New KIPI-plugin in the repos: Expoblending

[newmikey]

For a lot of people this will sound like old news as it was already published back in March on the digikam website with the release of the newest version of Kipi-plugins. For those who do not yet know the parent-program, DigiKam:

"digiKam is an advanced digital photo management application for Linux, Windows, and Mac-OSX.

The people who inspired digiKam's design are the photographers like you who want to view, manage, edit, enhance, organize, tag, and share photographs under Linux systems."

I have only now downloaded "Expoblending" with a recent update through Synaptic but as shown on the DigiKam website, it is also available on MacOS and Windows. Expoblending uses align_image_stack(http://sourceforge.net/...itle=Align_image_stack#What_is_align_image_stack.3F) to register hand-held exposuresand Enfuse(Enfuse - PanoTools.org Wiki) to fuse the exposures.

Expoblending can work with JPEGs, TIFFs and even directly off of RAW files (including PEF and DNG) , where a bitdepth of 16 is maintained). Except for selecting the files to be processed and checking off a few options when processing the final images, the whole thing is fully automated. I have given it a try on a few handheld shots of the cathedral in Brussels that I took this weekend I'm quite satisfied with the userfriendliness of the processing and with the end-result. You can be the judge.

These were the original exposures (normal, -2 en +2 stops):


Lets start Expoblending:


And add three jpeg files (the eventual result will be an 8-bit PNG file):

or of course the RAW files, Pentax PEFs in this case(the eventual result will be a 16-bit PNG file):


We can now choose to have the three hand-held shot automatically registered:

This does take some time, especially when processing RAWs:

After which we are ready for the next and final step:


A few parameters can be adjusted to taste for Enfuse, which is normally a command-line tool such as having the levels adjusted automatically. You can obviously leave the last step out to be executed to taste in an image-editing package, like the GIMP.


And the final result can be saved:


This is the endresult, after some USM:


All of the screenprints are on my Fotki page Expoblend album | Mike Bing | Fotki.com

I feel that with exposure-blending the result remains more natural looking than with any HDR process I used. On top of that, noise is kept to a minimul, different lighting sources are replicated more as I remember having seen them and the amount of detail is exquisite. Not to mention the fact that a tripod is no longer essential!

[longtom]

Thank you for this.

In the old day we called it HDR and used otpfs for that.  Still a good option for the non KDE user. 

An excellent how to for that one will find in the February edition of the PCLinuxOS Magazine.

[everge48]

Great Howto! Thanks.

[newmikey]

Thank you for this.

In the old day we called it HDR and used otpfs for that.  Still a good option for the non KDE user.  

An excellent how to for that one will find in the February edition of the PCLinuxOS Magazine.

We still call it HDR and we still use QTPFSGUI for the "real" work although the program is now called LuminanceHDR . (Available through the PCLinuxOS repos) I would also like to point out that Gnome programs can be used under KDE and KDE programs can likewise be used under Gnome. All that's needed is some libraries and Synaptic will pull those in automagically. PCLinuxOS DPE (the Digital Photography Edition) is heavily reliant on KDE and Gnome apps running under.....LXDE!

There often is confusion between exposure blending and HDR and I would like to point out that the results are far from identical!

With HDR you are actually creating a 24 or 48-bit HDR image which cannot be shown on a normal screen or interpreted by the human eye in print as the dynamic range exceeds the ability of screen or paper to display all nuances. A process called tonemapping is then used to bring back the wide tonescale to one that we can display/print interpret. There are many different tonemapping algorithms of which I can mention f.i. Mantiuk and Fattal - many more exist. A tonemapping algorithm is basically a mathematical recipe of how to map each tone from the HDR image to a corresponding tone in a regular, or LDR, image.

Exposure-blending, as shown above with the Kipi-plugin, is fundamentally different in that no intermediary image with a wider dynamic range (hence "HDR") is created. The program will merely take correctly exposed sections from different images and recombine them to a new image, invisibly blending the seams  together.

In the example above, the dynamic range of each individual image is preserved by combining the stained glass windows from the underexposed version with other areas of the under- and correctly exposed ones into one image.

HDR has its uses but can be pretty ugly or unrealistic when pushed over the top, while exposure blending will usually result in a more natural-looking image. On the other hand, HDR has far more ability to compress an extremely wide dynamic range into an image than the more limited scope of an exposure-blend.

Thought I'd just make the point. I use both techniques and sometimes I like one better than the other or vice-versa. Until recently I used a GIMP script-fu for exposure blending but it was heavily dependent on the use of a tripod to make sure the images register without ghosting. This KIPI-plugin solves that issue and allows shooting without tripod.

[coffeetime]

WoW!

Great how-to. Thanks newmikey.

[longtom]

Thank you newmikey.

Certainly useful for me.  However - my Synaptic doesn't have a LuminanceHDR.  Any special repo you are having?

[AndrzejL]

Wow! I just found it! Well done!

Andy

[newmikey]

Thank you newmikey.

Certainly useful for me.  However - my Synaptic doesn't have a LuminanceHDR.  Any special repo you are having?

In our PCLinuxOS repos it appears as Luminance-2.0 with version number SVN691-1 and description "This is a graphical user interface (based on the Qt4 toolkit) that provides a workflow for HDR imaging."

Expoblending is avilable from the repos as "kipi-plugins-expoblending". Make sure you also install "Enfuse" as it is not pulled in automagically (although expoblending will complain if it is not installed.

[newmikey]

Just as a "by the way", this is the image derived from the same 3 raw shots but now processed as real HDR in Luminance with the Mantiuk8 operator. Levels and unsharp masking added in Gimp. It is easy to spot the difference with the result derived from exposure blending.

[Was_Just19]

Thank you newmikey.

Certainly useful for me.  However - my Synaptic doesn't have a LuminanceHDR.  Any special repo you are having?

qtpfsgui   in PCLOS repository .......  not yet changed to Luninance

[longtom]

Thank you newmikey.

Certainly useful for me.  However - my Synaptic doesn't have a LuminanceHDR.  Any special repo you are having?

qtpfsgui   in PCLOS repository .......  not yet changed to Luninance

Thanks JohnBoy - I thought I was going nuts....

[NimbusII]

Hi Newmikey.
                       It does a pretty good job HDR wise... very impressive. Just a shame it`s within digikam.. 

[newmikey]

Hi Newmikey.
                       It does a pretty good job HDR wise... very impressive. Just a shame it`s within digikam.. 

It actually works standalone as well - the entry in the menu is:
[Desktop Entry]
Categories=Qt;KDE;Graphics;X-MandrivaLinux-Multimedia-Graphics;
Comment=A tool to blend bracketed images
Icon=expoblending
Name=ExpoBlending

On my menu (KDE standard menu) it is found in the category Graphics

[Was_Just19]

Hi Newmikey.
                       It does a pretty good job HDR wise... very impressive. Just a shame it`s within digikam.. 

...
On my menu (KDE standard menu) it is found in the category Graphics

Same here