# Structured light, infinite focus

Im interested in projecting a static image across a room that stays focused over a wide range of distances from the projector, without re-adjustment, for a structured light setup.

ie, the target may move anywhere from a couple feet to 10 feet from the projector.

Is such a thing possible? How/is this achieved in practice?

• The easy approach to this is just to stop the lens in the projector right down. Unfortunately this means the image will be rather dim.
– user107153
Commented May 9, 2016 at 14:59
• Use a laser scanner. That's typically the equipment for something like this, isn't it? Commented May 9, 2016 at 18:11
• Typically laser scanners yes, but attempting to build an alternative setup with a bare minimum of parts / complexity. Commented May 9, 2016 at 19:04
• Also, Ive seen several setups with regular projectors, so curious what depth range they cover. Commented May 9, 2016 at 19:34

... projecting a static image across a room that stays focused over a wide range of distances from the projector, ...

A 3D projection is created and mapped to the 2D surfaces in the room. To record the view and show it to others you simply track the position of the camera.

Here is a before view of this person's room:

Here is the room with fake wall texture and additional objects:

Here is a screenshot from part 3 of the PlayStation video listed below:

In another part his room becomes flooded and he is attacked by a sea monster:

That movie was created with a room, a RED camera, two PlayStation Move controllers, a computer, the Sony PlayStation SDK, and a film crew. The room is at least 12' x 12'.

There is relatively simple hardware available that can be assembled and controlled to produce a 3D projection mapping on the 2D surfaces in your room, it's not simple to do.

• This is a primer on projection mapping, but my question was on specific details of focus over a large dynamic area. Cheers Commented Sep 18, 2018 at 11:58
• This answer deals with your question asking for a "yes" or "no" answer and provides an outline of a few of the many methods. What is your budget?
– Rob
Commented Sep 18, 2018 at 13:39
• Unfortunately none of those links cover a wide depth range as requested, but instead focus on perspective correction issues, not focal issues. Cheers. Commented Sep 19, 2018 at 15:12
• Cheers it is correct.
– Rob
Commented Sep 19, 2018 at 17:18