Polhemus FastSCAN®

© 2004 by EST · Last updated: 25.03.2008
FastSCAN Options
> Stylus’ > RBF utility software > Sweep Registration > Refraction correction > AAOP file format

Mechanical Stylus
Adding a mechanical stylus option to your FastSCAN system gives you the ability to create 3D landmarks within your digitized surface model. Once initialized, the stylus operates in either Point mode or Line mode. In point mode, simply pressing the stylus button generates a position and orientation landmark anywhere within the FastSCAN’s operating range. These stylus points (landmarks) are registered automatically within the FastSCAN software and displayed on the screen. Stylus points are saved with your FastSCAN files for easy review or export at any time.

The stylus’ line mode offers you the ability to freely draw a 3D line within your digitized surface model. Line references as well as points can be quickly exported in a delimited format for easy import into your Excel worksheet or other application of choice. Polhemus offers two sizes of the mechanical stylus; the 3 inch (ST3) and the 8 inch (ST8). Each is available in your choice of nib, pointed or rounded, to accommodate your specific needs.
 
FASTSCAN Options
FASTSCAN Options
3 inch stylus option
8 inch stylus option
 
Optical Stylus
The optical stylus, like the mechanical, also gives you the ability to create 3D landmarks within your digitized surface model. There is an additional piece of hardware added to the 3D scanning wand that, when initialized, gives you the ability to place landmarks on the surface of the object you are scanning using a non-contact laser dot.

The FastSCAN optical stylus uses a hinged shutter mechanism to reduce the laser fan to a single point when you are operating the system in laser pointer mode. The location of the point on the object's surface and the orientation of the wand are registered in 3D whenever the wand trigger is depressed while operating the optical stylus.
 

FASTSCAN Options

FASTSCAN Options

(a)

(b)

The Optical stylus shutter, with the shutter positioned for laser pointer mode (a), and the shutter positioned for normal scanning mode (b).


As with the mechanical stylus, 3D stylus line or points can be quickly exported in a delimited format for easy import into your Excel worksheet or other application of choice.

RBF Utility Software
Radial Basis Function (RBF) utility software offers powerful benefits to your 3D basic surface scan:
  • Automatic hole filling - solid surface rendering of areas of your scan for which you did not collect complete data (such as deep into an ear canal, for example, if you were to scan an ear).
  • Smooth extrapolation of surfaces - using the normals of known points collected during your scan, RBF algorthyms generate predictive trajectories for use in hole filling that might otherwise be closed with a simplified linear surface between known points. The result is a watertight surface rendering that mirrors the object you’ve scanned more completely.
  • Mesh simplification with scan detail preservation
  • Export capability for guaranteed closed, water tight meshes
  • RBF Mesh is characterized by more uniform triangles
  • Enhanced Low Pass filtering (smoothing) of scan

  • Sweep Registration
    Small errors associated with the sweeps (e.g. slight object movement), may be corrected through a process of sweep registration. The process, once initialized, is fully automatic and takes just a few seconds.

    Refraction Correction
    This option provides you with a parameter setting specifically designed to meet the needs of those who need to scan an object, perhaps dynamically or under load, a sheet of glass. The user is required to set the parameters of the glass thickness and refractive index measurements, please contact Polhemus Sales for more information.

    AAOP file format
    AAOP, a standard in much of the Orthotic and Prosthetic community, is a medical file export format which uses a cylindrical co-ordinate system. The user must define a central axis about which the object is defined. Points on the surface are then defined in slices and at fixed angles (as set by the user) along the central axis.
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