BoundsFinder borked?

Studio Operators Bugs Composer

 

Hi there.

I want to determine the Domain of Definition (DoD) of an image and found the BoundsFinder to probably be the tool of choice.

My workflow is

Video In -> ChromaKey -> BoundsFinder ->(triggering some other stuff).

While the ChromaKey delivers a Matte as expected, the BoundsFinder outputs erratic Values for Top Bound X and Bottom Bound X.

This could be tested pretty easily by feeding a Solid Color (say...1920x1080) into the BoundsFinder.
It will then output 1918 for *both* Top & Bottom X, whereas something like 0/1920 would be the expected values.

Am I doing something wrong, or is this a bug?

Cheers & all the best.

Eric.



   EricWest

 
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Eifert@Aximmetry
5/25/2022 1:06:41 PM
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Hi Eric,

The Chroma Keyer module produces a black and white matte, where black is the keyed-out part.
While the Bounds Finder module works with alpha.

So you need to turn the black and white into alpha. Aximmetry has a module that does just that, called the Alpha Merger module:

Note however that Bounds Finder finds the top most pixel and bottom most pixel. That is why the output pins are named Top and Bottom.

If you also want to find the left most and right most pixel, you will have to rotate the image like this:

Warmest regards,

 
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EricWest
5/25/2022 1:17:06 PM
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Hi @Eifert.

Ahh...okay...I was misinterpreting the name 'Bounds' as well as 'Top' and 'Bottom'.

From the name of the tool I was expecting to get the typical 2D BoundingBox (aka Domain of Definition)
in terms of TopLeftPixel(X,Y) and BottomRightPixel(X,Y).

Maybe a tool like that would make a good feature request? ... :-)

Cheers & all the best.

Eric.


 
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Eifert@Aximmetry
5/25/2022 1:44:22 PM
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Hi Eric,

This gives you the TopLeftPixel(X,Y) and BottomRightPixel(X,Y):

For example, you can crop along the bounding box lines like this:

Sadly, the "Bounds Finder" name for the module is quite misleading.

Warmest regards,

 
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EricWest
5/30/2022 6:50:37 AM
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Hi Eifert.

Brilliant! Thanks for the setup. This works like a charme!

Cheers & all the best.

Eric.


 
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ahmed ahmed
5/30/2022 12:19:18 PM
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Hi Eifert

Can you add your suggestion as linked compound to aximmetry Common package library ?

I mean this suggestion




 
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EricWest
5/30/2022 1:08:37 PM
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That's a good idea.
I would even think that making this into a 'real' tool should be comparably simple for the dev team.

In the mean time, what prevents you from building it according to the screenshot?... :-)
(Which brings up another forum request.... could we attach files (like xcomps) to our posts?... :-))

 
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Eifert@Aximmetry
5/31/2022 2:55:20 PM
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Hi,

We will consider adding it to the library.

Eric, you can attach a link where people can download it, we suggest using google drive, like this: https://drive.google.com/file/d/19bahPX-sLZRSERHPzp2VEJlA-soiVpYw 

Warmest regards,