How to: Foreground object extraction with aliased border

[Radim]

Hello,

it is possible extract foreground from image if I have: 1) exact image of foreground and 2) exact image - foreground + object on it ---> so that I can get object which has fine--aliased borders?

I want exact object - so I do not want use Background Eraser, it is possible somehow mathematically??

[LeviFiction]

You do know that by setting the Sharpness value you can get the anti-aliasing or aliasing. But in the case of what you've just shown here, I was able to use the Arithmetic operation (Image->Arithmetic) to perform a difference evaluation on the two images. The result is a very ugly oval surrounded by black. I was then able to use this to either make a selection using the Magic Wand tool or make a mask from the image source luminance. If I did the mask I had to use Levels to get rid of the unnecessary grey portions.

Also you may have to do some painting of the mask for any areas that don't transfer well.

[Radim]

Thank you, I played with Arithmetics in PSP X2 - but can't fix correct extracted object transparency. Here is what I get:

[LeviFiction]

Again, you will have to do some editing. Threshold adds too many jagged edges. You want to keep the original transparency along the edges. Use something like "Levels" on the mask. This allows you to control how many colors are clipped. For example, by dragging in the white area many of the almost white pixels become completely white. By dragging in the black handle most of the nearly black pixels become black. By adjusting the midtones (greys) toward the white side most of the grey pixels will start toward white.

From there you can use a white paint brush to fill in the portions of the mask that didn't respond well.

There is no one step process, at least that I know of, for properly subtracting the background and keeping the anti-aliasing while unmixing the colors. So it's going to take some extra work on your part to get the mask looking the way you want it to.

[Radim]

Thank you. I understood, finaly.

EDIT: here are my simple steps, video - http://lib.uphero.com/object-extract/
EDIT 2: updated video, steps are now better visible.

[Ron P.]

What's up with your website? The link you provided goes to a page that says your website is under review for malicious content.

[LeviFiction]

I think the redirect page says it all.

The webhost that uses the uphero.com domain (000webhost) manually checks all of its free accounts to make sure all of the sites it has are free of malicious content. It's something they do for all of their sites not just the ones they suspect or have gotten complaints on.

[Radim]

I think the redirect page says it all.

The webhost that uses the uphero.com domain (000webhost) manually checks all of its free accounts to make sure all of the sites it has are free of malicious content. It's something they do for all of their sites not just the ones they suspect or have gotten complaints on.

Thanks, so I know that I am in right hands..?