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Feature #11113

Camera-specific hot pixels

Added by Christoph Schmidt over 3 years ago. Updated over 3 years ago.

Status:
Incomplete
Priority:
Low
Assignee:
-
Category:
-
Target version:
-
Start date:
08/15/2016
Due date:
% Done:

20%

Estimated time:
Affected Version:
2.0.5
System:
Ubuntu
bitness:
64-bit
hardware architecture:
amd64/x86

Description

On my camera I get some hot pixels at longer exposure times, the higher the ISO the more. Using the "hot pixels" filter in darktable does not really give convincing results; sometimes playing with the filter parameters helps, but often I end up removing hot pixels by hand.

Therefore I would like to propose a different method to detect hot pixels: the user takes at least two photos at the longest possible exposure, one with the lens cap on to obtain a complete dark photo and one against a light source to obtain a complete white photo. On the dark photo will be some white pixels and vice versa. darktable could use these photos to locate the hot pixels and remove them. Possible improvements could be to provide one pair of photos for each ISO level and to add a switch which allows the application of the hot pixel filter automatically upon import of photos from the given camera.

hot pixels.nef (19.6 MB) hot pixels.nef Roman Lebedev, 08/25/2016 08:22 PM

History

#1 Updated by Roman Lebedev over 3 years ago

(can you be even less specific? :)
Which camera?

#2 Updated by Roman Lebedev over 3 years ago

  • % Done changed from 0 to 20
  • Status changed from New to Incomplete

#3 Updated by Christoph Schmidt over 3 years ago

Roman Lebedev wrote:

Which camera?

Nikon D5200.

#4 Updated by Roman Lebedev over 3 years ago

While here, can you take picture of anything recognizable with D5200 with mode 12bit-compressed and mode 12bit-uncompressed.
Upload it here, and to rawsamples.ch (do name the files appropriately)

#5 Updated by Christoph Schmidt over 3 years ago

Attached is a photo which was taken with the lens cap on to see the hot pixels. To my knowledge the D5200 stores raw images only as compressed 14 bit.

But please let me emphasize that I'm not looking for a solution to the problem with my particular camera but I'd like to propose a different way of how to detect hot pixels, completely independent from my camera.

#6 Updated by Christoph Schmidt over 3 years ago

It seems the file upload is not working. You can find the photo here:

https://dl.dropboxusercontent.com/u/378725/hot%20pixels.nef

#7 Updated by Roman Lebedev over 3 years ago

Test upload please ignore.
Upload works?

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