IMAGE DYNAMIC-RANGE ENHANCEMENT AND STABILIZATION IN THE CONTEXT OF THE LOGARITHMIC IMAGE-PROCESSING MODEL

Images of a scene observed under a variable illumination or with a var iable optical aperture are not identical. Does a privileged representa nt exist? In which physical setting? In which mathematical context? Wi th which meaning and criterion? How to obtain it? The authors answer t o such questions in the physical setting of logarithmic imaging proces ses, For such a purpose, they use the logarithmic image processing (LI P) model, known to be a compatible mathematical framework. After short recalls on this model, the paper presents two image transforms: one p erforms an optimal enhancement and stabilization of the overall dynami c range, and the other does of the mean dynamic range. The results obt ained on X-ray images, as well as for some natural scenes, are shown. Also the implementation of the transforms is addressed.