Numerous adaptive contrast enhancement techniques have been developed to improve the visual utility of imagery. Most of these techniques involve the use of neighborhood operators, and some require manual input of scene-dependent functions to operate properly on different images. The local range modification (LRM) technique described in this paper does not involve neighborhood operators in the conventional sense of the word nor does it require design of scene-dependent functions, yet it yields results comparable to more computation-intensive techniques. In this paper, a unified description of the spatial filter-based adaptive contrast enhancement algorithms is presented. LRM is then described and qualitatively compared with the other algorithms in terms of efficiency, effectiveness, and artifact generation.