The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Roy S. Berns - One of the best experts on this subject based on the ideXlab platform.
-
Colorimetry PART II: IMAGING APPLICATIONS
Optics & Photonics News, 1995Co-Authors: Roy S. BernsAbstract:Colorimetry applied to Imaging, known as device-independent color Imaging, has a historical basis in color television that is useful in Improving the color fidelity of color computer peripherals such as CRT displays and printers.
-
crt Colorimetry part ii metrology
Color Research and Application, 1993Co-Authors: Roy S. Berns, M E Gorzynski, Ricardo J. MottaAbstract:The colorimetric characterization of computer-controlled CRT displays require radiometric measurements with high precision and accuracy in order to achieve acceptable colorimetric accuracy in defining stimuli generated with this type of imaging modality. Precision and accuracy requirements for photometers, colorimeters, and spectroradiometers were evaluated. When models are used to relate digital counts defining a stimulus and resulting spectral radiant exitance, displays are assumed to exhibit channel and spatial independence. A variety of tests and the results of evaluating four imaging systems are described. From these analyses, measurement accuracy is mainly limited by wavelength scale in the case of spectro-radiometers and filter fit in the case of colorimeters. Measurement precision is limited by the number of significant figures for fixed-range devices and signal-to-noise limitations for low-luminance stimuli. Display accuracy is limited by a lack of channel and spatial independence. Display precision is mainly limited by the electronic design of the display and the stability and load independence of the gun amplifiers. © 1993 John Wiley & Sons, Inc.
-
CRT Colorimetry. part I: Theory and practice
Color Research & Application, 1993Co-Authors: Roy S. Berns, Ricardo J. Motta, M E GorzynskiAbstract:The relationship was derived for computer-controlled color CRT displays between spectral radiant exitance emitted and digital counts. The derivation was historical and could be traced to pioneering work in photographic sensitometry, vacuum tube physics, and broadcast television. By performing radiometric measurements relative to a display's maximum exitance, the model simplified to a two-stage model. The first stage was a nonlinear transformation relating normalized digital-to-analog converter values to device-dependent monitor tristimulus values using model parameters of gain, offset, and gamma. The second stage was a linear transformation where the device-dependent monitor tristimulus values were transformed to device-independent CIE tristimulus values. By using the model, colorimetric characterization accuracy of better than 0.5 CIELAB color-difference units for 125 colors sampling the display color gamut was achieved by measuring the CIE tristimulus values of only eight colors. The model had equivalent performance to methods using extensive measurements and table lookup. (C) 1993 John Wiley & Sons, Inc.
Keith K. Niall - One of the best experts on this subject based on the ideXlab platform.
-
Outlines of a Theory of Photopic Colorimetry (Part III): Advanced Colorimetry, or Full-Blooded Colorimetry (Second Article)
Erwin Schrödinger's Color Theory, 2017Co-Authors: Keith K. NiallAbstract:There are familiar relations among colors which remain unrepresented in the affine geometry of basic Colorimetry. An advanced Colorimetry will incorporate maximum color similarity. Advanced Colorimetry applies Riemannian geometry, not Euclidean geometry. A line element is proposed for color space; it preserves additivity of brightness. The line element bridges heterochromatic differences and just-noticeable differences in color. One problem is that the Bezold-Brucke phenomenon pervades this range of conditions; a correction factor must then be applied to the line element. Then two constraints conflict: the constraint that both large and small differences are accounted for, and the constraint that Fechner’s law holds uniformly across color space. This tension changes the theory of advanced Colorimetry to a transitional theory or heuristic account.
-
Outlines of a Theory of Photopic Colorimetry (Part II) Basic Colorimetry or Affine Color Properties, Continued (First Article)
Erwin Schrödinger's Color Theory, 2017Co-Authors: Keith K. NiallAbstract:A formal system of human color perception has been described, which is known as basic Colorimetry. Positions of the associated color space represent spectral colors, purples, and the color white – among others. Actual colors in color space form at least a three-dimensional color envelope. This chapter describes some affine-invariant properties of the color envelope. The role which plane projective geometry plays in the subordinate color plane is the same as the role which affine geometry plays in color space. The derivation of color coordinates is demonstrated for an arbitrary function of wavelength, as is the derivation of color coordinates under affine transformation of color space. A relation is established between the color matches which are made by dichromat observers, and color matches made by trichromats (color-normal observers). Basic Colorimetry provides the foundation for advanced Colorimetry as developed in a subsequent chapter.
Laura Flori - One of the best experts on this subject based on the ideXlab platform.
-
Practical applications of cutaneous Colorimetry
Clinics in Dermatology, 1995Co-Authors: Lucio Andreassi, Laura FloriAbstract:Dermatologists have long tried to quantify skin color and had few results until the advent of tristimulus Colorimetry. With the Minolta colorimeter, quantification of skin color has become a simple matter: skin color can be measured rapidly, noninvasively, and reproducibly. The instrument, which can be used by paramedical staff, provides data that lend themselves for comparison, irrespective of where they are collected. The instrument has enabled definition of the range of physiologic values of skin color, and has revealed marked variations between exposed and nonexposed skin. Constitutional skin color characterizes an individual's phenotype better than facultative skin color and is highly indicative of vulnerability to sunlight. It is therefore a parameter for predicting the immediate and delayed response to light stimulation. On the practical level, colorimetric skin color values can be used to study pigmentation capacity, to program photochemotherapy, and to predict the risk of, and prevent, actinic cancer. Colorimetry can be used to quantify the intensity of erythema of spontaneous and experimental lesions. It has been used to monitor the efficacy of anti-inflammatory treatment of psoriasis and atopic dermatitis. It has also been used in the study of reactions induced by physical and allergic stimuli. Finally, Colorimetry is useful in cosmetology for choosing appropriate sunscreens, for studying the effect of depigmentation products, and for determining the delicacy of detergents, and in any other situation that requires the measurement of parameters correlated with skin color that cannot be appreciated by visual observation.
Zsolt Ajtony - One of the best experts on this subject based on the ideXlab platform.
-
Application of laser-based photoacoustic spectroscopy and Colorimetry for quantification of anthocyanin in hard boiled candy
Microchemical Journal, 2017Co-Authors: Mihaly Kovacs, Ottó Dóka, Dane Bicanic, Zsolt AjtonyAbstract:The analytical performance of the newly proposed laser-based photoacoustic spectroscopy (LPAS) and colorimetric method for quantification of anthocyanin (E163) in commercially available hard boiled candies are compared to that of the spectrophotometry (SP). Both LPAS and Colorimetry are direct methods that unlike SP do not require the extraction of the analyte or some additional sample treatment. Results indicate that LPAS and Colorimetry are both suitable for quickly screening content of anthocyanin in hard boiled candies. The correlation between the two methods and spectrophotometry is linear with R2 = 0.9989 for LPAS and R2 = 0.9570 for Colorimetry.
Lucio Andreassi - One of the best experts on this subject based on the ideXlab platform.
-
Practical applications of cutaneous Colorimetry
Clinics in Dermatology, 1995Co-Authors: Lucio Andreassi, Laura FloriAbstract:Dermatologists have long tried to quantify skin color and had few results until the advent of tristimulus Colorimetry. With the Minolta colorimeter, quantification of skin color has become a simple matter: skin color can be measured rapidly, noninvasively, and reproducibly. The instrument, which can be used by paramedical staff, provides data that lend themselves for comparison, irrespective of where they are collected. The instrument has enabled definition of the range of physiologic values of skin color, and has revealed marked variations between exposed and nonexposed skin. Constitutional skin color characterizes an individual's phenotype better than facultative skin color and is highly indicative of vulnerability to sunlight. It is therefore a parameter for predicting the immediate and delayed response to light stimulation. On the practical level, colorimetric skin color values can be used to study pigmentation capacity, to program photochemotherapy, and to predict the risk of, and prevent, actinic cancer. Colorimetry can be used to quantify the intensity of erythema of spontaneous and experimental lesions. It has been used to monitor the efficacy of anti-inflammatory treatment of psoriasis and atopic dermatitis. It has also been used in the study of reactions induced by physical and allergic stimuli. Finally, Colorimetry is useful in cosmetology for choosing appropriate sunscreens, for studying the effect of depigmentation products, and for determining the delicacy of detergents, and in any other situation that requires the measurement of parameters correlated with skin color that cannot be appreciated by visual observation.