(I just now posted this as a feature request - that was before I found out you had a chat forum. Sorry, I'm new to Sourceforge, signed up today)
Hello. I've just finished reading your description of enblend
(http://enblend.sourceforge.net/details.htm) and it occurred to me when I
was reading about the pyramid and the detection/separation of spatial
frequency information, that this is a process that could easily be adapted
to taking two (or more) images of a single scene (not a panorama but almost
fully overlapping) - usually an extreme macro closeup - which were taken
with different focus depths, and extracting the in-focus information from
each and blending them so that the composite image had the focused parts
from each of the inputs, i.e. a simulated increase in depth of field.
Now, there is seldom anything new in computing, so having had this idea I
did a search to see if anyone had done it before or had written code to do
this function. What I found first was a paper on increasing depth of
fields using wavelets
(http://bigwww.epfl.ch/publications/forster0401.html), so I still had hope
that this was a new algorithm :-), but my hopes for having found a new
algorithm were dashed when I saw this page:
*HOWEVER* I can't find anyone who has actually implemented this algorithm
in free software (although I did find one commercial implementation:
I wish I had the expertise to add this feature to your program but my
programming expertise lies elsewhere (I'm not innumerate but I tend to be
weak on anything that involves higher maths; I remember starting to
struggle a bit at university 30 years ago when we got to FFTs... that's
about my limit), so...
I was hoping you or one of your collaborators might be interested in adding
this feature to your program (or creating a spin-off program with 99% of
the code base in common but the panorama interface removed for
My interest in this comes from being a nature photographer and frequently
not being able to focus on an entire butterfly, beetle, or even flower when
using a good macro lens which unfortunately has an almost paper-flat depth
of focus. I frequently will have the front wing of a butterfly in focus in
one frame and the rear wing in focus in the next, but am unable to focus on
both simultaneously unless I'm very lucky and catch a butterfly basking in
the sun with its wings flat :-)
I'll be more than happy to supply images that would make good tests.
One small complication *may* be that the camera moves a tiny amount forward
or backwards between frames, making perhaps a 1% difference in scale. From
reading the autosift documentation, it sounds like the SIFT algorithm
should compensate for that. However until we try to align some images I
don't even know if it is an issue. Hopefully my hand is steady enough that
it doesn't happen.
Graham Toal <firstname.lastname@example.org>
PS The same code, probably unchanged, could also work for increasing the detail from a range of exposures (under, correct, and over) - in effect, a simulated fill-in flash.
> The same code, probably unchanged, could also work for increasing the detail from a range of exposures (under, correct, and over) - in effect, a simulated fill-in flash.
Also I forgot to mention improving resolution by sub-pixel
So... three things which are closely related,
* Resolution (sub-pixel registration)
* Focus/depth of field enhancement
* Contrast/dynamic range enhancement
All of which are closely related to enhance and hugin/autosift.
(Actually there's another closely related area I haven't mentioned, and that is 3D image registration and perhaps depth map extraction from focus info. Save that for another year :-) )
There seem to be more tools available for supperresolution and contrast enhancement than there are for depth of field enhancement.
Although it would be nice to have a toolset which did all of the above, I don't want to be greedy, so my enhancement request is only for the original suggestion, which was enhanced depth of field - which I'm hoping will 'fall out in the wash' due to the pyramid data structure that you've already computed, and so with luck it won't be a major hack to add...
PS. Still Googling now I have a few new keywords to try... found this,
it seems to do the right function but not very well... maybe because he's using an FFT to find the focused areas? http://www.hadleyweb.pwp.blueyonder.co.uk/CZ5/combinez5.htm -
His 'problems' page highlights issues that I don't think
we would see using software like enhance:
After about three hours of Googling :-( I finally found the original web page that got me interested in this subject - this guy uses a commercial package called "syncroscopy" to photograph beetles. Some of the images in his set are quite superb:
(Tool: http://www.syncroscopy.com/syncroscopy/am.asp )
By the way, here's another page on the subject:
Looks like PanoTools has a hacked version of the code (uses the red channel only, for focusing - again, just short of ideal, still haven't found a completely free and technically excellent solution)
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