[Darktable-users] How to remove stuck/dead pixels from raw (DNG)?

[Sven Beauprez]

I've posted following question to stack exchange, but there are maybe not
that many darktable users on there, so I repost it here:
http://photo.stackexchange.com/questions/24744/how-to-get-rid-of-dead-stuck-pixels-in-a-chdk-generated-dng

Can darktable help to get rid of dead/stuck pixels in the beginning of my
workflow (or as a last step just before exporting is fine too)? Something
that can easily be reused on all my DNG files?

A sample image/DNG can be found on stack exchange.

regards,

Sven

[Chris Nuzzaco]

I can get rid of dead pixels very easily, and it has a lot more user controls than other programs. Give it a shot, you'll love it.
Chris Nuzzacowww.chrisnuzzaco.com

Date: Fri, 29 Jun 2012 11:44:23 +0200
From: ***@gmail.com
To: darktable-***@lists.sourceforge.net
Subject: [Darktable-users] How to remove stuck/dead pixels from raw (DNG)?


I've posted following question to stack exchange, but there are maybe not that many darktable users on there, so I repost it here:http://photo.stackexchange.com/questions/24744/how-to-get-rid-of-dead-stuck-pixels-in-a-chdk-generated-dng

Can darktable help to get rid of dead/stuck pixels in the beginning of my workflow (or as a last step just before exporting is fine too)? Something that can easily be reused on all my DNG files?

A sample image/DNG can be found on stack exchange.
regards,
Sven

[Jose Carlos Garcia Sogo]

Look in "More plugins..." for the module called "Hot pixels"

Post by Sven Beauprez
I've posted following question to stack exchange, but there are maybe not
http://photo.stackexchange.com/questions/24744/how-to-get-rid-of-dead-stuck-pixels-in-a-chdk-generated-dng
Can darktable help to get rid of dead/stuck pixels in the beginning of my
workflow (or as a last step just before exporting is fine too)? Something
that can easily be reused on all my DNG files?
A sample image/DNG can be found on stack exchange.
regards,
Sven
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[Sven Beauprez]

[Jose Carlos Garcia Sogo]

I should have mentioned that I have tried that, but it only detects a small amount: in the DNG I posted, it only found a few thousands, but there are even more that it does not detect.

I have just look at the png you posted, and is astonishing. What light
and ISO did you have? I am not sure if those are dead-pixels or noise,
and how it got produced.

I've played with the settings and switched on and off the 3 pixel option, but I don't find any good setting. Maybe somebody can help here based on the DNG I posted?

Maybe you could try with "Chroma denoise"

[Sven Beauprez]

[Simon Spannagel]

Hi,

there seems to be another problem than dead pixels. If you turn on the
"dead pixel" module and check the "show corrected pixels" box you will
see that none of your strange artifacts will eb corrected but some other
"correct" pixels.

Simon

Post by unknown
For others who jump into the thread, this is the image we are talking
https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png
https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG )
The lighting and ISO doesn't matter, it is on all the raw files I have.
I've been playing around with several denoisnig features/modules
(based on
http://photo.stackexchange.com/questions/15655/should-i-use-a-single-denoising-method-with-aggressive-settings-or-combine-diff ),
but without satisfying results.
On Fri, Jun 29, 2012 at 12:45 PM, Jose Carlos Garcia Sogo
On Fri, Jun 29, 2012 at 12:31 PM, Sven Beauprez

Post by unknown
I should have mentioned that I have tried that, but it only

detects a small amount: in the DNG I posted, it only found a few
thousands, but there are even more that it does not detect.
I have just look at the png you posted, and is astonishing. What light
and ISO did you have? I am not sure if those are dead-pixels or noise,
and how it got produced.

Post by unknown
I've played with the settings and switched on and off the 3

pixel option, but I don't find any good setting. Maybe somebody
can help here based on the DNG I posted?
Maybe you could try with "Chroma denoise"
--
José Carlos García Sogo
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[Sven Beauprez]

[Jose Carlos Garcia Sogo]

Post by unknown
https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png
(and original DNG: https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG )
The lighting and ISO doesn't matter, it is on all the raw files I have.

Then, I only see three scenarios:
+ Your sensor is broken.
+ The DNG (or the software that generates it) is broken. If it is
'in camera', that is broken
+ We have a bug and we are showing those artifacts.

Have you tried opening that DNG with other different software?

[Sven Beauprez]

[Patrick Shanahan]

This post might be inappropriate. Click to display it.

[Sven Beauprez]

Having that many dead/stuck pixels is not that bad. All camera's have them
(it would be technically impossible or at least extremely expensive to made
sensors without bad/stuck pixels) and those are corrected through in-camera
software.

The CHDK I used had a bug in it and a more recent version has been posted
on their forums, so the dead/stuck pixels are taken into account now (via
interpolation) when generating the DNG as it should be.


Still wondering if this could not be corrected through post-processing
also??


Thnx for all the answers anyway!

Post by Patrick Shanahan

Post by unknown
I will test it with other software, but I am pretty sure it is the second
scenario (the DNG is created by a P&S canon ixus 300 HS with CHDK on it

to

Post by unknown
create the raw files). I am investigating that path on the CHDK forums.
I was also hoping that DT could help with the raw files I already got...

The light areas of your *.DNG file are speckled with small dark spots
which appear *much* larger than single pixels. UFRaw displays them
readily, as does RawTherapee. If that is the file direct from your
camera, you have camera problems, sensor or software. If your Canon IXUS
300 HS is within warranty, I would return it immediately for refund or
exchange. If not new, try shooting in jpeg format and see if it still
exists (probably).
No good news, I'm afraid. There is one or two other avenues I can see,
(1) try another card, (2) if you dl direct from camera, try using a
card-reader or vice versa.
gud luk,
--
(paka)Patrick Shanahan Plainfield, Indiana, USA HOG # US1244711
http://wahoo.no-ip.org Photo Album: http://wahoo.no-ip.org/gallery2
http://en.opensuse.org openSUSE Community Member
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[unknown]

I should have mentioned that I have tried that, but it only detects a small a=
mount: in the DNG I posted, it only found a few thousands, but there are eve=
n more that it does not detect.=20

I've played with the settings and switched on and off the 3 pixel option, bu=
t I don't find any good setting. Maybe somebody can help here based on the D=
NG I posted?

Post by Jose Carlos Garcia Sogo
Look in "More plugins..." for the module called "Hot pixels"
=20

=20
I've posted following question to stack exchange, but there are maybe not=
http://photo.stackexchange.com/questions/24744/how-to-get-rid-of-dead-stu=

ck-pixels-in-a-chdk-generated-dng

Post by Jose Carlos Garcia Sogo

=20
Can darktable help to get rid of dead/stuck pixels in the beginning of my=
workflow (or as a last step just before exporting is fine too)? Something=
that can easily be reused on all my DNG files?
=20
A sample image/DNG can be found on stack exchange.
=20
regards,
=20
Sven
=20
=20
=20
=20
=20
=20
-------------------------------------------------------------------------=

-----

Post by Jose Carlos Garcia Sogo

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Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions=
will include endpoint security, mobile security and the latest in malware=
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_______________________________________________
Darktable-users mailing list
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=20

=20
=20
=20
--=20
Jos=C3=A9 Carlos Garc=C3=ADa Sogo

[unknown]

--20cf30363cd1d284a304c39b2ccc
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

For others who jump into the thread, this is the image we are talking
about: Loading Image...
(and original DNG: https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG )

The lighting and ISO doesn't matter, it is on all the raw files I have.

I've been playing around with several denoisnig features/modules (based on
http://photo.stackexchange.com/questions/15655/should-i-use-a-single-denoising-method-with-aggressive-settings-or-combine-diff
),
but without satisfying results.



On Fri, Jun 29, 2012 at 12:45 PM, Jose Carlos Garcia Sogo

Post by unknown
I should have mentioned that I have tried that, but it only detects a

small amount: in the DNG I posted, it only found a few thousands, but there
are even more that it does not detect.
I have just look at the png you posted, and is astonishing. What light
and ISO did you have? I am not sure if those are dead-pixels or noise,
and how it got produced.

Post by unknown
I've played with the settings and switched on and off the 3 pixel

option, but I don't find any good setting. Maybe somebody can help here
based on the DNG I posted?
Maybe you could try with "Chroma denoise"
--
José Carlos García Sogo

--20cf30363cd1d284a304c39b2ccc
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable <div><br></div>For others who jump into the thread, this is the image we are talking about:? <a href="https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png" style="padding: 7px 8px; background-color: #F6FEFF; border-left: 1px solid #8FF1FF; margin: 10px 0px; display: inline-block; color: #3B5053; font-size: 13px; ">Loading Image...</a>?<div>(and original DNG:? <a href="https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG">https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG</a>?)</div><div><br></div><div>The lighting and ISO doesn&#39;t matter, it is on all the raw files I have.</div> <div><br></div><div>I&#39;ve been playing around with several denoisnig features/modules (based on? <a href="http://photo.stackexchange.com/questions/15655/should-i-use-a-single-denoising-method-with-aggressive-settings-or-combine-diff">http://photo.stackexchange.com/questions/15655/should-i-use-a-single-denoising-method-with-aggressive-settings-or-combine-diff</a>?), but without satisfying results.</div> <div><br></div><div><br><br><div class="gmail_quote">On Fri, Jun 29, 2012 at 12:45 PM, Jose Carlos Garcia Sogo <span dir="ltr">&lt;<a href="mailto:***@gmail.com" target="_blank">***@gmail.com</a>&gt;</span> wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Fri, Jun 29, 2012 at 12:31 PM, Sven Beauprez &lt;<a href="mailto:***@gmail.com">***@gmail.com</a>&gt; wrote:<br>

&gt;<br>
&gt; I should have mentioned that I have tried that, but it only detects a small amount: in the DNG I posted, it only found a few thousands, but there are even more that it does not detect.<br>
&gt;<br>
<br>
</div>I have just look at the png you posted, and is astonishing. What light<br>
and ISO did you have? I am not sure if those are dead-pixels or noise,<br>
and how it got produced.<br>
<div class="im"><br>
&gt; I&#39;ve played with the settings and switched on and off the 3 pixel option, but I don&#39;t find any good setting. Maybe somebody can help here based on the DNG I posted?<br>
<br>
</div>Maybe you could try with &quot;Chroma denoise&quot;<br>
<div class="HOEnZb"><div class="h5"><br>
--<br>
José Carlos García Sogo<br>
  <a href="mailto:***@gmail.com">***@gmail.com</a><br>
</div></div></blockquote></div><br></div>

--20cf30363cd1d284a304c39b2ccc--

[unknown]

--0023544706d8dde34a04c39c703f
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

True, it looks more as a combination of dead and stuck pixels...

Post by Simon Spannagel
Hi,
there seems to be another problem than dead pixels. If you turn on the
"dead pixel" module and check the "show corrected pixels" box you will see
that none of your strange artifacts will eb corrected but some other
"correct" pixels.
Simon
For others who jump into the thread, this is the image we are talking
https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png
(and original DNG: https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG
)
The lighting and ISO doesn't matter, it is on all the raw files I have.
I've been playing around with several denoisnig features/modules (based
on
http://photo.stackexchange.com/questions/15655/should-i-use-a-single-denoising-method-with-aggressive-settings-or-combine-diff ),
but without satisfying results.
On Fri, Jun 29, 2012 at 12:45 PM, Jose Carlos Garcia Sogo <

Post by unknown
I should have mentioned that I have tried that, but it only detects a

small amount: in the DNG I posted, it only found a few thousands, but there
are even more that it does not detect.
I have just look at the png you posted, and is astonishing. What light
and ISO did you have? I am not sure if those are dead-pixels or noise,
and how it got produced.

Post by unknown
I've played with the settings and switched on and off the 3 pixel

option, but I don't find any good setting. Maybe somebody can help here
based on the DNG I posted?
Maybe you could try with "Chroma denoise"
--
José Carlos García Sogo

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--0023544706d8dde34a04c39c703f
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable <div><br></div>True, it looks more as a combination of dead and stuck pixels...<div><br><div><br><br><div class="gmail_quote">On Fri, Jun 29, 2012 at 2:07 PM, Simon Spannagel <span dir="ltr">&lt;<a href="mailto:***@kth.se" target="_blank">***@kth.se</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">



<div bgcolor="#FFFFFF" text="#000000">
<tt>Hi,<br>
<br>
there seems to be another problem than dead pixels. If you turn on
the &quot;dead pixel&quot; module and check the &quot;show corrected pixels&quot; box
you will see that none of your strange artifacts will eb corrected
but some other &quot;correct&quot; pixels.<br>
<br>
Simon<br>
<br>
<br>
<br>
</tt>
<div>Am 29.06.2012 13:59, schrieb Sven
Beauprez:<br>
</div>
<blockquote type="cite"><div><div class="h5">

<div><br>
</div>
For others who jump into the thread, this is the image we are
talking about: 
<a href="https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png" target="_blank">https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png</a> 
<div>(and original DNG: 
<a href="https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG" target="_blank">https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG</a> )</div>
<div><br>
</div>
<div>The lighting and ISO doesn&#39;t matter, it is on all the raw
files I have.</div>
<div><br>
</div>
<div>I&#39;ve been playing around with several denoisnig
features/modules (based on 
<a href="http://photo.stackexchange.com/questions/15655/should-i-use-a-single-denoising-method-with-aggressive-settings-or-combine-diff" target="_blank">http://photo.stackexchange.com/questions/15655/should-i-use-a-single-denoising-method-with-aggressive-settings-or-combine-diff</a> ),
but without satisfying results.</div>
<div><br>
</div>
<div><br>
<br>
<div class="gmail_quote">On Fri, Jun 29, 2012 at 12:45 PM, Jose
Carlos Garcia Sogo <span dir="ltr">&lt;<a href="mailto:***@gmail.com" target="_blank">***@gmail.com</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>On Fri, Jun 29, 2012 at 12:31 PM, Sven
Beauprez &lt;<a href="mailto:***@gmail.com" target="_blank">***@gmail.com</a>&gt;
wrote:<br>
&gt;<br>
&gt; I should have mentioned that I have tried that, but
it only detects a small amount: in the DNG I posted, it
only found a few thousands, but there are even more that
it does not detect.<br>
&gt;<br>
<br>
</div>
I have just look at the png you posted, and is astonishing.
What light<br>
and ISO did you have? I am not sure if those are dead-pixels
or noise,<br>
and how it got produced.<br>
<div><br>
&gt; I&#39;ve played with the settings and switched on and off
the 3 pixel option, but I don&#39;t find any good setting.
Maybe somebody can help here based on the DNG I posted?<br>
<br>
</div>
Maybe you could try with &quot;Chroma denoise&quot;<br>
<div>
<div><br>
--<br>
José Carlos García Sogo<br>
  <a href="mailto:***@gmail.com" target="_blank">***@gmail.com</a><br>
</div>
</div>
</blockquote>
</div>
<br>
</div>
<br>
<fieldset></fieldset>
<br>
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[unknown]

--00235446ff04b91e4204c39c7f5e
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

I will test it with other software, but I am pretty sure it is the second
scenario (the DNG is created by a P&S canon ixus 300 HS with CHDK on it to
create the raw files). I am investigating that path on the CHDK forums.


I was also hoping that DT could help with the raw files I already got...



On Fri, Jun 29, 2012 at 2:27 PM, Jose Carlos Garcia Sogo

Post by unknown

Post by unknown
For others who jump into the thread, this is the image we are talking
https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png

https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG )

Post by unknown
The lighting and ISO doesn't matter, it is on all the raw files I have.

+ Your sensor is broken.
+ The DNG (or the software that generates it) is broken. If it is
'in camera', that is broken
+ We have a bug and we are showing those artifacts.
Have you tried opening that DNG with other different software?
--
José Carlos García Sogo

--00235446ff04b91e4204c39c7f5e
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable <div><br></div><div>I will test it with other software, but?I am pretty sure it is the second scenario (the DNG is created by a P&amp;S canon ixus 300 HS with CHDK on it to create the raw files). I am investigating that path on the CHDK forums.</div> <div><br></div><div><br></div><div>I was also hoping that DT could help with the raw files I already got...</div><div><br></div><div><br><br><div class="gmail_quote">On Fri, Jun 29, 2012 at 2:27 PM, Jose Carlos Garcia Sogo <span dir="ltr">&lt;<a href="mailto:***@gmail.com" target="_blank">***@gmail.com</a>&gt;</span> wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Fri, Jun 29, 2012 at 1:59 PM, Sven Beauprez &lt;<a href="mailto:***@gmail.com">***@gmail.com</a>&gt; wrote:<br>

&gt;<br>
&gt; For others who jump into the thread, this is the image we are talking about:<br>
&gt; <a href="https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png" target="_blank">https://www.dropbox.com/s/j35pcba3hz37ovs/DetailWithStuckPixels.png</a><br>
&gt; (and original DNG:  <a href="https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG" target="_blank">https://www.dropbox.com/s/mufnsrxcqzfbnwj/CRW_6640.DNG</a> )<br>
&gt;<br>
&gt; The lighting and ISO doesn&#39;t matter, it is on all the raw files I have.<br>
<br>
</div>Then, I only see three scenarios:<br>
 + Your sensor is broken.<br>
 + The DNG (or the software that generates it) is broken. If it is<br>
&#39;in camera&#39;, that is broken<br>
 + We have a bug and we are showing those artifacts.<br>
<br>
Have you tried opening that DNG with other different software?<br>
<div class="HOEnZb"><div class="h5"><br>
--<br>
José Carlos García Sogo<br>
  <a href="mailto:***@gmail.com">***@gmail.com</a><br>
</div></div></blockquote></div><br></div>

--00235446ff04b91e4204c39c7f5e--