How does 3D scanning work?
3D scanners, or to be precise Optical Measuring Machines are touchless metrologic systems made to catch data about a geometry of a given object – even those that are most complicated. During the process of 3D scanning, or in other words 3D digitalization, they change real objects into a shape of a precise and sophisticated digital model, in most cases saved as a network of STL triangles, which could easily be put under the process of quality control or reverse engineering.
Optical measuring machines stand out with a very good versatility and agilit. With these undoubtable benefits, there is no lack of quality in terms of measurement, where accuracy is more or less than 0.02mm.
A good example of such a machine is SCANTECH Simscan, which being on 20 cm long and weighs 0,5kg.
Types of 3D scanners
Each scanner is built out of a projection unit and set of cameras that are angled in a known process of calibration. This is necessary to generate a trustworthy data that are describing the measured object. Calibration is about scanner observing a special plate being put in various positions, so that the system can set the angle between the cameras, that could have changed with the influence of temperature and shocks.
Due to the type of the projection unit, there are two main scanner types:
- Structural light scanners
- Laser scanners
Modern structural light scanners mostly use LED projector and two cameras, which are tracking variation of displayed lines. This type of a system requires tripod or a robot on which the head would be mounted. Such a measurement takes place with in a static way. It means, that during a single scan neither the head nor the scanned object cannot move.
Laser scanners use a laser emitter which purpose is to light stipes on the measured object, whereas two cameras are registering their deformations. The process of measurement is carried out in a dynamic way, which means that the system is generating data in a constant way, without any interruption of singular scans, as it would be in structural light scanners. Thanks to that, the “tripod” a human holding the scanner that significantly increases the measurement and mobility features.