Ghosting compensation in relief images for directional prints

摘要

A method is provided for combining two source images in a relief image with structural elements having at least two principle surface orientations, such that a first image is observed in a first viewing direction and a second image is observed in a second viewing direction. The method reduces a ghosting effect and comprises the steps of: a) printing a test relief image comprising patches with structural elements having a first basic colour on a surface with a first principle orientation and a second basic colour on a surface with a second principle orientation, a basic colour being a colour having a predefined amount of colorant; b) measuring for each patch a first observed colour in a first viewing direction and a second observed colour in a second viewing direction; c) scaling a first source image and a second source image such that each image element has a size corresponding to a structural element in the relief image; d) selecting for each position in the relief image a structural element from a patch in the test relief image, wherefor a sum of a colour difference between an image element of the scaled first source image and a first observed colour and a colour difference between an image element of the scaled second source image and a second observed colour becomes minimal, and e) composing a relief image from the selected structural elements.