Question/Suggestion: correct for lens warp

Are there any plans to improve the camera view of the cutting bed in the future to provide us with an accurate representation of what’s on there by correcting for the warping that occurs of the image from the curved lens on the camera?

Many photography apps have preset tools to correct for curvature of images from particular lenses. One would think that if the GF camera centres itself on the cutting bed, takes its picture, then the image could be deformed using registration marks or points inside the machine to bring it back into proper flat perspective including a relatively accurate preview of cut/engrave locations.

Attached is a sample of the distortion: I created a 1" square grid measuring 16" x 8" and added 1/2" circles at the corners and the centre point of the grid. I lightly engraved that onto a sheet of cardboard. Then, I took this screenshot showing the engraved marks below the design in the GF app to easily see and measure the distortion occurring. By applying some perspective warp/skew it should be pretty straight forward to get closer than it is right now. (Easy for me to say right!!!) I’ve done this type of image correction using the utility imagemagick in web application lots of times over the years, albeit that was over 10 years ago the last time I was doing this sort of thing.

Anyhow, I hope this can be considered for future updates, I believe this would be a feature EVERY user would appreciate.

It does a lot of dewarping already but it’s not fool proof. There are a lot of variables that can impact it.

If you want to test this, type in different material thickness values and you can see how the display changes.

If you set focus on any of the areas above, you should get a very accurate match. In a perfect world, the rest of the image would match also - but any deviation from that exact vertical plane where the set focus measurement was taken will appear off. Errors can be from a system that is not perfectly flat, differences in the thickness of the material (if you caliper around the edges of most material, it’s very often several thousandths off in different areas), warp or imperfections in the crumbtray surface that change the distance from the material surface to the camera, etc.

3 Likes

It has steadily improved over the last 2+ years as they’ve continued to refine the software. The camera calibration routine can make a big difference, I rerun it any time I move my machine. The set focus tool allows you to choose a spot on the bed to center the algorithm for the best visual representation at that position. They’re continually upgrading and improving visual placement.

3 Likes

This is an example of the unwarped image - it is way beyond typical curvature issues:
image

4 Likes

They have done a great job in improving the dewarp for the past three years. It’s pretty good IMO for that little lid camera in such an expanse.

After I did the lid camera calibration, I am pretty used to dead on placement with the preview image wherever I cut.

That said, some machines have had issues. I had to send one back for a warranty replacement because it was not even within the 1/4" accuracy.

I know they will continue to work on this though. The set focus functionality was a game changer though.

I do admit that I am pleased with the progress. Folks who might have come on later might have different metrics.

2 Likes

This was all very helpful. I’m going to go through the camera calibration test, and see how that might change things a bit. I’m glad they’ve made good strides in the preview image quality and hopefully there’s even more to come. Like anything, I’m just getting to know the quirks of this machine compared to others I’ve worked on. So far it’s still a great machine and I’m happy with the purchase every time I use it. Onward and upward. :slight_smile:

3 Likes

Thanks for the great suggestions, everyone. We’re continuing to work to improve the lid image quality.
@glowforge42 Thanks for letting us know about this.
I’m so glad you’re enjoying your Glowforge and hope you continue exploring and contributing to our community of makers!