Tom Hodson on Nostr: Is there a name for an image operation where you start with an RGB image, then ...

Is there a name for an image operation where you start with an RGB image, then subtract out a background color and solve for the RBGA image that will give you the original image when composited onto that background?

I was looking at the nice pictures on mixtela's latest post [1] and enjoying how well then blend into the background.

I downloaded the image and it's a jpeg with no transparency, presumably just taken in a nice white photo booth.

But I wondered could you swap out the white for transparency so you can put this image over other background colours?

[1] https://mitxela.com/projects/fluid-pendant