Doing chromakey through Runrev

[Jacques Hausser]

Hi Jonathan,

I'm surprised that nobody answered till now. I did not try  
chromakeying myself, but I would suggest
1) to sample the color of blue background (perhaps at different places  
to get an amplitude of variation of the color - it is never absolutely  
constant) with the mouseColor function. Alternatively, put arbitrary  
limits at + - n pixels of each channel of the sampled color.
2) to identify pixels of the image of which the color is in these limits
3) to set the corresponding pixels of the alphadata or ot the maskdata  
of this image to 0. Then the image with be transparent except for what  
you want to keep
4) to replace the  pixels of the imageData of your new background  
image by the non-transparent pixels of the first image
-- or alternatively to put the partially transparent image over the  
background image, what allow to change the scale, for example, and  
then to use a snapshot to merge the two images (at screen definition)
6) to use the alphadata or the maskdata of the first image to identify  
the limits of the incrusted one, and to apply some blurring algorithm  
to the pixels around this limit. Without that, the limit will appear  
jaggered.

The two images must of course have exactly the same dimensions in  
pixel rows and columns. Look at the dictionnary for imageData,MaskData  
and alphaData for details... and tell us about your experiences !

good luck

Jacques

Le 16 nov. 2008 à 21:59, Jonathan Lynch a écrit :

> Does anyone have any suggestions on how to do professional-quality
> photographic chromakeying (like blue screen or green screen) with  
> RunRev?
>
> -- 
> Do all things with love
> _______________________________________________
> use-revolution mailing list
> use-revolution at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your  
> subscription preferences:
> http://lists.runrev.com/mailman/listinfo/use-revolution

******************************************
Prof. Jacques Hausser
Department of Ecology and Evolution
Biophore / Sorge
University of Lausanne
CH 1015 Lausanne
please use my private address:
6 route de Burtigny
CH-1269 Bassins
tel/fax: 	++ 41 22 366 19 40
mobile:	++ 41 79 757 05 24
E-Mail:	jacques.hausser at unil.ch
*******************************************