Being able to validate the performance of any 3D laser scanner is (or should be) of particular interest to accredited crime laboratories that plan on deploying scanning technology to crime scenes.
While currently 3D laser scanning is not listed as a scope of accreditation for crime laboratories, many knowledgeable people (including members of the American Society of Crime Laboratory Directors/Laboratory Accreditation Board) feel that the time is not far off when this will change. Once this happens, laboratories will need to address many issues surrounding their 3D laser scanning system including calibrations, maintenance and controls, proficiency testing and traceability.
Leica Geosystems is fortunate to have among our very large installed base of ScanStation users many accredited crime laboratories. Several of our customers regularly perform audits of other crime laboratories around the country and early on they started to educate us on their needs.
We listened and learned what they needed to incorporate Leica’s scanning technology into their operations. Then we developed the tools, training and workflows they required. When the 2009 National Research Council of the National Academies report on strengthening forensic science in the United States was published we realized more than ever that our mentors had provided us with good advice.
No matter if your accreditation standard is ISO 17025 or ISO 17020 (which more and more stand alone crime scene units are seeking accreditation under) or if your accrediting body is ASCLD/LAB, A2LA or FQS, we have the answers and services you need for your successful deployment of the Leica ScanStation.
We invite you to spend some time reviewing the information found in this section and then measure your agencies’ goals against our organization’s ability to provide what you need.
Leica ISO/IEC 17025 Accreditation Certificate
Video: ScanStation Length and Angle Measurement
Leica’s accreditation letter as calibration laboratory for length and angle
File: Leica Accreditation Certificate for Length and Angle.pdf
“ASCLD/LAB-International accredited laboratories and laboratories seeking accreditation under the ASCLD/LAB-International programs must demonstrate that measurement results have known relationships to accepted references that, where possible, are traceable to the International System of Units (SI) through a National Metrology Institute (NMI) (e.g., National Institute of Standards and Technology [NIST]).”
ASCLD/LAB Policy on Traceability of Measurement Results, Reference Standards and Reference Materials
Section 3.3 – The Traceability Requirements
“Checks needed to maintain confidence in the calibration status of reference, primary, transfer or working standards and reference materials shall be carried out according to defined procedures and schedules.”
ISO/IEC 17025:2005(E) Section 188.8.131.52 – Intermediate Checks
“Where relevant, equipment shall be subjected to in-service checks between regular calibrations.”
ISO/IEC 17020:1998(E) Section 9.9 – Facilities and equipment
In August of 2011 Leica Geosystems became the first (and still only) 3D laser manufacturer to provide our customers with a reference standard which enables them to perform a quick and easy scanner accuracy check between calibrations as required by both ISO 17025 and ISO 17020.
For this reference standard (calibrated artifact) to achieve National Institute of Standards and Technology (NIST) traceability to the SI, Leica Geosystems contracted with the Large Scale Coordinate Metrology Group at NIST to perform individual calibrations on specific Leica Geosystems twin-target poles by carefully measuring multiple times between the target centers on each end of the artifact using a wavelength-compensated helium neon linear interferometer. NIST then applies serial numbers to each component of the (now NIST-traceable artifact) target system and generates a Report of Calibration which is provided to Leica Geosystems customers when they purchase one with their ScanStation.
In 2013, Leica Geosystems introduced a new traceable twin-target pole created specifically for use with the Leica ScanStation PS20 3D laser scanner. The new quality assurance tool was recognized by the U.S. National Institute of Standards and Technology (NIST) as leading to improved forensics. In an article published on its website, NIST cited its close collaboration with Leica Geosystems in the development of this tool and noted the pressure building within the forensics community to have crime laboratories and/or stand-alone crime scene units in the United States adhere to specific standards in their services that require traceability to the SI.
A ScanStation user has the ability in the field to quickly perform a simple and intuitive check on-board the scanner which definitively validates the accuracy of 3D laser scans made using the Leica Geosystems ScanStation series of scanners. This not only provides Quality Assurance Managers with a way to satisfy ISO requirements, it is a simple and intuitive way for investigators (and jurors) to understand that the ScanStation was collecting accurate data.
It can also be used as part of the initial validation study required by most agencies.
Leica’s Public Safety Group training team teaches this use of this tool as a best practice when laser scanning. Contact us for more information.
File: Example Calibration Report for a Leica Twin-Target Pole from the National Institute of Standards and Technology (NIST)