Distorted overlay

Hello, in a bit of a pickle here and have done camera calibration and alignment several times. This is the issue I am having. After calibrating the lens, then going to alignment, the captured image after engraving the alignment pattern looks perfect, nice and square. Then after doing the alignment by selecting the cross hairs, the overlay on the work area is distorted at the edges, unlike the preview after calibration. I’ve attached some images for clarification. Is there something I’m missing? Thanks!


You’re runing 0.8.07 - The camera code received a very large rewrite for 0.9.00, so I suggest updating and trying again with that version (or later) first.

Also, not related to the curvature, but accuracy in general, when running the alignment cut, scaling it up helps the accuracy. It looks like you could go to 200% without issues.

Hey Oz,

Every resourceful and responsive, thanks mate! I’ll update and scale up the alignment. Really appreciate your help. So the purpose of the alignment would be to get the 4 cords hairs closer to the corners of your bed? That does make more sense.


The alignment is to figure out where the camera is in relation to the bed (angle, distance, etc). You click the targets so LightBurn can figure out the mapping between them.

It’s kind of like calibrating the axis on your machine. If you cut a square that’s 10cm, and measure it with calipers, you might be fairly accurate, but if you scale that up 10x to 100cm, or 100x to 1M, the small amount of inaccuracy in your measurement is amplified. This works the same way - if you take the measurements at the largest scale you can, the errors are minimized.

Hey Oz,

Updates to 9.0.2 but the calibration seems to be whacking the hell out. When I try and capture the image it’ll give me a wildly large score number and the image captured is whack. What’s going on?

Look at the size of the calibration card in the image above the capture. Then look at yours. What’s different? (hint: it’s not supposed to be a postage stamp. :slight_smile:)

Haha. Yes. Touche. I was holding it during tests. Same thing. I’ll get some more photos of the whacky captured images and numbers. Is it normal? Persevere?

Yeah, they happen sometimes, particularly in fisheye mode. It’s really sensitive, and small adjustments can make a big difference.

Make sure the capture is:

  • In focus
  • Very still (movement will blur it)
  • Facing the camera
  • Evenly lit (not a total deal breaker, but helpful)

Another camera question, When I go to the 2nd step, If I do the targets at 75% it is just ok, but it cuts/engraves toward the back of the machine, anything over 75%, it tries to go beyond the max Y that was entered and I get the rattle of bottomed out stepper, To be fair, I did increase the range of my K40 to 220X320mm.