Posted on Tuesday 30 November 2004

It seems my post on the SeeLinder has generated a bit of interest but one question that keeps cropping up is how can you film a subject in three dimensions? I'm not sure how the Japanese inventors have solved this problem but the prospect of arranging 360 cameras into a circle is probably not it. I can think of one way do it which only needs a relatively small number of cameras, perhaps 6 and makes use of a clever type of image interpolation known as View Morphing.

This is also something that I also happen to think is really, really cool.

Morphing is a simple technique of interpolating between two images. The first time I ever saw it was on Michael Jackson's film clip "Black or White" which smoothly transitioned between the faces of dozens of different people. The trick can be performed on very cheap hardware and there are plenty of inexpensive or free programs that can do it. The problem however with conventional morphing is that it is fairly dumb about how it is interpolating so if the images are very different (such a head at two different angles) the interpolated images become distorted and unnatural looking. But if the geometry under which the photgraphs were taken is already known (as would be the case in a 3D televison set up) then the interpolation can be designed to correctly interpolate the images without distortion, synthesizing viewpoints unseen by any camera.

Here is an animation of the rotation of the Mona Lisa in 20 frames (64K MPEG). Those eyes really follow you around the room, don't they?

You can read much more about View Morphing right here.