China
Africa
Explore chapters and articles related to this topic
Color fundamentals for digital imaging
Published in Sharma Gaurav, Digital Color Imaging Handbook, 2017
Sampling of the spectral distribution provides the most direct and complete technique for recording color information. A spectroradiometer is a device that measures the power of optical radiation as a function of wavelength. Figure 1.31 shows the schematic cross section of a spectroradiometer. The light is collimated by the lens onto a dispersive element, which decomposes it into its spectrum. The spectrum is then sampled and recorded using single or multiple detectors. Typically, a diffraction grating is used as the dispersive element, because it provides an almost linear relationship between wavelength and displacement in the detector plane, as opposed to an optical prism, for which the correspondence is highly nonlinear. The linear relationship considerably simplifies calibration procedures.
Light Sources
Published in Toru Yoshizawa, Handbook of Optical Metrology, 2015
The measurements of color light sources (lamps, LEDs, and displays) involve spectroradiometers and tristimulus colorimeters. In order to characterize the color, lamps are usually measured for spectral irradiance, whereas displays are measured for spectral radiance. When a spectroradiometer is designed to measure spectral irradiance (W/m2·nm), it is equipped with a diffuser or a small integrating sphere as input optics, while a spectroradiometer, which is designed to measure spectral radiance (W/sr · m2· nm), employs imaging optics. A spectroradiometer could be one of a mechanical scanning type, which are more accurate but slow, or of diode-array type, which are fast, but less accurate devices. Spectroradiometers are calibrated against spectral irradiance and radiance standards [49], which suggest that their measurement uncertainty is determined first by that of the reference source. Other factors influencing the measurement uncertainty are wavelength error, detector non-linearity, bandwidth, stray light of monochromator, measurement noise, etc. [44]. Tristimulus colorimeters are used to calibrate display devices and printers by generating color profiles used in the workflow. Accurate color profiles are important to ensure that screen displays match the final printed products. Tristimulus colorimeters are low-cost and high-speed devices, but their measurement uncertainty tend to be higher than spectroradiometers.
Lighting
Published in Sue Reed, Dino Pisaniello, Geza Benke, Principles of Occupational Health & Hygiene, 2020
A spectroradiometer is an instrument for measuring the spectral irradiance (W/m2.nm W/m2/micrometer). It is able to measure both the wavelength and amplitude of the light emitted from a light source. An example of a spectroradiometer is shown in Figure 15.10.
Blue light exposure in the workplace: a case study of nail salons
Published in Archives of Environmental & Occupational Health, 2022
SoYoung Lee, Sharyn Gaskin, Bruno Piccoli, Dino Pisaniello
A specbos 1211 UV spectroradiometer (JETI, Germany, S/N: 2010143), with LiMeS software (Version 4.1.0m), was used to measure the spectral radiance of light sources in the simulation experiments and was set in the wavelength range from 300 to 700 nm at 1 nm intervals. Before exposure assessment simulations, the spectroradiometer was calibrated by the National Institute of Standards and Technology Traceable Light Source (JETI, Germany).