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Results for “Interferometry”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Geological interpretations of the topography of selected regions of Venus from Arecibo to Goldstone radar interferometry

We report on the geological interpretation of the mapping analysis of several successful radar experiments, which are part of a program to generate a high resolution digital elevation model (DEM) of the equatorial region of Venus between Phoebe Regio and far western Ovda Regio. These experiments used radar interferometry with Arecibo transmitting and Goldstone receiving.

Venus↗
NASA NTRS1998

Single Pass Polarimetric SAR Interferometry

During the past ten years, the NASA/JPL AIRSAR system has produced polarimetric and interferometric SAR data. SAR polarimetry is useful for characterizing scattering mechanisms while SAR interferometry yields high resolution topographic maps.

paralimetry↗
NASA NTRS2021

Simultaneous Focused Laser Differential Interferometry and High-Speed Schlieren in a Mach 6 Flow

An instrument is demonstrated that is capable of simultaneous and independent flow density fluctuation measurements over the same line-of-sight by combining two optical techniques: focused laser differential interferometry (FLDI) and high-speed schlieren (HSS). The FLDI instrument measures fluctuations at a single point in the flowfield at 10 MHz, with the resulting signal most sensitive in the region nearest the focal plane of the FLDI laser beam. The HSS instrument acquires images at 20 kHz along the same optical axis as the FLDI beam, but with the resulting signal path averaged over the entire HSS line-of-sight. The introduction of the HSS optics into the FLDI beam path provides two high-quality measurement capabilities in a single system with no degradation of performance relative to stand-alone FLDI or HSS instruments.

Focused Laser Differential Interferometry↗
NASA NTRS2022

A Method for Measuring Optical Distortion in Curved Optical Surfaces using Moiré Interferometry

In FY2020, KSC’s Applied Physics Lab created a computer based image processing system to allow inspection of the new visors being developed for the Artemis Program. This system was based on an ASTM standard where the distortion of an image is used to determine the optical aberrations in a visor, but this approach is restricted to small fields-of-view (small areas of the visor) and is limited in its ability to reliably detect and measure distortion. From our experience with flat surface inspection, we know that other optical techniques can offer higher sensitivity and accuracy. [1] This memorandum describes a method to model and measure the distortion in curved optical surfaces using moir´e interferometry. We were able to apply this process to examine samples of the xEMU Artemis astronaut helmets. Design details are provided along with examples to illustrate performance.

Optical Distortion↗