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Search Publications by: Bala Muralikrishnan (Fed)

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Displaying 51 - 75 of 170

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

Terrestrial laser scanner geometric error model parameter correlations in the Two-face, Length-consistency, and Network methods of self-calibration

April 26, 2018
Author(s)
Balasubramanian Muralikrishnan, Ling Wang, Prem K. Rachakonda, Daniel S. Sawyer
Terrestrial laser scanners (TLS) are increasingly used in a variety of applications where accuracies on the order of few tenths of a millimeter or smaller are routinely demanded. Self-calibration is a quick and cost-effective way to improve the accuracy of

Method to Determine the Center of a Contrast Target from Terrestrial Laser Scanner Data

November 3, 2017
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Daniel S. Sawyer, Ling Wang
Terrestrial laser scanners (TLSs) are instruments that can measure 3D coordinates of objects at high speed resulting in high density 3D point cloud data without the necessity of a cooperative target. Contrast targets, also known as checkerboard targets

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

Techniques to Evaluate Terrestrial Laser Scanner Errors

July 26, 2017
Author(s)
Bala Muralikrishnan, Prem K. Rachakonda
Forensic photography has been one of the most important tool for investigators over many decades. They preserve the history of the scene and provides a way for investigators to revisit the scene. However, it is difficult to ascertain any objective

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