Range filters: Localintensity subrange filters and their properties

A local filter which uses the local-intensity subrange of tinuities in mean intensity4, range filters will detect pixel intensity values within a window is described. edges. This paper investigates the effectiveness of The range filter is an extension of the rank filter and has these filters for this task. been found useful for detecting edges. The deterThe local subrange is calculated by ordering the N ministic and noise properties of the range filter are pixels within the window according to intensity, ie described and compared with those of the commonly used Sobel filter. (f,, f*, f?$ ., fN) (1)