METHOD OF AND APPARATUS FOR PROCESSING IMAGE SIGNALS AT A POINT OF INTEREST BASED ON IMAGE SIGNAL CURVATURE

An image signal (Sij) from an original which gears image information is processed by generating a new image signal (S'ij) from the image signal (Sij). It is first determined whether the configuration of the distribution of the image signal (Sij) at a point of interest (i, j) is upwardly convex, or a downwardly convex, or otherwise. An image emphasis signal (S.sub.G ij) larger than the image signal (Sij) at the point of interest (i, j) is employed as the new image signal (S'ij) if the configuration is upwardly convex. An image emphasis signal (S.sub.L ij) smaller than the image signal (Sij) at the point of interest (i, j) is employed as the new image signal (S'ij) if the configuration is downwardly convex. The original image signal (Sij) or an unsharp signal (Uij), generated from the new image signal (S'ij), is employed as the new image signal (S'ij) if the configuration is otherwise.