US Patent 7502142 Image data processing system

In an image data processing device, a notice pixel is selected from among a plurality of pixels constituting an image. A specified direction in which ink ejected on a recording medium would bleed by a relatively large amount on the recording medium is obtained. Then, a color-difference vector indicative of the magnitude and direction of a color-difference between the notice pixel and neighboring pixels disposed adjacent thereto is calculated, and a directional component which is a component of the color-difference vector in the specified direction is calculated. Further, a total density value which is a sum of the density value of the notice pixel and density values of the neighboring pixels is calculated, and a density reduction value is determined according to the directional component and the total density value. Then, the density value of the notice pixel is reduced by an amount represented by the density reduction value.