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National and international comparisons in Rockwell hardness tests show significant differences. Uncertainties in the geometry of the Rockwell diamond indenters are largely responsible for these differences. By using a stylus instrument, with a series of calibration and check standards, and calibration and uncertainty calculation procedures , we have(More)
ACCF Areal Cross Correlation Function, a statistical function of three dimensional surface topography ANOVA Analysis of Variance ATF Bureau of Alcohol, Tobacco, Firearms, and Explosives BF Breech face CCF Cross Correlation Function, a statistical function of two dimensional surface topography DAS Data Acquisition Station, a component of IBIS (below)
A simplified realization for the Gaussian filter in surface metrology is presented in this paper. The sampling function u u sin is used for simplifying the Gaussian function. According to the central limit theorem, when n approaches infinity, the function () n u u sin approaches the form of a Gaussian function. So designed, the Gaussian filter is easily(More)
In the quality control of engineering surfaces, we aim to understand and maintain a good relationship between the manufacturing process and surface function. This is achieved by controlling the surface texture. The control process involves: 1) learning the functional parameters and their control values through controlled experiments or through a long(More)
Parameters of surface roughness and step height are currently measured at the National Institute of Standards and Technology (NIST) by means of a computerized/stylus instrument. For roughness height parameters, we use a calibration ball as a master to calibrate the instrument to be employed during a measurement. Profiles of the calibrating master and the(More)
In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, NIST and the ATF initiated a joint project, entitled the National Ballistics Imaging Comparison (NBIC). The NBIC project aims to(More)
Some automated bullet identification systems calculate a correlation score between two land impressions to measure their similarity. When extracting a compressed profile from the land impression of a fired bullet, inclusion of areas that do not contain valid individual striation information may lead to sub-optimal extraction and therefore may deteriorate(More)
The program responds to the mandate of the Justice System Improvement Act of 1979, which directed NIJ to encourage research and development to improve the criminal justice system and to disseminate the results to Federal, State, and local agencies. The Law Enforcement and Corrections Standards and Testing Program is an applied research effort that(More)