Luminous intensity distributions enable an evaluation of the spatial radiation characteristic of a light source. This radiation characteristic is determined by the structural properties of the light source, its operating parameters and the properties of the measuring system. This paper describes some possible methods and rules for comparing luminous intensity distributions. The focus is on the development of calculation rules for quantifying the differences between two luminous intensity distributions. The difference measures developed allow the user to establish an objective comparison between luminous intensity distributions, this comparison being completely independent of the measuring system, the properties of the luminous intensity distributions and the users themselves. Further, the dependence of the properties of luminous intensity distributions resulting from measurement practice, such as adjustment uncertainties, regions that cannot be covered or measured, deviations of the total luminous flux, data noise and resolution differences, are discussed, and appropriate pre-processing and correction steps proposed. In addition, various visualisations of the differences between two luminous intensity distributions are demonstrated and the functionality of the difference measures developed is documented.
Array spectroradiometers are used pervasively in light measurement. However, their properties are not widely understood by users. This report seeks to educate users in the characteristics of array spectroradiometers that are important to obtaining accurate measurement results. Moreover, performance indices are proposed that will enable users to rank instruments according to the properties that affect their applications. In many cases, if the array spectroradiometer is properly characterized, correction can be made to measurements that will improve the accuracy. Details of the nature and use of these corrections are given. Calibration procedures and uncertainties are discussed for various common quantities, giving a sound foundation to measurements. Background information, underlying the discussions, is found in the annexes and references.
Instrumentation for photometry, radiometry and colorimetry has developed significantly over the past fifty years. New measurement techniques and types of detectors as well as miniaturisation of computers and electronic hardware have fundamentally changed both the size, design and complexity of instrumentation and the way that we go about our measurement work. There has also been a significant change in mindset as the increasing need for accountability for measurement results and recognition of the role of traceability and measurement uncertainty have become more pronounced. This paper summarises the state of photometric laboratories in the 1960s and list some of the key highlights in the development of instrumentation and measurement techniques since then. It is not intended as a strict chronological account of technological invention, but a reflection of how and when these technologies were adopted and adapted to light measurements, along with accompanying key papers published in Lighting Research and Technology and associated journals over that time.
New regulations are coming into force in several regions with respect to temporal light modulation (TLM) of lighting products. However, standardized test methods and even basic understanding of requirements are largely lacking in the area. Newly introduced metrics, like the stroboscopic visibility measure, are used in these regulations without the existence of standardized measurement methods to support these.-\n--\n-This document provides recommendations on measurement protocols to measure periodic waveforms and light modulations. The recommendations should enable test and calibration laboratories to apply the same measurement methodology and to report the results in a consistent and reproducible way. The document covers methods of measurement for TLM and temporal light artefacts (TLA) of lighting equipment. Its primary application is for general lighting purposes; however, the principles can be applied to other fields (e.g. display equipment, or facade lighting), though these generally require different input optics for the measurement equipment.-\n--\n-The recommendations given in this document can be used to measure non-periodic signals, but there might be specific aspects of these signals that will not be covered in this document (e.g. signal-triggering). This document sets the stage for an understanding of these new metrics and provides guidelines for the correct measurement of them. The document is meant to provide respective recommendations, which do not imply any kind of standardization. In addition to this Technical Note a CIE Technical Report is in preparation, which will cover a test method for flicker and the stroboscopic effect using existing or new metrics to be developed is going to follow this publication in due course. Keywords: temporal light artefacts, TLA, time-modulated lighting systems, temporal light modulation, TLM, LED, flicker, flicker index, modulation depth, percent flicker, Stroboscopic visibility measure, SVM
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.