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Bug #10978

rawprepare can produce very different results in preview and full pipe

Added by Pedro Côrte-Real over 3 years ago. Updated over 1 year ago.

Status:
New
Priority:
Low
Assignee:
Category:
-
Target version:
-
Start date:
04/03/2016
Due date:
% Done:

0%

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

Description

Before I forget again here are the steps to reproduce this issue:

- Open any image and go to "raw black/white point"
- Take one of the four black levels and move it up to a high value (to make it obvious)
- At this point the preview and the full pipe produce very different results (see the attached screenshot)

My understanding is that this happens because the preview pipe is using a demosaiced RGB image and then applying the wrong blackpoint to each of the channels. In most cases this doesn't matter because the blackpoints are similar enough between all four channels that the preview isn't too off.

To fix this properly we probably need to use FC and FCxtrans() to figure correspondence in bayer/xtrans and CYGM may be trickier. For the same reason as CYGM the green channel is also going to be more complex because it has two different blackpoints. A full fix would be to make MIPF 4-channel (RGGB) instead of 3 (RGB) all the way through to demosaic where it would get turned into 3 channel. This would also simplify CYGM a bit. Since this is mostly a correctness issue and in real world usage doesn't show up much (at all?) we can also just ignore it.

rawprepare_pipes_difference.png (477 KB) rawprepare_pipes_difference.png Pedro Côrte-Real, 04/03/2016 03:51 PM

History

#1 Updated by Roman Lebedev almost 3 years ago

  • % Done changed from 0 to 50
  • Assignee set to Roman Lebedev
  • Status changed from New to In Progress

#2 Updated by Roman Lebedev over 1 year ago

  • % Done changed from 50 to 0
  • Status changed from In Progress to New

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