FORMING IMAGE ON MEDIA USING SCREENING TILE WITH THRESHOLDS DETERMINED BY DISPLACING CENTER OF EACH CELL SPOT FUNCTION ACCORING TO DISPLACEMENT VECTOR AND DITHER CURVE

A method of forming a screened image includes providing a contone image, a screening tile structure of M by N cells, a dither magnitude curve, a spot function for each of the cells in the screening tile, and a displacement vector for each of the cells in the screening tile. Threshold values for each of the cells are constructed by displacing the center of each cell spot function according to the displacement vectors and according to the dither curve. A halftone image is constructed from the contone image and the screening tile by comparing value of each pixel from the contone image to a corresponding threshold value from the screening tile. If the pixel value exceeds the threshold value set a corresponding pixel in the halftone image to one otherwise set the corresponding pixel in the halftone image to zero.