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Bug #10995

Exposure module : automatic mode does not help deflickering

Added by stockage divers about 4 years ago. Updated over 3 years ago.

Status:
Fixed
Priority:
Low
Assignee:
Category:
Darkroom
Target version:
Start date:
04/17/2016
Due date:
% Done:

100%

Estimated time:
Affected Version:
git development version
System:
all
bitness:
64-bit
hardware architecture:
amd64/x86

Description

Given several similar photos shot in manual mode for a timelapse, using the automatic mode in exposure module does not reduce flickering. Instead, the result can go as far as whitening out or blacking out some of the photos in the timelapse.
Step to reproduce:
- Take a random photo in the timelapse
- Adjust exposure in automatic mode so that the photo is correctly exposed
- Copy/paste the exposure to all the other photos
Result: Flickering is still present and some photos are largely over or under-exposed
Expected result : all photos have the same exposure and no flickering

Test samples:
http://wikisend.com/download/319804/IMGP7778.PEF
http://wikisend.com/download/190918/IMGP7779.PEF
Automatic exposure with percentile=55% and target level=-9.37EV will give good result on IMGP7778.PEF but not on IMGP7779.PEF (underexposed at -27 computed EC)

IMGP7779.PEF (15 MB) IMGP7779.PEF stockage divers, 04/17/2016 10:08 PM
IMGP7778.PEF (15.1 MB) IMGP7778.PEF stockage divers, 04/17/2016 10:12 PM

Related issues

Copied to darktable - Camera Support #10996: Rawspeed: PENTAX K-5 probably has wrong black levelNew04/17/2016

Associated revisions

Revision f20a6371 (diff)
Added by Roman Lebedev about 4 years ago

Exposure iop: raw_to_ev(): avoid unsigned underflow :(. Refs #10995

Technically this does change output, but:
1. Only for severely underexposed images
2. Only for very low percentile values

When the bug was happening, it was producing
visually obviously wrong results,
thus i call it a bugfix.

Revision c1be2cc2 (diff)
Added by Roman Lebedev about 4 years ago

Exposure iop: compute_correction(): use sep blacks. Refs #10995, Refs #10996.

For some cameras rawspeed provides some really bogus value
for black level, e.g for PENTAX K-5 it is reported as 512,
while sep blacks are calculated at ~67.

For deflickering it is really unfortunate.

Since this is the only place where we use black level,
and everywhere else we use sep blacks, let's just
average those. If sep blacks are wrong - we will notice.

Note: this technically does change the output,
but only in cases where rawspeed is lying.

Revision 21ae9464 (diff)
Added by Roman Lebedev about 4 years ago

Exposure iop: raw_to_ev(): avoid unsigned underflow :(. Refs #10995

Technically this does change output, but:
1. Only for severely underexposed images
2. Only for very low percentile values

When the bug was happening, it was producing
visually obviously wrong results,
thus i call it a bugfix.

(cherry picked from commit f20a63717ff42f007cbac7055e81149f52eb421c)

Revision c3dfcbb2 (diff)
Added by Roman Lebedev about 4 years ago

Exposure iop: compute_correction(): use sep blacks. Refs #10995, Refs #10996.

For some cameras rawspeed provides some really bogus value
for black level, e.g for PENTAX K-5 it is reported as 512,
while sep blacks are calculated at ~67.

For deflickering it is really unfortunate.

Since this is the only place where we use black level,
and everywhere else we use sep blacks, let's just
average those. If sep blacks are wrong - we will notice.

Note: this technically does change the output,
but only in cases where rawspeed is lying.

(cherry picked from commit c1be2cc2fbfe42d3c6c367be0e19046c5b00bad8)

Revision e9f10d74
Added by Roman Lebedev about 4 years ago

Merge remote-tracking branch 'upstream/master' into lab-io

  • upstream/master: (24 commits)
    Attach Xmp data to EXR files
    No caps for "darktable" in EXR comment
    Get a bugfix for cacorrect from RawTherapee
    Add Slovenian to available languages
    [l10n] Add Slovenian translation
    Fix lock/checkmark icons in prefs
    minor cleanups debug.lua
    Exposure iop: compute_correction(): use sep blacks. Refs #10995, Refs #10996.
    Exposure iop: raw_to_ev(): avoid unsigned underflow :(. Refs #10995
    lua complete rewrite of threading
    lua doc : skip documentation for the knight view
    noiseprofile: Add Canon G15
    Allow line lengths of 115 when formatting
    Fixup of my address in darktable-cli.pod
    [l10n] Swedish update
    Update French translation.
    Update French translation.
    Update French translation of the user manual
    Minor update of doc/usermanual/po/fr.po
    Watermark IOP: gui_update(): unselect all 9 alignment toggles
    ...

History

#1 Updated by Roman Lebedev about 4 years ago

  • System changed from Ubuntu to all
  • Affected Version changed from 2.0.3 to git development version
  • % Done changed from 0 to 20
  • Assignee set to Roman Lebedev
  • Status changed from New to Triaged

#3 Updated by Roman Lebedev about 4 years ago

#4 Updated by Roman Lebedev about 4 years ago

  • % Done changed from 20 to 100
  • Status changed from Triaged to Fixed

Thank you for this report.
Should be fixed now.
Will be part of 2.0.4

Please test, and do report if you manage to find something else wrong.

#5 Updated by stockage divers about 4 years ago

Tested with v2.04, I confirm this bug is fixed.
Thank you.

#6 Updated by Roman Lebedev over 3 years ago

  • Target version set to 2.2.0

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