Hugin Lens Calibrator, LensFun, and digiKam

[Dmitri Popov]

Hello,

I've been trying to create a lens profile for use with the LensFun library (so I could fix lens distortion in digiKam), but I hit the wall. I've written a blog article explaining the problem, and I could use some input:

http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/

Thanks!

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

[tosca]

I tried (or 'we', as several others from the french PhotoLinux forum tried too, in order to help me) with the Powershot S100, and never get an acceptable result; it seems obvious when you read the documentation, but small differences can make the result completely impredictable!

As it is, I still shoot in RAW+JPEG with this camera (never done this with my DSLRs), hoping the issue will be solved in some Linux program someday in the future.

I'm afraid this is not very helpful...

Marie-Noëlle

2013/2/9 Dmitri Popov <[hidden email]>

Hello,

I've been trying to create a lens profile for use with the LensFun library (so I could fix lens distortion in digiKam), but I hit the wall. I've written a blog article explaining the problem, and I could use some input:

http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/

Thanks!

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

--


Mes dernières photos sont dans ma galerie.
Connaissez-vous Image Fixe, le photo-club de Saint Jean du Gard ?
Et parcourez les Cévennes à ma façon avec Cévennes Plurielles,

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

[Benjamin Girault]

Hi Dmitri,

2013/2/9 Dmitri Popov <[hidden email]>:
> I've been trying to create a lens profile for use with the LensFun library
> (so I could fix lens distortion in digiKam), but I hit the wall. I've
> written a blog article explaining the problem, and I could use some input:
>
> http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/

Someone on the Hugin mailing list published a tutorial on how to shoot
photos with the goal of calibrating a lens and a camera and use them
to get a LensFun profile. Here it is:

http://wilson.homeunix.com/lens_calibration_tutorial/

I haven't tried it so I cannot guarantee anything. Hopefully you can
get answers to your issue.

Best,

--
Benjamin.
_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

[Gilles Caulier-4]

Dmitri,

In 3.0.0, someone has posted a patch to fix some glitch problem to rendering image correction with Lensfun. It's appears in some specific case. Not sure that your problem will be fixed with 3.0.0. Look here for details :

https://bugs.kde.org/show_bug.cgi?id=284708

Also, as i use current code from LensFun repository, i can said that next version will include new lens profile and work better that last stable 0.2.6

I hope that can help you...

Best

Gilles Caulier

2013/2/9 Benjamin Girault <[hidden email]>

Hi Dmitri,

2013/2/9 Dmitri Popov <[hidden email]>:

> I've been trying to create a lens profile for use with the LensFun library
> (so I could fix lens distortion in digiKam), but I hit the wall. I've
> written a blog article explaining the problem, and I could use some input:
>
> http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/

Someone on the Hugin mailing list published a tutorial on how to shoot
photos with the goal of calibrating a lens and a camera and use them
to get a LensFun profile. Here it is:

http://wilson.homeunix.com/lens_calibration_tutorial/

I haven't tried it so I cannot guarantee anything. Hopefully you can
get answers to your issue.

Best,

--
Benjamin.

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

[Dmitri Popov]

Thanks you Gilles and others for your replies and pointers! I'll keep trying, and let you know om my progress.

Best,

Dmitri

---

From: Gilles Caulier <[hidden email]>
To: digiKam - Home Manage your photographs as a professional with the power of open source <[hidden email]>
Sent: Saturday, February 9, 2013 10:26 PM
Subject: Re: [Digikam-users] Hugin Lens Calibrator, LensFun, and digiKam

Dmitri,

In 3.0.0, someone has posted a patch to fix some glitch problem to rendering image correction with Lensfun. It's appears in some specific case. Not sure that your problem will be fixed with 3.0.0. Look here for details :

https://bugs.kde.org/show_bug.cgi?id=284708

Also, as i use current code from LensFun repository, i can said that next version will include new lens profile and work better that last stable 0.2.6

I hope that can help you...

Best

Gilles Caulier

2013/2/9 Benjamin Girault <[hidden email]>

Hi Dmitri,

2013/2/9 Dmitri Popov <[hidden email]>:

> I've been trying to create a lens profile for use with the LensFun library
> (so I could fix lens distortion in digiKam), but I hit the wall. I've
> written a blog article explaining the problem, and I could use some input:
>
> http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/

Someone on the Hugin mailing list published a tutorial on how to shoot
photos with the goal of calibrating a lens and a camera and use them
to get a LensFun profile. Here it is:

http://wilson.homeunix.com/lens_calibration_tutorial/

I haven't tried it so I cannot guarantee anything. Hopefully you can
get answers to your issue.

Best,

--
Benjamin.

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

Yes, back when Marie-Noelle posted long ago, I spent a few one
afternoon taking some shots and selected control points following the
docs, but it didn't work. My experience then was that even after
adding the lines to the lens library, it didn't seem to properly find
the entry and apply the correction. I ran out of time to play with it
back then, but I am interested and will try help if I can.

On a digikam off-topic note: it occurred to me that while the lensfun
method of taking multiple images and locating control points to
calculate distortion is more flexible, potentially more accurate, and
certainly more likely to work across any camera or lens model, there
might be an easier approach. Since for many point-and-shoots like the
S100, the JPG processor does a decent job, it seems like a single shot
taken using raw+jpg (for each focal length / zoom), it should be
possible to determine the distortion correction the camera uses
without the tedious work of multiple images and locating control
points. Anyone aware if this has been implemented?

JDR

On Mon, Feb 11, 2013 at 8:51 AM, Dmitri Popov <[hidden email]> wrote:

> Thanks you Gilles and others for your replies and pointers! I'll keep
> trying, and let you know om my progress.
>
> Best,
> Dmitri
>
> ________________________________
> From: Gilles Caulier <[hidden email]>
> To: digiKam - Home Manage your photographs as a professional with the power
> of open source <[hidden email]>
> Sent: Saturday, February 9, 2013 10:26 PM
> Subject: Re: [Digikam-users] Hugin Lens Calibrator, LensFun, and digiKam
>
> Dmitri,
>
> In 3.0.0, someone has posted a patch to fix some glitch problem to rendering
> image correction with Lensfun. It's appears in some specific case. Not sure
> that your problem will be fixed with 3.0.0. Look here for details :
>
> https://bugs.kde.org/show_bug.cgi?id=284708
>
> Also, as i use current code from LensFun repository, i can said that next
> version will include new lens profile and work better that last stable 0.2.6
>
> I hope that can help you...
>
> Best
>
> Gilles Caulier
>
>
> 2013/2/9 Benjamin Girault <[hidden email]>
>
> Hi Dmitri,
>
> 2013/2/9 Dmitri Popov <[hidden email]>:
>> I've been trying to create a lens profile for use with the LensFun library
>> (so I could fix lens distortion in digiKam), but I hit the wall. I've
>> written a blog article explaining the problem, and I could use some input:
>>
>>
>> http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/
>
> Someone on the Hugin mailing list published a tutorial on how to shoot
> photos with the goal of calibrating a lens and a camera and use them
> to get a LensFun profile. Here it is:
>
> http://wilson.homeunix.com/lens_calibration_tutorial/
>
> I haven't tried it so I cannot guarantee anything. Hopefully you can
> get answers to your issue.
>
> Best,
>
> --
> Benjamin.
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>
>
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>
>
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users
>

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

[Roel Arends]

Dear Gilles and others,

 

On

http://lensfun.berlios.de/

i saw that there is a new lensfun release 02.7 available.

 

Hopefully you can implement this in Digikam as soon as possible.

 

Kind regards,

Roel Arends

 

 

 

 

On Monday 11 February 2013 06:51:34 Dmitri Popov wrote:

Thanks you Gilles and others for your replies and pointers! I'll keep trying, and let you know om my progress.

Best,

Dmitri

---

Dmitri,

In 3.0.0, someone has posted a patch to fix some glitch problem to rendering image correction with Lensfun. It's appears in some specific case. Not sure that your problem will be fixed with 3.0.0. Look here for details :

https://bugs.kde.org/show_bug.cgi?id=284708

Also, as i use current code from LensFun repository, i can said that next version will include new lens profile and work better that last stable 0.2.6

I hope that can help you...

Best

Gilles Caulier

2013/2/9 Benjamin Girault <[hidden email]>

Hi Dmitri,

2013/2/9 Dmitri Popov <[hidden email]>:

> I've been trying to create a lens profile for use with the LensFun library
> (so I could fix lens distortion in digiKam), but I hit the wall. I've
> written a blog article explaining the problem, and I could use some input:
>
> http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/

Someone on the Hugin mailing list published a tutorial on how to shoot
photos with the goal of calibrating a lens and a camera and use them
to get a LensFun profile. Here it is:

http://wilson.homeunix.com/lens_calibration_tutorial/

I haven't tried it so I cannot guarantee anything. Hopefully you can
get answers to your issue.

Best,

--
Benjamin.

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

[Milan Knížek-2]

Dmitri Popov píše v So 09. 02. 2013 v 08:58 -0800:
> Hello,
>
Hello Dmitri,

>
> I've been trying to create a lens profile for use with the LensFun
> library (so I could fix lens distortion in digiKam), but I hit the
> wall. I've written a blog article explaining the problem, and I could
> use some input:
>
>
> http://scribblesandsnaps.com/2013/02/09/monkeying-around-with-lens-calibration/
>
>

To check if your lensfun parameters are correct, you can use hugin or

even Image Magick:
http://www.imagemagick.org/Usage/lens/#ready_made

If that works ok, the trouble might be either with lensfun or digiKam
like others suggested.


And just a small note - if you are only after calibrating the lens
distortion, then taking a picture of a tailored image displayed on a
flat panel (LCD) is quite convenient (compared to looking for
geometrical lines in a real scene).

The image can be created using GIMP's "fill gradient" tool (foreground
to backround color with a hard step and "saw" repeating). Example is
attached.

If it does not work well with the Hugin Lens Calibrator, try to make the
stripes wider.

Milan
>

--
http://milan-knizek.net/
About linux and photography (Czech only)
O linuxu a fotografování

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

[tosca]

I had exactly the same approach a while ago and would be very interested if such a solution exists.

Marie-Noëlle

2013/2/11 JD Rogers <[hidden email]>

Since for many point-and-shoots like the
S100, the JPG processor does a decent job, it seems like a single shot
taken using raw+jpg (for each focal length / zoom), it should be
possible to determine the distortion correction the camera uses
without the tedious work of multiple images and locating control
points. Anyone aware if this has been implemented?

JDR

 

--


Mes dernières photos sont dans ma galerie.
Connaissez-vous Image Fixe, le photo-club de Saint Jean du Gard ?
Et parcourez les Cévennes à ma façon avec Cévennes Plurielles,

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users