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Forensic Topography and Surface Metrology

Summary:

Provide SI-traceable measurements and standards for ballistic and toolmark identification and surface texture and microform calibrations. Enable innovations in forensic science and manufacturing by developing and implementing state of the art optical and contact surface metrology techniques, algorithms and SRMs. Develop a statistical foundation and a practical procedure to estimate error rates for firearm and toolmark evidence identifications in forensic science.

Major Deliverables:

  • SRM 2460 and 2461 standard bullets and cartridge cases.
  • SRM 2071-2075 sinusoidal profile roughness specimens.
  • NIST roughness and step height calibration system.
  • NIST 2D/3D topography measurement system.
  • NIST's Surface Metrology Algorithm Testing System (SMATS).
  • A microform calibration system with the world's lowest uncertainty for calibration of the standard Rockwell hardness diamond indenters.
  • A traceability and quality system for bullets and cartridge cases evidence identifications to support the National Integrated Ballistics Information Network (NIBIN) of the ATF.
  • A Congruent Matching Cells (CMC) method for image-related forensic evidence identifications.
  • An error rate procedure for estimating error rates for firearm and toolmark identifications.
  • Led the development of two ISO working draft standard ISO WD 25178-600 and ISO WD 25178-607 which are approved for balloting as committee drafts by ISO TC 213/WG 16 on 9/16/2014.
  • Led the revision for the ISO/FDIS 6508-3:2014(E) standard on the microform geometrical specification of Rockwell diamond indenters based on NIST researches, tests and suggestions.

Description:

The Forensic Topography and Surface Metrology Project develops measurement methods, reference artifacts, and objective identification criteria to support forensic toolmark and firearm identifications and surface metrology. The research team has developed NIST Standard Reference Material (SRM) sinusoidal roughness specimens and SRM standard bullets and cartridge cases. The team also developed a 2D/3D ballistic signature acquisition system and applied unambiguous surface similarity metrics to improve the accuracy of ballistics identifications in the course of research in support of the 2008 National Academies Report. In 2008, NIST and the Bureau of Alcohol Tobacco, Firearms and Explosives (ATF) initiated the National Ballistics Imaging Comparison, which introduced procedures for using its bullet and cartridge case SRMs for quality control of automated identification systems widely used in crime labs. A significant advancement at NIST is the recent development of an analytical approach, known as the Congruent Matching Cells (CMC) method, to improve further the accuracy of ballistic identifications, and to estimate the error rate for firearm evidence identifications in forensic science. The research team led ISO standard committees in developing and revising ISO standards in surface metrology and Rockwell hardness standardization.

A. Develop the next generation ballistics identification system characterized by high correlation accuracy, high correlation speed and error rate report to support firearms and toolmark identifications in the U.S.

B. Conduct the National Ballistics Imaging Comparison (NBIC) Project to develop a traceability and quality system for ballistics identifications within the National Integrated Ballistics Information Network (NIBIN).

  • 19 ballistics examiners from 13 U.S. crime laboratories participated.
  • Each participant performed 24 periodic image acquisitions and correlations for NIST SRM bullets and casings over the course of a year (2008-09).
  • Control charts and control limits were developed for the traceability and quality system.
  • Published the report at the Forensic Science International, Vol.216, 2012.

C.  Investigated topography measurement instruments to be used for NIST Ballistics Identification System (NBIS).

D.Invented a “Congruent Matching” theory for accurate ballistics identifications.

-Completed three programs using the CMC method for breech face correlations.

-Completed validation tests using topography and optical images to support the CMC method.

E.Developed an error rate procedure, completed initial error rate calculations with breakthrough results.

F.NIST is the only NMI conducting forensic topography measurements. Team members held 22 presentations include invited talks at PTB (Germany) NPL (UK) and European Network of Forensic Science Institutes (ENFSI) Expert Working Group (EWG); received a “Most Outstanding Presentation Award” at California Association of Criminalists (CAC) 2013 Spring Meeting.

G.The NIST Ballistics Identification System (NBIS) provides a model for developing the next generation ballistics identification system.A U.S. manufacturer is developing their next generation systems based on NBIS.A US manufacturer send an email to NIST in September 2013: “We feel, the Error Rate Software based on the (NIST developed) Congruent Matching Cell theory, could revolutionize the science of firearms comparison, and we wanted a license to sell it…”

Major Activity in Surface and Microform Metrology

A. Surface Metrology:

  • Provide to U.S. industry world-leading calibrations of surface roughness and step heights, traceable to the SI unit of length. Industry relies on NIST for high accuracy measurements and best in the world uncertainties.
  • Participate in three surface texture/microform CIPM Key Comparisons with other National Metrology Institutes of the world. NIST surface texture calibrations are listed in Appendix C of the CIPM MRA.
  • Develop and distribute surface roughness SRMs. NIST SRMs are used by manufacturers to calibrate their systems, verify performance, and provide traceability critical to accreditation.
  • Provide standardized digital filtering and surface roughness parameter calculations to industry. The Surface Metrology Algorithm Testing System (SMATS) is a web-based software system developed to allow users to verify the accuracy of their own surface metrology software. (pml.nist.gov/smats).
  • Developed electro-formed replicas of the precision random profile roughness specimens to support US industry for smooth engineering quality control.  

B. Microform Metrology:

  • Long-term calibration reproducibility for NIST Primary Rockwell diamond indenters #3581 and #2809-101.

C. ISO and ASME standardization works:

The research team led ISO standard committees in developing and revising ISO standards is surface metrology and Rockwell hardness standardization that include:

Vorburger led the development of two ISO working draft standard “ISO WD 25178-600 Geometrical product specifications (GPS) — Surface texture: Areal — Part 600: Metrological characteristics for areal-topography measuring methods” and the “ISO WD 25178-607 Geometrical product specification (GPS) — Surface texture: Areal — Part 607: Nominal characteristics of non-contact (confocal microscopy) instruments.”

Since 1990’s, Song led research and publications and proposed a revision for microform geometrical specification of Rockwell diamond indenters specified inthe old ISO 6508 standard.In March 2004, the new ISO/FDIS 6508-3:2014(E) standard entitled “Metallic materials — Rockwell hardness test — Part 3: Calibration of reference blocks” has made as suggested by NIST to relax the tolerance range for cone flank straightness from “0.5 μm for maximum” to “0.5 μm for average and 0.7 μm for maximum”, that makes it possible to develop NIST SRM Rockwell diamond indenters in conformance with the revised ISO standard to support U.S. manufacturers.

T.B. Renegar led the ASME B46 standard committee to revise the ASME B46-2009 standard entitled “Surface texture—roughness, waviness and lay”.

Figure 1. SRM 2460 standard bullets.
Figure 1. SRM 2460 standard bullets.

Major Accomplishments:

2014

·         Complete the NIST FMC project: designed a scheme for NIST Ballistics Identification System (NBIS); investigated topography measurement instruments to be used for NBIS; Invented a “Congruent Matching” theory for accurate ballistics identifications; completed three programs using the CMC method for breech face correlations; completed validation tests using topography and optical images to support the CMC method.

 

·         Developed an error rate excel program, completed initial error rate calculations with breakthrough results, drafted a report, passed ERB review and submitted to Science.

 

·         Developed two ISO WD 25178 standards in surface metrology, and revised an ISO 6506 standard in Rockwell hardness tests.

 

·         Completed 3 major journal papers, 3 drafts, 12 presentations.

2013

  • Develop an error rate procedure for firearm and toolmark identifications to support U.S. ballistics identifications in forensic science.
  • Complete the National Ballistics Imaging Comparison Phase 2 project (NBIC-2), develop a traceability and quality system for U.S ballistics identifications within the National Integrated Ballistics Information Network (NIBIN).
  • Completed the SBIR phase 1 project “Precision Random Profile Roughness Specimens” to provide U.S. manufacturers a reference standard for the quality control of smooth engineering surfaces.

2012

  • Completed measurements and correlations for SRM 2461 Standard Cartridge Cases; 120 Cartridge Cases were delivered in FY2012.
  • Designed and fabricated SOA Bullet and Casing Replication Rig; developed prototype SRM 2460a polymer bullets, CCFmax =  97.2 %.
  • Started SBIR subtopic “High-precision Random Profile Roughness Specimens.”

2011

  • The ASME B46.1-2009 Standard Completed National Ballistics Imaging Comparison (NBIC) project published the report in FSI (907871); presented an invited Special Session Talk at IAFS.
  • Designed and fabricated SOA Toolmark Creation Rig.
  • Participated in three CIPM key comparisons.

2010

  • Led the development of ASME B46.1-2009 standard (two awards from ASME). Led ASME B46 and ISO TC 213 Working Groups.
  • Three Indenters were calibrated for the CIPM Key Comparison.
  • Principal author of International Standard on Classification of Methods for Measurement of Areal Surface Texture. This led to high participation by industry in the standardization process.

Lead Organizational Unit:

pml

Source of Extramural Funding:

  • DOJ’s National Institute of Justice (NIJ) through OLES, avg. $300k per year.
  • NIST’s Forensic Measurement Challenge (FMC) project funding 400K in 2012 and 500K in 2013.
  • Submitted two proposals for NIJ 2013 basic and applied science research project.2004 OLES funding $300K,
  • 2004 NIJ funding $250K
  • 2003 NIST FMC funding, $500K,
  • 2002 NIST FMC funding $400K

Customers/Contributors/Collaborators:

Industry, Markets and Applications: Surface metrology affects the function of a variety of industrial products ranging over roadways, ship hulls and propellers, automobile and aerospace components, microelectronics, and optics.

Customers: U.S. manufacturers, such as, GM, Ford, GE, Army, Navy, Air Force, Boeing, Intel, Cummins, Lockheed, Los Alamos, VEECO, Pratt and Whitney, Hughes… Collaborators include ATF and NIJ (external) Metallurgy and former SED (internal).

Why are they interested?

  • Forensic topography metrology: The Chairman of ENFSI recognized the NIST SRM bullet project as “the first step towards harmonization and laboratory assessment…”. Science News highlighted the NIST project as “…plays an important, behind-the-scenes role in making automated bullet identification a more effective crime-fighting tool.”
  • Surface and microform metrology: A GE design engineer: “…Thanks to NIST for providing these specimens as they were invaluable for helping us to clear up surface finish measurement issues…”

Related Programs and Projects:

  • NIST: ITL, MML, OLES
  • ATF
  • Oakland Police Department

Associated Products:

  • SRM 2460 standard bullets.
  • SRM 2461 standard cartridge cases.
  • SRM 2071–2075 sinusoidal profile roughness specimens.
  • NIST’s Surface Metrology Algorithm Testing System (pml.nist.gov/smats).
  • NIST 3D ballistics correlation program.
  • Automated Rockwell diamond indenter calibration program.
  • U.S. and ISO Documentary Standards: Principal authors of ASME B46.1-2009, ISO 25178-6, and revision of ISO/FDIS 6508-3:2014(E) standard Project Team Leader for 5 other published standards and balloted drafts.
Contact

Physical Measurement Laboratory (PML)
Semiconductor & Dimensional Metrology Division (683)

General Information:
301-975-5609 Telephone
301-869-0822 Facsimile

100 Bureau Drive, M/S 8212
Gaithersburg, Maryland 20899-8212