Wednesday, 17 January 2018

Medium range 3D scanner

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Contact

Rudy ERCEK

Description

This system consists in acquiring, via a sensor 3D, the geometry of an object in order to be able to virtually handle it thereafter via its 3D numerical representation.

With an aim of providing of such models 3D, a system of acquisition 3D is available in the lab. It is the Fastscan model of the Polhemus company, based on the technology of the laser stripe triangulation.

It allows to acquire objects of average sizes (about several centimetres with a few tens of centimetres) with a precision going until the half-millimetre.

Principle

The arm of the scanner is equipped with a laser source and two monochromatic cameras. The user sweeps the surface of the object with the laser beam. The deformation of this one is seen by the two cameras, which makes it possible the computer to gradually reconstitute, by combining various sweepings, the surface of the object in three dimensions.

Scanning limitations

Taking into account the technique used in this system, a certain variety of objects cannot be treated.

The objects should not be:

  • transparent
  • metallic
  • reflective
  • too much sinuous(surface inaccessible to the laser beam)

Post-processing

In order to correct and/or specify the aspect of the models obtained, following postprocessings are possible:

  • automatic filling of the holes in the grid due to an incomplete scanning
  • smoothing of the surface
  • simplification of the model

Exported 3D Format

The generated models can be exported in several formats usually employed in the various fields of the 3D. They are thus directly exploitable for visualization, filing, treatment or analyzes.

The supported formats are as follows:

  • 3D Studio (3ds)
  • AutoCAD (dxf)
  • IGES (igs)
  • Inventor (iv)
  • Lightwave object (lwo)
  • Matlab (mat),
  • STL (stl)
  • VRML (wrl)
  • Wavefront Object (obj)
  • Object File Format (off)

Result samples

As example, here results obtained with an archaeological fragment:

9260.jpg

9620 scanne.jpg

screen display of the fragment

digitized fragment

3D model obtained

Objects can be digitalized at laboratory by a person experienced with the use of the system. The generated models can be exported on CD in one (or several) of the formats here before.