IMAGE OUTPUT APPARATUS, EDGE ENHANCEMENT METHOD, AND RECORDING MEDIUM

An image output apparatus includes an addition amount calculation unit that calculates, based on a target pixel and each of adjacent pixels before and after the target pixel in an input image, an edge enhancement addition amount to be added to a pixel value of the target pixel; a variation calculation unit that calculates a linear variation in accordance with a shape of an edge gradient formed by the target pixel and each of the adjacent pixels; a weight processing unit that assigns a weight to the edge enhancement addition amount in accordance with the linear variation; and an addition amount addition unit that adds the weighted edge enhancement addition amount to the pixel value of the target pixel and outputs the added pixel value.