Methods to record and analyse the shape and internal structure of small and large items, via not only 3D modeling like photogrammetry and laser scanning, but also CAT, ultrasound analyses, georadar testing, microclimatic surveys…
The three-dimensional acquisition of an object can be performed with different techniques, according to the required accuracy and object’s dimensions. Art-Test offers a variety of services to comply with any need, and will help you chose the right one.
Traditionally for painting, 3D acquisition consists of a raking light photography, which allows to visualize and enhance the behaviour of the artwork’s surface. This is a qualitative and only visual method while nowadays other quantitative and non-invasive approaches are available.
Triangulation-based laser scanners are active sensors which employs a single spot or a profile measurement principle to derive the 3D information of an object. The profile measurement systems are the most commonly used where a camera analyses the deformation of the projected line-profile and derive the range information. Laser scanners generally requires different acquisitions from different standpoints that should be afterwards registered together. Triangulation laser scanner are not very fast and allow the digitization of object in a range up to ca 2 meter.
Stripe-projection systems are also active sensors which project a known pattern (typically a sequence of black and white grid lines) imaged by a camera from another viewpoint. The deformation of the projected lines is used to recover the 3D information of the analysed object.
Stripe-projection systems perform very fast acquisitions but have aquite small field of view.
The photogrammetric approach is based only on images (at least two) acquired generally with calibrated cameras. It is a unexpensive and quite fast digitization method based on the optical triangulation principle. The field of view varies according to used objective and sensor.
Together with the recovered geometric model, photogrammetry has also the colour/texture information while the other two methods generally require extra acquisition it.
The texture information can be projected onto the 3D geometry to recover a photo-realist 3D model.
Other texture information, like diagnostic acquisitions, can also be overlapped onto the model to show .
On the 3D geometric model, metric measurements can be performed to help the restorers, create virtual copies or to reproduce it by 3D prototyping.