Author/Editor		Hautiere, Nicolas; Tarel, Jen-Philippe; Aubert, Didier; Dumont, Eric
Title		Blind contrast enhancement assessment by gradient ratioing at visible edges
Type		članek
Source		Image Anal Stereol
Vol. and No.		Letnik 27, št. 2
Publication year		2008
Volume		str. 87-95
Language		eng
Abstract		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.
Descriptors		IMAGE PROCESSING, COMPUTER-ASSISTED CONTRAST MEDIA MOTOR VEHICLES DARKNESS