hugin-devs team mailing list archive

[Christoph Spiel <cspiel@xxxxxxxxxx>]

Thank you for a report in exemplary form.  The small input image sizes
in particular are highly appreciated!

Enfuse weights each *overlapping* pixel of the input images at that very
pixel.  Naturally, if there is no overlap, there is nothing to weight.
The extreme case is no pixels at all, a hole in the image and then your
case where only a single image participates because of masking out all
others or, generally no image overlap.  Enfuse (and Enblend) simply copy
solitary pixels to the output image *unchanged*.  We could even issue a
warning on this case: "Nothing to fuse" or "Nothing to blend".

In your example the problem is homegrown by masking out all but one
image.  The luminance match for the default exposure optimum stems from
the non-masked image falling well into the maximum of the Gaussian with
mu=.5.  If you want to stick with your workflow and still want a
different mu, choose as un-masked image the one that best matches your
desired mu.


** Changed in: enblend
     Assignee: (unassigned) => Christoph Spiel (cspiel)

** Changed in: enblend
       Status: New => Triaged

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https://bugs.launchpad.net/bugs/1649122

Title:
  Enfuse brightness mismatch in deghosted area

Status in Enblend:
  Triaged

Bug description:
  Enfuse results in a brightness mismatch of dark deghosted areas when
  exposure-mu is decreased from its default value.

  Program Version:
  - enfuse 4.1.3 (could not compile 4.2)

  Platforms:
  - Debian Jessie
  - OS X 10.11.6 via MacPorts

  
  == Testcase Files ==

  https://www.dropbox.com/sh/8la13xukmfamjk5/AACI6mruatMEsZ27wZgl8ysha?dl=0

  Bracketed exposures:
  161022_tc2_7079.tif - RGBA
  161022_tc2_7081.tif - RGBA
  161022_tc2_7083.tif - RGBA
  161022_tc2_7085.tif - RGBA
  161022_tc2_7086.tif - RGB

  Enfused results:
  161022_mu00.tif - exposure-mu=0.0
  161022_mu02.tif - exposure-mu=0.2
  161022_mu05.tif - exposure-mu=0.5 (default)

  Commands to reproduce:
  $ enfuse --exposure-mu=0.0 -o 161022_mu00.tif 161022_tc2_70??.tif
  $ enfuse --exposure-mu=0.2 -o 161022_mu02.tif 161022_tc2_70??.tif
  $ enfuse --exposure-mu=0.5 -o 161022_mu05.tif 161022_tc2_70??.tif

  
  == Detailed Description ==

  Deghosting;
  All exposures except the lightest one (..7086) share the same alpha channel which masks a dark area in the middle of the image for deghosting of moving leaves. The masking is binary, there are no partially masked pixels.

  When I change the exposure-mu parameter from its default 0.5 to a
  smaller value to darken the image, the deghosted area stays much
  lighter than its surroundings. The problem does not occur when
  deghosting a bright area using pixels from a dark exposure.

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