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-   -   'HDR' effect from single JPEG (https://forums.steves-digicams.com/hdr/165725-hdr-effect-single-jpeg.html)

MartinSykes Feb 4, 2010 2:35 PM

'HDR' effect from single JPEG
 
[EDIT]
This program has moved on a lot since the first version posted here. There is now a dedicated website available : http://www.autohdr.co.uk and it is still completely free to download. Here's a quick example from the latest version:

After:
http://www.martinandanna.talktalk.ne...oHDR4after.jpg

Before:
http://www.martinandanna.talktalk.net/img/AutoHDR4.jpg



Hi,

New to the forums - I recently stumbled across HDR photography and liked the images it produces. I know my next step should be to get a better digicam (mine doesn't even do RAW as far as I can tell) but in the meantime I've got a load of old jpegs that I wanted to do something with.

I tried a few freeware programs which just seemed to do some simple and unimpressive tone-mapping which wasn't the effect I wanted so I wrote my own program. I've put it here http://www.martinandanna.talktalk.net/autohdr.html if anyone would like to try it and feedback would be welcome. I've only been playing with it for a few days but I've found some ways to reduce halos in most pictures and keep sky and faces smooth in most situations. Got some more ideas but they'll be more work to program.

Very simple to use - you just open an image, process it automatically and save the result. There are a couple of options you can adjust but the defaults work well on most things I've tried. I think this is my favourite so far. I love the effect it gives on clouds and water.

Original:
http://www.martinandanna.talktalk.net/docs/Original.JPG

Processed on default settings:
http://www.martinandanna.talktalk.ne.../Processed.bmp

ewheeler20 Feb 4, 2010 3:57 PM

3 Attachment(s)
Wow. you made this program? I'm impressed! I have been really searching for a way to make a psuedo HDR out of a jpeg (my camera also does not take RAW). Is there a way to make the "new" image on the right side look like what will be processed before you actually hit the "process image" button"?

That may be my only critique at this point. It took a few minutes to process is why i say that. I would like to see a preview before it happens.

But that is great!

Here, i have included the middle exposure of a bracketed set I took for HDR purposes.
The second image is the psuedo from your program in default (then added saturation).
The third image is from all three exposures done in photomatix.

MartinSykes Feb 5, 2010 2:30 AM

My algorithm is pretty scaleable so I should be able to show a quick preview based on a scaled down image. With a small bit of work it should look exactly like the final version.

The program itself is based on a pretty simple concept but was quite tricky to get working right. It essentially measures the tonal range at many points on the image, interpolates between them to get a map and then applies a slightly different tonal mapping at every pixel. The first parameter just sets the level of mixing between the original and processed image. The second one controls how many sample points it uses and what is considered 'local' - LDR uses fewer points but looks at a large area round each. HDR++ uses lots of points and only a small area round each.

The other enhancement I was thinking of was searching for strong edges first and not measuring tonal changes across boundaries. If I get that right it should automatically remove the remaining halos that show up sometimes.

MartinSykes Feb 5, 2010 3:22 AM

Another one I just did:
http://www.martinandanna.talktalk.net/docs/nathis.bmp

simple Feb 5, 2010 11:24 AM

hey martin i will give it a go mate :) .....and see what i can come up with

Hards80 Feb 5, 2010 11:31 AM

i will give it a shot when i get home too

one thing i am noticing just from the few samples i have seen, and not trying it yet, it seems to be boosting global contrast maybe a bit too heavily.

MartinSykes Feb 5, 2010 1:42 PM

Thanks guys - There is a very soft/soft/normal/hard/very hard setting which is used to blend the final image with the original so you can reduce the effect easily.
I think I've got a breakthrough on the halo problem too. Will see how it goes and then post a few intermediate pictures explaining what it's doing.

Hards80 Feb 5, 2010 2:16 PM

1 Attachment(s)
Martin,

here is my test shot from your program.

The parameters were Soft / HDR++, no other processing.
HDR on top, original on bottom.

simple Feb 5, 2010 2:30 PM

haha im just uploading mine now ive also gone soft hdr as i think it gives the best results

simple Feb 5, 2010 2:38 PM

original
http://img694.imageshack.us/img694/3...stitch600a.jpg

autohdr pseudo soft / hdr
http://img17.imageshack.us/img17/1172/hdrsoft.png

above psuedo image with a little xtra editing
http://img20.imageshack.us/img20/9599/hdrsoftcopy.jpg

i find if you go any higher than soft the blue sky aquires a bit too much noise and dark patches but you have enough choices there so i guess it is not really a problem .


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