After several attempts at calibrating the lens, the software now hangs and can't find the pattern

Colt4587 · April 12, 2019, 12:21am

I’m on attempt #4 at getting the lens calibrated. Everything appears to go well, but the farther from center I get, the farther off the laser head is from reality. I’m on attempt #4 at lens calibration, but I’ve now reached a new issue.

On the previous attempts, when I hit “capture image” the result was immediate, I got a score (or not at all) and I could try again. On this attempt, the software lags, I sometimes get a spinny ball of death, and it absolutely refuses to see the pattern. I’ve unplugged the USB cable and re-plugged in, I’ve restarted the computer. Any ideas on what I can do? As of right now, 12 inches to the right of center is more than an inch off and I can’t calibrate to fix it.

LightBurn · April 12, 2019, 12:33am

If you have a honeycomb bed, cover it with paper, cardboard, or a sheet (just during the lens calibration). The code that looks for the circles pattern can be confused by the presence of other circular shapes in the image.

Colt4587 · April 12, 2019, 12:34am

An update…

I returned to the shop computer to continue trying, and it was randomly working. However, now when I hit “update overlay” it’s just grey. Even though the preview window is showing the bed, I only get a grey square when I hit the update overlay button. Also the grey square isn’t square, but has a corner chopped off. Which I assume means I need to continue doing the calibration.

Colt4587 · April 12, 2019, 12:34am

Ok, I’ll give that a try.

Colt4587 · April 12, 2019, 1:10am

Ok, so is the above picture normal? I’ve re-calibrated several times now, from putting the card closer to the camera (so that it fills up more space) to clear down in the corners of my bed, and this happens each time.

Also, no matter what I do, I cannot get the laser to be accurate enough for what I would need. I’ve blown the camera alignment up to 300 from 100 thinking that maybe that would help. But if I go outside of the center of the bed it becomes off by at least an inch or more.

For a photo example, the laser head should have been on the center of the square in this example:

My bed size is 51x36, is it just too large for this camera to be accurate? Or (more than likely) is it just me doing it wrong?

Colt4587 · April 12, 2019, 1:38am

I’m also running into this, where it says it’s a “great” result, but I don’t think it actually is:

Colt4587 · April 12, 2019, 1:39am

And now it is completely unusable, as it crashes everytime I try and update the overlay. Even though the video feed is coming in fine (on the right there)

Colt4587 · April 12, 2019, 1:58am

Attempting to re-calibrate again, and I’ve watched the youtube video and gone over several parts of it. I still am unable to get this to work right. The calibration part has lots it’s marbles now.

Colt4587 · April 12, 2019, 4:44pm

The woes continue today, I gave up last night and thought maybe things would work better today. I’ve reinstalled Lightburn just in case. But now I either get "no pattern detected, or this:

Colt4587 · April 12, 2019, 5:33pm

I have no idea what is happening, but I am just running into more issues. I’m beginning to wonder if I have a defective unit or something. I have the camera firmly mounted to the housing, the door does not wobble and opens to the same position every time. I have calibrated fully, and made sure each “score” was .2 or under.

I was running the camera calibration, and in it’s burning process I got extremely weird behavior, lines in the circles that weren’t burned, random Y movements way out of line. Here is an example of an extreme issue:

A circle that is not a cirlce:

The laser head is still off by over an inch, and yes, when I tell it to cut a 1" square or circle it’s exactly one inch.

Any thoughts? I’m having enough issues here that I may have to return the camera

LightBurn · April 12, 2019, 8:30pm

First things first: when you multi-post to the forum, our email, and FB in rapid succession in the hope of getting “instant help” just stresses us out. LightBurn is one dev and two support helpers, and sometimes we do inconvenient things like sleep or eat.

To your problem:

The first issue I can see is that your calibration picture is tiny in several of the pics you posted. It should be close to the size shown in the sample image. It’s important to hold it very still, so it’s best not to hold it by hand, but to place it on something like a box. The camera doesn’t even have to be mounted to the machine for this part.

The second issue I got from your email - the camera does not look like it’s in focus when pointed at the bed. Have a look at this thread for a great suggestion from one of the forum members: Simple Aid For Focusing The Camera

The camera is focused manually. There’s a small glue dot in the threads of the lens. If you remove that with an exacto knife, or just hold the base of the sensor (not the board) and twist the lens, you can release it and focus the camera. Un-dock and drag out the camera control window to full screen so you can tell more easily when it’s focused. It doesn’t take much of a turn to change it.

And finally, you asked about the corner being cut off. In the preview images you posted I can’t see the corner of the bed, so it makes sense that it wouldn’t be visible in the corrected image either. Try to aim the camera so it can see the whole usable region of your laser bed. This is easier if you jog the laser to each corner then use a small piece of tape or something that you can see from the camera view. Adjust the mounting position and angle of the camera so you can see the four corner marks and that should help. Do this after focusing, but before running the camera alignment process or you’ll need to redo it.

Also, when doing the alignment process, make sure that the top of whatever you’re cutting for the alignment card is at the same height as your laser focus point, and that other things you’re trying to capture are also at that same height.

For example, if you run the alignment process with the paper at 25mm from your laser head, then later you put an object on the bed that’s 5mm high, you need to lower the bed by 5mm to compensate for the added height before you capture (ust set the laser focus to the top of the object again). If you don’t do that before you capture, the alignment will be off.

Colt4587 · April 12, 2019, 9:54pm

First things first: when you multi-post to the forum, our email, and FB in rapid succession in the hope of getting “instant help” just stresses us out. LightBurn is one dev and two support helpers, and sometimes we do inconvenient things like sleep or eat

I do appreciate that I will not get an immediate response. But when I spent 4 straight hours attempting to make it work last night, and then most of the morning into the afternoon today trying to get it to work, I will seek out other channels and other non-official opinions on the matter. Especially when I’m not entirely sure if what I’m seeing is in line with other’s experiences. I apologize if I stressed you out, I was just having quite a myriad of issues, and wanted to at least get something going before this weekend

The first issue I can see is that your calibration picture is tiny in several of the pics you posted. It should be close to the size shown in the sample image. It’s important to hold it very still, so it’s best not to hold it by hand, but to place it on something like a box. The camera doesn’t even have to be mounted to the machine for this part.

I did realize that I was making an error there after watching the youtube video again. In the example photos that are driven in the software, the fisheye lens is so prevalent that it’s hard to make out what size it should actually be, or even which part of the 9 segment’s I’m supposed to be using. I’ve since corrected this though, but still have issues.

The second issue I got from your email - the camera does not look like it’s in focus when pointed at the bed. Have a look at this thread for a great suggestion from one of the forum members: Simple Aid For Focusing The Camera

I did find another post in the forum about camera focusing, and have already broken the glue and attempted to focus the camera. My issue is that it does appear to be in focus now, and even if it wasn’t I am physically unable to screw the lens in any more to make it more in focus. Here is an up to date picture of the focus:

And finally, you asked about the corner being cut off. In the preview images you posted I can’t see the corner of the bed, so it makes sense that it wouldn’t be visible in the corrected image either. Try to aim the camera so it can see the whole usable region of your laser bed.

You can see in the current view that the lower corners are visible:

But I still get the cutoff:

Also, when doing the alignment process, make sure that the top of whatever you’re cutting for the alignment card is at the same height as your laser focus point, and that other things you’re trying to capture are also at that same height.

Yes, I always do this, I have a piece of acrylic that that I use to manually focus the laser head to be 5mm above the object to be engraved cut. I have an auto focus Z bed as well, but I never use it.

Were you able to watch the videos when doing the camera alignment? Is that normal?

This is the current accuracy I’m getting:

On Screen:

Actually Engraved:

Some more examples:

10mm squares:

Oval:

Using the position laser command, I am able to use my micrometer to figure out I’m off by 2-5 mm’s.

LightBurn · April 12, 2019, 10:04pm

Did you enable the ‘Fisheye Lens’ box when doing the correction?

Getting good lens calibration is important - if that doesn’t go well, the alignment will be harder to get right. You mentioned that your scores were 0.2 or less, which is good - I generally get 0.15 or less. I also rarely to the corner calibrations - did you do those too, or skip them?

Is that 2-5 mm off near the corners, or dead center? (usually the center is accurate, and it drifts a bit more toward the edges).

If the center is accurate and the sides are off, you should be able to use the Width / Height / Shift adjustments in the camera control window. If clicking the up/down arrows moves too much, you can manually enter numbers that are in between. Once dialed in, click “Save” in the camera control window to save those adjustments.

Turning off the lighting in the machine may help as well - the top of the image looks a little bit blown out, which can make things halo a little.

LightBurn · April 12, 2019, 10:10pm

Understood. We occasionally have users who will post here, on FB, email me directly, and email the support email, and it ties up all our resources answering the same questions multiple times, so I like to nip that behavior, that’s all.

You also showed your marker cut doing a jog right in the middle of it - That’s not normal, and if the crosshair position was also off, that would cause issues with the alignment. How are you connected to the laser? USB or Network?

Colt4587 · April 12, 2019, 10:23pm

Did you enable the ‘Fisheye Lens’ box when doing the correction?

Yep, I believe it is checked by default too, but I did make sure it was still checked each time.

Is that 2-5 mm off near the corners, or dead center? (usually the center is accurate, and it drifts a bit more toward the edges).

I would say it’s always about 2mm off, even center, but drifts towards the sides for sure.

If the center is accurate and the sides are off, you should be able to use the Width / Height / Shift adjustments in the camera control window. If clicking the up/down arrows moves too much, you can manually enter numbers that are in between. Once dialed in, click “Save” in the camera control window to save those adjustments.

Possible that I’m doing it wrong, but whenever I shifted it in one area, it just threw another area off more. I was using the X and Y shift when doing it, not width and height. I assumed width and height just cut off the image, of which I don’t have a lot to lose there. Is there a recommended method to dial this in?

Turning off the lighting in the machine may help as well - the top of the image looks a little bit blown out, which can make things halo a little.

The lighting came pre-installed, and I don’t believe there is a way to turn it off. It would also be very dark without it. I was hoping for some sort of contrast control, but I’ve read in other posts that’s not possible. I have been either putting white sheets of paper, dark pieces of wood to modify it when I calibrate.

You also showed your marker cut doing a jog right in the middle of it - That’s not normal, and if the crosshair position was also off, that would cause issues with the alignment. How are you connected to the laser? USB or Network?

I have since done a few alignments since then, and they haven’t done that (but are still off as mentioned earlier) since, so must have been a fluke or something. I am connected via USB to the laser.

LightBurn · April 12, 2019, 10:33pm

Nope - Width and Height scale the width and height of the captured image, so if the center is accurate but the sides are off, this helps. It’s “live” so changes you make will be reflected in the background capture as you change it.

The Shift controls move the captured image left / right / up / down as a whole. The Width & Height controls scale horizontally / vertically. If you engrave a 5-dot pattern similar to the markers, then capture it, dialing it in should be pretty quick - Use the width / height controls to scale the capture so it’s the same scale as the original vectors, then use the shift controls to line them up.

Try that and let me know how that goes.