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From: avi@dgp.toronto.edu (Avi Naiman)
Newsgroups: comp.lang.postscript
Subject: Re: Halftoning Algorithm
Message-ID: <1990Nov23.134554.24723@jarvis.csri.toronto.edu>
Date: 23 Nov 90 18:45:54 GMT
References: <225043@<1990Nov18> <49400002@primerd> <1713@chinacat.Unicom.COM> <1504@cluster.cs.su.oz.au> <7344@hub.ucsb.edu>
Organization: CSRI, University of Toronto
Lines: 32

In article <7344@hub.ucsb.edu> steve@tweedledee.ucsb.edu (Steve Trainoff) writes:

> In short, the FS algorithm works best on displays like CRT's or inkjet
> printers that don't have problems turning on single pixels.

Actually, contrary to popular assumptions, CRTs also suffer from this
spatial non-linearity.  The average intensity of a checkerboard pattern
of alternating black and white pixels will usually be darker than the
mean of the black and white levels (see, for example, [Mulligan and
Stone 89]).  In my work, I have found monitors on which the
space-averaged (normalized) luminance of a checkerboard is as low as 0.2,
rather than the expected 0.5 [Naiman 90].

%L Mulligan and Stone 89
%A Jeffrey B. Mulligan
%A Leland S. Stone
%T Halftoning Method for the Generation of Motion Stimuli
%J Journal of the Optical Society of America A
%V 6
%N 8
%D August 1989
%P 1217-1227

%L Naiman 90
%A Avi C. Naiman
%T The Use of Grayscale for Improved Character Presentation
%D 1990
%C Toronto, Ontario
%R Ph. D. Thesis, Department of Computer Science, University of Toronto
-- 
Avi Naiman
avi@dgp.toronto.edu