NON-LINEAR VIDEO SHARPENING FILTER

A nonlinear video filter which provides an output of increased sharpness with reduced artifacts as compared to prior art filters. A "pivot" value is identified at a pixel based on the value of pixels neighboring that pixel. Then, a new value for the pixel is computed by adding to the pivot value, an amount based on the difference between the original pixel value and the pivot value. The pivot value may be computed as the average of the original values for a number, e.g., 2.sup.n, neighboring pixels, or as the average of the maximum and minimum original pixel values among the 2.sup.n neighboring pixels. The difference between the original pixel value and the pivot value is multiplied by a factor k, and then added to the pivot value. For computational simplicity, the factor k is selected to be a power of two. Filtering for k=2, k=4 and k=16 are illustrated. The new value is limited to the maximum and minimum original pixel values among the 2.sup.n original pixel values to avoid overshoot.