Advice for setting up camera directly above

[pelted (Chris Born)]

I picked up the 140 degree camera from the shop and built a bracket over my OpenBuilds machines for the camera. My issue is that the circle pattern card is too far away when laid flat on the build surface to get anything better than a .33 on the captures. This leads to some warping of the image that is just not getting compensated for. In the end the variance across the machine for position accuracy can be anywhere from close to spot on to several millimeters off.

[LightBurn (Oz)]

Read here for some tips on the calibration:

Non fish eye camera calibration

With the last several versions of LightBurn you can choose fisheye or not (in fact, prior versions didn’t specialize fisheye lenses at all). A few tips: The camera doesn’t need to be on the machine for the lens calibration - It’s ONLY the lens and pattern that matter for this part, and the pattern can be scaled up. If you do want to do it on the machine, if you have a honeycomb bed, cover it (bedsheet, paper, wood, etc) - it gets misinterpreted as more circles and confuses the software. …

[pelted (Chris Born)]

Scaling the pattern up was the next thing I was going to try. The camera is 500mm above the spoiler board with 5 t-tracks running up the y-axis. I’ll try covering the hole board with a clean piece of MDF as well. I’m also not trying to get the full build depth (y-axis) on the camera, but not sure if the camera system expects the full bed to be in view or not. (Full x is covered and why the camera is where it is) Should I be using the fisheye setting for the 140 Lens? The first time i tried it it was really wonky and didn’t take so I’ve used regular each time since but having issues with the final result.

[pelted (Chris Born)]

Yeah, this is getting frustrating. See the images: Not sure how to make this work better. This time the print is double sized as well.

Even the middle shot to start with tops out near 40 with this setup.

This is the best I could get on this one after maybe 10 captures:

[pelted (Chris Born)]

This is the layout of showing the camera (circled in red). It is directly above the work surface about 500mm. I dropped a clean MDF over the build surface to mitigate any false reads.

[LightBurn (Oz)]

1. That card is visibly curled - See point #3 on the link I sent above. Glue it to a piece of foamboard or something very flat (wood, tile, etc)
2. You have a fisheye lens, so you can point the card toward the camera a bit for the non-middle captures
3. You can move the card inward from the corner some, and that will make it easier too
4. Make sure the camera image is well focused - Use the camera app on your computer to view it full screen, and adjust the focus to be as clear as possible before you start