Targets for Relative Range Error Measurement of 3D Imaging Systems

Abstract

The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is supporting the development of documentary standards for performance evaluation of laser scanners. There is currently one published documentary Standard, the ASTM E2938, for the evaluation of a 3D imaging system along the ranging direction. The Standard calls for one pointto-point length along the ranging direction and requires the use of plane targets. There is also ongoing work within ASTM E57.02 (WK43218) to create a documentary standard for point-topoint performance evaluation of spherical coordinate 3D imaging systems (terrestrial laser scanners). This draft standard calls for multiple positions and orientation of a reference length within the work volume, with some of them along the ranging direction. While the draft (WK43218) recommends the use of sphere targets for most test positions, there is still some discussion within the committee on how best to handle the ranging direction tests. The options currently under discussion include using sphere targets for ranging direction tests also, referring those tests to the ASTM E2938 for a plane-based evaluation, or allowing the use of alternate target geometries such as pyramidal target, etc. In this context, the DMG at NIST has investigated the use of different target geometries and their influence on the measurements.