Oce-Nederland B.v.

Abraham Moolenaar

Petrus A Cornelissen

The invention relates to a method and device for reproducing grey values by reproducing pixels with specific dimensions and degrees of coverage. Use is made of a method based on error diffusion, wherein no clustering of identical pixels is the objective in edge zones while such clustering is the objective outside such zones.

Method and image reproduction device for reproducing grey values using a

A method and device for parallel intralinear halftoning of digitized grey value images divided into lines pixels, including (1) successive thresholding of grey values of the pixels and (2) transportation of a quantization error for each pixel to at least one neighboring pixel still to be thresholded by adjusting the grey value of the at least one neighboring pixel with at least a portion of the quantization error. The halftoning includes: dividing each of the lines of pixels into at least two disparate groups of pixels; separately thresholding each group of pixels within each line; and transporting the quantization error from a pixel of one group to at least one pixel of at least one other disparate group.

Method and device for intralinearly halftoning digitized grey value

In the coding of image data corresponding to a raster of pixel values, a generalized run length coding is used in respect of the difference between the pixel values in the raster line to be coded and the pixel values in the same position in the preceding raster line, such that with respect to multi-value pixels (gray values), the generalized run length coding comprises an approximation of the course of the differences as a function of the position in the raster line with a linear function and the code then contains the number of pixels and a characterization of the approximating function, and with respect to binary pixels (on/off), the length is simply a determination of the series of pixel values each equal to the pixel value in the same position in the preceding raster line, wherein in a particularly effective embodiment, this generalized run length coding with respect to the preceding line is combined with generalized run length coding of the pixel values within a line, both methods each being performed in parallel, and the method delivering the most effective code that is the longest series of pixels, compensated for by the length of the code itself, is selected for the actual encoding.

Method and apparatus for coding digital image data

The original image reproduced on a pixel raster is taken apart into a number of adjoining pixel structures and these are each replaced by a resolution-independent replacement surface, in accordance with rules described in the application. The replacement surfaces together form a resolution-independent intermediate image which is mapped on a new pixel raster with the required different resolution.

Growing community of inventors

Venlo, Netherlands

Abraham Moolenaar