Handling Camera Calibration Fi | Forum

Handling Camera Calibration File in Jib Tracking System

Dear Eifert,

I have encountered a problem regarding how to handle Camera Calibration file while using the jib as a tracking system. As shown in the picture, this is the jib we are using, and this jib can work normally and transmit position information through the Free-D protocol.

Due to the mechanical structure limitations of the jib, 6DOF seems unable to work here, so we chose PTZ as the option for Camera Calibrator. However, this has led to the problem shown in the video I provided. When we only rotate the camera angle, everything is relatively normal, but when we rotate the arm, there is a significant offset between the virtual LED and the actual LED position.

In this case, how should we deal with this problem?

You can find video here: https://drive.google.com/file/d/1Pk1RoiSKmKXLBiXj3Iy4gZS7j7u_Xu8i/view?usp=sharing

Warmest Regards,

Ruizhong

TwentyStudios

If you want to move the camera freely 6DOF you need to calibrate using the 6DOF calibrator. If the tracking data from the jib isn’t accurate (consistent), you won’t be able to calibrate it accurately with the 6DOF method either, since it relies on accurate tracking for this part of the calibration.

It looks like your pan/tilt calibration is already very accurate, but without reliable 6DOF data from the jib you will never be able to get good results, no matter how much you calibrate it.

Eifert@Aximmetry

Hi,

If the jib can send the PTZ position (camera rotation) data and jib position data (arm's position) separately to Aximmetry, then:

You should make a PTZ calibration with the PTZ position data. And set the PTZ rotation center height to the height difference between the Jib position data and the actual height of the PTZ rotation center. And do the calibration without causing changes in the Jib position data.
In the Tracked camera compound set the Tracking Device to your PTZ position data and the Zoom Device to Jib position data.

In this case, the Zoom delay will apply to the Jib's position data.

If the jib adds together the PTZ and jib position and sends it to Aximmetry, then:

You should try making 6DOF calibration work. You might be able to place the calibration board in a position where the jib can reach every calibration position.

Otherwise, you could do the PTZ calibration and then in Aximmetry edit the camera compound so that it uses the jib's position. It won't be perfect, but it will be probably better than what is in your video. I can show you how to edit the camera compound for this.
But first, you should make sure that the tracking data you get from jib is accurate enough as @TwentyStudios said. You can write out the tracking data like this in Aximmetry's Flow Editor:

You should check if the position changes are the same as in the real world.

Warmest regards,

Handling Camera Calibration File in Jib Tracking System

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