In general, the augmented reality stuff I have seen, don't really "stick" their virtual stuff to the real world very well. I.e. they tend to float around a bit. So, that is perfect for any ghost-like stuff. Though, if something should look rock-solid, don't put that in the augment reality display. So architectural items are probably not viable. You might be able to get away with non-ghostly things, if they are moving, and don't need to be seen touching real things. So, a flying bat would work. But a walking mummy would not, because his feet won't be sticking well to the ground.
No real experience here, but I would not go for a bland graveyard. It still needs to look good. I suggest being strict about differentiating between what is done as augmented reality, vs. real. So, you might separate ghostly things vs. what might be a real-life item. So, you could have a physical pirate, but have the ghost of one of his victims tormenting him in the virtual world. But, be sure to keep ALL the pirates as real things, and ALL the ghostly things as virtual.
Here is an idea. A flying saucer that is beaming up victims, if the victims can be virtual. The victim could be a real person, that gets opaqued by an effect on the virtual display. For example, the user looks towards some people with the augmented reality viewing device, and the people are about to walk into another part of your exhibit. The effect I mentioned stays on until the person is no longer in sight because they walked into the other exhibit. Ideally, if you had a programmer to do it, you might even capture a picture of the person, and show them being taken up into the flying saucer. I can even see trying to catch a front-facing image of the victim. Then, use the front-facing image to levitate them into the flying saucer.
Now you've done it. My imagination is going wild now. Perhaps you've seen the effect at the end of Disney's haunted mansion, where you see yourself in a mirror, where a ghost seems to be sitting with you. Can people be walking along a pathway, and you see someone walking near you get beamed-up? The same approach can be used as with the augmented reality version, where the "beam effect" from the flying saucer, obscures the view of the real person in the partially reflective sheet.
Alternatively, perhaps the "mirror" is simply a clear sheet. But, the audience is seeing a full projection of themselves and the others. See the attached sketch. Note that I positioned the camera and projector at the same elevation as the audience's eye. That way, the viewpoint will be correct. I put an object there to hide the camera & projector. But, a projector that has its image centered can be hard to come by. Perhaps one with a standard offset can be turned onto its side to do it.
No real experience here, but I would not go for a bland graveyard. It still needs to look good. I suggest being strict about differentiating between what is done as augmented reality, vs. real. So, you might separate ghostly things vs. what might be a real-life item. So, you could have a physical pirate, but have the ghost of one of his victims tormenting him in the virtual world. But, be sure to keep ALL the pirates as real things, and ALL the ghostly things as virtual.
Here is an idea. A flying saucer that is beaming up victims, if the victims can be virtual. The victim could be a real person, that gets opaqued by an effect on the virtual display. For example, the user looks towards some people with the augmented reality viewing device, and the people are about to walk into another part of your exhibit. The effect I mentioned stays on until the person is no longer in sight because they walked into the other exhibit. Ideally, if you had a programmer to do it, you might even capture a picture of the person, and show them being taken up into the flying saucer. I can even see trying to catch a front-facing image of the victim. Then, use the front-facing image to levitate them into the flying saucer.
Now you've done it. My imagination is going wild now. Perhaps you've seen the effect at the end of Disney's haunted mansion, where you see yourself in a mirror, where a ghost seems to be sitting with you. Can people be walking along a pathway, and you see someone walking near you get beamed-up? The same approach can be used as with the augmented reality version, where the "beam effect" from the flying saucer, obscures the view of the real person in the partially reflective sheet.
Alternatively, perhaps the "mirror" is simply a clear sheet. But, the audience is seeing a full projection of themselves and the others. See the attached sketch. Note that I positioned the camera and projector at the same elevation as the audience's eye. That way, the viewpoint will be correct. I put an object there to hide the camera & projector. But, a projector that has its image centered can be hard to come by. Perhaps one with a standard offset can be turned onto its side to do it.