Lit environments quality: A software for the analysis of luminance maps obtained with the HDR imaging technique

•Analysis of the main factors that influence lit environments’ perception.•Brightness is the key to obtain visual comfort and energy savings.•Report of the main available relations between brightness and luminance.•Description of a software for luminance maps analysis.•Software application to various simple case studies. Energy performance of lighting systems has assumed a significant role in the assessment of buildings’ consumptions and consequently lighting design is aimed to reduce installed power but at the same time to achieve an excellent lighting quality both for visual and health purposes. Lighting design is nowadays essentially based on illuminance values on visual tasks and surrounding areas, but today designers’ and researchers’ interest is focused on the analysis of luminance maps obtained through video luminance meters or with numeric simulation tools. Luminance maps availability focus the attention on a more accurate study of the light reaching the eyes (luminance), rather than on the light that arrives on surfaces (illuminance). However luminance values, based on photopic sensitivity, do not always adequately describe the quality of a lit environment and how it is perceived; therefore it is necessary to consider parameters like brightness or equivalent luminance. The first part of this work describes primary factors that influence lit environments’ perception along with the main available luminance–brightness relations. Moreover a software for the luminance maps’ analysis is described with the goal of finding and testing the most significant parameters for the lit environment's description, both for comfort and energy purposes.