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Keying based on hue and saturation

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Chris Orcfilm
Keying based on hue and saturation
on Dec 10, 2017 at 11:12:01 pm

Hi all, likely overlooking the obvious here but hitting dead ends. I need to key the attached:

Keying the blue saturated area from the grey unsaturated area regardless of lightness.

Any suggestions are appreciated.

BC Canada


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Dave LaRonde
Re: Keying based on hue and saturation
on Dec 11, 2017 at 3:33:22 pm

When you key, you create transparency in the keyed areas. Is there a reason you need to create such transparency?

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Simon Ubsdell
Re: Keying based on hue and saturation
on Dec 11, 2017 at 6:58:54 pm
Last Edited By Simon Ubsdell on Dec 11, 2017 at 8:24:53 pm

[Chris Orcfilm] "Keying the blue saturated area from the grey unsaturated area regardless of lightness."

Your problem is that despite what it may look like to the naked eye, your image is almost entirely blue.

Here's a map of where the blue is greater than either red or green. Only the few black areas are where another channel is higher than blue.



Even a very good HSV keyer isn't going to be able to identify the areas you are seeing as "not blue". And Ae doesn't have a good HSV keyer.

Edit: That said, you might want to try tweaking the image slightly with a Curves before applying the keyer, reducing the blue in the highlights. You can start to get a more reasonable result that way.





Simon Ubsdell
tokyo productions
hawaiki


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