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Search Publications by: Meghan Shilling (Fed)

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Displaying 1 - 20 of 20

X-ray Computed Tomography Instrument Performance Evaluation, Part III: Sensitivity to Detector Geometry and Rotation Stage Errors at Different Magnifications

September 29, 2021
Author(s)
Prashanth Jaganmohan, Bala Muralikrishnan, Meghan Shilling, Ed Morse
With steadily increasing use in dimensional metrology applications, especially for delicate parts and those with complex internal features, X-ray computed tomography (XCT) has transitioned from a medical imaging tool to an inspection tool in industrial

X-ray computed tomography instrument performance evaluation: Detecting geometry errors using a calibrated artifact

April 30, 2019
Author(s)
Balasubramanian Muralikrishnan, Katharine M. Shilling, Steven D. Phillips, Wei Ren, Vincent D. Lee, Felix H. Kim, Gabriel Alberts, Valentina Aloisi
X-ray computed tomography (XCT) is uniquely suitable for non-destructive dimensional metrology of delicate or internal features generated from the additive manufacturing process. While XCT has long been used in medical imaging, it has only been used for

Concept to Commercialization of an Artifact for Evaluating 3D Imaging Systems per the ASTM E3125- 17

June 29, 2018
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Vincent D. Lee, Katharine M. Shilling, Daniel S. Sawyer, Geraldine S. Cheok, Luc Cournoyer, Joe Gleason
The newly released ASTM E3125-17 standard describes several point-to-point distance tests to evaluate the performance of spherical coordinate 3D imaging systems, commonly referred to as terrestrial laser scanners (TLS). The relative-range error test, which

Challenges in measuring spherical geometry using terrestrial laser scanners

November 1, 2017
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Katharine M. Shilling, Vincent D. Lee, Daniel S. Sawyer, Geraldine S. Cheok, Luc Cournoyer
Terrestrial laser scanners (TLS) measure 3D coordinates in a scene by recording the range, the azimuth angle, and elevation angle of discrete points on target surfaces. They are increasingly used in a variety of applications, including manufacturing and

An Overview of Activities at NIST Towards the Proposed ASTM E57 3D Imaging System Point-to-Point Distance Standard

October 16, 2017
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Katharine M. Shilling, Geraldine S. Cheok, Daniel S. Sawyer
The Dimensional Metrology Group (DMG) at the National Institute of Standards & Technology (NIST), along with various other organizations has been involved in the development of a documentary standard for 3D imaging instruments that acquire data in

Methods and Considerations to Determine Sphere Center from Terrestrial Laser Scanner Point Cloud Data

September 6, 2017
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Luc Cournoyer, Geraldine S. Cheok, Vincent D. Lee, Katharine M. Shilling, Daniel S. Sawyer
The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is performing research to support the development of documentary standards within ASTM E57 committee. This committee is addressing the point-to-point

Relative range error evaluation of terrestrial laser scanners using a plate, a sphere, and a novel dual-sphere-plate target

July 21, 2017
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Vincent D. Lee, Katharine M. Shilling, Daniel S. Sawyer, Geraldine S. Cheok
Terrestrial laser scanners (TLS) are a class of 3D imaging systems that produce a 3D point cloud by measuring the range and two angles at different sampling locations. The ranging unit of a TLS realizes the SI unit of length. Relative range error is one

Targets for Relative Range Error Measurement of 3D Imaging Systems

May 1, 2017
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Katharine M. Shilling, Geraldine S. Cheok, Vincent D. Lee, Christopher J. Blackburn, Dennis S. Everett, Daniel S. Sawyer
The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is performing research to support the development of documentary standards within ASTM E57 for the point-to-point performance evaluation of 3D imaging

Report on the May 2016 ASTM E57.02 instrument runoff at NIST, Part 1 – Background information and key findings

October 19, 2016
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Katharine M. Shilling, Vincent D. Lee, Christopher J. Blackburn, Daniel S. Sawyer, Geraldine S. Cheok, Luc Cournoyer
There is ongoing activity within ASTM E57.02 working group WK43218 [1] to develop a documentary standard for point-to-point distance performance evaluation of 3D imaging systems. The Dimensional Metrology Group (DMG) at the National Institute of Standards

Report on the May 2016 ASTM E57.02 instrument runoff at NIST, Part 2 - NIST realization of test procedures and uncertainties in the reference lengths

October 19, 2016
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Katharine M. Shilling, Vincent D. Lee, Christopher J. Blackburn, Daniel S. Sawyer, Geraldine S. Cheok, Luc Cournoyer
There is ongoing activity within ASTM E57.02 working group WK43218 [1] to develop a documentary standard for point-to-point distance performance evaluation of 3D imaging systems. The Dimensional Metrology Group (DMG) at the National Institute of Standards

Targets for Relative Range Error Measurement of 3D Imaging Systems.

July 25, 2016
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Katharine M. Shilling, Geraldine S. Cheok, Vincent D. Lee, Christopher J. Blackburn, Dennis S. Everett, Daniel S. Sawyer
The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is performing research to support the development of documentary standards within ASTM E57 for the point-to-point performance evaluation of 3D imaging

Towards the Development of a Documentary Standard for Derived-Point to Derived-Point Distance Performance Evaluation of Spherical Coordinate 3D Imaging Systems

October 30, 2015
Author(s)
Balasubramanian Muralikrishnan, Katharine M. Shilling, Prem K. Rachakonda, Wei Ren, Vincent D. Lee, Daniel S. Sawyer
This paper describes ongoing research work within the Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) in support of the development of a documentary standard for derived-point to derived-point distance

Techniques to Evaluate Laser Scanners for Advanced Manufacturing Applications

July 23, 2015
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Katharine M. Shilling, Daniel S. Sawyer, Geraldine S. Cheok, Kamel S. Saidi
Laser scanners have become indispensable tools for fast and accurate 3D image acquisition applications such as part inspection, reverse engineering, cultural heritage digitization, surveying, automotive robotic navigation etc. The Dimensional Metrology

Laser scanner two-face errors on spherical targets

November 11, 2014
Author(s)
Balasubramanian Muralikrishnan, Katharine M. Shilling, Daniel S. Sawyer, Prem K. Rachakonda, Vincent D. Lee, Steven D. Phillips, Geraldine S. Cheok, Kamel S. Saidi
Geometric misalignments within the construction of a laser scanner such as offsets, tilts, and eccentricities, result in systematic errors in the measured point coordinates (range and angles). Many of these sources of error are sensitive to two-face

POINT REMOVAL FOR FITTING SPHERES TO 3-D LASER SCANNER DATA

November 11, 2014
Author(s)
Katharine M. Shilling, Balasubramanian Muralikrishnan, Daniel S. Sawyer
The proliferation of laser scanners in a number of industries such as the metrology of large artifacts, digitization and reverse engineering, historical preservation and archiving has led to the need for documentary Standards to establish and compare the