Method and device for generating halftone pattern for multistage output device

PURPOSE: To provide a method and a device for generating a halftone image for a multilevel output device using a dither matrix generated by minimizing a visual cost function. CONSTITUTION: This device is provided with a digital image source 10 such as a film scanner, digital electronic camera, computer graphic terminal or digital memory device storing digital images. The digital image source 10 sends the pixel value of No level to an adder 12 and successively sends the (x) and (y) addresses corresponding to the position of pixel value to modular arithmetic units 14 and 16. The modulus of addresses Nx and Ny (namely least significant bit) is fetched into the modular arithmetic units 14 and 16 and modular addresses Mx and My are respectively generated. COPYRIGHT: (C)1995,JPO