[ptx] Re: Enblend suggestion: focus score weighting

[Andrew C Mihal]

On Fri, 18 Jun 2004, Sebastian Nowozin wrote:

> And even if such tool would know about the global overlap and choose the
> best focused pixel everytime, erasing all others, enblend would have
> nothing to blend between, as there is only image whose pixel is enabled
> for every global pixel.

This is definitely a danger. It should only erase a pixel if it is 
characteristically bad, and try to leave as many overlapping pixels as 
possible. It must also avoid excessive fragmentation of the images. If you 
end up with lots of little disconnected in-focus areas, then it is likely 
they will end up being redundant and ignored anyway.

> Maybe such intermediate tool could produce an additional alpha-mask for
> each image and enblend would use that alpha mask as "focus weighting"
> and adjust the blending to prefer pixels that are in focus, but falling
> back to unfocused ones if no other is available.

I worry that the focus weight and enblend's blend mask weight are mutually
exclusive metrics. Imagine a region where the blend mask says image A 
should be mostly faded out. What if image B is mostly out-of-focus there? 
If you give A extra weight, there will be a splotch.

Andrew

---------------------------------
Andrew Mihal
www-cad.eecs.berkeley.edu/~mihal
mihal at eecs.berkeley.edu