Laser 3D scanning
Laser 3D scanning is certainly the most common and used 3D scanning technique. Digitally capturing the shape of the object using laser light to get a digital representation of the real object. These 3D scanners are able to measure really fine details and capture free-form shapes to generate highly accurate point clouds.
This laser scanning technique is perfect for measurement and inspection of complex geometries. It allows getting measurements and data from where it is impractical with traditional methods!
A scanner using laser light is a little bit like a camera: it can only capture what is in its field of view. With this process, a laser dot or line is projected on an object from the device and a sensor measures the distance to the surface of this object.
By processing this data, it can be converted into a triangulated mesh, and then a CAD model.
Photogrammetry
Photogrammetry is a science of making a measurement from photographs! It seems pretty simple, no? This method uses the parallax obtained between several pictures, taken from different points of view. Photogrammetry can be used to record complex 2D and 3D motion fields. It imitates the stereoscopy of the binocular human vision, and it is used to get all information of existing physical objects. Indeed, this process collects the data regarding the shape, the volume, and the depth of the subject that you are trying to scan.
This is the method used to turn several pictures into an accurate 3D design. It won’t allow you to get the most accurate result, but by using good photogrammetry software you could actually reach a satisfying result!
Structured Light Scanning
With this Structured Light Scanning method, one of the camera positions used in previous scanning methods is actually replaced by a projector that projects different light patterns on the surface of an object. The way the objects distorts these patterns is recorded, allowing to create the 3D scan.
The structured light scanning process is used in facial or environment recognition technologies.