Chromatic Analysis Research Articles

Study of various interventions in the façades of a historical building—Methodology proposal, chromatic and material analysis

AbstractVisible spectroscopy, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X‐ray spectroscopy (EDS) in addition to scanning electron microscopy (SEM) have been used for determining the color and chemical composition of the architectural elements of the façades of a historical building, which today is the seat of the Diputación Provincial of Cadiz. It dates from 1770 and was built as Custom Headquarters. It is near the port and is almost encircled by the walls of the city. The determination of the color and chemical composition of the materials that provoke this color and the determination of the layers found in the extracted samples from significant zones allow to define the various interventions over the façade and to localize the time in which they were made. This is possible by comparing with graphical registries and historical documentation. The objective is a study of the color of the different façades that the building has had in order to know the history of the building and to choose materials and colors that should be used in a restoration intervention of this historical building. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 382–390, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.

Separating reflection components based on chromaticity and noise analysis

Many algorithms in computer vision assume diffuse only reflections and deem specular reflections to be outliers. However, in the real world, the presence of specular reflections is inevitable since there are many dielectric inhomogeneous objects which have both diffuse and specular reflections. To resolve this problem, we present a method to separate the two reflection components. The method is principally based on the distribution of specular and diffuse points in a two-dimensional maximum chromaticity-intensity space. We found that, by utilizing the space and known illumination color, the problem of reflection component separation can be simplified into the problem of identifying diffuse maximum chromaticity. To be able to identify the diffuse maximum chromaticity correctly, an analysis of the noise is required since most real images suffer from it. Unlike existing methods, the proposed method can separate the reflection components robustly for any kind of surface roughness and light direction.

Chromatic Consistency Analysis for Object Identification in Noisy Scene

A re-extraction scheme is presented for chromatically complex object in noisy scene. Image features of target objects are described in terms of color sampeles with a palette represented by normalized trichromatic vectors. Within the framework of Euclidean geometry, chromatic consistency is defined and applied to pixelwise matching of oberrved imagery with the palette. 2D expansion of the palette is evaluated for indexing intensity discrepancy due to the object imasges. The chromatic consistency and intensity discrepancy are jointly exploited to re-extract target objects.

Investigation of the antioxidant properties of tomatoes after processing

A study was made of the antioxidant content, activity and colour of two New Zealand commercially grown tomatoes ( Lycopersicon esculentum L . var. Excell and Aranca) cultivated in glasshouses using hydroponic techniques. Excell tomatoes were harvested and stored individually while cultivar Aranca was harvested by cutting the vine, which consisted of a group of eight tomatoes. Both cultivars of tomatoes were stored in the dark for 4 days at 15°C to simulate normal pre-purchase storing conditions. The antioxidant content of the raw tomatoes after 4 days of storage were markedly different while the CIE LAB colour values of the cut inner surfaces of the two cultivars were similar. After 4 days storage, subsamples of each cultivar were either boiled, baked or fried, and analysis of CIE colour, ascorbic acid, total phenolics, lycopene and antioxidant activity (using the ABTS assay) was undertaken. Boiling and baking had a relatively small effect on the ascorbic, total phenolic, lycopene and antioxidant activity of the two cultivars while frying significantly reduced ( P<0.001) the ascorbic, total phenolic and lycopene contents of the two cultivars. Chromatic colour analysis showed that both cultivars became significantly ( P<0.001) darker and less red after cooking by all methods. In a following experiment, the two cultivars of tomatoes were sliced and allowed to soak for 20 min in a mixture of olive oil and white vinegar, or olive oil and white vinegar separately. CIE colour of the two cultivars showed no change after processing but the treatments of oil and vinegar separately and together reduced ( P<0.05) the red component of the colour. Treating the two cultivars of tomatoes with the oil and vinegar mixture resulted in a significant reduction ( P<0.001) in the ascorbic acid, total phenolic and antioxidant activity of the tomatoes. Treatment with oil significantly reduced the amount of lycopene that could be extracted from the tomatoes while treatment with vinegar had no effect.

Colour characteristics of honeys as influenced by pollen grain content: a multivariate study

AbstractA chromatic analysis by tristimulus colorimetry and a pollen analysis (pollen grains contained in each honey sample, considering their volume and geometrical shape) were carried out on 33 Eucalyptus unifloral honeys; the colour of the pollen grains was also considered. Multiple linear regression (MLR) and partial least squares regression (PLSR) were used to establish equations relating the chromatic variables to the pollen data, ie number and morphology of the pollen grains, thus allowing the prediction of the ultimate colour from the botanical characteristics. The results obtained show that lightness (L*) is significantly (p &lt; 0.05) related to the pollen type Olea europaea; on the other hand, the variable that better relates to the chroma $(C_{ab}^{*})$ is the Zea mays pollen type. Copyright © 2004 Society of Chemical Industry

Differential algebraic method for arbitrary order curvilinear-axis combined geometric–chromatic aberration analysis

The principle of differential algebra is applied to analyse and calculate arbitrary order curvilinear-axis combined geometric–chromatic aberrations of electron optical systems. Expressions of differential algebraic form of high order combined aberrations are obtained and arbitrary order combined aberrations can be calculated numerically. As an example, a typical wide electron beam focusing system with curved optical axes named magnetic immersion lens has been studied. All the second-order and third-order combined geometric–chromatic aberrations of the lens have been calculated, and the patterns of the corresponding geometric aberrations and combined aberrations have been given as well.

Estudio comparativo del impacto de la dieta frente a pravastatina en los centros de análisis cromático del área 19 de Brodman, mediante el análisis computarizado cromático (Estudio CARDIOCOLOUR)

Hypercholesterolemia causes important neurodegenerative changes in the cerebral cortex, which are manifested by defects in the color perception by the neurons of Brodman area 19. Extensive interventional epidemiological data from both primary and secondary-prevention clinical trials indicate that cardiac ischemic events decrease when total cholesterol or LDL-C is reduced. Our goal was to elucidate the effects of diet compared with a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (pravastatin) on color perception using computerized chromatic analysis (CCA) and plasma cholesterol levels. We studied 191 normotensive patients (133 men and 58 women) with pre-study plasma cholesterol levels in excess of 200 mg/dl. Seventy of these patients were treated with the American Heart Association Step II diet for six months. The remaining 121 were treated with pravastatin, 61 patients with 10 mg and 60 patients with 40 mg. They were examined by CCA after excluding any general or ophthalmological pathology. Chromatic vision recovered by 23% with diet, 38% with pravastatin 10 mg and 92% with pravastatin 40 mg. This study confirmed a strong association between therapeutic intervention with either diet or pravastatin and improved color vision.

An Infrared and X-ray Absorption Study of the Equilibria and Structures of Chromate, Bichromate, and Dichromate in Ambient Aqueous Solutions

The structure and equilibrium of chromate (CrO42-), bichromate (HCrO4-), and dichromate (Cr2O72-) in ambient aqueous solutions was investigated by both IR and X-ray absorption fine structure (XAFS) spectroscopy. The individual IR bands for each of these species have been identified, and quantitative analysis of the IR bands was used to examine the chemical equilibria. A dilution study at a constant, low solution pH revealed the speciation change from dichromate dominance at high total chrome concentration to bichromate dominance at low total chrome concentration, thereby unequivocally confirming the existence of the bichromate species. The equilibrium constants, obtained from the quantitative analysis of the IR data, agree well with previously reported values. The quantitative IR analysis also revealed that the asymmetric νas(CrO3) stretching frequency is virtually coincident for the bi- and dichromate. The complete structural analysis of chromate, bichromate, and dichromate was obtained from an XAFS study of chromate solutions of varying total chrome concentration. The XAFS results confirm the νas(CrO3) IR band assignment for both the bi- and dichromate species by showing that the first-shell structure around the central chrome atom is nearly identical for the bi-and dichromate molecular ions. Within experimental uncertainty, the Cr−O bond distance that is associated with the νas(CrO3) vibrational mode was found to be identical for the bi- and dichromate structures.

Chromatic analysis of autofluorescence emitted from squamous cell carcinomas arising in the oral cavity: a preliminary study

Chromatic analysis was carried out to characterize the color quality of autofluorescence emitted from oral squamous cell carcinomas (SCC) and to objectively compare autofluorescence among various tissues. The following specimens were studied: 33 SCC, 3 epithelial dysplasias, 39 benign lesions, 31 dorsa of the tongue and 18 dental plaques. Autofluorescence depicted on fluorescence photographs was measured with a chroma meter. Chromatic values of autofluorescence differed significantly between SCC and non-cancerous tissues and between different stages of SCC. Autofluorescence of SCC tended to shift from orange to reddish orange with advancement of stage. These results suggest that autofluorescence of oral SCC chromatically differs from that of other tissues and depends on the stage of cancer.

Chromatic analysis of autofluorescence emitted from squamous cell carcinomas arising in the oral cavity: a preliminary study

Chromatic analysis of autofluorescence emitted from squamous cell carcinomas arising in the oral cavity: a preliminary study

Chromatic modulation based acoustic analysis technique for in-process monitoring of laser materials processing

The analysis of acoustic waves produced during laser materials processing is widely carried out for characterizing, monitoring, and controlling the process. Traditional methods used in analyzing the acoustic data such as rms signal strength and variation analysis, frequency spectrum analysis are based on signal intensity modulation which offers the advantage of inherent simplicity. However, these basic intensity monitoring systems tend to be sensitive to spurious changes in intensity resulting from variations in the various electrical components within the system and the noise of the industrial environment. In addition, it is known that the acoustic intensity is dependent on the distance and observation angle between its source and acoustic sensor. In this article, a type of acoustic analyzing method based on chromatic modulation is presented. Chromatic modulation offers not only much more acoustic information, precise distinction of the ambiguous signals, and robust monitoring in the laser processing system, but it could also make control of the laser process easier by simple chromatic output factors. It is also shown in this article how a chromatic modulation technique may be utilized as an acoustic analysis method to monitor the laser cleaning process. Consequently, it was found that the chromatic acoustic analysis method could be successfully applied for surface monitoring in the laser cleaning process and could provide correct monitoring information in spite of sensor stand-off variation.

大村湾を対象としたＣＣＤカメラによる水色の感度特性と水質モデル作成

The experimental paper on a digital camera has been published by us in the Proceedings of Civil Engineering in the Ocean, 1994. In published paper, Standard CIE chromaticity analyses were applied to the measurement of upwelling irradiance spectra expressed as transparency and suspended solid amounts using the digital camera and satellite (Landsat-5/TM) data.In this paper, the authors make the model of water quality in the Omura bay using digital camera. And also, proposed CIE chromaticity was used to make water quality model. The transparency model of correction mode was analyzed the correlation coefficient of 0.81. Result using single band model was compared to the result from multi band model. Limitations of each model are discussed using proposed model for water quality of the Omura bay, Nagasaki Prefecture, Japan.

Extraction of information from acoustic vibration signals using Gabor transform type devices

A technique for interpreting acoustic signals is presented based upon the use of Gabor type devices. This interpretation technique processes the information acquired from vibration sensors and presents the information as three time-varying parameters which represent the dominant signal frequency, the nominal breadth of the frequency content of the signal and its effective energy content. The technique is an extension of the chromatic analysis used successfully in the optical domain. The information produced by this analysis proves to be more convenient for defining a signal than that yielded by the conventional Fourier transform approach. By way of an example, the Gabor transform based technique is applied to the monitoring of acoustic signals generated by a high-voltage circuit breaker (as used on power transmission networks). Results are presented which indicate that the technique is capable of quantifying trends in complicated time-varying acoustical signals.

Chromatic Image Analysis for Cotton Trash and Color Measurements

The U.S. cotton classification system has been undergoing significant changes, moving from human classing to the use of precise instruments. Along with this trend, the current research is an effort to develop a new computer vision system to measure detailed trash and color attributes of raw cotton. The system primarily consists of a color ccd camera, xenon flash light, and customized software. In this paper, we introduce a new trash and spot identification method, multidimension thresholding, and the methods for characterizing size, spatial density, shape, and color of trash and spots present in cotton samples. We report on the trash and color measurements of twelve cotton samples, including statistical data and distribution curves, and we compare the results from this system with those from other instruments such as the Spinlab and Motion Control hvi machines and the Minolta Chroma Meter CR-210. Finally, we investigate the influence of trash and spots on cotton color values.

An XPS study of the adsorption of chromate on goethite ( α-FeOOH)

The adsorption behavior of inorganic oxyanions on soil minerals is an important factor in the transport of subsurface environmental pollutants. We have studied the adsorption of chromate (CrO 4 2−) from aqueous solution on the surface of the mineral goethite ( α-FeOOH) as a function of pH and adsorbate concentration in 0.05 M NaNO 3 solution. Results obtained from the dried surface by X-ray photoelectron spectroscopy (XPS) are in good agreement with data from spectrophotometric analysis of chromate remaining in the supernatant liquid. Chromate adsorption increases with decreasing pH of the solution and eventually reaches a maximum at pH 6.5. The chromium XPS signal indicates that initially a small amount of chromium adsorbs in the +3 oxidation state via a redox reaction, but that the large majority of chromium remains in the +6 oxidation state.

Modelling the Radiometric Color of Inland Waters: Implications to a) Remote Sensing and b) Limnological Color Scales

Utilizing a bio-optical model previously developed for Lake Ontario, the responsiveness of chromaticity coordinates (X, Y, Z), dominant wavelength (λ dom), and associated spectral purity (p) to the abundance of color-producing agents (CPA) residing within the Lake Ladoga water column was determined. CPA considered were phytoplankton (chl), suspended minerals (sm), and dissolved organic carbon (doc). Waters that contain simultaneously low concentrations of chl, sm, and doc are shown to appear blue to turquoise in color (472–500 nm). Highly turbid waters (i.e., waters containing high concentrations of chl and/or sm) with low concentrations of doc are shown to display colors ranging from green to brown (> 500 nm). Waters with large concentrations of doc, irrespective of turbidity, are shown to be invariably brownish (560–570 nm). With increasing CPA content, X, Y, and Z (and, consequently, λ dom) asymptotically approach constant limit values. An “end-point” dominant wavelength at about 572 nm appears to be intrinsically characteristic of all natural waters. It is shown that when one or more CPA exceeds a critical concentration, the spectral purity p asymptotically approaches values in the range 0.35 to 0.45 for all waters (exceptive of those containing solely chl in the restricted concentration range < 0.5 μg/L). Optical distinctiveness, particularly with respect to indigenous doc, of natural waters, while impacting the spectral purity of the “end-point” radiometric color, does not produce a comparable impact on the “end-point” color itself. This work reinforces the restrictive application of chromaticity analyses to the remote sensing of binary aquatic systems comprised of water plus one CPA. It also illustrates that neither panchromatic nor two-channel ratio images can provide unambiguous inference of water quality parameters. Correspondence between radiometric water color descriptors (X, Y, Z, λ dom, and p) and water color scales traditionally used in limnology is established, illustrating that the platinum-cobalt scale would be most appropriate for assessing waters that were radiometrically yellow, provided that the yellow hue were not invariably attributed to doc.

Computerized chromatic visual field analysis in M.S.

Computerized chromatic visual field analysis in M.S.

Satellite remote sensing of waste water reservoirs

Abstract SPOT multi-spectral images of nearly 100 water reservoirs were analysed. The image analysis was supported by ground measurements which included water sampling and detailed laboratory analysis of the water constituents and concentration. The analysed reservoirs covered a wide range, from open drinking water reservoirs to polluted hypertrophic ones. Classification of reservoirs by their water quality is achieved by the study of the spectral distribution of the reflected solar radiation, taking into account the atmospheric effects. The techniques included chromatic coordinates analysis and principal component analysis. An optical model of the volume reflectance of the water body was constructed, based on the radiative transfer equation which includes the scattering properties of the main water constituents. Numerical simulations, based on the model, support the experimental findings regarding the reservoir c1assilication according to water quality and composition.

Separation of chromate and tungstate by reversed-phase high-performance chromatography using rutin as chelating reagent

Rutin was used as a chelating reagent to form ternary complexes with metal ions and hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide, CTAB). The retention behaviour of ternary complexes of Cr(VI) and W(VI) on a Nucleosil C 18 column were examined. For chromatographic analysis the sample solution had to be changed because these ternary complexes did not give any peaks in aqueous mediu. A solid-phase extraction step with polyethylene as sorbent and methanol as eluent was introduced. Cr(VI) and W(VI) complexes in methanolic medium gave sharp peaks in the chromatogram and were separated from each other and other metal ions by using a mobile phase of 42.5% (v/v) tetrahydrofuran containing 0.003 M CTAB. The method was applied to the analysis of chromate in geological samples.

A Monitoring of Water Quality in Omura Bay Using a CCD Color Sensor

The experimental paper on a digital camera has been published by us in the Proceedings of Civil Engineering in the Ocean, 1994. In this paper, Standard CIE chromaticity analyses are applied to the mesurement of upwelling irradiance spectra expressed as transparency and suspended solid amounts using the digital camera and satellite (LANDSAT-5/TM) data.The results of these analyses serve as a basis for discussion of several problems (high and low altitude remote sensing techniques) in the application of chromaticity to water quality prediction.