How remove backgroud camera

Hello to all. I'm working with Vuforia, Unity and the Moverio BT-350 viewer. The problem is that in addition to the virtual information, the video taken by the camera in the background also appears on the viewer's lens. Since the lenses are transparent, it would be nice if you could remove the video from the camera and leave only the virtual information. I searched on the internet but none of the solutions found work. Is there a way to remove the video from the camera in the background? If with Moverio BT-350 it is not possible, are there other viewers that simply allow the removal of the video in the background and possibly also the alignment of the virtual information with the objects of the real world? (in practice I noticed that the video does not exactly correspond to the real world, so the virtual images without video in the background I suppose appear to be translated with respect to the target image of reference). Thanks in advance for an answer.