ASSESSMENT TOOL FOR LUMINANCE IN SIGNS AND LUMINOUS ANNOUNCEMENTS

Abstract

The impact on electricity costs and the negative effects on environments such as astronomy, health and the environment, have led to public administrations regulate lighting installations considering light pollution as an important objective to counteract. Current regulations regarding light pollution set maximum luminance values, particularly in what concerns the assessment of signs and luminous announcements. The determination of the points of the scene where these peaks occur is subject to observation opinion of the technician who perform the action. The sensitivity of the human eye to brightness is nonlinear and misleading in that its purpose is to identify the scene and not the measure of values and light intensities. Moreover, the use of conventional luminance meter involves measuring point to point on the scene. This requires making many measurements in order to sweep the whole scene and determine where the maximum is reached. This action is not only tedious and error prone, but involves taking measurements at different successive instants which affects repeatability errors and variation over time in unstable scenarios. This paper proposes the use of digital cameras to evaluate the brightness, particularly for signs and luminous announcements. In this sense, digital photography has color and brightness information from all points within it. Originally, the information provided by the picture is oriented to the reproduction of the image so that contemplate some corrections and compensations to adapt to human vision.