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Photo enhancement


neddie
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Has anyone heard of or used this program called Photomatix ( http://www.hdrsoft.com ) ?

The idea is to take a set of photos of the same subject but with different exposure settings. So for example one photo might have the foreground nicely exposed but the sky has all the details bleached out of it. A second might have the foreground far too dark but with some nice colours and details in the sky. And so on. Then the program combines all the photos into one result, so all parts of the picture show up together. Sounds like a great idea, and the examples on the site look pretty cool. But the program is windows-only.

 

My question is, would it be possible to magic up something similar with other tools? If I had a series of photos of the same subject, I could use hugin to stitch them together into a multi-layer tiff. So all I would need then is for the Gimp to have some plugin etc which would combine the layers in such a way that the best bits of each layer were used to form one single image. Preferably without manually drawing lassoos around the bits which would be tedious as well as prone to making nasty joins.

 

Any ideas how this could be done?

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Simple stuff can be done in Gimp but this is where the Gimp is really stuck being 8-bit ....

The way to do a simple one is to make two images .. with different exposure settings (works best from raw files not jpeg) and then apply one as background and another as foreground...as layers...

 

Then you use the gradient filter and set one to background and the other to transparency...

 

The problem is you will see the gradient in 8bit...

 

if your interested i have a few Ive done but its no match for photoshop.... not even close in this.

you might try lightzone ?

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Thanks, lightzone looks interesting, I'll have a look. Looks a bit similar to Digikam's image editor, but maybe it's got some extra tricks.

 

And yes I'd thought of a gradient filter but maybe the horizon is not horizontal or regular, or maybe the daylight is visible through a doorway smack in the centre, etc.

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Thanks, lightzone looks interesting, I'll have a look. Looks a bit similar to Digikam's image editor, but maybe it's got some extra tricks.

 

And yes I'd thought of a gradient filter but maybe the horizon is not horizontal or regular, or maybe the daylight is visible through a doorway smack in the centre, etc.

Different techniques to try are....

if its not horizontal no prob, you draw the gradient line non horiz or even use a circualr gradient (for example light through a window doorway)

but in general a burn tool works on the door prob...

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  • 4 weeks later...

Just an update, I noticed Gowator's link during this rant which told me about a free app called qtpfsgui (what a horrible name! :o) Unfortunately it doesn't look like this is available in rpm form (I looked in urpmi and on rpm.pbone.net) so it looks like the only option is to try to compile it from source.

 

In the meantime, a couple of other possibly interesting links: the all knowing Wikipedia has an article on High Dynamic Range imaging. And there's a flickr group trying (with varying degrees of success) to do the same using Gimp. There's an example at gimp.org but it's exactly what I didn't want - manual fiddling with the join, that'll take ages and it's bound to look scraggy at the end of it. This photoshop tutorial looks more like it, using whole-image functions rather than manual brush strokes. I hate the look of their final image though, all washed out and bland.

 

And lastly, another flickr page on using psftools from the command line to merge photos. Don't want to mess with the command line myself but this qtpfsgui program includes psftools so hopefully will do a similar job.

 

I'll post an update if I get this thing compiled and running...

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Hey! Yeah both photomatrix and the other dodgy named app LOL! are basically performing what is known as Tone Mapping!

 

It has all sprung up from HDR Imaging for 3D and other Post Effect apps! HDR lets you simulate realistic lighting conditions in 3D environments. It works because you have photos with multi exposure values. Some have detail in the shadow areas and others have detail in the highlight areas.

 

Basically 'Tone Mapping' is an attempt to convert an HDR file (which cannot be displayed on a screen! Well not all at once) into a file that is 24bit and visible on a normal screen!

 

It makes some amazing imagery! I have been playing with it for quite a while now!

 

The app with the dodgy name, works well on windows, except it is very memory hungry and a tad slow!

 

Well, cheers all!

 

C

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