Lens & Tracking Calibration

The main objective of the Lens & Tracking Calibration Tool is to generate a Lens Profile as well as an align the tracking system.
Additional this tool can position/align screens within the correct 3D location/orientation.

Prerequisites

• At least one calibration screen or for a more complex wall in real life, can use a multiscreen in SP.
• A supported tracking system
• Media Input into SP
• A camera object within SP
• A map input within the camera object to allow the tracking system to be driving the camera in SP.

*Please remember to range the encoder values within SP for the camera object.

*Double check with the Viewer to see whether the video feed is coming in correctly without any cropping or black boarders.

Add the Lens & Tracking Calibration tool

Once everything has been setup and the camera object is linked properly to the incoming data, the Lens Calibration process can begin.

Go to the camera object, and under the Tools tab, add a new tool under the Calibration folder. Depending on the different situation, a different tool can be used. For more information, click here.

Click on the icon to open the Calibration Wizard window.

Tracking Modes

There are different Calibration modes available depending on the situation with the tracking system and the setup.

Start Calibration

Before capturing any images for observations, it is important to ensure that the majority of the markers can be detected properly by the system.

• If a marker is visible by the system cannot pick it up as a valid marker, there will be no overlay drawn ontop if it. From the capture window, you would just see the marker itself.
• When a valid marker is picked up by the system, an overlay would be drawn over the marker showing the ID of the marker with a colored background.
• When a marker is picked up by the system but it does not match the ones that should be in the associated calibration screen, an overlay would be drawn over the marker but with a greyed out background.
  

*Adjust the iris, gain, brightness of the display, and general lighting give the system a better chance at picking up the markers from the camera feed

!Bring the iris/exposure to the highest possible F-Stop number (iris closed as possible) to have a high range of focus within the optical system.

*The back focus of the camera (if applicable) should also be adjusted and not change anymore once the calibration process has started

Multiple images would need to be captured for the same Zoom and Focus step. Therefore, before you are ready to move to the next zoom/focus step, it is important that the zoom / focus values stay the same during the entire period.

To capture an image click on the icon:

*Press “F9” on your Keyboard to captures frames.

!It´s very important that the camera and image for each single capture doesn’t move any more, to make sure that the captured image and the incoming tracking data really belong together.

Once an image has been captured, it would appear on the left hand side of the Calibration Wizard window.
Repeat the capturing process until the entire image sensor of the camera has been covered.

*Try to get the calibration markers to be as close to the edges and corners of the image sensor of the camera as possible.

Move the camera to multiple locations within the tracking space to capture different locations as well as different rotations from the system.

!It is important to go to the edge of your tracking space as much as possible while maintaining good tracking data.
It is also important to change the pan and tilt as much as possible when taking these captures.

!If possible, try to capture some images at a slight angle on all axis and not have the camera always looking at the calibration screen straight on.

Run Calibration

When a good distribution has been achieved, it is a good idea to run the calibration process now and look at the error margin. To do so, press the icon.

*Depending the number of total images captures, this process might take some time.

After the calibration is completed, an error margin number would be displayed on each of the captured image. Also, an overall error would be given to a specific zoom/focus step.

*In an ideal situation, the error should be below 1.

If the error is higher than expected, try the following steps:

• review the already captured images and see if some are extremely high. If so, disable them and run the calibration again.
• capture more images at different angles / positions.
• check if the tracking system is deliver “clean” data.
  

For more details of how to understand the calibration results, please refer to the Observations view.

Continue with different zoom and/or focus step

Simply change zoom and/or focus to the next needed calibration values and continue capturing images.