On Thu, 7 Dec 2006, metafor wrote:
i am wondering if someone already did a patch to separate color channels in order to track some specific objects more easily. for example only display objects with have a certain red value (bigger 200 in RGB) and so on.
Don't do that, because then it can't distinguish between red, yellow, white and purple. There are a bunch of techniques for dealing with that. For example, use Red minus Green minus Blue, as a way to detect only Red but not other colours. (I did that for my currently-running exhibition with Andrée Préfontaine at Glendon Gallery, that has a fruit-controlled audio sampler)
I don't know how to do that in GEM, but in GridFlow, you just multiply each picture by a column matrix; e.g. here are objects for separating redness and greenness:
[#inner (3 1 # 1 -1 -1)] for the tomato slice [#inner (3 1 # -1 1 -1)] for the kiwi slice
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju | Freelance Digital Arts Engineer, Montréal QC Canada