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Search Publications by: Bala Muralikrishnan (Fed)

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Displaying 126 - 150 of 170

Performance Evaluation Experiments on a Laser Spot Triangulation Probe

November 25, 2011
Author(s)
Balasubramanian Muralikrishnan, Wei Ren, Dennis S. Everett, Eric S. Stanfield, Theodore D. Doiron
Laser triangulation probes are increasingly used for dimensional measurements in a variety of applications. At the National Institute of Standards and Technology, we have recently explored the use of laser spot triangulation probes to determine dimensional

NON-CONTACT DIMENSIONAL MEASUREMENTS OF BIPOLAR FUEL CELL PLATES

November 15, 2011
Author(s)
Balasubramanian Muralikrishnan, Wei Ren, Dennis S. Everett, Eric S. Stanfield, Theodore D. Doiron
Non-contact dimensional measurement of fuel cell plates is critical to the eventual rapid manufacture by supporting in-process measurement and control. This need has been identified by the Department of Energy’s Hydrogen Program, and by numerous

Dimensional Metrology of Bipolar Fuel Cell Plates Using Laser Spot Triangulation Probes

March 22, 2011
Author(s)
Balasubramanian Muralikrishnan, Wei Ren, Dennis S. Everett, Eric S. Stanfield, Theodore D. Doiron
As in any engineering component, manufacturing a bipolar fuel cell plate for a polymer electrolyte membrane (PEM) hydrogen fuel cell power stack to within its stated design tolerances is critical in achieving the intended function. In a bipolar fuel cell

Geometric effects when measuring small holes with micro contact probes.

March 1, 2011
Author(s)
Jack A. Stone Jr., Balasubramanian Muralikrishnan, Chittaranjan Sahay
A coordinate measuring machine with a suitably small probe can be used to measure micro-features such as the diameter and form of small holes (often about 100 micrometers in diameter). When measuring small holes, the clearance between the probe tip and the

Measuring Scale Errors in a Laser Tracker s Horizontal Angle Encoder through Simple Length Measurement and Two-face System Tests

November 1, 2010
Author(s)
Balasubramanian Muralikrishnan, Christopher J. Blackburn, Daniel S. Sawyer, Steven D. Phillips, Robert Bridges, Quan Ma
We describe a method to estimate the scale errors in the horizontal angle encoder of a laser tracker in this paper. The method does not require expensive instrumentation such as a rotary stage or even a calibrated artifact. An uncalibrated but stable

Micro-feature dimensional and form measurements with the NIST fiber probe on a CMM

July 30, 2010
Author(s)
Balasubramanian Muralikrishnan, Jack A. Stone Jr., John R. Stoup, Chittaranjan Sahay
The NIST fiber probe is a Coordinate Measuring Machine (CMM) probing system intended for diameter and form measurement of micro features and small holes. This Moore M48 CMM at NIST can measure holes down to 500 um diameter with the Movamatic probe; the

Choosing test positions for laser tracker evaluation and future Standards development

July 15, 2010
Author(s)
Balasubramanian Muralikrishnan, Daniel S. Sawyer, Christopher J. Blackburn, Steven D. Phillips, Craig M. Shakarji, Ed Morse, Robert Bridges
A working group within the ISO TC 213 committee is developing a draft document [11] for evaluating the performance of laser trackers. The ASME B89.4.19 Standard [1] and the draft VDI/VDE 2617 part 10 [2] describe some useful tests that are incorporated

RECIST vs. Volume Measurement in Medical CT Using Ellipsoids of Known Size

April 12, 2010
Author(s)
Zachary H. Levine, Bruce R. Borchardt, Nolan J. Brandenburg, Charles W. Clark, Balasubramanian Muralikrishnan, Craig M. Shakarji, Joseph J. Chen, Eliot L. Siegel
(a) Purpose: We wanted to test the extent to which two common methods of determining the sizes of tumors would perform when compared to a statistically significant number of well-characterized reference objects. The size of the objects was chosen to

Performance Evaluation and Metrics for Perception in Intelligent Manufacturing

December 31, 2009
Author(s)
Roger D. Eastman, Tsai H. Hong, Jane Shi, Tobias Hanning, Bala Muralikrishnan, S. S. Young, Tommy Chang
Real-time three-dimensional vision has been rapidly advancing over the past twenty years, leading to a number of successful laboratory demonstrations, including real-time visual servoing, autonomous vehicle navigation , and real-time people and vehicle

Recent developments in large-scale dimensional metrology

July 30, 2009
Author(s)
G Peggs, P.G Maropoulos, E.B Hughes, Alistair Forbes, S Robson, M Ziebart, Bala Muralikrishnan
With ever-more demanding requirements for the accurate manufacture of large components, dimensional measuring techniques are becoming progressively more sophisticated. This review describes some of the more recently-developed techniques and the state-of

ASME B89.4.19 Performance Evaluation Tests and Geometric Misalignments in Laser Trackers

January 30, 2009
Author(s)
Balasubramanian Muralikrishnan, Daniel S. Sawyer, Christopher J. Blackburn, Steven D. Phillips, Bruce R. Borchardt, William T. Estler
Small and unintended offsets, tilts, and eccentricity of the mechanical and optical components in laser trackers introduce systematic errors in the measured spherical coordinates (angles and range readings), and possibly in the calculated lengths of

Performance Evaluation of Laser Trackers

September 15, 2008
Author(s)
Balasubramanian Muralikrishnan, Daniel S. Sawyer, Christopher J. Blackburn, Steven D. Phillips, Bruce R. Borchardt, William T. Estler
The American Society for Mechanical Engineers (ASME) recently released the ASME B89.4.19 Standard [1] on performance evaluation of spherical coordinate instruments such as laser trackers. At the National Institute of Standards and Technology (NIST), we can