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Sub-pixel Spatial Resolution Micro-roughness Measurements with Interlaced StitchingIn this paper we describe a method to increase the spatial resolution of surface micro-roughness measurements. As the surface specifications for precision optics become more demanding, the metrology instruments must cover a broad spatial frequency range. Generally, multiple instruments are used to cover the full range of the specifications. For example, a Fizeau interferometer would be used to test low spatial frequency surface errors, a white light interferometer would be used for mid spatial frequency errors, and an AFM would be used for high spatial frequency errors. For some precision optics, three instruments would be necessary. However, in many applications, an increase in the spatial resolution of a metrology instrument could negate the need for multiple instruments. A solution to increase the spatial resolution of micro-roughness measurements obtained using white light interferometry with "interlaced stitching" will be presented. In "interlaced stitching", multiple interferometric measurements are made as the optic under test (or the CCD array) is laterally shifted at sub-pixel increments. The measurements are then combined to construct a measurement with higher spatial resolution. Initial results obtained while implementing a similar process used to increase the spatial resolution of measurements made with a commercially available Fizeau interferometer will be presented.
Document ID
20050215492
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Mooney, James T.
(Alabama Univ. Huntsville, AL, United States)
Stahl, H. Philip
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Optics
Meeting Information
Meeting: SPIE Optics and Photonics 2005 Conference
Location: San Diego, CA
Country: United States
Start Date: July 31, 2005
End Date: August 2, 2005
Sponsors: International Society for Optical Engineering
Distribution Limits
Public
Copyright
Other

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