Image target stop positioning

Hello,

I am using Vuforia + HoloLens.

I have a image to calibrate my scene. (ImageTarget parent, complete scene child)

At the moment I scan the image and deactivate the objecttracker afterwards. 

So my complete scene is in the position I like. And the position, rotation, etc doesnt change.

But now I want to scan a second image continuously.

To sum up: 2 images

1. Image: track image once, stop positioning, always visible

2. Image: tracking always available