Luminance-Based Measures of Contour Distinctness of 3D Objects as a Component of Light Modeling

Abstract

ABSTRACTThis article presents possible luminance-based measures of contour distinctness of 3D objects observed under real daylight conditions. Contour distinctness is considered here as a component of the broader concept of light modeling and is a significant metric of quality lighting. We set up an experiment where different measures of contour distinctness were studied with the help of high dynamic range imaging techniques. Measures obtained from the luminance maps were brought into correlation with survey results from 32 subjects. The analytical comparison showed that the contrast measurement (calculated with the Weber formula), luminance ratio between average luminance of the object and average luminance of the background, mean of paired point luminance ratio (mean point LR) measurements around the contour of the object, and percentage of the invisible part of the contour are good predictors for contour distinctness of the observed 3D objects. The proposed measures expressed in numerical values are comprehensive and easy to obtain and can be practically applicable after the further development.