Background Eraser Question

[Keithchr]

I have a jpeg of two people standing in front of some foliage. I want to use the background eraser to remove the foliage.
The tool removes most of the foliage but leaves small unerased areas all over. I have to go over it many times to remove everything which takes ages.
I am using the default settings for the background eraser tool. The only setting I have changed is the size (to 150).
It certainly does not seem as easy to use this tool as the Corel tutorial on background removal makes it seem!
Am I doing something wrong here? Any help or advice is gratefully received.
Thanks.

[LeviFiction]

The background eraser tool works better on areas of little color variation. The tutorial they showed, they were removing a sky with very little variation compared to foliage. Which is the big thing, it samples a color under the center of the brush and compares all of the colors that it moves over. Colors that match within a given tolerance are erased, but it also attempts to find edges and keep them intact. How sharp or soft the edges it finds are is determined by the "Sharpness" setting. the higher the sharpness the sharper the edges, and harder the erasing. The lower the softer the edges, and erasing starts going semi-transparent near the edges (similar to decreasing the hardness of the normal eraser brush).

It attempts to intelligently determine the tolerance automatically so that you can get more accurate result. And it's usually pretty good.

But Foliage is not going to be easy. Especially if shadowing makes the colors near the edges darker and somewhat matchy to the foliage.

I have two videos on using the background eraser tool (took me like 20 minutes to go over everything) but I doubt it'd be helpful to you in this case.

Start large with the brush to get the majority of the area. Then shrink the brush a bit and zoom in around the tougher areas. You want to make sure you're accurate as you get smaller. Once you've gotten it down to as good as you can, you can switch to other tools to finish the clean up. Selections, the normal eraser, and such like that really help in this situation.


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Another option, sometimes, is to duplicate the layer, then try running a few filters to really bump up the difference between the background and foreground of the image. This will make the erasing easier and doesn't destroy the original image. Once it's erased you can create a selection based on the transparency of the current layer. And use that to delete the background of the original layer.

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Depending on the difficulty of the image you might want to look into other tools. Yes in some cases they can take just as long but they might give better results.

For something like this I'd first try the Object Extractor (if you're using X3 to X5) and see if that can't get decent results. The one thing I like about the object extractor is that it doesn't actually delete the areas of the layer. So grabbing the eraser tool and using the right-mouse button I can get the areas back that the object extractor tool was a bit over-zealous about erasing.

If that doesn't seem to work you can try using the free-hand selection tool on either "edge seeker" mode or "Smart edge" mode and see if it can accurately trace the edges of the person or object you're trying to preserve. Once the selection is made you can invert the selection and delete the background that way.

Lots of ways to deal with difficult images when otherwise great tools become inadequate.

[Keithchr]

Thanks Levi.
A very helpful and comprehensive reply.

[photodrawken]

Another option, sometimes, is to duplicate the layer, then try running a few filters to really bump up the difference between the background and foreground of the image.

To expand on this suggestion, I've found it helpful in some cases to use Image...Split Channel to split the image into CMYK (or RGB, or HSL) images. Then use the Background Eraser on whichever split image gives the most contrast between the people and foliage. Back in the original image, use Layers...New Mask Layer...From Image to use the image transparency of your erased image as the mask. Finally, paint on the mask to touch up.

[brucet]

Tutorials always make background removal seem easier than it always is. I don't get on with it at all.
I find the eraser tool quicker. Then zoom in and resize and start again.

Every method I know will take time. Accept that it will require some work and try a number of methods. Once you find what works for you then practice will speed things up.
regards

[hartpaul]

And also consider a selection based on the people and invert it and delete.

[photodrawken]

Tutorials always make background removal seem easier than it always is. I don't get on with it at all.

If I had to pick my favourite tool, it would be "Old Reliable" -- the Background Eraser.

However, its use is for one purpose only: to get a nice transparent edge around a subject. After that, the Eraser should be used to eliminate everything else.

I might add that my method of separating an object from its background is to use a mask. All the tools I use, whether the Extraction filter, the Background Eraser, the Eraser, selections, etc., are simply means to an end -- getting a precise mask.