I'm trying to setup a way to do video conferencing between two individuals. The tricky part is that the users need to be able to touch the screen and have the other user see their hand on their end. The only way this will work is if the camera is behind the screen filming through it. This has led us to this theoretical setup: camera + projector on one side of a transparent screen / person on the other side. The issues that we've run into are:

  • we don't know of a screen material that will allow for a rear projector that will also allow the filming through it
  • the image being projected onto the individual

Please let me know if there are any screens that come to mind or an alternative setup or if I should stop right now.


1 Answer 1


You will need a one-way mirror for this. It's related to something called front projection.

This setup is typically, except from the touch part, used with auto-cues (text projected in front of a camera that f.ex. a news anchor reads from appearing looking into the camera).

For example:

One-way mirror setup

For a full body you would of course need a bigger mirror and you would need to project the image from top (or side), turn the mirror 90 degrees so it reflect what comes from top (or side), as well as a layer between the projector and mirror (can be as simple as a cloth)

One-way mirror full body setup

In addition to that, you would need a video mixer so you can super-impose/mix in the interface that is supposedly touched (same as the projected image from the TV or projector) (alt. do it in post with composition/video editing software).

The tricky part is to get the overlayed video (the user-interface) synchronized with the touches from the talent. You would need initially to perform some calibration, f.ex. an image with fixed corners and a center that is projected while the talent touches these spots. Then scale/zoom/place video/camera to match the super-imposed image that is projected.

The other tricky part is the lighting conditions. The room need to be relative dark for the mirror to work properly at the same time as the talent is properly lit for the camera. You can darken the area behind and around the mirror with black colored textile in addition to turn off all none-talent lights and so forth.

Hope this helps!

  • Thanks for your help on this. We have tried a solution like this and the major drawback has been that from the perspective of the person standing in front of the screen, the image of the other person that can be seen in the mirror appears in the "back" of the set up and not the "front". The intention is for the two people using the system to appear basically face to face. Can you think of any way to bring the image in the mirror to the front?
    – Chaz
    Nov 15, 2012 at 21:35
  • The only way I can think of this to be possible are either to place another smaller one-way mirror in front of the person which reflect the video of the other person - with all the implications that introduces (being visible in the video, forcing the person to stay in one spot, local lighting conditions etc). The other is to go for more modern technology such as the Goggle's Project Glass (en.wikipedia.org/wiki/Project_Glass) that can project image right in front of the person who wears them. This could eliminate the other requirements mentioned earlier.
    – user2995
    Nov 15, 2012 at 22:03

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