Passive Stereo Projection & Videography For Cheap

Home-Brew Passive Stereographic Projection

My 3D movie screening... in a nuclear missile silo

The goal for this project was to assemble a portable 3D theater for under $1,000.

Parts List

3D Projectors

These components are all available new and used from EBay and Amazon. The major consideration is portability: these parts have to be easy to transport on a bicycle, and have the ability to be powered by battery. The only part which does not meet the criteria is the DualHead2Go unit which requires 5V DC. The plan is to provide this via a custom power cable to the USB bus of a laptop.

Operation

3D Projection of Power-Tool Drag Races

The display is suitable for stereopair imagery- an image with the image for the left eye on the left, and the right eye on the right.

The Matrox DualHead2Go vertically bisects a 2048x768 VGA signal into 1024x768 signals which are feed projectors with polarizing filters corresponding to the left and right lenses of the 3D glasses.

Simply enough, Lenses from a pair of 3D glasses are used for polarizing filters as the light from the 3M MPro110 is cool enough as to not melt or distort the plastic. The projectors' beams are then superimposed (painstakingly so) and focused upon the silver screen.

The first thought was to use the projectors without filters by flipping one upside down and using 45/135 polarized glasses. In practice, projection through 0/90 polarizing filters does not dim the light too much, and re-factoring viewing software to rotate one half of a stereo pair would have consumed too much time.

Software

Stereoscopic Video in the Blender

The Blender is known mostly as a tool for modelling 3D objects. It is, however, also quite useful for creating stereopair imagery. The Blender Game Engine provides an option for stereographic output of computer generated "game" output, and the Blender Video Sequence Editor has post-processing modules which can be used to composite two seperate video streams into a single stereopair movie file.

Stereopair videos can be displayed reasonably well with Videolan.


Stereo Videography

Sterereo

Facts about human vision

Technique

Got a direct hit... in 3D video!!!

In order to create the illusion of human sight, the lenses of two cameras are placed less than 2.5 inches apart from each other. Unless the photographing distant objects, the cameras are also converged upon each other slightly. The eye has a broad field of view, so the cameras use wide angle lenses.

Parts List

Sterereo

Early Experiments