How to disable camera lens correction?

LightBurn Software Questions Tips and Tricks
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1

I am a bit confused about the camera lens calibration in Lightburn.

My camera give a non distorded image, but Lightburn seems to apply a correction on it when I try to make aligment and then I got a distorded picture.

Is there a way to say to Lightburn to just use the image as it come from the camera ?

Here is the camera view from Lightburn Camera control panel (or any other software) :

image
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And here is the picture when I try to make aligment :

image

There is a clear disortion that appear at the left border, but I got no distorsion in any other software.

Any idea ?

Also when I use “Custom camera setting” I can only choose two differents kind of lens, while there are tens when I choose “Default setting”.

(I managed to mitigate the problem by choosing a lens in “Camera default setting” then switch back to “Camera custom setting”)

But why Lightburn apply a lens correction when it is not required ? I probably missed something…

EDIT: Also, I already try a full lens calibration with good captures scores, but the problem was worst

2

When you did the lens calibration, did you use fisheye or standard lens? If you’re confident your laser has no distortion then choose standard lens and repeat calibration.

3

I tried both multiple times, but I think I remember that the first time I did aligment it had worked but I did not make eny lens calibration after Lightburn installation, but now that I have try lens calibration (just for test/nothing because the aligment was working well), I am unable to get a non-distorted picture even if the camera is straight.

4

In that case there’s likely something wrong in the way you’re approaching the calibration. Is the calibration pattern adhered to a known flat surface? If not, suggest you do so and repeat the calibration. Again, if your camera has no distortion then use the standard lens type. Make sure you’re getting great scores, preferably under .2.

5

You’re probably right, thanks, I will redo lens calibration from start, but I still not understand that there is not a mode “no lens correction” when it is clear that it is unnecessary.

EDIT: if you look at the first picture I posted, straight from the camera, it is clear that “camera alignement” could work without any “camera lens correction”

6

That is the “standard”. I suspect there are things being calibrated other than fisheye distortion.

If you want to try eliminating any existing lens calibration you could remove any corrections from the .prefs file. It might work to export your camera calibration, modify to eliminate any lens correction, and then reimport but I haven’t tried that.

7

It works great now !

image
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I just edit the file prefs.ini in %LOCALAPPDATA%\LightBurn\prefs.ini and reset the camera matrix and set fisheyes to false :

                "cameraIsFisheye": false,
                "cameraMatrix": [
                ],
                "distortionMatrix": [
                ],
                "inversePerspective": [
                ],

It would be really nice to have a button to make this reset

8

Nice. But that image does look distorted to me if you look at the gantry and the rails. They are curved.

9

I think it is only a perspective ilusion, I draw two straight lines and they are perfectly parrallel to the gantry

image
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The camera is not perfectly aligned.

Edit: it look it is, but with a screenshot & checking in picture editor it is not, I think it is related to light and lack of alignment

10

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