Changes In Hue Research Articles

Biochemical and microbial changes during the storage of minimally processed cantaloupe.

The effect of storage time on pH, titratable acidity, degrees Brix, organic acids, sugars, amino acids, and color of minimally processed cantaloupe melon (Cucumis melo L. var. reticulatus Naud. cv. Mission) was determined at 4 degrees C and 20 degrees C. Changes in most of the biochemical parameters with storage time were relatively slow at the lower temperature. At 20 degrees C, a 17% loss in soluble solids and a 2-fold increase in acidity occurred after 2 days. Organic acid content also increased considerably with time at this temperature as a result of the production of lactic acid. Oxalic, citric, malic, and succinic acids were the organic acids, and glucose, fructose, and sucrose were the sugars present in the freshly cut cantaloupe. Malic acid concentration decreased concurrently with lactic acid production indicating the possible involvement of anaerobic malo-lactic fermentation along with sugar utilization by lactic acid bacteria. The effect of storage on microbial growth was determined at 4, 10, and 20 degrees C. Gram-negative stained rods grew at a slower rate at 4 degrees C and 10 degrees C than the Gram-positive mesophilic bacteria that dominated microorganism growth at 20 degrees C. Eighteen amino acids were identified in fresh cantaloupe: aspartic acid, glutamic acid, asparagine, serine, glutamine, glycine, histidine, arginine, threonine, alanine, proline, tyrosine, valine, methionine, isoleucine, leucine, phenyl alanine, and lysine. The dominant amino acids were aspartic acid, glutamic acid, arginine, and alanine. Total amino acid content decreased rapidly at 20 degrees C, but only a slight decrease occurred at 4 degrees C after prolonged storage. Changes in lightness (L), chroma, and hue at both temperatures indicate the absence of browning reactions. The results indicate the potential use of lactic acid and lactic acid bacteria as quality control markers in minimally processed fruits.

Dye distribution in the dyeing of mixed denier polyester fabrics

Microfibre polyester is sometimes blended with higher denier fibres to achieve good aesthetic effects at lower cost. Two polyester yarns of 1.4 and 0.7 denier were dyed singly and together with a range of depths of CI Disperse Blue 79, and the dye distribution over the course of the dyeings was examined. The uptake is initially greater on the microfibre, but as dyeing is continued the distribution becomes more even, and eventually the same concentration of dye is present on both fibres. Based on the common observation that a given concentration of dye produces a lighter shade on a microfibre, the redistribution of dye during the process causes a continuing shade change even though the bath exhaustion is constant. A mixture of three dyes produced a stable hue on a fabric of 1.0 denier polyester after 20 min at a fixed dyeing temperature, but when dyed on a fabric of 1.0 and 0.5 denier yarns, a change in hue continued for more than 60 min.

A SURVEY OF COMPUTER VISION METHODS FOR LOCATING FRUIT ON TREES

A review of previous studies to automate the location of fruit on trees using computer vision methods wasperformed. The main features of these approaches are described, paying special attention to the sensors and accessoriesutilized for capturing tree images, the image processing strategy used to detect the fruit, and the results obtained in termsof the correct/false detection rates and the ability to detect fruit independent of its maturity stage. The majority of theseworks use CCD cameras to capture the images and use local or shape-based analysis to detect the fruit. Systems usinglocal analysis, like intensity or color pixel classification, allow for rapid detection and were able to detect fruit at specificmaturity stages, i.e., fruit with a color different from the background. However, systems based on shape analysis weremore independent of hue changes, were not limited to detecting fruit with a color different from the color of thebackground; however, their algorithms were more time consuming. The best results obtained indicate that more than 85%of visible fruits are usually detectable, although with CCD sensors there were a number of false detections that in mostcases were above >5%. The approaches using range images and shape analysis were capable of detecting fruit of anycolor, did not generate false alarms, and gave precise information about the fruit three-dimensional position. In spite ofthese promising results, the problem of total fruit occlusion limits the amount of fruit that can be harvested, ranging from40 to 100% of total fruit, depending on fruiting and viewing conditions. This fact seriously affects the feasibility of futureharvesting robots relying on images that do not contain a high percentage of visible fruit. Therefore, new techniques toreduce total occlusion should be studied in order to make the process feasible.

Reflective properties of domestic fowl (Gallus g. domesticus), the fabric of their housing and the characteristics of the light environment in environmentally controlled poultry houses

1. The light intensity and spectral power distribution in 3 broiler and 6 layer houses were sampled and converted to a measure which takes account of the domestic fowl's spectral sensitivity (termed lux corrected). Light intensity was highly variable around the layer houses (mean 33.2, s.d. 37.7 lux (corrected)) and to a lesser extent in the broiler houses (mean 5.2, s.d. 2.2 lux (corrected)). The mean intensities were also very much lower than on a sunny, June day at midday at Silsoe (42,937 lux (corrected)) and of different power distributions. 2. The reflectivity of the plumage of 15 traditional breeds of domestic fowl was surveyed. Most feathers showed a characteristic pattern of reflectivity , increasing either side of a wavelength of λ=400 nm. In 13 breeds the tail and wing feathers were darker than the breast and back feathers. Reflectivity at λ=700 nm was a good predictor of reflectivity at λ=320 nm. Food, bedding, wood and skin all had similar reflectivities to feathers. Metal, plastic and rubber all had more constant reflectivities across the spectrum. 3. The reflectivities of the fresh, feathered carcases of 3 male broilers (Cobb) and 3 layer hens (ISA Brown) were measured. There were small changes in hue and saturation within and between individual carcases, even for the apparently white broiler chickens. 4. Photographs were taken, with and without a UVA-only pass filter, of a broiler cock (Cobb), layer hen (ISA Brown) and cock jungle fowl. No additional patternation was evident in the UVA-only photographs and the jungle fowl lost most of its ornamentation. The texture of bare skin was enhanced in the UVA-only photographs. 5. The implications of these results for poultry behaviour are discussed.

COLOR PARAMETER CHANGES IN BANANA SLICES DURING OSMOTIC DEHYDRATION

ABSTRACT Twenty-seven conditions of osmotic dehydration ( temperature 50, 60 and 70 ° C, pH 6, 7 and 8 and sucrose solution 50, 60 and 70 ° Brix) were applied to banana slices and results of L, hue, chroma and total difference of color were analyzed. Statistical analysis of L, chroma and hue changes in banana slices permitted to select five following treatments: 3 ( 50 ° Brix, temp. 70 ° C and pH 6.0), 10 (60 ° Brix, temp. 50 ° C and pH 6.0), 15 ( 60 ° Brix, temp. 70 ° C and pH 7.0 ), 17 ( 60 ° Brix, temp. 60 ° C and pH 8.0 ) and 25 ( 70 ° Brix, temp. 50 ° C and pH 8.0 ) as the most adequate conditions due to color changes that were not different in comparison to color parameters of raw ripe fruit chips.

Factors affecting the deterioration of the cellulosic fibres in black-dyed New Zealand flax (phormium tenax)

The fibre from New Zealand flax (Phormium tenax) is destabilized by a commonly used traditional black dye, which is an iron/plant polyphenol complex. By characterizing a variety of old and modern samples it has been shown that low pH and high iron content are responsible for the degradation. As degradation proceeds, the hue changes and the extent of degradation—as measured by water and 1% sodium hydroxide solubilities—increases. The fibre has a high proportion of the non-cellulosic xylan polysaccharide and this contributes to the high rate of degradation because it is susceptible to degradation and releases acetic acid. The rate of degradation in accelerated aging tests was increased by raising the relative humidity.

Colour memory matching analysed using different representation spaces

The choice of the representation space is relevant when analysing the results of a colour memory experiment. If we are interested in determining which colours are best or worst remembered using the colour difference between the reference and matching stimuli, we need spaces with a high degree of uniformity. In this paper, the results of a previous experiment with 10 colours, 100 observers and three time gaps have been processed in five representation spaces with different uniformity degrees: CIE , CIE , SVF, Rlab and Llab. For most colours and in all the spaces, reference colours above a particular lightness value are remembered as even lighter, whereas below a certain value they are remembered as darker or equally light. Chroma either increases or suffers no variations. Changes in hue appear to be, in contrast, unsystematic. These results basically agree with the previous literature. CIE , CIE and Rlab spaces yield practically identical results. The best remembered colours are orange and oxide red, and yellow is the worst remembered colour. In the SVF space, the worst remembered colours are blue and yellow, although the results for pink become comparable as the delay increases. Pink is also the worst remembered colour in the Llab space.

The Effect of Year, Cultivar, Location, and Storage Regime on Pecan Kernel Color

The Munsell color system was used to study kernel color differences between four pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars (`Cheyenne', `Choctaw', `Western', and `Wichita') grown at four locations (Tulare, Calif., and Brownwood, Crystal City, and El Paso, Texas) during two seasons (1987 and 1988) and stored under different temperatures (20 to 24 °C and -5 °C). Kernel color changed over time from yellow to red hues and from lighter to darker values, but changed very little in chroma. Initial ratings of each color attribute by cultivar were positively correlated with patterns of change in that attribute over time. Kernels collected in 1987 were more yellow and had greater color saturation than kernels collected in 1988. `Cheyenne' kernels were the most yellow of the cultivars tested and `Wichita' kernels were the most red. `Cheyenne' kernels were lighter than those of any other cultivar. Kernels frozen 6 or 12 months were more red in hue than unfrozen kernels, but could not be distinguished on the basis of value (lightness). Kernels frozen 12 months had reduced chroma compared to those frozen 6 months or unfrozen. Shelled kernels of `Wichita' changed hue more in storage than kernels of other cultivars. Shelled kernels held at 20 to 24 °C became darker and developed red coloration quicker than unshelled pecans. Variation in hue and value accounted for the majority of color difference between cultivars. Changes in hue accounted for the majority of color change over time. Differences among cultivars in value (lightness) were consistent over time.

Constitution and dyeing properties of a 2:2 copper complex azomethine dye

A copper(II) complex azomethine dye with a 2-(2-pyridylmethylene-amino)phenol (PMAP) ligand was prepared and characterized on the basis of IR, UV/VIS, MS, X-ray and elemental analysis. The structure comprised a dinuclear [Cu 2L 2(O 2CMe)] + (L = deprotonated PMAP) cation and the well separated perchlorate anion. Both phenolate residues and the acetate moiety bridged the two copper(II) centers, giving a Cu 2(μ-O) 2(μ-1,3-MeCO 2) core. The possibility of spectrophotometric determination of copper with this ligand was investigated, as was the possibility of wool dyeing with Cu-PMAP, and the stability of the dye-wool bonding at pH 4.5 and 5.5. The color hue changes on the dyeing samples with a ∗, b ∗ coordinates (CIELAB diagram) are given.

Further Studies on Transparent Glaze Fading: Chemical and Appearance Kinetics

The light fading of transparent glazes is described from two perspectives: first in terms of the colorant loss from photochemical reaction, then in terms of the color changes that result from that colorant loss. The authors postulate that if the rate of colorant loss depends only on the amount of light absorbed at the photochemically active wavelengths, then the results of light exposure of dark and pale glazes should be very different. The loss of colorant in highly absorbing glazes should be constant with exposure, but only minor spectral changes that cause slight hue and chroma changes are produced. In paler glazes that absorb less light, colorant loss from light exposure should be slower than for dark glazes, and it should also become progressively slower as colorant is lost. Despite this slower colorant loss in pale glazes, large spectral changes result, giving rise to the large chroma losses and value increases that are the changes normally associated with fading paints. The general trends predicted by this simple model were observed in fading experiments of Pigment Red 66 glazes. Although some discrepancies from the idealized fading behavior were observed, these trends are suggested as a starting point for identifying glaze applications that may be at high risk of light-induced damage and may thus warrant special care or condition monitoring.

Multichannel techniques in color image enhancement and modeling

We present novel multichannel methods in two target research areas. The first area is color image modeling. Multichannel AR models have been developed and applied to color texture segmentation and synthesis. The second area is color image equalization, which is performed on the three RGB channels simultaneously, using the joint PDF. Alternatively, equalization at the HSI domain is performed in order to avoid changes in digital image hue. A parallel algorithm is proposed for color image histogram calculation and equalization.

Properties and application of luster pigments

AbstractIn contrast to conventional pigments, which interact with light by absorption and/or diffuse scattering, effect or luster pigments show optical properties that are due to specular reflection of light by aligned flaky particles. Their main property is goniochromaticity, i.e. the change of lightness and/or color hue with the viewing angle of the observer. The paper describes the different type of luster pigments, their optical properties and applications and manufacturing methods.

Observations on skin colour changes in juvenile lumpsuckers

This study reports on an experimental investigation of colour change in young lumpsuckers Cyclopterus lumpus, employing Munsell colour charts to quantify skin hue, colour value and chroma. Juvenile lumpsuckers can live pelagically close to the sea surface, or can attach to floating seaweed and debris with their suckers. When swimming they adopt a cryptic default light green coloration, with the dorsum being darker than the belly (countershading). This default colour is also seen in complete darkness. When attached to objects they take a colour stimulus from below and to the sides and change colour. They can achieve good colour matches (noticeable in 3 min; complete within 15 min) with substrata that are green‐yellow in colour, especially the brown alga Ascophyllum nodosum. Colour matching is largely dependent upon changes in colour value (i.e. lightness/darkness) produced by melanin dispersal or concentration in the melanophores. Thus, on artificial backgrounds outside the range of achievable hue matching, they still achieve good matchings of colour value. Slight hue changes were recorded (probably reflecting interaction of basic skin colour with melanin dispersal state), but chroma (brightness) variations were negligible. Lumpsucker colour depends upon light intensity, allowing sustained colour matching as weed illumination changes.

Clock recovery and reconstruction of PAL pictures for MPEG coded streams transported over ATM networks

The problem of clock recovery for an MPEG audio/video decoder, when the MPEG stream is transmitted over an ATM network and the decoded signal is to be converted to a PAL/NTSC format, is addressed. The presence of ATM cell delay variation represents a jitter source for the reconstruction of the main presentation reference signals associated with the coded streams. Since the PAL/NTSC synchronization signals are obtained from these signals, care must be taken to avoid visible artifacts in the displayed images, typically hue changes. It is shown that the clock recovery design, based on consumer quality video display requirements, is not more complex than ordinary PLLs used in transmission systems, while the buffer size requirements can be certainly contained within acceptable limits.

The influence of contrast adaptation on color appearance

Most models of color vision assume that signals from the three classes of cone receptor are recoded into only three independent post-receptoral channels: one that encodes luminance and two that encode color. Stimuli that are equated for their effects on two of the channels should be discriminable only to the remaining channel, and are thus assumed to isolate the responses of single channels. We used an asymmetric matching task to examine whether such models can account for changes in color appearance following adaptation to contrast--to temporal variations in luminance and chromaticity around a fixed mean luminance and chromaticity. The experiments extend to suprathreshold color appearance the threshold adaptation paradigm of Krauskopf, Williams and Heeley [(1982) Vision Research, 32, 1123-1131]. Adaptation changes the perceived color of chromatic test stimuli both by reducing their saturation (contrast) and by changing their hue (direction within the equiluminant plane). The saturation losses are largest for test stimuli that lie along the chromatic axis defining the adapting modulation, while the hue changes are rotations away from the adapting direction and toward an orthogonal direction within the S and L-M plane. Similar selective changes in both perceived color and perceived lightness occur following adaptation to stimuli that covary in luminance and chromaticity. The selectivity of the aftereffects for multiple directions within color-luminance space is inconsistent with sensitivity changes in only three independent channels. These aftereffects suggest instead that color appearance depends on channels that can be selectively tuned to any color-luminance direction, and that there are no directions that invariably isolate responses in only a single channel. We use the perceived color changes to examine the spectral sensitivities of the chromatic channels and to estimate the distribution of channels. We also examine how adaptation alters the contrast-response function, how it affects reaction times for luminance and chromatic contrast, the extent to which the aftereffects exhibit interocular transfer, and the way in which the perceived color changes differ from those induced by conventional light adaptation.

811 PB 196 FOLIAR VARIATIONS IN FALL COLOR DEVELOPMENT AMONG FIVE PLANT SPECIES

Variations in the pattern of fall color development in the leaves of Acer rubrum, Acer saccharum, Quercus coccinea, Oxydendrum arboreum and Euonymus alatus were determined. CIELAB coordinates were measured with a Minolta CR-2000b calorimeter at a marked location on 5 tagged leaves from 2 plants of each species. The changes in hue follow similar trends in these species, but the time of onset varies. Onset of red color development increased variability in hue between leaves of the same species. Based on color changes in E. alatus anthocyanin development occurs prior to significant loss of chlorophyll and red coloration remains masked, whereas in A. rubrum anthocyanin development occurs in association with or following the loss of chlorophyll. This results in differences in the pattern of hue and chroma development between these species.

Canopy Position Influences CIELAB Coordinates of Peach Color

Differences in color development between exposed and shaded fruit during the growing season were determined for `Loring' and `Raritan Rose' peach (Prunus persica L. Batsch). The surface color of fruit exposed to sunlight in the upper canopy, and in the shade in the lower canopy, was measured with a tristimulus calorimeter, and L* a* b* values were recorded for each fruit from 17 July through harvest. Color changes (ΔE* ab) during maturation for both cultivars at either canopy position were characterized by large changes in hue (Δ H*ab) and lesser changes in lightness (Δ L*ab) and chroma (Δ C*ab). Upper canopy fruit of both cultivars were redder and darker than the lower canopy fruit initially and at harvest. Flesh firmness for `Loring' and `Raritan Rose' tended to correlate with color change from initial sampling to harvest.

Review Of Colour Terms And Simultaneous Contrast Research For Cartography

Colours that are next to a map colour change its appearance by simultaneous contrast (the term induction is also used to describe the effect). The problem of simultaneous contrast on maps has been described repeatedly in the general literature on colour use in cartography and has been recognized as a confounding variable in cartographic research on colour. This review article clarifies important distinctions between lightness constancy and brightness contrast effects that interfere with the interpretation of the results of previous research. Likewise, induced changes in hue are often described as shifts toward the complement of the surrounding colour but many different definitions of complementarity exist, and these distinctions are described. Review of the induction literature from other disciplines reveals conflicting conclusions based on varied stimulus configurations that do not approximate the complexity of a map. To establish a perceptual structure relevant to the map reading context, induction must be judged under realistic illumination conditions and test colours must be embedded in a matrix of other colours that includes reference whites. Review of past attempts to explain induced changes in colour reveals that the opponent process approach is the most common and promising avenue for modelling induction.

Munsell Colors of Soils Simulated by Mixtures of Goethite and Hematite with Kaolinite

AbstractThe colors and color patterns of soils are widely used to infer other soil properties. It is desirable to understand, at least semiquantitatively, the effect various pigments have on soil color. The purpose of this study was to determine how hematite and goethite pigments influence soil color. We prepared simulated soil mixtures consisting of kaolinite and 2.5, 5, 10, 20, 40, 80, 160, 320, 640, and 1000 g kg−1 of pigment (either a synthetic goethite, one of two synthetic hematites, or a mixture of goethite and hematite). We determined the reflectance spectra of the samples, and calculated their colors in the Munsell system. For hematite and goethite pigments mixed with kaolinite, more than half of the change in hue occurred as the Hm/(Hm+Gt) ratio increased from 0 to 0.25, and hue changed relatively little as the Hm/(Hm+Gt) ratio increased from 0.50 to 1.00. Most of the change in color occurred as pigment content increased from 2.5 to 160 g kg−1. Doubling of pigment content from 160 to 320 g kg−1 had very little impact on the colors of the mixtures, while further increases in pigment content between 320 and 1000 g kg−1 caused some changes in color, but less than for the 2.5 to 160 g kg−1 range. A one unit increase in chroma corresponded approximately to a doubling of pigment content in the series 2.5, 5, 10, 20, 40, 80, 160 g kg−1 for the goethite as well as the hematite pigments studied. For one hematite, hues became progressively redder and changed by more than 5 units of hue as pigment content increased from 0.25 to 160 g kg−1.

SEASONAL VARIABILITY OF TOMATO COLOR THERMAL KINETICS

ABSTRACT Quality management of fresh firuit and vegetables has been limited by the lack of mathematical models to predict quality changes during expected storage life. Regression models developed for prediction of color changes in tomatoes were tested with previously collected data to determine their applicability to different years, cultivars and ripening treatments (ethylene-treated vs. vine-ripened). Large differences in estimated parameter values negated the possibility of applying a single numerical model to all ripening tomatoes, but the analysis indicated that separate models based on the same mathematical formulation but with different-valued parameters were possible for each ripening treatment. Differences in ethylene-treated versus vine-ripened fruit were most apparent in the change of hue over storage time and the change in chroma relative to hue.