the blue decoration of these ceramics and the approach proposed allows for establishing the feature of each. Thus it shows that Fe ions are distributed homogeneously over the whole glaze without any significant difference in blue and white parts. They do not play a significant role in the color. In contrast, Co ions exhibit a heterogeneous distribution with CoAl2O4 particles close to the body/glaze interphase. These particles play a key role in the blue color and, the hue variations seem in greater part to link to their density and repartition. Co dispersed in the glassy matrix is also bivalent and mainly in tetragonal coordination, leading also to a blue color. Mn ion distribution is similar to the one of Co but without presenting local high concentrations associated to Mn based particles. Mn affects the darkness of the color and for the sample without CoAl2O4 particle; it is the main color contribution. The presence of CoAl2O4 crystals was confirmed by μXRD, which revealed, in addition, a variation of cell parameters certainly linking to a Co partial substitution.

Usefulness of virtual chromoendoscopy in the evaluation of subtle small bowel ulcerative lesions by endoscopists with no experience in videocapsule.

Background and study aims: In videocapsule endoscopy examination (VCE), subtle variations in mucosal hue or pattern such as those seen in ulcerations can be difficult to detect, depending on the experience of the reader. Our aim was to test whether virtual chromoendoscopy (VC) techniques, designed to enhance the contrast between the lesion and the normal mucosa, could improve the characterization of ulcerative mucosal lesions. Patients and methods: Fifteen trainees or young gastroenterologists with no experience in VCE were randomly assigned to evaluate 250 true ulcerative and 100 false ulcerative, difficult-to-interpret small bowel lesions, initially as white light images (WLI) and then, in a second round, with the addition of one VC setting or again as WLI, labeling them as real lesions or artifacts. Results: On the overall image evaluation, an improvement in lesion characterization was observed by adding any chromoendoscopy setting, especially Blue mode and FICE 1, with increases in accuracy of 13 % [95 %CI 0.8, 25.3] and 7.1 % [95 %CI – 17.0, 31.3], respectively. However, when only false ulcerative images were considered, with the same presets (Blue mode and FICE 1), there was a loss in accuracy of 10.7 % [95 %CI – 10.9, 32.3] and 7.3 % [95 %CI – 1.3, 16.0], respectively. The interobserver agreement was poor for both readings. Conclusions: VC helps beginner VCE readers correctly categorize difficult-to-interpret small bowel mucosal ulcerative lesions. However, false lesions tend to be misinterpreted as true ulcerative with the same presets. Therefore care is advised in using VC especially under poor bowel preparation.