Fuzzy detection of edge-direction for video line doubling

Video line doubling can be realized using time-space interpolation filters. To improve their performances for moving diagonal lines, we have developed a fuzzy edge-direction detector. This fuzzy detector works by identifying small pixel variations in five orientations (0/spl deg/, /spl plusmn/45/spl deg/, and /spl plusmn/60/spl deg/) and by using rules to infer the prevailing direction. This direction is then used to spatially rotate the interpolation filter. For the fuzzy detector, three fuzzy sets are used to characterize the inputs, and two rule bases have been validated. This article presents the characteristics of the fuzzy edge-direction detector along with the methodology used for fuzzy sets positioning. Detection and interpolation results are also presented.