Patent ID: 8934142
Filing Date: 2015-01-13
Classification: H04N

Abstract:
1. A method of determining a halftone screen for use in transforming a continuous tone image into a halftone image, the method comprising the steps of: (a) determining a first halftone tile for a first gray level, the first halftone tile comprising a plurality of pixels locations; (b) selecting a plurality of the pixel locations to form a pixel pool; (c) selecting a subset of pixel locations from the pixel pool; (d) increasing intensity of pixels at the selected pixel locations to activate the pixels to form a second halftone tile for a subsequent gray level; (e) generating a filtered image of the second halftone tile; (f) selecting n activated pixels from the pixel pool having the highest density in the filtered image and n non-activated pixels from the pixel pool having the lowest density in the filtered image; (g) moving the intensity added from the n pixels having the highest density to the n pixels having the lower density to generate a new second halftone tile; (h) repeating steps (c) to (g) until a predetermined condition is met; (i) determining the halftone tile for the current gray level as the final second halftone tile; (j) removing the n selected pixels from the pixel pool; (k) repeating steps (c) to (j) until the pixel pool is empty for each subsequent gray level; and (l) determining a halftone screen comprising a plurality of the final second halftone tiles.