[ptx] Enblend Multiresolution Spline Blender

[Terje Mathisen]

JD Smith wrote:

> On Sun, 2004-03-07 at 01:41, Terje Mathisen wrote:
>>I.e. the key idea behind enblend (and the pyramid blender) is to 
>>effectively split the two source images into multiple layers, according 
>>to detail frequencies. This means that there is no way to conver this 
>>into just a single blending mask.
> 
> I agree.  Obviously this is more complicated than simply formulating a
> good set of alpha masks and stacking (otherwise there wouldn't be papers
> on it ;).  What I envision is changing both the mask and the image data
> in the file, with some compromise made to deliver one mask and one image
> per input image, such that, without modification, the alpha-stack would
> be exactly equivalent to the result of a full run, and yet some
> flexibility is still preserved for fiddling.  Since I don't know the
> algorithm well, it's not immediately obvious if a useful such factoring
> is possible, e.g.:
> 
> sum(i){newimage[i] * newmask[i]} == sum(i){sum(f){weight[i][f] * image[i][f]}}
> 
> where f is the frequency, and image[i][f] is the f blurred frequency
> image of image i.  I imagine for most regions it should be very possible
> to come up with a useful factoring into newimage and newmask.  It's
> certainly trivial to come with any number of valid factorings (e.g. set
> newmask=1): the trick is to make them useful.  

I just got an idea: What about a simple option to leave the original 
(mapped) source images in the output?

I.e. go from an N-layer input file to an N+1 layer output file, with all 
the original source images hidden:

If you then discover any tiney mistakes/ghosts/duplicated moving objects 
etc, you can fix it by selectively making gaps in the mask layer of the 
blended image, recovering the original output.

It would also be possible to do the same today, by loading the enblend 
output as a new layer on top of the m_TIFF input file. Since they are of 
the same size, this is easy, right?
:-)

Terje

-- 
- <Terje.Mathisen at hda.hydro.com>
"almost all programming can be viewed as an exercise in caching"