Abstract: A method is provided for processing a relief raster image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel into several pass images that are printed using a printer with several colorants including a white colorant. For each pixel a relief part, a white part and a skin part are discriminated in order to combine the demands for height and color variation across the surface of the image. The skin part comprises pixels for which a colorant composition based on the color channels of the relief raster image is established. In order to print a color in the skin part that is independent of a height of the pixel, the relief part comprises an arbitrary colorant composition and the white part comprises mainly white colorant.

Abstract: A method is provided for processing a relief raster image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel into several pass images that are printed using a printer with several colorants including a white colorant. For each pixel a relief part, a white part and a skin part are discriminated in order to combine the demands for height and color variation across the surface of the image. The skin part comprises pixels for which a colorant composition based on the color channels of the relief raster image is established. In order to print a color in the skin part that is independent of a height of the pixel, the relief part comprises an arbitrary colorant composition and the white part comprises mainly white colorant.

Abstract: A method is provided for processing a rasterized relief image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel into several pass images that are printed using a printer with several colorants including a white colorant. For each pixel a relief part, a white part and a skin part are discriminated in order to combine the demands for height and color variation across the surface of the image. The skin part comprises pixels for which a colorant composition based on the color channels of the rasterized relief image is established. In order to print a color in the skin part that is independent of a height of the pixel and independent of the colorant composition of a neighboring pixels, pass images are composed that include only neighboring pass pixels that do not disturb the color forming of a pass pixel contributing to a skin part.

Abstract: A method is provided for processing a rasterized relief image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel into several pass images that are printed using a printer with several colorants including a white colorant. For each pixel a relief part, a white part and a skin part are discriminated in order to combine the demands for height and color variation across the surface of the image. The skin part comprises pixels for which a colorant composition based on the color channels of the rasterized relief image is established. In order to print a color in the skin part that is independent of a height of the pixel and independent of the colorant composition of a neighboring pixels, pass images are composed that include only neighboring pass pixels that do not disturb the color forming of a pass pixel contributing to a skin part.

Abstract: A method for generating a halftone image includes the steps of, for each input pixel, adding a previously determined error term to the input pixel value to obtain a modified input pixel value; determining an error diffusion threshold level based on the input pixel value; applying a quantization operation to the modified input pixel value using the determined error diffusion threshold level for obtaining an output pixel value; and determining an error contribution. The error diffusion threshold level depends on a result of a comparison operation performed between the input pixel value and a threshold value selected from a set of threshold values, the selection of the threshold value being based on the position of the input pixel in the input image.