ON THE SPECTRUM

In the first of what will be occasional reports, John O’Hagan, chair of CIE-UK, will give updates on the international lighting body's recent activities

Around one in 20 of the male population are not 'colour normal observers'. This means they sometimes cannot distinguish colours that the rest of us take for granted. Often, it is the inability to pick out red – a colour often used to highlight our presentations, including the beam from laser pointers. Enhancement of Images for ColourDeficient Observers, Technical Report CIE 240:2020, summarises the methods used to enhance images in order to be easily recognised by colour-deficient observers.

The methods are classified into three major categories: recolouring, edge enhancement and pattern superposition. The pros and cons of each are discussed. The document provides recommendations on how to choose an enhancement method for a specific application with the proviso that there is no unique technique covering all cases. It also describes some evaluation methods of the enhancement techniques to be proposed in the future. Three types of test images (a natural scene, a scientific visualisation and an office document) are provided for the evaluations. A short video about the new publication is available (https://youtu.be/ NZyrzSxkDUo), presented by Po-Chieh Hung, chair of the technical committee that prepared the report.

The latest publication from CIE is Recommended Reference Solar Spectra for Industrial Applications, Technical Report CIE 241:2020. Reference solar spectra are needed for many applications, including the assessment of solar radiation on materials. The document contains a large selection of simulation benchmarks for total, direct and diffuse components of solar spectra under various atmospheric conditions and solar geometries (defined by the air mass).

To generate these, a freely available solar spectral irradiance model has been used to produce tables and figures of the irradiance under several different atmospheric conditions, in the form of explicit meteorological input parameters. The data in this document are to a large extent comparable to those in the earlier publication, CIE 085-1989, but presented with a higher spectral sampling. The respective solar spectra are the basis for national and international standard reference spectra for various applications. They have been extensively validated against measured spectra. Again, a short video about the new publication is available (https://vimeo.com/468892809), presented by the chair of the CIE technical committee responsible, Dr Shigeo Suga.

Finally, two new technical committees have been formed: ● TC 1-98: A Roadmap Toward

Basing CIE Colorimetry on Cone

Fundamentals will give explicit consideration of the impacts of normal variations in cone fundamentals due to the factors of age, field of view and individual diversity. ● JTC 19 (D6/D2): Terms and Definitions for Horticultural Lighting is an international standard that will take into account terms from existing national or regional publications.

The inability to pick out red is common in non-colour-normal observers

About CIE-UK

The UK national committee of the International Commission on Illumination or CIE (Commission Internationale de l´Eclairage), CIE-UK was founded along with the CIE in 1913, though each evolved from earlier organisations. The SLL is one of the Sponsor Members. It is a charity, with five trustees, supported by an executive secretary (Allan Howard). All roles are carried out by volunteers. Members come from professional bodies, academia, industry and government organisations, plus a small number of individual members. The CIE publishes international standards, technical reports, technical notes and position statements. These are prepared by experts from around the world, including 25 from the UK who are currently contributing to the development of new publications. CIE-UK also has three members on the CIE's board of administration. UK members of the SLL are eligible for the CIE-UK members’ discount for CIE publications, which represents a two-thirds reduction on the list price. A discount is also available for some CIE events. • Publications can be purchased via the relevant link at http://cie.co.at/.

Email sll@cibse.org for the discount code • If you are interested in joining CIE-UK, contact

Allan Howard, FSLL: allan. howard@wspgroup.com