Building a DIY 3D scanner is a very ambitious project for most enthusiasts. To make a scanner, the proper design must first be chosen, and the appropriate parts obtained. A 3D scanner is a machine capable of producing three dimensional computer models from real world objects, which can then be used to create computer generated images or loaded into a 3D printer to produce a three dimensional copy of the original. Scanning devices or webcams are often used to capture the image of the object. As 3D scanners are not widely commercially available, most individuals who want one have to create a DIY 3D scanner.
There are several designs that can be used to make a DIY 3D scanner. The laser scanner uses a laser that can project a line of light against a flat surface. Ordinary lasers produce a beam, so the line must be created using a special lens or an oscillator. By pairing a webcam with a line of laser light, a computer can use triangulation to determine the shape of the object the laser reflects off.
Another kind of DIY 3D scanner uses two webcams, or, sometimes, specialized webcams with two lenses and image sensors. These systems mimic human depth perception and calculate the shape of the object based on the difference in image between the two webcams, known as the "parallax." This type of scan requires only a single image, so cheap digital cameras may be used instead of webcams. Most builders prefer to use webcams anyway because of their low cost, good software support, wide availability, and video capture option.
One type of more advanced DIY 3D scanner is a structured light scanner. This scanner uses one camera or webcam and a projector. The projector projects a complex digital reference image similar to a 2D barcode, except full color. The computer then attempts to triangulate every visible point of the target object using the known positions of the camera and the projector, as well as the known reference image. Although this method is very fast, it can sometimes fail when scanning objects that have different shades or colors, because the computer can fail to distinguish the target object from the reference image.
These designs all capture only one side of an object. While this is fine for users who are only creating a static image or a mask, it is a severe limitation for those who wish to scan objects for placement in virtual environments or video games. To solve this problem, any of these systems can be paired with a turn table to rotate a small object while the scanner is active. The rate of rotation must be known for the scanning software to work. Many designs use old record players or pottery wheels as turn tables.
