US 2003/0117653 A1 · Adequate quantisation in multilevel halftoning

Abstract

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 choosing for any pixel p a real subset Sp containing Np allowed values out of the set S of N allowed levels quantizing the input pixel value of the pixel p to obtain an output pixel value out of the Np values in Sp by means of a halftoning algorithm, rendering the image by rendering the pixels with the output device using the obtained output pixel values. 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.

Claims9

Dependent claims

A method for reproducing an electronic image, comprising pixels having an input pixel value Ip, on a multilevel output device having N allowable output pixel values, comprising the steps of:

for each pixel p choosing a real subset Sp from said N allowable output pixel values, said subset Sp containing Np allowed output pixel values where 0<Np<N,
halftoning said electronic image by a multilevel halftoning algorithm by quantizing, for each of said pixels, said input pixel value to obtain a corresponding output pixel value out of the Np allowed values in Sp,
rendering said image on said multilevel output device by rendering said pixels using said obtained output pixel values.

Dependencies are inferred from the claim text.

Adequate quantisation in multilevel halftoning

Life of this patent

Adequate quantisation in multilevel halftoning

Life of this patent

Abstract

Claims9