Camera Lens Calibration

Before you can use your camera, you'll need to calibrate it to compensate for the distortion present in all camera lenses using the Camera Calibration Wizard. The wizard will walk you through the process of capturing a series of images of a printed target so LightBurn can calculate and correct for the distortion of the camera lens.

Camera Lens Calibration only needs to be done once per camera - moving the camera doesn't require a new calibration.

Did you already go through the Camera Lens Calibration process and export a LightBurn Camera File? If so, you can import the file and reuse that calibration.

Jump to importing a Lens Calibration

Open The Camera Calibration Wizard¶

There are a few ways to open the Camera Lens Calibration Wizard outside of creating a new camera:

• Click the Calibration button for the camera you want to align in the Cameras Window.
• Click the Calibrate Lens button in the Edit Camera window.

Before You Begin¶

1. Download and print the AprilTag calibration pattern, or load it in full screen on a tablet, with the screen set to always on. The pattern needs to be at least ⅛th the size of your laser bed.

   Don't have a printer?

   If you don't have a paper printer or struggle to get a clear print, try taking the file to a print shop, office supply store, or local library to get it printed, or load the pattern onto a tablet screen.

   Download PDF

   Download LBRN2

2. If you printed the calibration pattern on thin paper, attach the printed calibration pattern to something stiff and flat, such as cardboard, wood, or a clipboard.

3. Make sure the bed of your laser has good, consistent lighting and the camera is in focus. If you're using an official LightBurn camera, most can be manually focused by gently twisting their lenses.
4. Select the correct camera in the Cameras window.
5. You do not need to have your camera mounted in the machine as long as it's perfectly still. You will need to have it mounted in the correct placement for the Alignment process, though, so it may make sense to make sure it's installed now.

Quick Start¶

Need more help? Jump ahead to the full directions.

Camera Lens Calibration Walkthrough

The Camera Calibration Wizard has on-screen directions to walk you through the process. Here's a quick overview if you want to just jump in and get started.

1. Prepare the calibration pattern as described above.
2. Open the Camera Lens Calibration Wizard and click Next to continue.
3. Capture 5 images of the calibration pattern in the locations highlighted by the wizard - the four corners and the center of the workspace. You can use the jogging controls to move your laser out of the way. Click Next to continue.
4. Select your Calibration Model. You can preview the results of each model by selecting it. You want straight lines to appear straight, and should pay attention to what the corners of the bed look like.
5. If you're happy with the results, you can start on Camera Workspace Alignment.

Camera Workspace Alignment

Walkthrough¶

If you want more detailed help with Camera Lens Calibration, you're in the right place.

1. Prepare the Calibration Pattern¶

As described above, make sure you have the AprilTag pattern printed or loaded up on a tablet screen. LightBurn can detect the tags and use their location, size, and distortion to calculate the distortion of the camera lens, so it can correct for that distortion.

2. Open the Camera Lens Calibration Wizard¶

There are a few ways to open the Camera Lens Calibration Wizard outside of creating a new camera:

• Click the Calibration button for the camera you want to align in the Cameras Window.
• Click the Calibrate Lens button in the Edit Camera window.

3. Capture Calibration Frames¶

The next screen will walk you through capturing Calibration Frames, which are images showing the calibration pattern in each corner of your laser's bed as well as the center.

1. Place your calibration pattern on the bed of the laser and adjust it to be in the highlighted box (the blue overlay shown in the top left in the screenshot above). Detected tags will be highlighted in green. You can use the Jogging Controls in the bottom right to move the laser head out of your way.
2. Click the Capture button to capture a frame. If you're unhappy with the frame you captured, you can discard it with the Discard button.
3. Move the calibration pattern to fit in the next box and repeat the process.

After you've captured the 5 required frames, you should see something like the screenshot below.

At this point, the view of the calibration tags should be more accurate than at the beginning, but will likely not look entirely correct. You can keep going to take more calibration frames, or click Next to continue to the next step.

4. Choose Calibration Model¶

There are 4 different mathematical models LightBurn can apply for the corrections.

Click the model options on the right to preview what the camera image looks like under each. A large, high contrast pattern (for instance, the calibration pattern) can be helpful for checking the accuracy of the calibration. Select the model that looks the most accurate and click the Next button to continue.

Each model includes a description with more information.

5. Success!¶

On the final screen, click Finish to close the process and save your changes. Next, you'll need to do Camera Alignment to align your camera to your workspace.

Import Existing Calibration¶

What's Happening¶

Feel free to skip this section if you're not interested.

All cameras distort the image they capture at least a little, and the larger the area they can capture, the more serious that warping is. Wide-angle or fisheye lenses that can capture large workspaces from relatively close will be particularly badly distorted.

The Camera Lens Calibration process is required so that LightBurn can figure out the distortion pattern of your particular camera and correct for it in the software. The AprilTag calibration pattern you use for this process is important for the improved process, and allows for a simplified calibration process compared to the older dot pattern.