I'd have to look it up and I'm not home at the moment. Can see later on. I would have thought that it would be normalized to have a jnd equal to 1 but I'm not sure.
Ken Sent from my iPhone ___ Ken Knoblauch Inserm U846 Stem-Cell and Brain Research Institute 18 av du Doyen Lépine 69500 Bron France Tel : 04 72 91 34 77 Fax : 04 72 91 34 61 portable : 06 84 10 64 10 http://www.sbri.fr/members/kenneth-knoblauch.html On 1 juin 2013, at 18:44, "John Fox" <j...@mcmaster.ca> wrote: > Hi Ken, > > I just tried that, and with a distance of 15 as the criterion, which seemed > to work well for Lav distances, I get fewer matches for the following example > that we've been using: > >> cols <- c("#010101", "#EEEEEE", "#AA0000", "#00AA00", "#0000AA", "#AAAA00", >> "#AA00AA", "#00AAAA") >> (nms <- rgb2col(cols, near=15)) > [1] "black" "gray93" "firebrick" "#00AA00" > [5] "#0000AA" "#AAAA00" "#AA00AA" "lightseagreen" > > Do you know what a JND is supposed to be on the Luv distance scale? The > Wikipedia article on CIELUV colours doesn't say. > > Best, > John > >> -----Original Message----- >> From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- >> project.org] On Behalf Of Ken Knoblauch >> Sent: Saturday, June 01, 2013 12:18 PM >> To: John Fox >> Cc: <r-help@r-project.org>; Michael Friendly; Martin Maechler >> Subject: Re: [R] measuring distances between colours? >> >> Hi John, >> >> Out of curiosity and if it is not much trouble, I would be curious if >> Luv worked any better than Lab. I think that Luv is supposed to be >> preferred for monitors and Lab for surfaces but they are generally >> pretty similar. >> >> Best, >> >> Ken >> >> Sent from my iPhone >> >> ___ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
