Agfa-gevaert

Koen Van De Velde

Paul A Delabastita

Pieter Paul Vuylsteke

Paul Suetens

Luc Minnebo

The method reproduces an electronic image, having pixels, as a multilevel halftone image on a multilevel output device having N different allowed output values (possible density levels) by The real subset may be formed by the allowed output values closest to the input pixel value. The quantization may be done by an error diffusion algorithm The used method prevents occurrence of pixels having deviating densities distorting the output image.

Adequate quantisation in multilevel halftoning

A method of correcting artefacts in a processed digital image represented by a multi-scale gradient representation being obtained by non-linear processing of a multi-scale gradient representation of an original image. A modified gradient representation is generated by modifying gradient images of the multi-scale gradient representation of the processed image so that the directions of the gradient images are pixel-wise equal to those of the gradient images of the multi-scale gradient representation of the original image. A reconstruction algorithm is then applied to the modified gradient representation.

Method for correcting artefacts in a digital image

A multi-resolution representation is generated of at least one color component of a color image in a selected color space by applying a decomposition procedure to the color component. The multi-resolution representation(s) is (are) modified by application of at least one non-linear modifying function. Next, modified color component images are generated by applying the inverse of the decomposition step to the modified multi-resolution representations(s).

Method of enhancing color images

A multi-level printing process using a printer by converting electronic page data to multi-level bitmap data with a specific number of gradation levels Nlev at a specified spatial resolution higher than that of the printer; converting the multi-level bitmap data to a lower spatial resolution; reducing the number of gradation levels by a processing technique to some lower number Nlevp giving a second multi-level bitmap; and printing the multi-level output bitmap by a printer having at least Nlevp different gradation levels at a single pixel location.

Growing community of inventors

Duffel, Belgium

Koen Van De Velde