[Sidefx-houdini-list] COPS - Average Colour Luminance in Image

Mark Alexander malexander at sidefx.com
Thu Apr 19 14:46:10 EDT 2007

> Mark A showed me a cool way of doing this using CHOPs. Read the
> whole image into CHOPs then... 

Yes, you read the entire image into CHOPs via an Image CHOP (Alpha = 
none, Crop = Full Image), then append an Area CHOP, then trim the 
channel to the last frame using a Trim CHOP, then use a Math CHOP to sum 
the channels, and then use another Math CHOP (or, the same one) to scale 
the value by 1/(xres * yres). You'll end up with a single channel with a 
single point, and that will be the average value.


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