Color Science Seminar: Color Rendering Indexes for Color Blind Observers

Color Science Seminar
Color Rendering Indexes for Color Blind Observers

Dr. Rafael Huertas
Associate Professor, Department of Optics
University of Granada

Abstract:
Color rendering index (CRI) measures the ability of a light source to accurately reproduce the colors of the objects it illuminates, in comparison with a natural or standard light source. Light sources with a high CRI are desirable in color-critical applications such as neonatal care, photography, etc. The International Commission of Illumination (CIE) recommends the use of the CIE Ra index, which traditionally has been the international standard color rendering index. Lighting industry has experimented a revolution during last years, with the development of LED lamps, and in this case CIE Ra's ability to predict color appearance has been criticized in favor of other measures. Thus, different proposals have been published in the last years, such as Color Quality Scale (CQS) index Qa, which will be used in this work. It must be noted that the mentioned indexes are only valid for normal color vision people. However, color vision deficiencies (CVD) are quite widespread, since around 8% of the male and 0.5% of the female Caucasian population is affected by this condition. In fact, CVD has gained relevance in the last decade, with a surge of proposals for aid systems that aim to improve the color discrimination capabilities of CVD subjects. Thus, it would be desirable to have a measure of the color reproduction of a lamp valid for CVD people, which will depend on the type and severity of the deficiency. These figures could be included in the commercial lamps’ specifications for the most typical CVD types. The goal of the work is adapting the CRI and CQS for CVD observes, through simulation by algorithms of CVD of different types and severities. The results show that CVD does increase the value of Ra and Qa, as could be expected.

Speaker Bio:
Rafael Huertas earned a BS in Physics in 1997, and a BS in Optics and Optometry in 1998 at the University of Granada (Spain). In 2004 he received his PhD in Physics at the same university. Since 2011 he has been an Associate Professor at the Department of Optics of University of Granada. He is currently accredited as a Full Professor by the Spanish accreditation agency. He has taught different courses in the degrees of Physics and Optics and Optometry and “Basic Colorimetry”, “Applied Advanced Colorimetry”, “Advanced Color Image Processing” in different masters, nationals, and internationals (Erasmus Mundus). He has been director of 2 doctoral thesis, and several Master Thesis, Summer Research Projects, End-of-Degree Projects, etc. He participates in several outreach activities: “European researcher's night”, “Semana de la Ciencia”, “Campus Científico de Verano”, etc. He has been Coordinator of the Degree in Optics and Optometry from 2017 to 2021. From 2021 to present he is Head of the Department of Optics. His research interests include basic and applied colorimetry: color-difference formulas, color spaces, color vision deficiencies, color in images, texture, and food color. He has been member of different CIE Technical Committees: TC 1-86 “Models of Colour Emotion and Harmony”, TC 1-93 “Calculation of Self-luminous Neutral Scale”, and Advisor of TC 1-55 “Uniform Color Space for Industrial Color Difference Evaluation”. He has participated in 19 research projects, as lead researcher in 3 of them. To date he has published 46 scientific papers in international journals with impact factor, 17 chapters of books, and 103 contributions to scientific conferences.  He has also participated in 1 patent: “Método y Dispositivo para Caracterizar y Clasificar el Color de Aceites de Oliva” (ES2397466 B1. Code: A23D7/00, A23D9/00, G01N21/00, G01N21/17, G01N21/25. URL: http://hdl.handle.net/10481/30087)

Intended Audience:
All are Welcome!

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