This function performs Ulichney's [1] perturbed error diffusion using Floyd's and Steinberg's [2] 4-weight error filter and a 50% perturbation between weights 1-3/16 and 5-7/16.

y = ulichney(x)

y = ulichney(x) calculates the error diffusion halftone pattern, y of type uint8(logical), for grayscale image x with perturbed filter weights and a serpentine scanning order.
and also returns the count c of the sample windows (periodograms) for the calculation of sample variance.

See Also
errdif, dotdiff, bayer, cdod

[1] R. A. Ulichney, Digital Halftoning, MIT Press, Cambridge, Mass., 1987
[2] R. W. Floyd, and L. Steinberg, An adaptive algorithm for spatial grayscale, Proc. Soc. Inf. Displ. 17, 75-77 (1976).

Daniel L. Lau, Dated: 02/22/1997, Updated 04/16/04.

Dr. Daniel Leo Lau
Department of Electrical and Computer Engineering
University of Kentucky
453 Anderson Hall
Lexington, KY 40506-0046, USA
(859) 257-2300 x273

last edited on 4/19/04