Open AccessBLIND CONTRAST ENHANCEMENT ASSESSMENT BY GRADIENT RATIOING AT VISIBLE EDGES
Author(s) -
Nicolas Hautière,
Jean Philippe Tarel,
A. Didier,
Éric Dumont
Publication year - 2011
Publication title -
image analysis and stereology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.237
H-Index - 27
eISSN - 1854-5165
pISSN - 1580-3139
DOI - 10.5566/ias.v27.p87-95
Subject(s) - visibility , contrast (vision) , computer science , artificial intelligence , computer vision , daylight , image (mathematics) , tone mapping , image contrast , image quality , image restoration , contrast enhancement , remote sensing , image processing , optics , geology , physics , high dynamic range , dynamic range , medicine , magnetic resonance imaging , radiology
The contrast of outdoor images acquired under adverse weather conditions, especially foggy weather, is altered by the scattering of daylight by atmospheric particles. As a consequence, differentmethods have been designed to restore the contrast of these images. However, there is a lack of methodology to assess the performances of the methods or to rate them. Unlike image quality assessment or image restoration areas, there is no easy way to have a reference image, which makes the problem not straightforward to solve. In this paper, an approach is proposed which consists in computing the ratio between the gradient of the visible edges between the image before and after contrast restoration. In this way, an indicator of visibility enhancement is provided based on the concept of visibility level, commonly used in lighting engineering. Finally, the methodology is applied to contrast enhancement assessment and to the comparison of tone-mapping operators