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Colorimetry
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Colorimetry, the measurement of color, attempts to quantify the perception of color. The Commission Internationale de l’Éclairage (International Commission on Illumination [CIE]) is a voluntary organization of scientists and engineers from all over the world who are interested in light and color. The recommendations constituting modern colorimetry were first published by the CIE in 1931 and have been regularly updated since then [1].
Color fundamentals for digital imaging
Published in Sharma Gaurav, Digital Color Imaging Handbook, 2017
Systems for recording color information include both color measurement instrumentation useful for large uniform regions and color image capture devices designed to capture spatially varying color information. Color measurement instruments are used primarily for determining the color characteristics of objects and of imaging input and output devices. They include both spectral measuring devices such as spectroradiometers/spectrophotometers and filter-based instruments that directly measure colorimetry. The correct color measurement instrument for a particular application depends on several factors including the cost of the instrument, the accuracy desired, the variety of viewing conditions for which a calibration is desired, and the number and type of devices that must be calibrated. Color image capture devices include conventional and digital color cameras, which record color information from a scene of real world objects, and color scanners, which record color information from a prior reproduction such as a printed color image, slide, or negative.
Basic concepts in photometry, radiometry, and colorimetry
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
The perception of color is a psychophysical phenomenon, and the measurement of color must be defined in such a way that the results correlate accurately with what the visual sensation of color is to a normal human observer. Colorimetry is the measurement science used to quantify and describe physically the human color perception. The basis of colorimetry was established by CIE in 1931 based on a number of visual experiments that defined a set of three spectral weighting functions [39]. These functions, shown in Figure 8.11, are called the CIE 1931 XYZ color matching functions denoted as x¯(λ),y¯(λ),z¯(λ). These functions were derived from a linear transformation of the original set of color matching functions in such a way that y¯(λ) is equal to V(λ).
Improved and Robust Spectral Reflectance Estimation
Published in LEUKOS, 2021
Jingjing Zhang, Youri Meuret, Xiangguo Wang, Kevin A. G. Smet
Final spectral reflectance estimation accuracy of the trained/optimized system was evaluated using four fitness measures: the mean root mean square error (RMSE) and goodness of fit coefficient (GFC) of the estimated spectral reflectance and the ground truth for spectral accuracy assessment (Cao et al. 2017; l’Eclairage 2005) and the mean CIE1976 u′v′ chromaticity differences (Δu′v′) and luminance differences (ΔY) between the estimated and ground truth chromaticity and luminance values obtained under some reference illuminant for color accuracy evaluation (Urban et al. 2009; X. Zhang et al. 2017). Good color accuracy is crucial for various human vision and colorimetry applications. The four parameters are given by
Assessment Techniques for Studying the Effects of Fire on Stone Materials: A Literature Review
Published in International Journal of Architectural Heritage, 2020
Edite Martinho, Amélia Dionísio
According to Wyszecki and Stiles (1982), “colour (in the psychophysical sense) is that characteristic of a visible radiant power by which an observer may distinguish differences between two structure-free fields of view of the same size and shape, such as may be caused by differences in the spectral composition of the radiant power concerned in the observation. Psychophysical colour is specified by the tristimulus values of the radiant power (colour stimulus) entering the eye.” The aim of colorimetry is to convert color perception into numbers. Due to the presence of three types of receptors in the human eye, the most common color model is 3D. For a detailed description of colorimetric terms and definitions, see Wyszecki and Stiles (1982).
Thermodynamics and kinetics to develop an analytical method for sensing of aqueous Hg(II) using caffeic acid decorated AgNPs
Published in Inorganic and Nano-Metal Chemistry, 2023
Ritu Painuli, Sapna Raghav, Prakash C. Jha, Mohd Athar, Dinesh Kumar
Thus, to overcome the impediments mentioned above, there is a need to develop a simple, fast, easy-to-be sampling, highly selective, on-site, and inexpensive route for detecting noxious metal ions at ultra-trace levels.(20–23) Colorimetric sensors have alluring advantages due to their effortlessness, rapidity, high sensitivity, and ease of measurement, allowing online, real-time qualitative or semi-quantitative analysis.(24–30) In the past few decades, colorimetric probes based on noble metal nanoparticles, particularly silver and gold (AgNPs and AuNPs) have received significant consideration due to their SPR changes. The SPR of AgNPs and AuNPs changes brilliantly on adding target analytes. Further, it shifts their characteristic SPR peak and color change, equivalent to their aggregation and dispersion state. This allows us to recognize the target analyte with naked eyes, with no requirement for expensive instruments. (31–34) Based on these metal nanoparticles, our research group has also developed colorimetric assays to detect the target analyte. (35–37) Caffeic acid (CA) has already been used to synthesize AgNPs by Lin and coworkers. (38) They demonstrated the in–vitro cytotoxicity of the synthesized NPs. In the present report, the CA–AgNPs have been used for the environmental application, i.e., to detect Hg(II) ions. CA is a natural plant polyphenol widely distributed in agricultural products, i.e., coffee, wine, olive oil, etc. It contains various biological properties such as antioxidant, antiviral, anti-carcinogenic etc. It has potential due to being a polyphenolic compound that reduced and stabilized the NPs to bind with metal ions in solution.