A homemade 3D scanner

Project stalled, 12/2004.

A 3D scanner computes space points which represents a real object in three dimensions. Professional scanners restitute with precision the shape and textures (colors) of an object, using white light and high quality optics; what is done here is not complicated so far and especially not so expensive ! A real scanner costs at least $30,000, this one less than $50.

Hardware

So, what is needed to build a cheap 3D scanner ?

• A motor. The object is scanned on the edges by steps, a motor makes it turn regularly. I use a stepper motor (taken from a 2D scanner), driven by the computer (parallel port). I soldered a plate on it, cheese box glued on a CD.
• A webcam. I use a Creative Webcam V which has no Automatic Gain Control, and I'm about to test it with a Philips ToUCam Pro (both of them use the pwc driver) for a better image quality and a full shape of the object (with one camera, convex data are missing).
• A laser pointer. Not very expensive, (not very good as well) a simple laser diode can be used to draw a light line on the object to scan. I use a little plastic tube full of water to deviate the laser spot into a laser line.
• A 4.5V battery and a switch. Batteries given with the laser pointer don't use to last a long time... Laser diodes are very difficult to power up, they need a constant current, and no peak at all.. I tried to power it up with a PC ATX PSU and it just burned. See this faq if you really don't want to use a battery.

More pictures: laser diode in action, laser with its cone used to reduce light diffusion, view of all the scanner with the duck on it.

Software

I developped my own software which drives the stepper motor, grabs image from the camera and extracts the points. Here is a screen shot of the first version with one camera. The image on the top is a screenshot of the full points created from the little duck.
Since I'm still workind on it, I don't give the software, it would not be easy to use nor to read. I will probably release working versions in future.

You might take a look at COPOS (french only) and CGAL projects.

Results

For the moment, all results I have are the plot image of the duck in the top of this page.