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PubMed2006

Significance of a basal melanin layer to production of non-iridescent structural plumage color: evidence from an amelanotic Steller's jay (Cyanocitta stelleri).

Non-iridescent structural plumage color is typically produced by coherent scattering of light within a matrix of keratin and air (a ;spongy layer') in feather barbs. It remains unclear what role, if any, the basal melanin layer underlying this spongy layer plays in the production of coloration. Amelanism in birds with structural color is a ;natural experiment' in which melanin pigmentation is lost, allowing us to identify the effects of the loss of melanin on structural color production. Here we use full-spectrum spectrometry, transmission electron microscopy and Fourier analysis to compare the color and nanostructure of an amelanotic Steller's jay (Cyanocitta stelleri Gmelin) feather with a normal blue Steller's jay feather. As a control, we also examined a white domestic chicken (Gallus gallus Linnaeus) feather. The pale amelanotic jay feather had a broad reflectance curve with a blue/green peak, while the typical blue feather had a typical distinct bell-shaped blue curve with a UV/violet peak. The white chicken feather had a typical white reflectance curve with no discrete peaks. Electron microscopy revealed that both the amelanotic and blue feather barbs contained well-formed spongy layers that were of the correct size and arrangement to produce their measured peak reflectance values, whereas the chicken feather had no spongy layer. The washed-out color of the amelanotic jay feather was thus most probably caused by the loss of the basal melanin layer, suggesting that melanin functions to absorb incoherently scattered white light from the feather barb thereby increasing the purity of the color produced by the spongy layer.

Animals↗

PubMed2003

Phase-only filtering on the three-dimensional Fourier spectrum of color images.

We propose what is to our knowledge a novel technique for filtering a two-dimensional multichannel color image based on its interpretation as a three-dimensional (3D) signal and the application of a 3D Fourier transform. The color image is considered to have the two usual spatial coordinates with the color distribution as the third dimension of the signal. This approach permits the 3D generalization of the usual phase-only filter and phase correlation, and color pattern recognition can be performed by means of a 3D correlation. We analyze two cases: whitening only along the color Fourier spectrum and whitening the whole 3D Fourier spectrum. We study the transformation induced in the color content of the image by the whitening of the color Fourier spectrum and how it affects the correlation distribution. In particular it is demonstrated that the whitening of the 3D Fourier spectrum improves the recognition performance of the correlation.

Journal Article↗

PubMed2006

Three-color mixing for classifying agricultural products for safety and quality.

A three-color mixing application for food safety inspection is presented. It is shown that the chromaticness of the visual signal resulting from the three-color mixing achieved through our device is directly related to the three-band ratio of light intensity at three selected wavebands. An optical visual device using three-color mixing to implement the three-band ratio criterion is presented. Inspection through human vision assisted by an optical device that implements the three-band ratio criterion would offer flexibility and significant cost savings as compared to inspection with a multispectral machine vision system that implements the same criterion. Example applications of this optical three-color mixing technique are given for the inspection of chicken carcasses with various diseases and for apples with fecal contamination. With proper selection of the three narrow wavebands, discrimination by chromaticness that has a direct relation with the three-band ratio can work very well. In particular, compared with the previously presented two-color mixing application, the conditions of chicken carcasses were more easily identified using the three-color mixing application. The novel three-color mixing technique for visual inspection can be implemented on visual devices for a variety of applications, ranging from target detection to food safety inspection.

Agriculture↗

PubMed2004

Corresponding-pair procedure: a new approach to simulation of dichromatic color perception.

The dichromatic color appearance of a chromatic stimulus T can be described if a stimulus S is found that verifies that a normal observer experiences the same sensation viewing S as a dichromat viewing T. If dichromatic and normal versions of the same color vision model are available, S can be computed by applying the inverse of the normal model to the descriptors of T obtained with the dichromatic model. We give analytical form to this algorithm, which we call the corresponding-pair procedure. The analytical form highlights the requisites that a color vision model must verify for this procedure to be used. To show the capabilities of the method, we apply the algorithm to different color vision models that verify such requisites. This algorithm avoids the need to introduce empirical information alien to the color model used, as was the case with previous methods. The relative simplicity of the procedure and its generality makes the prediction of dichromatic color appearance an additional test of the validity of color vision models.

Journal Article↗

PubMed2004

Accurate color synthesis of three-dimensional objects in an image.

Our study deals with color synthesis of a three-dimensional object in an image; i.e., given a single image, a target color can be accurately mapped onto the object such that the color appearance of the synthesized object closely resembles that of the actual one. As it is almost impossible to acquire the complete geometric description of the surfaces of an object in an image, this study attempted to recover the implicit description of geometry for the color synthesis. The description was obtained from either a series of spectral reflectances or the RGB signals at different surface positions on the basis of the dichromatic reflection model. The experimental results showed that this implicit image-based representation is related to the object geometry and is sufficient for accurate color synthesis of three-dimensional objects in an image. The method established is applicable to the color synthesis of both rigid and deformable objects and should contribute to color fidelity in virtual design, manufacturing, and retailing.

Journal Article↗

PubMed2004

Study of color variation in the solitary ascidian Halocynthia roretzi, collected in the Inland Sea of Japan.

In the vicinity of Yashiro Island in the Inland Sea of Japan, the solitary ascidian (tunicate) Halocynthia roretzi with tunics of various colors were collected. Samples of these animals were sorted into three groups on the basis of visual observation of tunic color. The red group includes animals with dark-red, light-red, or orange tunics. The pink group includes animals with tunic colors ranging between red and white. The white group includes only animals with completely white tunics. Animals in the white group lacked color internally, with the exception of the hepatopancreas and the gonads in breeding season; the epidermis and gill basket were white. In contrast, animals of both the red group and the pink group were colored internally, with red-orange epidermis and yellow gill basket. Alloreactivity was tested by mixed-hemocyte incubation between different animals belonging to the same color group and between animals belonging to different color groups. Alloreactivity between animals of the white group was 56.3%, between animals of the pink group was 60.0%, and between animals of the red group was 69.3%. The relatively high frequency of compatible combinations among the white animals is discussed.

Animals↗

PubMed1992

Physiological responses to illuminance and color temperature of lighting.

The present study was designed to examine the effects of illuminance and color temperature of room lighting. Four male students volunteered as subjects. Each of them performed a calculation task for 95 minutes under nine different lighting environments consisting of a combination of three levels of illuminance (320lx, 1000lx and 2000lx) and three levels of color temperature (3000 degrees K, 5000 degrees K and 7500 degrees K). Three types of fluorescent lamps were used as a light source to vary the color temperature. Blood pressure, critical flicker frequency (CFF) and accommodation time of eye movements were measured every 30 minutes during the task. The accommodation time was significantly influenced by the illuminance level and both the relaxation time and contraction time were prolonged under 2000lx. The diastolic blood pressure was significantly affected by the color temperature level and increased under 7500 degrees K. As for the CFF, the interaction between illuminance and color temperature was significant. These results mean that not only the illuminance but also color temperature produces physiological effects. The present study may be the first to recognize the effect of color temperature on the blood pressure.

Accommodation, Ocular↗

PubMed1989

Budd-Chiari syndrome: the results of duplex and color Doppler imaging.

This study was designed to evaluate duplex and color-flow Doppler imaging as potential noninvasive methods of diagnosing patients with Budd-Chiari syndrome and following them after surgery. Five patients with confirmed hepatic venoocclusive disease were imaged. All five underwent duplex Doppler examinations; three were also evaluated with color-flow Doppler. The hepatic vasculature was examined in all five patients; decompressive mesoatrial shunts were present and were evaluated in four of the five patients. Color-flow Doppler precisely defined intrahepatic, portal, and inferior vena caval circulatory dynamics. Correlation with angiography was excellent. In the two patients in whom hepatic vasculature was evaluated with duplex Doppler alone, the results were less impressive. Intrahepatic flow abnormalities were identified, but the sites of occlusion were not determined convincingly. Signals transmitted from the heart and the inability to visualize the hepatic veins made duplex Doppler evaluation problematic. Duplex Doppler was able to define patency and the direction of flow in the portal vein and inferior vena cava. Our results suggest that color-flow Doppler is an excellent technique for the initial evaluation of patients suspected of having Budd-Chiari syndrome. In the evaluation of decompressive mesoatrial shunts, color-flow Doppler produced dramatic images. However, both duplex and color-flow Doppler were highly accurate in determining the patency of decompressive shunts. Either duplex or color-flow Doppler may be used as the primary imaging procedure to determine shunt patency.

Adult↗

PubMed1989

Color-flow Doppler and conventional duplex scanning of the carotid bifurcation: prospective, double-blind, correlative study.

Color-flow Doppler is a useful adjunct in duplex sonography of peripheral vessels. This study was undertaken to see if color-flow Doppler could give semiquantitative information about the degree of stenosis at the origin of the internal carotid artery. The factors evaluated on color flow are the width of the lumen as estimated from the color-flow image relative to the width of the vessel, the degree of turbulence (evidenced by the mosaic pattern), and the pulse-repetition frequency necessary to prevent aliasing. A double-blind comparison with conventional duplex scanning in 146 carotid bifurcations in 74 patients was carried out. In 91%, the color-flow assessment was in complete agreement with the duplex assessment. In the remaining 9%, the color flow differed from the duplex by only one stenosis group, and the distributions of over- and under-estimation were equal. These results showed comparable assessment of the degree of stenosis with conventional duplex and color Doppler technology.

Adult↗

PubMed1989

Stenosis of the internal carotid artery: assessment using color Doppler imaging compared with angiography.

The percentage of diameter stenosis of the internal carotid artery was estimated directly from color Doppler images obtained in both longitudinal and transverse planes and compared with the results of digital subtraction angiography in 49 patients (95 carotid arteries). Peak systolic velocity measurements were obtained by placing the sample volume in the highest-velocity flow stream with the angle-correction cursor parallel to the color-encoded lumen. Arterial stenoses were categorized on a grade 1-5 scale: 1 = 0-15%, 2 = 16-49%, 3 = 50-75%, 4 = 76-99%, and 5 = occlusion. Percent diameter stenosis could not be determined in 12 color Doppler flow imaging studies (13%) due to calcified plaque. Of the remaining 83 arteries evaluated by both techniques, the respective categories by color Doppler flow imaging/angiography were grade 1 (16/26), grade 2 (25/24), grade 3 (30/19), grade 4 (5/8), and grade 5 (7/6). Percent diameter stenosis determined by color Doppler flow imaging was greater than by angiography in 25% and less than by angiography in 4%. Peak systolic velocity measurements did not separate the hemodynamically insignificant (less than 50% diameter stenosis) grade 1 and grade 2 lesions, but were in agreement in 86% of grades 3-5 stenotic categories, as determined by measurements from the color Doppler flow image. A direct measurement of percent diameter stenosis from the color Doppler flow image was possible in 87% of cases. Peak systolic velocity provided correlative diagnostic information when assessing hemodynamically significant lesions.

Angiography↗

PubMed1991

Arteriovenous malformations of the kidneys: diagnosis and follow-up with color Doppler sonography in six patients.

We performed color Doppler sonography in six patients with arteriovenous malformations of the kidneys. The diagnosis was established by angiography in all patients. Color Doppler sonograms were obtained at a large Doppler frequency-shift range (55 cm/sec of maximal average flow velocity at zero Doppler angle) to depict high-velocity blood flow in the malformation. In all patients, the malformations were seen as focal areas of flow, portrayed as a mixing of lighter colors. These were reflected by a rapid flow rate and marked tortuosity of the vessels. The sonograms showed a small peripheral malformation that was indistinct on selective renal angiography. However, flow in normal vessels grouped in the hilum obscured lighter-color flow of a small central malformation. In three patients who had total or partial ablation of the malformations with alcohol, follow-up color Doppler sonograms showed that the focal areas of flow, represented as mixing of lighter colors, disappeared or became smaller. This study shows that color Doppler sonography is a useful noninvasive procedure for diagnosing arteriovenous malformations of the kidney.

Adult↗

PubMed1992

The normal and abnormal scrotum in children: evaluation with color Doppler sonography.

The use of color Doppler sonography to evaluate the symptomatic testes in children with scrotal pain or swelling was prospectively studied with a fourth-generation color sonographic unit with a 7-MHz linear transducer. The 32 patients were 1 day to 18 years old (mean age, 8.6 years). Results were correlated with scintigraphic findings in 23 patients, with the final diagnosis established by surgery in 12 patients, and with clinical follow-up in all patients. Eight cases of testicular torsion, including two of acute torsion and six of late torsion, were correctly detected by color Doppler sonography and confirmed surgically. In the remaining patients, perfusion of the testis was correctly detected by color Doppler examination. The final diagnoses in these patients included torsion of the appendix testis (15 patients), epididymitis (five patients), epididymo-orchitis (one patient), yolk sac tumor of the testis (one patient), hydrocele (one patient), and local reaction to an insect bite (one patient). The ability to detect blood flow in the normal contralateral testis was also evaluated in 28 patients. Blood flow was demonstrated in normal testes larger than 1 cm3. Detection of flow in the very small normal prepubertal testis was often difficult, and no flow was identified in one testis. Flow was identified in central arteries in only six of 13 testes smaller than 1 cm3. We conclude that color Doppler sonography is helpful in the initial evaluation of pediatric testes, providing accurate evaluation of the involved hemi-scrotum in our patients and also providing the benefit of both structural and flow information. Until our sensitivity to low-velocity flow improves, we would not suggest the exclusive use of color Doppler sonography in the evaluation of testicular perfusion in the prepubertal patient. We advocate the addition of testicular scintigraphy to corroborate the presence of testicular perfusion when flow in intratesticular arteries cannot be established with certainty by color Doppler sonography.

Adolescent↗

PubMed1993

Flow characteristics of hepatic tumors at color Doppler sonography: correlation with arteriographic findings.

OBJECTIVE: We studied benign and malignant hepatic tumors with color Doppler sonography and arteriography in order to correlate color Doppler flow characteristics with tumor hemodynamics (vascularity, arteriovenous shunting, and portal vein involvement) shown by arteriography. We also evaluated the usefulness of color Doppler flow characteristics in discriminating between tumor types. SUBJECTS AND METHODS: We performed color Doppler sonography and hepatic arteriography in 58 patients with 72 hepatic lesions larger than 2.0 cm in diameter. Differences in pulsatile flow (peritumoral or intratumoral) and the highest systolic peak flow velocities reached were evaluated on color Doppler sonograms and compared with arteriographic findings. RESULTS: Color flow sonograms were obtained in 43 of 45 hepatocellular carcinomas, 15 of 16 cholangiocellular carcinomas or hepatic metastases, and six of 11 hemangiomas. Mixed peritumoral and intratumoral pulsatile flow was shown by arteriography in highly vascular tumors. The mean peak systolic flow velocity seen in hepatocellular carcinomas (0.52 m/sec) significantly exceeded the velocity seen in hemangiomas (0.16 m/sec), but not the velocity seen in other malignant hepatic tumors (0.51 m/sec). Six hepatocellular carcinomas, one cholangiocellular carcinoma, and two hepatic metastases with peak systolic flow velocities greater than 0.80 m/sec were each proved arteriographically to have arteriovenous shunting or portal vein involvement. CONCLUSION: Color Doppler sonography was useful for evaluating hepatic tumor hemodynamics as seen at arteriography, and peak systolic velocity may be useful in differentiating malignant hepatic tumors from hemangiomas.

Adult↗

PubMed2005

Effect of calcium chloride, zinc chloride, and water infusion on metmyoglobin reducing activity and fresh lamb color.

Calcium chloride (CaCl2), zinc chloride (ZnCl2), or water infusions were used to investigate the biochemical factors that affect fresh lamb color, and to examine the role of metmyoglobin-reducing activity in regulating this important quality attribute. Immediately after exsanguination, lamb carcasses (n = 6 per treatment) were infused (10% of BW) with 0.3 M CaCl2, 0.05 M ZnCl2, or water via a catheter inserted into the left carotid artery. The right LM was excised at 24-h postmortem and divided into two halves. The caudal portion was cut into 2.5-cm-thick chops and displayed for 6 d under 1,076 lx of white fluorescent lighting at 2 degrees C, whereas the cranial half was vacuum-packaged and stored at 2 degrees C for 3 wk before retail display. Objective color measurements and samples for biochemical analysis were taken at 0, 1, 3, and 6 d of display. In infused carcasses, pH decline was more rapid (P < 0.05) than in untreated controls, and it was greatest for CaCl2-infused carcasses. Calcium chloride-infused carcasses had lower (P < 0.01) NAD and higher (P < 0.001) NADPH concentrations than water- and ZnCl2-infused or untreated control carcasses. The negative effects of calcium infusion on fresh lamb color, higher (P < 0.01) metmyoglobin accumulation rate, and lower (P < 0.01) L*, a*, and b* color measurements could be explained by the lower amounts of unbound water (P < 0.01), shorter sarcomere length (P < 0.01), lower NAD concentrations (P < 0.01), and higher lipid peroxidation (P < 0.01). Zinc and water-infusions produced less (P < 0.01) lipid oxidation and improved the color and color stability of fresh lamb (P < 0.001). Rate of lipid oxidation in LM chops was greater (P < 0.01) after 3 wk of vacuum-packaged storage than 24-h postmortem. Metmyoglobin-reducing activities (sarcoplasmic and myofibrillar) were decreased in response to infusion treatments (P < 0.001), and ZnCl2 infusion resulted in the lowest metmyoglobin-reducing activities (P < 0.001). A significant association between the myofibrillar metmyoglobin-reducing activity and lipid peroxidation was observed, but metmyoglobin-reducing activities were not associated with any improvement in lamb color. Strategies to increase the antioxidant levels in lamb are very important to improve lamb quality, especially during vacuum-packaging storage.

Animals↗

PubMed1992

Color Doppler sonography in the evaluation of the adult acute scrotum.

Color Doppler sonography (CDS) was used to evaluate 35 adult males with acute scrotal discomfort. Correlative nuclear scintigraphy was performed in 15 patients. Surgical correlation was available in 10 patients with clinical follow-up in the remaining 25. The complete absence of intratesticular color flow was used as our criterion for testicular ischemia. This was found to be 100% sensitive and 100% specific in 8 patients with surgically confirmed testicular ischemia. Spontaneous detorsion was noted in one patient with hyperemia demonstrated by color imaging. Increased color flow was found in 20 patients with the clinical impression of scrotal inflammation. Nuclear scintigraphy and color Doppler imaging had 100% agreement in 15 patients. Color Doppler sonography is a useful and highly accurate diagnostic method in the evaluation of patients with the acute scrotal syndrome. Color flow imaging is comparable to nuclear scintigraphy in the diagnosis of testicular ischemia.

Acute Disease↗

PubMed1999

Quantitative characterization and study of the relationship between constitutive-facultative skin color and phototype in Caucasians.

In this study constitutive and facultative colorimetric values were quantified to determine the physiologic changes in Caucasian skin color and to define the correlation between skin color and phototype assessed according to the Fitzpatrick method. Our population consisted of 401 subjects ranging in age from 24 to 28 years with similar life styles. Skin color was measured with a Minolta CR-200 colorimeter on the upper medial quarter of the buttock (constitutive color) and on the cheek (facultative color). Advanced multivariate statistical analysis allowed differentiation between constitutive and facultative skin color in relation to the phototype to be quantified. Moreover, Kullback divergence showed that the probability of correctly determining a subject's phototype is high when the variables of constitutive and facultative skin color are considered together. This interesting result makes it possible, in the future, to use colorimetric values of exposed and nonexposed skin, together with determination of Fitzpatrick phototype and of other phenotypic characters, to better predict cutaneous sun reactivity.

Adult↗

PubMed1995

Children's color trails.

Color Trails for Children was developed in response to the need for instruments which minimize cultural bias in neuropsychological testing. The test, similar in format to Trail Making, was designed to provide an evaluation of speeded visuomotor tracking while minimizing the influence of language. The present research involves two exploratory studies which examine the relationship between Color Trails for Children and Trail Making, factors that may affect performance times, and discriminant validity. Results indicate that the tests appear to measure the same neuropsychological domains, and administration of Trail Making did not significantly alter performance times on Color Trails. Increasing age and IQ were related to quicker completion time for both tests. Females were found to complete Color Trails 2 and Trail Making Part B more quickly than males in this sample. Comparison between children diagnosed with learning disabilities, attention deficits, or mild neurological conditions and a preliminary standardization sample supported the discriminant validity of Color Traits to distinguish between normal controls and children with altered neuropsychological functioning. Comparison between clinical conditions indicated that Color Trails 2 was particularly sensitive in discriminating among the groups. Although further research is needed, results suggest that Color Trails has the potential to be an effective research and clinical tool in child neuropsychological assessment.

Journal Article↗

PubMed1998

[A study of color matching of maxillofacial prosthesis]

OBJECTIVE:The color difference between the patient's facial prosthesis and the surrounding skin have long puzzled both of dentist and patient.The purpose of the study was to introduce spectrophotometer into the color matching and set up a set of equations to increase the accuracy of the color matching,Referring to increase the accuracy of the color matching.Referring to color gamut,several sets of shade guide were made according to sixteen kinds of mixture-ratio of four pigments such as red,yellow,white and black,and every shade guide was measured.The mixture-ratio was related to the values of the CIE system by means of statistics,which resulted in the equations for color matching.In a word,use of the spectrophotometer may improve the accuracy of the the color matching of facial prosthesis.

Journal Article↗