Generally I am not a big fan of theoretical issues, especially when it comes to something as practical and visual as 3D modelling. This however is something I cannot really experiment with practically (or within an acceptable time frame), so for now it has to remain in the grounds of theory. It is also not strictly archaeological, although I’m sure some applications must come from it.
What I mean with Photorealistic 3D Video is taking the still photogrammetric models you’ve seen before and applying movement to it. This can be done by using either stop motion or a combination of cameras to acquire the original footage, then modelling individual frames and putting the frames in a sequence.
The acquisition of footage depends on what you are trying to achieve. If the object is still itself and it’s going to be moved frame by frame (like traditional stop motion animation) then a single camera is required. Instead of taking a single photo of the scene, like in standard animation, a series of images would be taken to make a Photogrammetric model, as explained previously on this blog. If instead the object is already in motion, as for example an individual acting out a scene, the trick is to use a large number of video-cameras that surround the object, using the same positions described before (a good example of this can be seen here http://www.webpronews.com/get-a-3d-print-of-yourself-in-texas-2013-08). With all the cameras then each frame is isolated as if photographs of the scene were taken at the same time from all angles. With either method, the results should be a large number of frames (24 for second or more depending on format), each of which is made up by 20 to 30 images.
The second step is the creation of the models. This can be done using 123D Catch or any other Photogrammetric software. Each series of images constituting a frame are hence transformed into a single rotatable 3D model.
Then all the frame models are run through other software, at present I am leaning towards gaming software, but video editing software or animation software may be more suitable, so possible options are Unity 3D, Maya or After Effects. Some alignment will have to take place, but by superimposing the models on top of each other and making it so that a single one is visible at a time should create an animation effect, again like stop motion. This is the part I am most unsure about, due to it being quite a demanding task, which may be far too complex for computers at this time. Still, in the future it should be more than possible.
At this stage the result is a series of still models that run through giving the illusion of movement. This can then be combined with technology that is now appearing on the market. In particular it could be used with the Oculus Rift that is soon going to revolutionise how 3D gaming works. By tracking the position of the user, it would be possible to not only see the Photorealistic Video, but also move around it as if it were real. By combining more than one model an entire scene could be created, meaning 3D films in which the user is actually present within the film can become a possibility, as well as uber-realistic videogames.