Mesopic visual efficiency IV: a model with relevance to nighttime driving and other applications

Abstract

The authors represent a research consortium 1 which has adopted a task performance based approach for nighttime driving to establish a system for photometry in the mesopic region. This article analyses the experimental investigations described in earlier articles on visual performance in the mesopic domain using reaction time, detection threshold, and discrimination threshold techniques. These results are used to develop a system for mesopic photometry, which balances the quality of the fit to the experimental data with the ease of practical implementation by the lighting industry. A more complex model is also described, which takes account of the chromatic visual response channels and thus provides a better fit to some of the experimental results (particularly those involving monochromatic stimuli), but describes the totality of the data less well and is furthermore less suitable for practical photometric measurements.

Road lighting research for drivers and pedestrians: The basis of luminance and illuminance recommendations

“…54 The mesopic system was derived from two parallel bodies of work, the European MOVE consortium [55][56][57][58] who used and driving on a test track. 62 The mesopic visual response is essentially a weighed combination of the scotopic (S) and photopic (P) responses, and hence the CIE mesopic system 53 provides the weighting factor according to the level of adaptation and the S/P ratio of lighting, this being established by consensus between the two bodies of work.…”

Proposed UK guidance for lighting in residential roads

“…Changing any of these parameters will change the efficiency of the visual system and the ability to perform the requisite task. 6,7 This complexity means that it is not possible to define a single spectral luminous efficiency function that will apply for all tasks and environmental conditions, or to devise a measurement system that will provide a complete prediction of visual performance for all situations. Instead, lighting standards and specifications are based on a small number of internationally agreed spectral luminous efficiency functions that, while they do not describe the details of human visual performance, nevertheless provide a measurement framework for quantifying 'light' in a way that correlates with human vision.…”

“…One theme is the development of a system of mesopic photometry to characterise the spectral sensitivity of the eye. Research carried out by the European MOVE consortium 6 and the US Lighting Research Centre 7 culminated, through CIE Technical Committee TC1-58 (Visual Performance in the Mesopic Range), in the CIE recommended system for mesopic photometry. 1 The second theme is applied research of typical pedestrian tasks under light sources of different SPD, including studies of brightness, obstacle detection and facial recognition.…”

Energy-saving quality road lighting with colloidal quantum dot nanophosphors

“…Consequently, the vision sensitivity of human eye in the mesopic regime is different than those in the scotopic and photopic regimes. Although the existence of these differences were well known and widely accepted, until most recently there has been no consensus on the luminance level boundaries and eye sensitivity function of the mesopic vision regime [17][18][19][20][21][22][23][24]. In 2010, this confusion was addressed by CIE that published a technical report (CIE 191:2010) on a recommended system for mesopic photometry [25].…”