Camera Fisheye Calibration

Applying fisheye calibration to the cameras

Now that you’re connected to the LumenPnP, you’ll need to set up the cameras so that they can accurately fine tune the machine’s position. The LumenPnP is a robust machine, but it needs both cameras to make sure it can pick and place components reliably every time. Note that these are very important calibration steps, but OpenPnP makes them relatively easy. Certain steps will probably need you to tune them more than once to get them perfect, others should stay mostly constant.

The first step is to correct for the fisheye effect of the webcams to help make sure they can identify distances accurately. This is not a step you will need to re-run unless you replace your webcams or lenses. Original OpenPnP documentation for reference.

Top Camera Calibration

  1. Click on the Machine Setup tab.

    Selecting the Machine setup tab from the main screen

  2. Click on the “Expand” checkbox to open all of the features about your machine.

    Expanding the Machine Config options

  3. Under Cameras click on OpenPnpCaptureCamera Top

Finding the Top Camera Settings
  1. In the lower detail pane, switch to the Lens Calibration tab
    Switching to the lens calibration tab
  1. Click Start Lens Calibration.

    Starting bottom camera lens calibration

  2. OpenPnP is now looking for a specific pattern of dots. If you have a v2 machine, you can find this pattern is on the back side of your datum board. If you have a v3 machine, you can find this pattern on the back side of the FTP board in your Getting Started Kit.

  3. Hold the pattern under the top camera as shown below. Check the camera view in OpenPnP to move the pattern into focus. If the focal distance is too close such that you can’t get the whole pattern in focus and in the field of view, screw in the lens a few turns and test again. If you’re having trouble adjusting the focus, try using the community-created lens adjustment tool.

  4. OpenPnP will flash when it takes an image of the pattern, and will require you to take a few for an accurate calibration. Slowly move the calibration pattern around the camera’s field of view until OpenPnP tells you that it’s gathered enough photos.

  1. Confirm that the Apply Calibration? checkbox is enabled checked after calibration is complete.

Bottom Camera Calibration

  1. Again, navigate to the Machine Setup tab

  2. Again, click the “Expand” checkbox if necessary

  3. Navigate to Heads > ReferenceHead H1 > Cameras > OpenPnPCaptureCamera Bottom

    Finding the Bottom Camera Settings

  4. Continue with the same steps starting from number 5 above for the bottom camera.