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During a recent wedding, I took a number of shots with my Nikon D90 at different exposures, hoping to merge them into HDR pictures. However, it was done in a hurry, i.e. with no auto-bracketing or tripod, etc. The images are of people standing, with bright sky as background.

When I use Hugin's align_image_stack command to align the images, and enfuse to do an exposure merge, the resulting image has a noticeable border around where the background (sky) merged with my subject like this:

enter image description here

Is this a problem with the alignment? It is possible that both my subject and my hands moved a little bit between the shots.

In any case, is there a way to salvage these photos so that I can still merge them into a correctly exposed shot?

I have access to Hugin, GIMP, and pfstools right now.

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1  
Why not just do a manual alignment with Hugin? If that doesn't produce the desired results, it sounds like you need to setup some layers with the HDR output and one of the original files and do some masking. –  dpollitt Jan 2 '12 at 20:48
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If you could post a crop of your current result (the "border"), it'd be much easier to see what problem you're having. –  Imre Jan 2 '12 at 21:10
    
@Imre I have attached an example of the problem. Thanks for suggesting it. –  hpy Jan 4 '12 at 21:33
    
If you shot in RAW, you can use 1 single image to perform tone-map instead of 3 exposures. –  rockacola Jan 4 '12 at 22:20

2 Answers 2

up vote 3 down vote accepted

I would align the pictures by hand in GIMP before attempting the HDR processing. Just load them all in layers, pick one as a reference then transform the others to match. You may need to translate, rotate and/or scale to achieve the best alignment. If a perfect alignment is not possible, then favor the high-contrast border areas, like where the sky meets the horizon, trees, etc.

Then do the HDR processing with these manually aligned pictures, skipping the align_image_stack step. Hopefully you'll get a better result that way.

If the people moved between shots (more than likely they did) and that resulted in blurring, then bring into GIMP that blurry tonemapped shot along with one of your source images, the one where the people is best exposed. Do manual surgery in GIMP to insert the people from the good LDR shot into the tonemapped picture.

Good luck.

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Do you mean as I transform one layer to match another, I save this transformed layer as a separate image, then try enfuse on it? Please also see my attached example image of the problem. Thanks! –  hpy Jan 4 '12 at 21:34
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@penyuan: Yes. Take the two original images, load them as layers into GIMP and figure out how to transform one to match the other. Concentrate on the trees more than anything else, you want the borders between trees and sky to match perfectly. If you can make the head match as well great, of course. Then enfuse with the aligned images. Finally, if the head comes out blurred, then replace it with the one that looks best from your two source pictures, then use the clone tool to clean up. –  Miguel Jan 4 '12 at 23:39

Photomatix allows you to select one exposure for specific areas of the frame. It's the best HDR program I've tried.

Here's an example, that includes people walking and moving around between exposures:

enter image description here

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