CamBar Alignment
This is an important step that calculates how the CamBar is mounted relative to the camera
- It does not need to be repeated if a good CamBar alignment is already present
- This could be from a previous calibration session or a tracking config
- The process works best using wide angle lenses. If calibrating a long focal length lens it is recommended to do the CamBar alignment using a wider lens and then swap back to the long lens and to skip this step
- It is vital that the CamBar is correctly mounted to the camera as described previously (forward, central and no rotation)
An automatic or manual method for determining the offset are offered.
The automatic process will use the tracking features and a instant recovery chart to try and optically align the CamBar to the camera.
To improve the accuracy of the CamBar alignment, it is important to make some physical measurements to help the system refine.
Use a tape measure to accurately measure from the camera sensor to the sensor mark on the side of the CamBar
A value should be entered for the Y (Height) and Z (Forward) directions.
Y values when the CamBar is ABOVE the sensor should be positive
Z values when the CamBar is INFRONT of the sensor should be negative
It’s important that these measurements are entered accurately
After the values have been entered into the UI ensure the following:
- Focus is set to infinity
- The instant recovery chart is placed in the centre of the camera frame and is stable and not moving
- If using a zoom lens, make sure it is fully wide
Proceed to the "Automatic Estimation" stage, at this point the system will start trying to align the two devices.
Over the next few seconds, the system will refine the position of the CamBar. This can be seen in the viewing frustums of the camera as well as in the offset values displayed in the UI.
When the values are stable press "Stop automatic offset automation" to end the process
The step can be repeated if necessary
If the chart is moved during this process, or the tracking is interrupted or unstable, then poor results will occur. Repeat the process if needed
The manual offset method allows the user to manually adjust the X,Y,Z and pan, tilt, roll values of the CamBar to try and visually match the devices.
The UI displays the point cloud from both the CamBar and main camera views, by adjusting the offset, the points in the main camera view will update to reflect the changes
Because at this stage of the lens calibration, as lens is not fully calibrated, it's likely that tracking points in the main camera view will be misaligned, particularly towards the edges of the frame
Doing a manual offset is tricky and it is typically recommended to use the optical, automatic method primarily. When doing a manual alignment, try and reduce the CamBar rotation and use measured values to reduce the amount of adjustment required