NextEngine Model 2020i Desktop Laser Scanner:

The Promise of Low Cost 3D Laser Scanners (Word document)

The Promise of Low Cost 3D Laser Scanners (pdf)

The Promise of Low Cost 3D Laser Scanners

S. G. Strait1, N. E. Smith1,2 and T. Penkrot1 Marshall University1, The University of Texas at Austin2

Introduction:

Three dimensional laser scanning effectively visualizes and quantifies complex morphology; however, the widespread use of this technology has been restricted by high equipment costs ($25-100K). This year a substantially lower cost ($2.3K) laser scanner was introduced to the market. This goal of this study was to evaluate the potential of this scanner for paleontological research.

System Description:

NextEngine Model 2020i Desktop 3D Scanner

$2.3K with educational discount, includes scanner, auto-positioner, part gripper, and ScanStudio 1.5.2 software.

Scanning Modes:

Two cameras and two sets of lasers (each with optics optimized for scanning at pre-set distances)

1)"Macro" mode

  • Specimen distance from scanner 16.5 cm
  • More accurate (manufacturer estimates 0.127 mm with a maximum ~16 points per mm)
  • Small field size (13.0 x 9.7 cm)

    2)"Wide" mode

  • Specimen distance from scanner 46.0 cm
  • Less accurate (manufacture estimates 0.38 mm with a maximum of ~6 points per mm)
  • Larger field size (34.3 x 25.7 cm)
  • Objects larger than the field can be scanned, but need to be composite-captured and merged

    Time Scanning:

  • Scan time about 3 minutes per view in highest resolution ("fine" scan mode)
  • Need between 6-32 scans per 3D model depending on the complexity and detail of the specimenRecommended System:
  • Windows 3GHzPC 4 GB RAM 256 MB Graphics Powered USB 2.0 Hub

    Scanning ("Geometry Pass"):

  • Three scanning pass types:

    1) 360 scan - auto-positionerautomatically rotates the specimen between 4 to 16 times (user defined).

    2) Bracket scan - includes three scans including a center scan and right and left of center scans (user defined between 23 to 90 degrees off center). This mode is especially useful for top and bottom scans to capture the morphology that is obscured during a 360 degree scan by the part gripper and base.

    3) Single scan - captures only the side of the specimen facing the scanner. Especially useful for touch-ups of complex and hard to reach areas.

    Photographic Surface Capture ("Texture Pass"):

  • Color ("texture") scanner
  • Camera takes a picture that is saved as a 2D .jpg file (the color data are not 3D but overlaid on the 3D files)
  • For broken specimens, the color ensures a clear distinction between actual bone and reconstructed surfaces.
  • Color makes alignment simpler

    Modern Canis skull, length ~26 cm

    Accuracy Study:

  • NextEngine marketed their Desktop Scanner as having a maximal accuracy and resolution of 0.127 mm (in "Macro" mode)
  • An accuracy study was performed on a certified scale bar (100 x 10 x 1 mm)
  • The scale bar was coated with ammonium chloride and scanned at ten different orientations that were aligned to form a single 3D model
  • The models were processed in the proprietary ScanStudio, exported to Geomagic Studio to transfer the created mesh into a solid
  • The scale bar was scanned and modeled six times
  • The length of each scale bar model was measured in AutoCAD

    Pros:

  • Very inexpensive
  • Very portable -can easily fit in a backpack for travel to museums (8.8" x 3.6" x 10.9", ~ 7 lbs)
  • Universal power supply that accommodates 110-220 volts
  • Easy to use and learn
  • Includes color and texture
  • Great support
  • Auto-alignment
  • Adjustment features when coating is not an option

    Cons:

  • Accuracy
  • Inadequate for small and/or topographically complex specimens
  • Auto-alignment can only be use with specimens that fit on the stage and are under 20 lbs
  • Auto-alignment based on your own calibration and stage can not be moved at all between scans
  • Trim feature extends all the way through the model (including any surfaces beneath the visible surface)
  • Measure functions minimal (includes point to point linear distance, surface and volume of entire model only)

    Acknowledgements:

    This study was funded by the National Science Foundation Biological Databases & Informatics program as part of the development of the PaleoView3D website (paleoview3d.org). We thank Mike Adkins, Shawn Zack, and Josh Boudreau for contributing to the images