Calibrating camera

So i have a 16mp fixed focus camera 30in above my 400x830 mm laser bed. I have ran the lens and alignment calibration atleast 5 times but it is not as accurate as i had hoped. i have the scale set at 200. but im wondering about the height, is 30in the correct height for it to be above the laser? when i use the camera selection i cant get a good answer.

You might be getting a little too ambitious on the size

While i would imagine it is possible to gt the calibration to give you a lot of workable positioning of the materials, if you want extreme accuracy you might have to use the camera , lower it, and use “half” the bed instead 400x400 area

Also, any changes in material thickness in a 400x800 will cause a lot of loss on acuracy

The question is, what accuracy were you aiming for?

My lightburn hero, back again. lol. I just see on videos that people point at a location and it goes exactly there, and queue up jobs and trust that it will go to the correct spot every time. so thats what my goal was. i honestly haven’t even used the back half of my bed since ive bought it, just came with the package, but if i could get the whole bed thatd be nice. i seen on they offer cameras for large working areas so i thought it would be okay

For rough positioning it should be perfectly fine
However, if you want it accurate to the mm, then you must also understand what the ligthburn algorithm does to “unbend” the image, and how the mathematical distances are based on assumptions that such a big area might not be able to calibrate exactly.

I am far from the best person to explain the math under the hood, but - at such a focal distance - adding 3mm of ply on the table above the calibration “zero” will set you off a bit
Now, is this “bit” within what you can accept? this is something you got to test

Something else that you might notice is, calibration will be the best dead under the center of the camera, and will tend to get wonkier on the corners.

So you could be “strategic” and map the bed calibration vs. Accuracy and use the most accurate spots for the fine work.

i have the camera perfectly centered, and i thought about that, so i have put my 400x400 honeeycomb tray thing right under the camera, so would i tell lightburn in settings that i only have a 400x400 workspace or would i leave the correct dimensions.

Few ways you can go about it

  • You can use the whole bed, calibrate as best as possible with your most common material already on the bed (so your hight is on average set).
    This should give you a rough positional accuracy and in the center 400x400 area (200 cut on each end) you should have fairly good accuracy
  • You can bring the camera lower and closer to the 1st 400x400 half
  • You can lower your camera from the center and use the center 400x400 but be more acurate and not have the 200 of each side in view.

Will depend greatly on your workflow i guess.

In an ideal world…
you could have a 16mp for the 400x800
And a 2nd camera for the 400x400 or even 200x200 at front for extreme accuracy
Actually, I am unsure if one can calibrate two cameras at once and then toggle them from the dropdown
@Rick might be able to clarify if this use case could actually work

Yes @gilaraujo, if I understand, you’d have to tell LightBurn that the machine was only 200x200 for the smaller to work, but in theory, yes it would. @SteelQuill, might be best to test this workflow further in your environment, and please let us know how things progress if you do. :slight_smile:

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The camera should not be centered, but seeing the origin of the laser. So if you use 400x400 instead of 400x800 for the camera, make sure the 400x400 area starts in the lower-left corner (assuming your homing reference is there).
Some additional remarks:

I went with this option. Had the hardest time with the fisheye lens, ultimately clicked that I am using a standard lens and haven’t had any problems, I thought it may cause issue. But the arducam 16 mp refused to recognize the pattern if I had selected fisheye. Do not recommend this brand of camera. Fisheye or standard lens.

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