How to reduce glare from glass during photo editing?

Question

I have taken a picture of a person standing inside the house via a window.

being outside, of course there is glare. I don't mind the glare as an artistic item, but wondered if there is a way to control the level of glare?

I am using paint.net as my main "power" editor, but Picasa picnik also is an option.

Answer

This looks like an image that you can never take again, so the issue is not how to improve a retake, but to rescue what information you can.

If you could return to the scene under identical outdoor lighting conditions, with the same objects in the background, and from the same location re-shoot the window into an empty unlit room, then you could (a) register the glare in the new photo with the glare in the old and (b) subtract it from the original photo. The result would be imperfect but it could reveal some details currently obscured in the center of the photo.

If perhaps you took more than one photo at that time and the subject in the window moved or changed substantially, then you might already have most of this information, because you could again (a) register the glare in one photo to that of the other, (b) compare the two images to identify changes larger than the registration error, and (c) subtract out the areas that did not change.

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